Scale the interface fractionally on Linux

Java2D on X11 (and so under XWayland) truncates its scale to a whole
number, drawing 150 % at 100 %. On Linux, pin Java2D to 1 and hand the
full factor to FlatLaf, taken from XSETTINGS Xft/DPI, KWin's Xwayland
scale or GDK_SCALE, or chosen in Options → Design.

The client's own sizes now go through UIScale: borders, gaps, dialog and
row sizes, icons (rendered at the scaled size, so they stay crisp),
custom-painted components and font sizes in the HTML views.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ts3-client/README.md

@@ -169,6 +169,18 @@ frontend supplies its own UI and audio backend while reusing `core` unchanged.
 - **Pick one in Options → Design**, which also shows a viewer of everything the pack
   contains; switching redraws the window right away.
 
+### Display scaling (Linux)
+- Java2D on X11 (and so under XWayland) only scales by whole numbers, so 125 % or
+  150 % comes out at 100 %. On Linux the client pins Java2D to 1 and hands the full
+  factor to FlatLaf instead, scaling its own sizes and icons to match.
+- The factor follows the desktop: XSETTINGS `Xft/DPI` (GNOME, Plasma), else KWin's
+  XWayland scale, else `GDK_SCALE`. For crisp text on Wayland, let X11 apps scale
+  themselves (Plasma: *Display Configuration → Legacy Applications → Apply scaling
+  themselves*; GNOME: the `xwayland-native-scaling` mutter feature), otherwise the
+  compositor upscales the window.
+- **Options → Design → Interface scale** overrides it (after a restart);
+  `-Dflatlaf.uiScale=` or `-Dsun.java2d.uiScale=` on the command line bypasses all this.
+
 ## Requirements
 - Java 26+ (developed/tested on Temurin 26)
 - The native Opus library on the system:
@@ -269,6 +281,7 @@ swing/  com.ts3client
     ├── HotkeyActions        carries a fired hotkey out on the client
     ├── NotificationsPanel   sound pack + per-action sound/important configuration
     ├── IconPackPanel        icon pack chooser + icon viewer (Options → Design)
+    ├── DisplayScale         interface scale on Linux (fractional, via FlatLaf)
     ├── ConnectDialog        connect form
     ├── BookmarksDialog      manage saved servers
     ├── IdentitiesDialog     manage identities (new/import/export/improve)

ts3-client/core/src/main/java/com/ts3client/config/Settings.java

@@ -154,6 +154,8 @@ public final class Settings {
 
     /** Look-and-feel variant; see {@link Appearance}. */
     public Appearance appearance = Appearance.LIGHT;
+    /** Interface scale factor, 1.0 being 100 %; 0 follows the desktop. Read at startup. */
+    public double uiScale = 0;
 
     // ---- window chrome ----
     /** Whether the status bar at the bottom of the window is shown. */
@@ -263,6 +265,7 @@ public final class Settings {
         iconPack = props.getProperty("iconPack", iconPack);
         iconPackDir = props.getProperty("iconPackDir", iconPackDir);
         appearance = parseAppearance(props.getProperty("appearance"), appearance);
+        uiScale = parseD(props.getProperty("uiScale"), uiScale);
         showStatusBar = parseB(props.getProperty("showStatusBar"), showStatusBar);
         showMasterVolumeSlider = parseB(props.getProperty("showMasterVolumeSlider"), showMasterVolumeSlider);
         infoSplitRatio = parseD(props.getProperty("infoSplitRatio"), infoSplitRatio);
@@ -311,6 +314,7 @@ public final class Settings {
         props.setProperty("iconPack", iconPack);
         props.setProperty("iconPackDir", iconPackDir);
         props.setProperty("appearance", appearance.name());
+        props.setProperty("uiScale", Double.toString(uiScale));
         props.setProperty("showStatusBar", Boolean.toString(showStatusBar));
         props.setProperty("showMasterVolumeSlider", Boolean.toString(showMasterVolumeSlider));
         props.setProperty("infoSplitRatio", Double.toString(infoSplitRatio));

ts3-client/swing/src/main/java/com/ts3client/Main.java

@@ -1,6 +1,7 @@
 package com.ts3client;
 
 import com.ts3client.config.Settings;
+import com.ts3client.ui.DisplayScale;
 import com.ts3client.ui.IconTheme;
 import com.ts3client.ui.LookAndFeelManager;
 import com.ts3client.ui.MainFrame;
@@ -21,6 +22,7 @@ public final class Main {
         }
 
         final Settings settings = Settings.load();
+        DisplayScale.configure(settings.uiScale);
 
         SwingUtilities.invokeLater(() -> {
             LookAndFeelManager.install(settings.appearance);

ts3-client/swing/src/main/java/com/ts3client/ui/AvatarDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ClientEntry;
 import com.ts3client.net.TeamspeakConnection;
 import com.ts3client.net.avatar.Avatar;
@@ -39,16 +41,16 @@ final class AvatarDialog extends JDialog {
 
         JPanel picture = new JPanel(new BorderLayout());
         picture.setBorder(BorderFactory.createCompoundBorder(
-                BorderFactory.createEmptyBorder(8, 8, 4, 8),
+                new ScaledEmptyBorder(8, 8, 4, 8),
                 BorderFactory.createLineBorder(Theme.border())));
         picture.add(preview, BorderLayout.CENTER);
 
         JLabel hint = new JLabel("<html>Images up to " + (conn.maxAvatarBytes() / 1024)
                 + " KiB may be uploaded to this server. Animated GIFs stay animated.</html>");
         hint.setFont(Theme.uiSmall());
-        hint.setBorder(BorderFactory.createEmptyBorder(0, 8, 0, 8));
+        hint.setBorder(new ScaledEmptyBorder(0, 8, 0, 8));
         status.setFont(Theme.uiSmall());
-        status.setBorder(BorderFactory.createEmptyBorder(2, 8, 0, 8));
+        status.setBorder(new ScaledEmptyBorder(2, 8, 0, 8));
 
         JPanel text = new JPanel();
         text.setLayout(new BoxLayout(text, BoxLayout.Y_AXIS));
@@ -57,13 +59,13 @@ final class AvatarDialog extends JDialog {
 
         JPanel buttons = new JPanel();
         buttons.setLayout(new BoxLayout(buttons, BoxLayout.X_AXIS));
-        buttons.setBorder(BorderFactory.createEmptyBorder(6, 8, 8, 8));
+        buttons.setBorder(new ScaledEmptyBorder(6, 8, 8, 8));
         choose.addActionListener(e -> chooseFile());
         remove.addActionListener(e -> removeAvatar());
         JButton close = new JButton("Close");
         close.addActionListener(e -> dispose());
         buttons.add(choose);
-        buttons.add(Box.createHorizontalStrut(4));
+        buttons.add(Box.createHorizontalStrut(UIScale.scale(4)));
         buttons.add(remove);
         buttons.add(Box.createHorizontalGlue());
         buttons.add(close);

ts3-client/swing/src/main/java/com/ts3client/ui/AvatarHtml.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.avatar.Avatar;
 
 import javax.imageio.ImageIO;
@@ -12,7 +13,8 @@ import java.util.Iterator;
 /**
  * Renders an avatar as an HTML {@code <img>} for the info views. Swing's HTML renderer
  * loads images by URL and plays animated GIFs on its own, so the tag simply points at
- * the repository's on-disk copy, scaled to fit a box while keeping its aspect ratio.
+ * the repository's on-disk copy, drawn at the interface scale and fitted to a box while
+ * keeping its aspect ratio.
  */
 final class AvatarHtml {
 
@@ -25,7 +27,8 @@ final class AvatarHtml {
     /** @return the tag, or an empty string if the avatar cannot be shown */
     static String imgTag(Avatar avatar, int maxSize) {
         if (avatar == null || avatar.file() == null) return "";
-        Dimension size = fit(dimensions(avatar.data()), maxSize);
+        Dimension natural = dimensions(avatar.data());
+        Dimension size = fit(natural == null ? null : UIScale.scale(natural), maxSize);
         String dims = size == null ? "" : " width='" + size.width + "' height='" + size.height + "'";
         return "<img src='" + avatar.file().toURI() + "'" + dims + ">";
     }

ts3-client/swing/src/main/java/com/ts3client/ui/AvatarView.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.JComponent;
 import java.awt.Dimension;
 import java.awt.Graphics;
@@ -22,7 +24,7 @@ final class AvatarView extends JComponent {
 
     AvatarView(int boxSize) {
         this.boxSize = boxSize;
-        setPreferredSize(new Dimension(boxSize, boxSize));
+        setPreferredSize(UIScale.scale(new Dimension(boxSize, boxSize)));
         setMinimumSize(getPreferredSize());
     }
 
@@ -47,7 +49,7 @@ final class AvatarView extends JComponent {
             imageHeight = image.getHeight(this);
             if (imageWidth < 0 || imageHeight < 0) return;
         }
-        double scale = Math.min(1.0, Math.min((double) getWidth() / imageWidth, (double) getHeight() / imageHeight));
+        double scale = Math.min(UIScale.getUserScaleFactor(), Math.min((double) getWidth() / imageWidth, (double) getHeight() / imageHeight));
         int w = Math.max(1, (int) Math.round(imageWidth * scale));
         int h = Math.max(1, (int) Math.round(imageHeight * scale));
         Graphics2D g2 = (Graphics2D) g.create();

ts3-client/swing/src/main/java/com/ts3client/ui/AwayMessagesDialog.java

@@ -1,8 +1,9 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.AwayMessages;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
@@ -39,13 +40,13 @@ public final class AwayMessagesDialog extends JDialog {
         table.setTableHeader(null);
         table.setShowGrid(false);
         table.setFillsViewportHeight(true);
-        table.setRowHeight(Math.max(20, table.getRowHeight()));
+        table.setRowHeight(Math.max(UIScale.scale(20), table.getRowHeight()));
         table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
         // Single click selects, double click starts editing — like a renameable list.
         table.putClientProperty("JTable.autoStartsEdit", Boolean.FALSE);
 
         JScrollPane scroll = new JScrollPane(table);
-        scroll.setBorder(BorderFactory.createEmptyBorder(8, 8, 4, 8));
+        scroll.setBorder(new ScaledEmptyBorder(8, 8, 4, 8));
 
         getContentPane().setLayout(new BorderLayout());
         getContentPane().add(scroll, BorderLayout.CENTER);
@@ -53,14 +54,14 @@ public final class AwayMessagesDialog extends JDialog {
 
         Dialogs.closeOnEscape(this, this::closeDialog);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
-        setSize(new Dimension(360, 300));
+        setSize(UIScale.scale(new Dimension(360, 300)));
         setLocationRelativeTo(owner);
     }
 
     private JPanel buildButtons() {
         JPanel buttons = new JPanel();
         buttons.setLayout(new BoxLayout(buttons, BoxLayout.X_AXIS));
-        buttons.setBorder(BorderFactory.createEmptyBorder(0, 8, 8, 8));
+        buttons.setBorder(new ScaledEmptyBorder(0, 8, 8, 8));
         addButton(buttons, "Add", this::addEntry);
         addButton(buttons, "Remove", this::removeSelected);
         buttons.add(Box.createHorizontalGlue());
@@ -72,7 +73,7 @@ public final class AwayMessagesDialog extends JDialog {
         JButton b = new JButton(text);
         b.addActionListener(e -> action.run());
         panel.add(b);
-        panel.add(Box.createHorizontalStrut(4));
+        panel.add(Box.createHorizontalStrut(UIScale.scale(4)));
     }
 
     private void addEntry() {

ts3-client/swing/src/main/java/com/ts3client/ui/BanAddDialog.java

@@ -1,11 +1,12 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.BanReasonPresets;
 import com.ts3client.net.ban.BanEntry;
 import com.ts3client.net.ban.BanPattern;
 import com.ts3client.net.ban.BanRule;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
@@ -75,24 +76,24 @@ final class BanAddDialog extends JDialog {
 
         JPanel form = new JPanel();
         form.setLayout(new BoxLayout(form, BoxLayout.Y_AXIS));
-        form.setBorder(BorderFactory.createEmptyBorder(12, 12, 8, 12));
+        form.setBorder(new ScaledEmptyBorder(12, 12, 8, 12));
         form.add(ReasonDialog.label("IP:"));
         form.add(ipField);
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(ReasonDialog.label("Name:"));
         form.add(nameField);
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(patternRow());
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(ReasonDialog.label("Unique ID:"));
         form.add(uidField);
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(ReasonDialog.label("myTeamSpeak ID:"));
         form.add(mytsidField);
-        form.add(Box.createVerticalStrut(12));
+        form.add(Box.createVerticalStrut(UIScale.scale(12)));
         form.add(reasonRow());
         form.add(reasonField);
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(ReasonDialog.label("Duration:"));
         form.add(duration);
 
@@ -119,7 +120,7 @@ final class BanAddDialog extends JDialog {
         row.setLayout(new BoxLayout(row, BoxLayout.X_AXIS));
         row.setAlignmentX(Component.LEFT_ALIGNMENT);
         row.add(new JLabel("Interpret IP/Name as:"));
-        row.add(Box.createHorizontalStrut(8));
+        row.add(Box.createHorizontalStrut(UIScale.scale(8)));
         row.add(patternBox);
         row.add(Box.createHorizontalGlue());
         ReasonDialog.fixHeight(row);
@@ -137,13 +138,13 @@ final class BanAddDialog extends JDialog {
         JPanel row = new JPanel();
         row.setLayout(new BoxLayout(row, BoxLayout.X_AXIS));
         row.setAlignmentX(Component.LEFT_ALIGNMENT);
-        row.setBorder(BorderFactory.createEmptyBorder(0, 0, 4, 0));
+        row.setBorder(new ScaledEmptyBorder(0, 0, 4, 0));
         row.add(new JLabel("Reason:"));
         row.add(Box.createHorizontalGlue());
         row.add(new JLabel("Preset:"));
-        row.add(Box.createHorizontalStrut(6));
+        row.add(Box.createHorizontalStrut(UIScale.scale(6)));
         row.add(presetBox);
-        row.add(Box.createHorizontalStrut(6));
+        row.add(Box.createHorizontalStrut(UIScale.scale(6)));
         row.add(save);
         ReasonDialog.fixHeight(row);
         return row;

ts3-client/swing/src/main/java/com/ts3client/ui/BanDialog.java

@@ -1,8 +1,9 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ban.BanRule;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
@@ -32,12 +33,12 @@ final class BanDialog extends JDialog {
 
         JPanel form = new JPanel();
         form.setLayout(new BoxLayout(form, BoxLayout.Y_AXIS));
-        form.setBorder(BorderFactory.createEmptyBorder(12, 12, 8, 12));
+        form.setBorder(new ScaledEmptyBorder(12, 12, 8, 12));
         form.add(ReasonDialog.label("Ban " + nickname + " from the server."));
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(ReasonDialog.label("Reason:"));
         form.add(reasonField);
-        form.add(Box.createVerticalStrut(8));
+        form.add(Box.createVerticalStrut(UIScale.scale(8)));
         form.add(ReasonDialog.label("Duration:"));
         form.add(duration);
 

ts3-client/swing/src/main/java/com/ts3client/ui/BanDurationPicker.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
@@ -42,9 +44,9 @@ final class BanDurationPicker extends JPanel {
         max.addActionListener(e -> setSeconds(maxSeconds));
 
         add(amount);
-        add(Box.createHorizontalStrut(4));
+        add(Box.createHorizontalStrut(UIScale.scale(4)));
         add(unit);
-        add(Box.createHorizontalStrut(4));
+        add(Box.createHorizontalStrut(UIScale.scale(4)));
         add(max);
         add(Box.createHorizontalGlue());
         ReasonDialog.fixHeight(this);

ts3-client/swing/src/main/java/com/ts3client/ui/BanListDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.BanReasonPresets;
 import com.ts3client.config.Settings;
 import com.ts3client.net.ServerModel;
@@ -8,7 +10,6 @@ import com.ts3client.net.ban.BanEntry;
 import com.ts3client.net.ban.BanRule;
 
 import javax.swing.AbstractAction;
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
@@ -122,9 +123,9 @@ final class BanListDialog extends JDialog {
         this.settings = settings;
         this.presets = presets;
 
-        JPanel content = new JPanel(new BorderLayout(0, 6));
+        JPanel content = new JPanel(new BorderLayout(0, UIScale.scale(6)));
         content.setBackground(Theme.windowBg());
-        content.setBorder(BorderFactory.createEmptyBorder(10, 12, 10, 12));
+        content.setBorder(new ScaledEmptyBorder(10, 12, 10, 12));
         content.add(buildToolbar(), BorderLayout.NORTH);
         content.add(buildTable(), BorderLayout.CENTER);
         content.add(buildBottom(), BorderLayout.SOUTH);
@@ -133,7 +134,7 @@ final class BanListDialog extends JDialog {
 
         serverNameChanged();
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
-        setPreferredSize(new Dimension(920, 460));
+        setPreferredSize(UIScale.scale(new Dimension(920, 460)));
         pack();
         setLocationRelativeTo(owner);
         reload();
@@ -172,18 +173,18 @@ final class BanListDialog extends JDialog {
         searchField.setMaximumSize(new Dimension(Integer.MAX_VALUE, searchField.getPreferredSize().height));
 
         bar.add(addButton);
-        bar.add(Box.createHorizontalStrut(6));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(6)));
         bar.add(removeButton);
-        bar.add(Box.createHorizontalStrut(6));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(6)));
         bar.add(editButton);
-        bar.add(Box.createHorizontalStrut(16));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(16)));
         bar.add(searchField);
         return bar;
     }
 
     private JScrollPane buildTable() {
         table.setFont(Theme.uiFont());
-        table.setRowHeight(20);
+        table.setRowHeight(UIScale.scale(20));
         table.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
         table.setFillsViewportHeight(true);
         table.setAutoCreateColumnsFromModel(false);
@@ -248,9 +249,9 @@ final class BanListDialog extends JDialog {
         options.setLayout(new BoxLayout(options, BoxLayout.X_AXIS));
         options.setOpaque(false);
         options.add(reload);
-        options.add(Box.createHorizontalStrut(12));
+        options.add(Box.createHorizontalStrut(UIScale.scale(12)));
         options.add(onlyOwn);
-        options.add(Box.createHorizontalStrut(12));
+        options.add(Box.createHorizontalStrut(UIScale.scale(12)));
         options.add(highlightOwn);
         options.add(Box.createHorizontalGlue());
 
@@ -260,7 +261,7 @@ final class BanListDialog extends JDialog {
         closeRow.setOpaque(false);
         closeRow.add(close, BorderLayout.EAST);
 
-        JPanel bottom = new JPanel(new BorderLayout(0, 8));
+        JPanel bottom = new JPanel(new BorderLayout(0, UIScale.scale(8)));
         bottom.setOpaque(false);
         bottom.add(status, BorderLayout.NORTH);
         bottom.add(options, BorderLayout.CENTER);
@@ -659,7 +660,7 @@ final class BanListDialog extends JDialog {
             g2.setColor(Theme.chatEvent());
             g2.setFont(getFont().deriveFont(Font.ITALIC));
             int y = (getHeight() + g2.getFontMetrics().getAscent() - g2.getFontMetrics().getDescent()) / 2;
-            g2.drawString("Search", getInsets().left + 2, y);
+            g2.drawString("Search", getInsets().left + UIScale.scale(2), y);
             g2.dispose();
         }
     }

ts3-client/swing/src/main/java/com/ts3client/ui/BookmarksDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Bookmark;
 import com.ts3client.config.Bookmarks;
 import com.ts3client.config.IdentityStore;
@@ -7,7 +9,6 @@ import com.ts3client.config.Settings;
 import com.ts3client.teamspeak.TeamSpeakImporter;
 import com.ts3client.teamspeak.TeamSpeakSettingsDb;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.DefaultListModel;
@@ -81,10 +82,10 @@ public final class BookmarksDialog extends JDialog {
         details = buildDetails();
 
         JScrollPane listScroll = new JScrollPane(list);
-        listScroll.setPreferredSize(new Dimension(180, 320));
+        listScroll.setPreferredSize(UIScale.scale(new Dimension(180, 320)));
 
         JSplitPane split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, listScroll, details);
-        split.setBorder(BorderFactory.createEmptyBorder(8, 8, 4, 8));
+        split.setBorder(new ScaledEmptyBorder(8, 8, 4, 8));
         split.setResizeWeight(0.3);
         split.setContinuousLayout(true);
 
@@ -105,7 +106,7 @@ public final class BookmarksDialog extends JDialog {
                 persist();
             }
         });
-        setSize(new Dimension(640, 400));
+        setSize(UIScale.scale(new Dimension(640, 400)));
         setLocationRelativeTo(owner);
     }
 
@@ -113,7 +114,7 @@ public final class BookmarksDialog extends JDialog {
 
     private JPanel buildDetails() {
         JPanel panel = new JPanel(new GridBagLayout());
-        panel.setBorder(BorderFactory.createEmptyBorder(0, 8, 0, 0));
+        panel.setBorder(new ScaledEmptyBorder(0, 8, 0, 0));
 
         channel.setToolTipText("Channel path, e.g. \"Lobby/Games\", or a channel id. "
                 + "Leave empty for the server's default channel.");
@@ -143,7 +144,7 @@ public final class BookmarksDialog extends JDialog {
     private void addRow(JPanel panel, int row, String text, java.awt.Component field) {
         GridBagConstraints c = new GridBagConstraints();
         c.gridy = row;
-        c.insets = new Insets(2, 0, 2, 4);
+        c.insets = UIScale.scale(new Insets(2, 0, 2, 4));
         c.anchor = GridBagConstraints.WEST;
         c.gridx = 0;
         panel.add(new JLabel(text), c);
@@ -156,7 +157,7 @@ public final class BookmarksDialog extends JDialog {
     private JPanel buildButtons() {
         JPanel buttons = new JPanel();
         buttons.setLayout(new BoxLayout(buttons, BoxLayout.X_AXIS));
-        buttons.setBorder(BorderFactory.createEmptyBorder(0, 8, 8, 8));
+        buttons.setBorder(new ScaledEmptyBorder(0, 8, 8, 8));
         addButton(buttons, "Add", this::addBookmark);
         addButton(buttons, "Remove", this::removeSelected);
         if (TeamSpeakSettingsDb.locate() != null) {
@@ -174,7 +175,7 @@ public final class BookmarksDialog extends JDialog {
         JButton b = new JButton(text);
         b.addActionListener(e -> action.run());
         panel.add(b);
-        panel.add(Box.createHorizontalStrut(4));
+        panel.add(Box.createHorizontalStrut(UIScale.scale(4)));
         return b;
     }
 

ts3-client/swing/src/main/java/com/ts3client/ui/ChannelAdvancedPanel.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ChannelSettings;
 
 import javax.swing.BorderFactory;
@@ -47,7 +49,7 @@ final class ChannelAdvancedPanel extends JPanel implements ChannelDialog.Tab {
 
     ChannelAdvancedPanel() {
         setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
-        setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
 
         phoneticName.setToolTipText("Set phonetic nickname used for this channel by text-to-speech.");
         deleteDelay.setToolTipText("<html><p>Delay in seconds after temporary channels are deleted"
@@ -79,12 +81,12 @@ final class ChannelAdvancedPanel extends JPanel implements ChannelDialog.Tab {
         other.setAlignmentX(0f);
         fixHeight(other);
         add(other);
-        add(Box.createVerticalStrut(6));
+        add(Box.createVerticalStrut(UIScale.scale(6)));
 
         JPanel limits = new JPanel();
         limits.setLayout(new BoxLayout(limits, BoxLayout.X_AXIS));
         limits.add(limitBox("Max Users", new JRadioButton[]{maxUsersUnlimited, maxUsersLimited}, maxUsers));
-        limits.add(Box.createHorizontalStrut(8));
+        limits.add(Box.createHorizontalStrut(UIScale.scale(8)));
         limits.add(limitBox("Family Max Users",
                 new JRadioButton[]{familyInherited, familyUnlimited, familyLimited}, familyMaxUsers));
         limits.setAlignmentX(0f);
@@ -140,7 +142,7 @@ final class ChannelAdvancedPanel extends JPanel implements ChannelDialog.Tab {
         JPanel panel = new JPanel(new GridBagLayout());
         panel.setBorder(BorderFactory.createTitledBorder("Other Settings"));
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(3, 4, 3, 4);
+        c.insets = UIScale.scale(new Insets(3, 4, 3, 4));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -155,7 +157,7 @@ final class ChannelAdvancedPanel extends JPanel implements ChannelDialog.Tab {
         c.gridy = 1;
         c.weightx = 0;
         panel.add(new JLabel("Delete delay:"), c);
-        JPanel delay = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 0));
+        JPanel delay = new JPanel(new FlowLayout(FlowLayout.LEFT, UIScale.scale(4), 0));
         delay.add(deleteDelay);
         delay.add(deleteDelayMax);
         c.gridx = 1;
@@ -183,7 +185,7 @@ final class ChannelAdvancedPanel extends JPanel implements ChannelDialog.Tab {
                 box.add(radio);
                 continue;
             }
-            JPanel row = new JPanel(new FlowLayout(FlowLayout.LEFT, 6, 0));
+            JPanel row = new JPanel(new FlowLayout(FlowLayout.LEFT, UIScale.scale(6), 0));
             row.setAlignmentX(0f);
             row.add(radio);
             row.add(spinner);

ts3-client/swing/src/main/java/com/ts3client/ui/ChannelAudioPanel.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ChannelSettings;
 
 import javax.swing.BorderFactory;
@@ -49,8 +51,8 @@ final class ChannelAudioPanel extends JPanel implements ChannelDialog.Tab {
     private final JPanel customSettings = new JPanel(new GridBagLayout());
 
     ChannelAudioPanel() {
-        super(new BorderLayout(8, 8));
+        super(new BorderLayout(UIScale.scale(8), UIScale.scale(8)));
-        setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
 
         ButtonGroup presets = new ButtonGroup();
         presets.add(voiceMobile);
@@ -126,7 +128,7 @@ final class ChannelAudioPanel extends JPanel implements ChannelDialog.Tab {
     private JPanel customBox() {
         customSettings.setBorder(BorderFactory.createTitledBorder("Custom Settings"));
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(4, 4, 4, 4);
+        c.insets = UIScale.scale(new Insets(4, 4, 4, 4));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -158,7 +160,7 @@ final class ChannelAudioPanel extends JPanel implements ChannelDialog.Tab {
     }
 
     private JPanel bandwidthRow() {
-        JPanel row = new JPanel(new BorderLayout(6, 0));
+        JPanel row = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         row.add(new JLabel("Bandwidth usage:"), BorderLayout.WEST);
         row.add(bandwidth, BorderLayout.CENTER);
         return row;

ts3-client/swing/src/main/java/com/ts3client/ui/ChannelDialog.java

@@ -1,10 +1,11 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ChannelNode;
 import com.ts3client.net.ChannelSettings;
 import com.ts3client.net.TeamspeakConnection;
 
-import javax.swing.BorderFactory;
 import javax.swing.ImageIcon;
 import javax.swing.JButton;
 import javax.swing.JDialog;
@@ -144,19 +145,19 @@ final class ChannelDialog extends JDialog {
 
         // The tabs need no more than their natural height, so they sit at the bottom
         // with the buttons and every spare pixel goes to the description instead.
-        JPanel bottom = new JPanel(new BorderLayout(0, 6));
+        JPanel bottom = new JPanel(new BorderLayout(0, UIScale.scale(6)));
         bottom.add(tabs, BorderLayout.CENTER);
         bottom.add(buttons(), BorderLayout.SOUTH);
 
-        getContentPane().setLayout(new BorderLayout(0, 6));
+        getContentPane().setLayout(new BorderLayout(0, UIScale.scale(6)));
         getContentPane().add(header(), BorderLayout.CENTER);
         getContentPane().add(bottom, BorderLayout.SOUTH);
 
         setEnabledForLoading(false);
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
-        setSize(new Dimension(560, 620));
+        setSize(UIScale.scale(new Dimension(560, 620)));
-        setMinimumSize(new Dimension(480, 520));
+        setMinimumSize(UIScale.scale(new Dimension(480, 520)));
         setLocationRelativeTo(owner);
 
         if (channel != null) load();
@@ -167,9 +168,9 @@ final class ChannelDialog extends JDialog {
 
     private JPanel header() {
         JPanel panel = new JPanel(new GridBagLayout());
-        panel.setBorder(BorderFactory.createEmptyBorder(8, 8, 0, 8));
+        panel.setBorder(new ScaledEmptyBorder(8, 8, 0, 8));
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(3, 4, 3, 4);
+        c.insets = UIScale.scale(new Insets(3, 4, 3, 4));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -248,7 +249,7 @@ final class ChannelDialog extends JDialog {
 
     private JPanel iconField() {
         iconButton.setToolTipText("Set channel icon.");
-        iconButton.setPreferredSize(new Dimension(26, 24));
+        iconButton.setPreferredSize(UIScale.scale(new Dimension(26, 24)));
         iconButton.setMargin(new Insets(1, 1, 1, 1));
         iconButton.addActionListener(a -> chooseIcon());
         iconButton.addMouseListener(new MouseAdapter() {
@@ -262,7 +263,7 @@ final class ChannelDialog extends JDialog {
                 if (e.isPopupTrigger()) showIconMenu(e);
             }
         });
-        JPanel row = new JPanel(new BorderLayout(4, 0));
+        JPanel row = new JPanel(new BorderLayout(UIScale.scale(4), 0));
         row.add(new JLabel("Icon:"), BorderLayout.WEST);
         row.add(iconButton, BorderLayout.CENTER);
         return row;
@@ -273,7 +274,7 @@ final class ChannelDialog extends JDialog {
         ok.addActionListener(a -> save());
         cancel.addActionListener(a -> dispose());
         JPanel panel = new JPanel(new BorderLayout());
-        panel.setBorder(BorderFactory.createEmptyBorder(0, 8, 8, 8));
+        panel.setBorder(new ScaledEmptyBorder(0, 8, 8, 8));
         JPanel right = new JPanel();
         right.add(ok);
         right.add(cancel);

ts3-client/swing/src/main/java/com/ts3client/ui/ChannelPermissionsPanel.java

@@ -1,5 +1,8 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
@@ -49,18 +52,18 @@ final class ChannelPermissionsPanel extends JPanel {
 
     ChannelPermissionsPanel() {
         setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
-        setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
 
         JPanel groups = new JPanel();
         groups.setLayout(new BoxLayout(groups, BoxLayout.X_AXIS));
         groups.add(group("Regular Needed Powers", REGULAR));
-        groups.add(Box.createHorizontalStrut(8));
+        groups.add(Box.createHorizontalStrut(UIScale.scale(8)));
         groups.add(group("File Transfer Needed Powers", FILE_TRANSFER));
         groups.setAlignmentX(0f);
         add(groups);
 
         status.setAlignmentX(0f);
-        status.setBorder(BorderFactory.createEmptyBorder(6, 2, 0, 2));
+        status.setBorder(new ScaledEmptyBorder(6, 2, 0, 2));
         add(status);
         add(Box.createVerticalGlue());
         setEditable(false);
@@ -119,7 +122,7 @@ final class ChannelPermissionsPanel extends JPanel {
         JPanel panel = new JPanel(new GridBagLayout());
         panel.setBorder(BorderFactory.createTitledBorder(title));
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(3, 4, 3, 4);
+        c.insets = UIScale.scale(new Insets(3, 4, 3, 4));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
         int row = 0;

ts3-client/swing/src/main/java/com/ts3client/ui/ChannelStandardPanel.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ChannelNode;
 import com.ts3client.net.ChannelSettings;
 
@@ -45,8 +47,8 @@ final class ChannelStandardPanel extends JPanel implements ChannelDialog.Tab {
      *                 excluding the channel being edited
      */
     ChannelStandardPanel(List<ChannelNode> siblings) {
-        super(new BorderLayout(8, 8));
+        super(new BorderLayout(UIScale.scale(8), UIScale.scale(8)));
-        setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
 
         temporary.setToolTipText("Channel will be deleted when the last user left.");
         semiPermanent.setToolTipText("Channel exists until server is restarted.");
@@ -67,7 +69,7 @@ final class ChannelStandardPanel extends JPanel implements ChannelDialog.Tab {
         for (ChannelNode sibling : siblings) order.addElement(new SortEntry(sibling.id, sibling.name));
         sortAfter.setModel(order);
         sortAfter.setToolTipText("Channel will be sorted below this channel.");
-        sortAfter.setPreferredSize(new Dimension(200, sortAfter.getPreferredSize().height));
+        sortAfter.setPreferredSize(new Dimension(UIScale.scale(200), sortAfter.getPreferredSize().height));
         Spinners.compact(talkPower);
 
         add(typeBox(), BorderLayout.WEST);
@@ -139,10 +141,10 @@ final class ChannelStandardPanel extends JPanel implements ChannelDialog.Tab {
         }
         JSeparator line = new JSeparator();
         line.setAlignmentX(0f);
-        line.setMaximumSize(new Dimension(Integer.MAX_VALUE, 8));
+        line.setMaximumSize(new Dimension(Integer.MAX_VALUE, UIScale.scale(8)));
-        box.add(Box.createVerticalStrut(4));
+        box.add(Box.createVerticalStrut(UIScale.scale(4)));
         box.add(line);
-        box.add(Box.createVerticalStrut(4));
+        box.add(Box.createVerticalStrut(UIScale.scale(4)));
         defaultChannel.setAlignmentX(0f);
         box.add(defaultChannel);
         box.add(Box.createVerticalGlue());
@@ -154,7 +156,7 @@ final class ChannelStandardPanel extends JPanel implements ChannelDialog.Tab {
         sort.setBorder(BorderFactory.createTitledBorder("Sort This Channel After:"));
         sort.add(sortAfter, BorderLayout.CENTER);
 
-        JPanel moderation = new JPanel(new FlowLayout(FlowLayout.LEFT, 6, 2));
+        JPanel moderation = new JPanel(new FlowLayout(FlowLayout.LEFT, UIScale.scale(6), UIScale.scale(2)));
         moderation.setBorder(BorderFactory.createTitledBorder("Moderation"));
         JLabel label = new JLabel("Needed Talk Power:");
         label.setToolTipText("Talk Power required to speak in this channel.");
@@ -168,7 +170,7 @@ final class ChannelStandardPanel extends JPanel implements ChannelDialog.Tab {
         c.gridx = 0;
         c.fill = GridBagConstraints.HORIZONTAL;
         c.weightx = 1;
-        c.insets = new Insets(0, 0, 6, 0);
+        c.insets = UIScale.scale(new Insets(0, 0, 6, 0));
         column.add(sort, c);
         column.add(moderation, c);
         c.weighty = 1;

ts3-client/swing/src/main/java/com/ts3client/ui/ChatPanel.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.text.BBCode;
 import com.ts3client.text.TsLink;
 
@@ -96,8 +98,8 @@ public final class ChatPanel extends JPanel {
         dragReorder.attach(tabs);
         add(tabs, BorderLayout.CENTER);
 
-        JPanel bottom = new JPanel(new BorderLayout(4, 0));
+        JPanel bottom = new JPanel(new BorderLayout(UIScale.scale(4), 0));
-        bottom.setBorder(BorderFactory.createEmptyBorder(4, 0, 0, 0));
+        bottom.setBorder(new ScaledEmptyBorder(4, 0, 0, 0));
         bottom.add(input, BorderLayout.CENTER);
         add(bottom, BorderLayout.SOUTH);
 
@@ -345,7 +347,8 @@ public final class ChatPanel extends JPanel {
         final int clientId;
         private String clientUniqueId;
         private String title;
-        final JEditorPane log = HtmlStyles.pane("font-family:sans-serif; font-size:11px; margin:4px 6px;");
+        final JEditorPane log = HtmlStyles.pane("font-family:sans-serif; font-size:11px; margin:"
+                + HtmlStyles.px(4) + " " + HtmlStyles.px(6) + ";");
         final JScrollPane scroll;
         /** Set for a static-content tab (e.g. a moved-out description); null for a conversation. */
         final String noteKey;
@@ -408,17 +411,17 @@ public final class ChatPanel extends JPanel {
         Component header(boolean closable) {
             // Only the height is pinned: a fixed width would freeze the tab at the width of
             // whatever name it was built with, clipping longer ones (and the bold unread font).
-            JPanel p = new JPanel(new FlowLayout(FlowLayout.LEFT, 2, 0)) {
+            JPanel p = new JPanel(new FlowLayout(FlowLayout.LEFT, UIScale.scale(2), 0)) {
                 @Override
                 public Dimension getPreferredSize() {
                     Dimension d = super.getPreferredSize();
-                    return new Dimension(d.width, Math.max(d.height, HEADER_HEIGHT));
+                    return new Dimension(d.width, Math.max(d.height, UIScale.scale(HEADER_HEIGHT)));
                 }
             };
             p.setOpaque(false);
             titleLabel = new JLabel(title, icon, JLabel.LEADING);
             titleLabel.setFont(Theme.uiFont());
-            titleLabel.setIconTextGap(3);
+            titleLabel.setIconTextGap(UIScale.scale(3));
             p.add(titleLabel);
             dragReorder.attach(p);
             dragReorder.attach(titleLabel);

ts3-client/swing/src/main/java/com/ts3client/ui/ClientVersionPanel.java

@@ -1,9 +1,10 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.ClientVersion;
 import com.ts3client.config.Settings;
 
-import javax.swing.BorderFactory;
 import javax.swing.DefaultListCellRenderer;
 import javax.swing.JCheckBox;
 import javax.swing.JComboBox;
@@ -45,10 +46,10 @@ final class ClientVersionPanel extends JPanel {
     private boolean filling;
 
     ClientVersionPanel(Settings settings) {
-        super(new BorderLayout(0, 8));
+        super(new BorderLayout(0, UIScale.scale(8)));
         this.settings = settings;
 
-        setBorder(BorderFactory.createEmptyBorder(12, 12, 12, 12));
+        setBorder(new ScaledEmptyBorder(12, 12, 12, 12));
         add(buildForm(), BorderLayout.NORTH);
 
         load();
@@ -67,7 +68,7 @@ final class ClientVersionPanel extends JPanel {
     private JComponent buildForm() {
         JPanel p = new JPanel(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(2, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(2, 2, 2, 2));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -110,7 +111,7 @@ final class ClientVersionPanel extends JPanel {
         c.gridx = 0;
         c.gridy = row;
         c.gridwidth = 2;
-        p.add(new JLabel("<html><body style='width:320px'>The three fields belong together: the "
+        p.add(new JLabel("<html><body style='width:" + HtmlStyles.px(320) + "'>The three fields belong together: the "
                 + "signature is TeamSpeak's, over that version and operating system. A server "
                 + "answers \"client is modified\" and refuses the connection when it does not "
                 + "accept the version — made up, or older than the server's minimum — so prefer "

ts3-client/swing/src/main/java/com/ts3client/ui/ClientVolumeDialog.java

@@ -1,9 +1,10 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ClientEntry;
 import com.ts3client.net.TeamspeakConnection;
 
-import javax.swing.BorderFactory;
 import javax.swing.JButton;
 import javax.swing.JDialog;
 import javax.swing.JLabel;
@@ -41,11 +42,11 @@ final class ClientVolumeDialog extends JDialog {
         slider.addChangeListener(e -> onChanged());
         FormPanel.limitWidth(value, 60);
 
-        JPanel content = new JPanel(new BorderLayout(8, 8));
+        JPanel content = new JPanel(new BorderLayout(UIScale.scale(8), UIScale.scale(8)));
-        content.setBorder(BorderFactory.createEmptyBorder(12, 12, 8, 12));
+        content.setBorder(new ScaledEmptyBorder(12, 12, 8, 12));
         content.add(new JLabel("Volume Modifier"), BorderLayout.NORTH);
         content.add(FormPanel.sliderWithLabel(slider, value), BorderLayout.CENTER);
-        JLabel hint = new JLabel("<html><body style='width:300px'>Values greater than +6 dB will cause clipping "
+        JLabel hint = new JLabel("<html><body style='width:" + HtmlStyles.px(300) + "'>Values greater than +6 dB will cause clipping "
                 + "and distortion that will negatively affect your audio quality. It is advised to choose "
                 + "lower values.</body></html>");
         hint.setForeground(Theme.chatSystem());
@@ -67,7 +68,7 @@ final class ClientVolumeDialog extends JDialog {
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
         pack();
-        setMinimumSize(new Dimension(360, getHeight()));
+        setMinimumSize(new Dimension(UIScale.scale(360), getHeight()));
         setLocationRelativeTo(owner);
     }
 

ts3-client/swing/src/main/java/com/ts3client/ui/ConnectDialog.java

@@ -1,9 +1,10 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.IdentityStore;
 import com.ts3client.config.Settings;
 
-import javax.swing.BorderFactory;
 import javax.swing.JButton;
 import javax.swing.JDialog;
 import javax.swing.JLabel;
@@ -49,9 +50,9 @@ public final class ConnectDialog extends JDialog {
         identityChooser = new IdentityChooser(identities, false, settings.defaultIdentityId);
 
         JPanel form = new JPanel(new GridBagLayout());
-        form.setBorder(BorderFactory.createEmptyBorder(12, 12, 8, 12));
+        form.setBorder(new ScaledEmptyBorder(12, 12, 8, 12));
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(4, 4, 4, 4);
+        c.insets = UIScale.scale(new Insets(4, 4, 4, 4));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -83,7 +84,7 @@ public final class ConnectDialog extends JDialog {
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
         pack();
-        setMinimumSize(new Dimension(340, getHeight()));
+        setMinimumSize(new Dimension(UIScale.scale(340), getHeight()));
         setLocationRelativeTo(owner);
     }
 

ts3-client/swing/src/main/java/com/ts3client/ui/ConnectionInfoDialog.java

@@ -1,9 +1,10 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ConnectionStats;
 import com.ts3client.net.TeamspeakConnection;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
@@ -62,9 +63,9 @@ public final class ConnectionInfoDialog extends JDialog {
         this.conn = conn;
         this.clientId = clientId;
 
-        JPanel content = new JPanel(new BorderLayout(0, 10));
+        JPanel content = new JPanel(new BorderLayout(0, UIScale.scale(10)));
         content.setBackground(Theme.windowBg());
-        content.setBorder(BorderFactory.createEmptyBorder(12, 14, 12, 14));
+        content.setBorder(new ScaledEmptyBorder(12, 14, 12, 14));
         content.add(buildSummary(), BorderLayout.NORTH);
         content.add(buildTabs(), BorderLayout.CENTER);
         content.add(buildButtons(), BorderLayout.SOUTH);
@@ -138,7 +139,7 @@ public final class ConnectionInfoDialog extends JDialog {
         lc.gridx = 0;
         lc.gridy = row;
         lc.anchor = GridBagConstraints.WEST;
-        lc.insets = new Insets(2, 0, 2, 16);
+        lc.insets = UIScale.scale(new Insets(2, 0, 2, 16));
         JLabel key = new JLabel(label);
         key.setFont(Theme.uiFont());
         key.setForeground(new Color(0x5A6B7B));
@@ -150,7 +151,7 @@ public final class ConnectionInfoDialog extends JDialog {
         vc.weightx = 1;
         vc.anchor = GridBagConstraints.WEST;
         vc.fill = GridBagConstraints.HORIZONTAL;
-        vc.insets = new Insets(2, 0, 2, 0);
+        vc.insets = UIScale.scale(new Insets(2, 0, 2, 0));
         grid.add(valueLabel, vc);
     }
 
@@ -256,7 +257,7 @@ public final class ConnectionInfoDialog extends JDialog {
         KindTab() {
             super(new GridBagLayout());
             setBackground(Theme.windowBg());
-            setBorder(BorderFactory.createEmptyBorder(10, 12, 10, 12));
+            setBorder(new ScaledEmptyBorder(10, 12, 10, 12));
             int row = 0;
             addRow(this, row++, "Packet loss", packetLoss);
             addRow(this, row++, "Packets (↑/↓)", packets);

ts3-client/swing/src/main/java/com/ts3client/ui/ContactDefaultsDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 import com.ts3client.contacts.ContactDefaults;
 import com.ts3client.contacts.ContactType;
@@ -50,13 +52,13 @@ final class ContactDefaultsDialog extends JDialog {
 
         JPanel content = new JPanel();
         content.setLayout(new javax.swing.BoxLayout(content, javax.swing.BoxLayout.Y_AXIS));
-        content.setBorder(BorderFactory.createEmptyBorder(12, 12, 8, 12));
+        content.setBorder(new ScaledEmptyBorder(12, 12, 8, 12));
         JLabel intro = new JLabel("Configure default settings when adding a client to the Contact Manager");
         intro.setAlignmentX(LEFT_ALIGNMENT);
         content.add(intro);
-        content.add(javax.swing.Box.createVerticalStrut(10));
+        content.add(javax.swing.Box.createVerticalStrut(UIScale.scale(10)));
         content.add(buildFlags());
-        content.add(javax.swing.Box.createVerticalStrut(10));
+        content.add(javax.swing.Box.createVerticalStrut(UIScale.scale(10)));
         content.add(buildDisplays());
 
         JPanel buttons = new JPanel(new FlowLayout(FlowLayout.RIGHT));
@@ -157,7 +159,7 @@ final class ContactDefaultsDialog extends JDialog {
         GridBagConstraints c = new GridBagConstraints();
         c.gridx = x;
         c.gridy = y;
-        c.insets = new Insets(1, 6, 1, 6);
+        c.insets = UIScale.scale(new Insets(1, 6, 1, 6));
         c.anchor = GridBagConstraints.CENTER;
         return c;
     }

ts3-client/swing/src/main/java/com/ts3client/ui/ContactsDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 import com.ts3client.contacts.Contact;
 import com.ts3client.contacts.ContactStore;
@@ -8,7 +10,6 @@ import com.ts3client.contacts.NicknameDisplay;
 import com.ts3client.teamspeak.TeamSpeakSettingsDb;
 import com.ts3client.text.TsLink;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.ButtonGroup;
@@ -99,7 +100,7 @@ final class ContactsDialog extends JDialog {
     private final JCheckBox ignoreAway = new JCheckBox("Hide away message");
     private final JRadioButton allowWhisper = new JRadioButton("Allow whisper");
     private final JRadioButton denyWhisper = new JRadioButton("Deny whisper");
-    private final JPanel details = new JPanel(new BorderLayout(0, 8));
+    private final JPanel details = new JPanel(new BorderLayout(0, UIScale.scale(8)));
 
     /** Set while the fields are being filled from a contact, so that does not count as an edit. */
     private boolean filling;
@@ -110,22 +111,22 @@ final class ContactsDialog extends JDialog {
         this.settings = settings;
 
         buildTree();
-        JPanel left = new JPanel(new BorderLayout(0, 4));
+        JPanel left = new JPanel(new BorderLayout(0, UIScale.scale(4)));
-        left.setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 4));
+        left.setBorder(new ScaledEmptyBorder(8, 8, 8, 4));
         JLabel hint = new JLabel("Drag & Drop users here");
         hint.setForeground(Theme.chatSystem());
         left.add(hint, BorderLayout.NORTH);
         JScrollPane scroll = new JScrollPane(tree);
-        scroll.setPreferredSize(new Dimension(300, 340));
+        scroll.setPreferredSize(UIScale.scale(new Dimension(300, 340)));
         left.add(scroll, BorderLayout.CENTER);
 
-        details.setBorder(BorderFactory.createEmptyBorder(8, 4, 8, 8));
+        details.setBorder(new ScaledEmptyBorder(8, 4, 8, 8));
         details.add(buildNicknameRow(), BorderLayout.NORTH);
         details.add(buildPages(), BorderLayout.CENTER);
 
         JPanel buttons = new JPanel(new BorderLayout());
-        buttons.setBorder(BorderFactory.createEmptyBorder(0, 8, 8, 8));
+        buttons.setBorder(new ScaledEmptyBorder(0, 8, 8, 8));
-        JPanel leftButtons = new JPanel(new FlowLayout(FlowLayout.LEFT, 6, 0));
+        JPanel leftButtons = new JPanel(new FlowLayout(FlowLayout.LEFT, UIScale.scale(6), 0));
         JButton defaults = new JButton("Set Defaults");
         defaults.setToolTipText("Set default display, ignore and hide options");
         defaults.addActionListener(e -> new ContactDefaultsDialog(this, settings).setVisible(true));
@@ -160,7 +161,7 @@ final class ContactsDialog extends JDialog {
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
         pack();
-        setMinimumSize(new Dimension(620, 400));
+        setMinimumSize(UIScale.scale(new Dimension(620, 400)));
         setLocationRelativeTo(owner);
     }
 
@@ -172,7 +173,7 @@ final class ContactsDialog extends JDialog {
         root.add(neutral);
         tree.setRootVisible(false);
         tree.setShowsRootHandles(true);
-        tree.setRowHeight(20);
+        tree.setRowHeight(UIScale.scale(20));
         tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
         tree.setCellRenderer(new ContactRenderer());
         tree.addTreeSelectionListener(e -> showSelected());
@@ -301,7 +302,7 @@ final class ContactsDialog extends JDialog {
     private JComponent buildNicknameRow() {
         JPanel row = new JPanel(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(2, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(2, 2, 2, 2));
         c.anchor = GridBagConstraints.WEST;
         c.gridy = 0;
         c.gridx = 0;
@@ -325,7 +326,7 @@ final class ContactsDialog extends JDialog {
         JTabbedPane pages = new JTabbedPane();
         pages.addTab("General", page(
                 radioGroup(neutralRadio, blockedRadio, friendRadio),
-                Box.createVerticalStrut(8),
+                Box.createVerticalStrut(UIScale.scale(8)),
                 labelled("Phonetic Nickname:", phoneticField)));
         neutralRadio.setToolTipText("Mark as neutral");
         blockedRadio.setToolTipText("Mark as blocked");
@@ -375,7 +376,7 @@ final class ContactsDialog extends JDialog {
     private static JPanel page(Component... rows) {
         JPanel p = new JPanel();
         p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
-        p.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
+        p.setBorder(new ScaledEmptyBorder(10, 10, 10, 10));
         for (Component row : rows) {
             if (row instanceof JComponent) ((JComponent) row).setAlignmentX(Component.LEFT_ALIGNMENT);
             p.add(row);
@@ -397,7 +398,7 @@ final class ContactsDialog extends JDialog {
     }
 
     private static JPanel labelled(String label, JComponent field) {
-        JPanel p = new JPanel(new BorderLayout(6, 0));
+        JPanel p = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         p.add(new JLabel(label), BorderLayout.WEST);
         p.add(field, BorderLayout.CENTER);
         p.setMaximumSize(new Dimension(Integer.MAX_VALUE, field.getPreferredSize().height));

ts3-client/swing/src/main/java/com/ts3client/ui/ContactsPanel.java

@@ -1,8 +1,9 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 
-import javax.swing.BorderFactory;
 import javax.swing.DefaultListCellRenderer;
 import javax.swing.JButton;
 import javax.swing.JCheckBox;
@@ -32,11 +33,11 @@ final class ContactsPanel extends JPanel {
     ContactsPanel(Settings settings) {
         super(new BorderLayout());
         this.settings = settings;
-        setBorder(BorderFactory.createEmptyBorder(12, 12, 12, 12));
+        setBorder(new ScaledEmptyBorder(12, 12, 12, 12));
 
         JPanel p = new JPanel(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(2, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(2, 2, 2, 2));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
         c.gridx = 0;
@@ -48,10 +49,10 @@ final class ContactsPanel extends JPanel {
         p.add(colorContacts, c);
 
         c.gridy = 1;
-        c.insets = new Insets(12, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(12, 2, 2, 2));
         p.add(new JLabel("Whispers: who is allowed to whisper to you"), c);
         c.gridy = 2;
-        c.insets = new Insets(2, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(2, 2, 2, 2));
         whisperPolicy.setSelectedItem(settings.whisperPolicy);
         whisperPolicy.setRenderer(new DefaultListCellRenderer() {
             @Override
@@ -68,7 +69,7 @@ final class ContactsPanel extends JPanel {
         p.add(whisperPolicy, c);
 
         c.gridy = 3;
-        c.insets = new Insets(12, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(12, 2, 2, 2));
         c.fill = GridBagConstraints.NONE;
         JButton defaults = new JButton("Contact defaults…");
         defaults.setToolTipText("Configure default settings when adding a client to the Contact Manager");

ts3-client/swing/src/main/java/com/ts3client/ui/DescriptionEditorDialog.java

@@ -1,8 +1,9 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.text.BBCode;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.JButton;
 import javax.swing.JColorChooser;
@@ -47,19 +48,19 @@ final class DescriptionEditorDialog extends JDialog {
         area.setText(description);
         area.setLineWrap(true);
         area.setWrapStyleWord(true);
-        area.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+        area.setFont(new Font(Font.MONOSPACED, Font.PLAIN, UIScale.scale(12)));
         area.setCaretPosition(0);
 
         preview.setEditable(false);
         preview.setBackground(Theme.chatBg());
-        preview.setBorder(BorderFactory.createEmptyBorder(6, 8, 6, 8));
+        preview.setBorder(new ScaledEmptyBorder(6, 8, 6, 8));
 
         body.add(new JScrollPane(area), EDIT_CARD);
         body.add(new JScrollPane(preview), PREVIEW_CARD);
 
         JLabel hint = new JLabel("Press Button to \"Preview\" the changes in channel info.");
         hint.setForeground(Theme.chatSystem());
-        hint.setBorder(BorderFactory.createEmptyBorder(4, 6, 0, 6));
+        hint.setBorder(new ScaledEmptyBorder(4, 6, 0, 6));
 
         getContentPane().setLayout(new BorderLayout());
         getContentPane().add(buildToolbar(), BorderLayout.NORTH);
@@ -71,8 +72,8 @@ final class DescriptionEditorDialog extends JDialog {
 
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
-        setSize(new Dimension(520, 380));
+        setSize(UIScale.scale(new Dimension(520, 380)));
-        setMinimumSize(new Dimension(360, 260));
+        setMinimumSize(UIScale.scale(new Dimension(360, 260)));
         setLocationRelativeTo(owner);
     }
 
@@ -134,7 +135,7 @@ final class DescriptionEditorDialog extends JDialog {
      * box, which would otherwise let one of them soak up all the free width.
      */
     private static JButton square(JButton button) {
-        Dimension size = new Dimension(Math.max(28, button.getPreferredSize().width),
+        Dimension size = new Dimension(Math.max(UIScale.scale(28), button.getPreferredSize().width),
                 button.getPreferredSize().height);
         button.setPreferredSize(size);
         button.setMaximumSize(size);
@@ -162,7 +163,7 @@ final class DescriptionEditorDialog extends JDialog {
     private void showPreview(boolean on) {
         previewButton.setSelected(on);
         if (on) {
-            preview.setText("<html><body style=\"font-family:sans-serif;font-size:9pt\">"
+            preview.setText("<html><body style=\"font-family:sans-serif;font-size:" + UIScale.scale(9) + "pt\">"
                     + BBCode.toHtml(area.getText()) + "</body></html>");
             preview.setCaretPosition(0);
         }

ts3-client/swing/src/main/java/com/ts3client/ui/DesignPanel.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 import com.ts3client.gfx.IconPack;
 
@@ -24,14 +26,15 @@ import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
 import java.awt.Insets;
 import java.io.File;
+import java.util.Arrays;
 
 /**
- * Options page for how the client looks: the light or dark look-and-feel, and the icon
+ * Options page for how the client looks: the light or dark look-and-feel, the interface
- * pack the user interface is drawn with — where to look for more of them, and a viewer
+ * scale, and the icon pack the user interface is drawn with — where to look for more of
- * showing everything the active pack contains.
+ * them, and a viewer showing everything the active pack contains.
  *
- * <p>Both apply right away so the change can be seen in the window behind the dialog;
+ * <p>Theme and pack apply right away so the change can be seen in the window behind the
- * cancelling puts the previous ones back.
+ * dialog; cancelling puts the previous ones back. The scale is only read at startup.
  */
 final class DesignPanel extends JPanel {
 
@@ -42,6 +45,9 @@ final class DesignPanel extends JPanel {
     /** Stands for "no pack": the icons the client draws itself. */
     private static final String BUILT_IN = "Built-in icons";
 
+    /** The scale factors offered besides following the desktop (0). */
+    private static final double[] SCALES = {0, 1, 1.25, 1.5, 1.75, 2, 2.5, 3};
+
     private final Settings settings;
     private final String originalPackId;
     private final String originalPackDir;
@@ -49,6 +55,7 @@ final class DesignPanel extends JPanel {
 
     private final JComboBox<Settings.Appearance> appearanceCombo =
             new JComboBox<>(Settings.Appearance.values());
+    private final JComboBox<Double> scaleCombo = new JComboBox<>();
     private final JComboBox<Object> packCombo = new JComboBox<>();
     private final JLabel packInfo = new JLabel();
     private final JTextField packDirField;
@@ -56,14 +63,14 @@ final class DesignPanel extends JPanel {
     private final JList<String> preview = new JList<>(previewModel);
 
     DesignPanel(Settings settings) {
-        super(new BorderLayout(0, 8));
+        super(new BorderLayout(0, UIScale.scale(8)));
         this.settings = settings;
         this.originalPackId = settings.iconPack;
         this.originalPackDir = settings.iconPackDir;
         this.originalAppearance = settings.appearance;
         this.packDirField = new JTextField(settings.iconPackDir, 18);
 
-        setBorder(BorderFactory.createEmptyBorder(12, 12, 12, 12));
+        setBorder(new ScaledEmptyBorder(12, 12, 12, 12));
         add(buildHeader(), BorderLayout.NORTH);
         add(buildPreview(), BorderLayout.CENTER);
 
@@ -73,6 +80,7 @@ final class DesignPanel extends JPanel {
     /** Copies the chosen appearance and pack into the settings; the caller saves them. */
     void apply() {
         settings.appearance = selectedAppearance();
+        if (scaleCombo.getSelectedItem() instanceof Double scale) settings.uiScale = scale;
         settings.iconPackDir = packDirField.getText().trim();
         Object selected = packCombo.getSelectedItem();
         settings.iconPack = selected instanceof IconPack pack ? pack.id() : "";
@@ -94,7 +102,7 @@ final class DesignPanel extends JPanel {
     private JComponent buildHeader() {
         JPanel p = new JPanel(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(2, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(2, 2, 2, 2));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -125,13 +133,17 @@ final class DesignPanel extends JPanel {
 
         int row = 0;
         addRow(p, c, row++, new JLabel("Theme:"), appearanceCombo);
+        if (DisplayScale.isManaged()) {
+            buildScaleCombo();
+            addRow(p, c, row++, new JLabel("Interface scale:"), scaleCombo);
+        }
         addRow(p, c, row++, new JLabel("Icon pack:"), packCombo);
         c.gridx = 1;
         c.gridy = row++;
         packInfo.setEnabled(false);
         p.add(packInfo, c);
 
-        JPanel dirRow = new JPanel(new BorderLayout(6, 0));
+        JPanel dirRow = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         JButton browse = new JButton("Browse…");
         browse.addActionListener(e -> browseForPackFolder());
         dirRow.add(packDirField, BorderLayout.CENTER);
@@ -141,18 +153,42 @@ final class DesignPanel extends JPanel {
         return p;
     }
 
+    private void buildScaleCombo() {
+        for (double scale : SCALES) scaleCombo.addItem(scale);
+        if (settings.uiScale > 0 && Arrays.stream(SCALES).noneMatch(s -> s == settings.uiScale)) {
+            scaleCombo.addItem(settings.uiScale);
+        }
+        scaleCombo.setSelectedItem(Math.max(0, settings.uiScale));
+        scaleCombo.setToolTipText("Size of text, icons and controls; takes effect after a restart");
+        scaleCombo.setRenderer(new DefaultListCellRenderer() {
+            @Override
+            public Component getListCellRendererComponent(JList<?> list, Object value, int index,
+                                                          boolean selected, boolean focus) {
+                super.getListCellRendererComponent(list, value, index, selected, focus);
+                double scale = value instanceof Double d ? d : 0;
+                setText(scale > 0 ? percent(scale)
+                        : "Automatic (" + percent(DisplayScale.detected()) + ")");
+                return this;
+            }
+        });
+    }
+
+    private static String percent(double scale) {
+        return Math.round(scale * 100) + "%";
+    }
+
     private JComponent buildPreview() {
         preview.setLayoutOrientation(JList.HORIZONTAL_WRAP);
         preview.setVisibleRowCount(-1);
-        preview.setFixedCellWidth(TILE);
+        preview.setFixedCellWidth(UIScale.scale(TILE));
-        preview.setFixedCellHeight(TILE);
+        preview.setFixedCellHeight(UIScale.scale(TILE));
         preview.setCellRenderer(new DefaultListCellRenderer() {
             @Override
             public Component getListCellRendererComponent(JList<?> list, Object value, int index,
                                                           boolean selected, boolean focus) {
                 super.getListCellRendererComponent(list, value, index, selected, focus);
                 String key = String.valueOf(value);
-                ImageIcon icon = Icons.of(key, PREVIEW_SIZE);
+                ImageIcon icon = Icons.of(key, UIScale.scale(PREVIEW_SIZE));
                 setText("");
                 setIcon(icon);
                 setToolTipText(key);
@@ -162,7 +198,7 @@ final class DesignPanel extends JPanel {
         });
 
         JScrollPane scroll = new JScrollPane(preview);
-        scroll.setPreferredSize(new Dimension(360, 200));
+        scroll.setPreferredSize(UIScale.scale(new Dimension(360, 200)));
         scroll.setBorder(BorderFactory.createTitledBorder("Icons in this pack"));
         return scroll;
     }

ts3-client/swing/src/main/java/com/ts3client/ui/DevicesPanel.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.audio.VoiceInput;
 import com.ts3client.audio.VoiceOutput;
 import com.ts3client.audio.desktop.AudioDevices;
@@ -75,9 +76,9 @@ final class DevicesPanel extends FormPanel {
         c.gridx = 0;
         c.gridy = row++;
         c.gridwidth = 2;
-        c.insets = new Insets(14, 4, 2, 4);
+        c.insets = UIScale.scale(new Insets(14, 4, 2, 4));
         add(new JLabel("Noise reduction"), c);
-        c.insets = new Insets(4, 4, 4, 4);
+        c.insets = UIScale.scale(new Insets(4, 4, 4, 4));
         c.gridwidth = 1;
 
         denoiseCheck = new JCheckBox("Remove background noise", settings.denoise);

ts3-client/swing/src/main/java/com/ts3client/ui/DisplayScale.java

@@ -0,0 +1,134 @@
+package com.ts3client.ui;
+
+import java.awt.Toolkit;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Decides how large the user interface is drawn on Linux, where Java2D only knows
+ * whole-number scale factors: asked for 150 %, it draws at 100 % — or, told
+ * 2 by the desktop, at 200 %, while FlatLaf's own scaling goes on top of that.
+ *
+ * <p>So on Linux Java2D is pinned to 1 and the whole factor, fractional or not, is
+ * handed to FlatLaf, which scales fonts and its own metrics; the client scales its own
+ * sizes through FlatLaf's {@link com.formdev.flatlaf.util.UIScale} to match.
+ *
+ * <p>The desktop's factor is read the way an X11 toolkit would learn it:
+ * <ol>
+ *   <li>{@code Xft/DPI} from XSETTINGS — GNOME and Plasma (through xsettingsd) publish
+ *       the device-pixel DPI there, fractional scale and text scaling included;</li>
+ *   <li>KWin's {@code [Xwayland] Scale}, which Plasma sets when X11 apps are left to
+ *       scale themselves — for sessions with no XSETTINGS daemon running;</li>
+ *   <li>{@code GDK_SCALE}, which Java2D would otherwise have honoured itself.</li>
+ * </ol>
+ * With the compositor scaling X11 apps (GNOME's default, and Plasma's "Scaled by the
+ * system") the client sees 96&nbsp;DPI and is drawn at 100&nbsp;%, which is what those
+ * modes expect; they then upscale the window, blurry but the right size.
+ *
+ * <p>A {@code sun.java2d.uiScale} or {@code flatlaf.uiScale} given on the command line
+ * turns all of this off.
+ */
+public final class DisplayScale {
+
+    private static final String JAVA2D_SCALE = "sun.java2d.uiScale";
+    private static final String FLATLAF_SCALE = "flatlaf.uiScale";
+    private static final double BASE_DPI = 96;
+    private static final double MAX_SCALE = 4;
+
+    private static boolean managed;
+    private static double detected = 1;
+
+    private DisplayScale() {
+    }
+
+    /**
+     * Sets the scale up; call before anything touches AWT.
+     *
+     * @param override the user's chosen factor, or 0 to follow the desktop
+     */
+    public static void configure(double override) {
+        if (!isLinux() || System.getProperty(JAVA2D_SCALE) != null
+                || System.getProperty(FLATLAF_SCALE) != null) {
+            return;
+        }
+        System.setProperty(JAVA2D_SCALE, "1");
+        managed = true;
+        detected = detect();
+        double factor = override > 0 ? override : detected;
+        System.setProperty(FLATLAF_SCALE, Double.toString(factor));
+    }
+
+    /** Whether the client sets the scale itself, so that the user may choose one. */
+    public static boolean isManaged() {
+        return managed;
+    }
+
+    /** The desktop's factor, as found at startup. */
+    public static double detected() {
+        return detected;
+    }
+
+    private static double detect() {
+        double scale = xftScale();
+        if (scale <= 0) scale = kwinXwaylandScale();
+        scale = Math.max(scale, gdkScale());
+        return Math.max(1, Math.min(MAX_SCALE, scale));
+    }
+
+    private static double xftScale() {
+        // The XSETTINGS value is in 1024ths of a DPI; -1 means "unset".
+        Object dpi = Toolkit.getDefaultToolkit().getDesktopProperty("gnome.Xft/DPI");
+        return dpi instanceof Integer d && d > 0 ? d / 1024.0 / BASE_DPI : 0;
+    }
+
+    private static double kwinXwaylandScale() {
+        // Left behind by a Wayland session, the key would be stale in an X11 one.
+        if (System.getenv("WAYLAND_DISPLAY") == null) return 0;
+        String configHome = System.getenv("XDG_CONFIG_HOME");
+        Path kwinrc = (configHome == null || configHome.isEmpty()
+                ? Path.of(System.getProperty("user.home"), ".config")
+                : Path.of(configHome)).resolve("kwinrc");
+        try {
+            return parseDouble(iniValue(Files.readAllLines(kwinrc), "Xwayland", "Scale"));
+        } catch (IOException e) {
+            return 0;
+        }
+    }
+
+    private static double gdkScale() {
+        return parseDouble(System.getenv("GDK_SCALE"));
+    }
+
+    /** The value of {@code key} in {@code [group]} of a KConfig-style file, or {@code null}. */
+    static String iniValue(List<String> lines, String group, String key) {
+        boolean inGroup = false;
+        for (String line : lines) {
+            String t = line.trim();
+            if (t.startsWith("[")) {
+                inGroup = t.equals("[" + group + "]");
+            } else if (inGroup) {
+                int eq = t.indexOf('=');
+                if (eq > 0 && t.substring(0, eq).trim().equals(key)) {
+                    return t.substring(eq + 1).trim();
+                }
+            }
+        }
+        return null;
+    }
+
+    private static double parseDouble(String s) {
+        if (s == null) return 0;
+        try {
+            return Double.parseDouble(s.trim());
+        } catch (NumberFormatException e) {
+            return 0;
+        }
+    }
+
+    private static boolean isLinux() {
+        return System.getProperty("os.name", "").toLowerCase(Locale.ROOT).startsWith("linux");
+    }
+}

ts3-client/swing/src/main/java/com/ts3client/ui/DropDownToggleButton.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.BorderFactory;
 import javax.swing.Icon;
 import javax.swing.JButton;
@@ -52,7 +54,7 @@ public final class DropDownToggleButton extends JPanel {
         // width comes out of the toggle half instead of being added to it.
         Dimension plain = button.getPreferredSize();
         button.setPreferredSize(new Dimension(
-                Math.max(icon.getIconWidth() + 8, plain.width - arrow.getPreferredSize().width),
+                Math.max(icon.getIconWidth() + UIScale.scale(8), plain.width - arrow.getPreferredSize().width),
                 plain.height));
 
         add(button, BorderLayout.CENTER);
@@ -109,12 +111,12 @@ public final class DropDownToggleButton extends JPanel {
 
         @Override
         public int getIconWidth() {
-            return 7;
+            return UIScale.scale(7);
         }
 
         @Override
         public int getIconHeight() {
-            return 4;
+            return UIScale.scale(4);
         }
     }
 }

ts3-client/swing/src/main/java/com/ts3client/ui/DropIndicatorTree.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ChannelNode;
 import com.ts3client.net.ClientEntry;
 import com.ts3client.net.ServerModel;
@@ -160,14 +161,16 @@ final class DropIndicatorTree extends JTree {
         if (highlight != null || loc.getChildIndex() < 0) {
             Rectangle r = getPathBounds(highlight != null ? highlight : loc.getPath());
             if (r != null) {
-                g2.setStroke(new BasicStroke(2f));
+                g2.setStroke(new BasicStroke(UIScale.scale(2f)));
-                g2.drawRoundRect(r.x, r.y + 1, r.width - 1, r.height - 3, 4, 4);
+                int arc = UIScale.scale(4);
+                g2.drawRoundRect(r.x, r.y + 1, r.width - 1, r.height - 3, arc, arc);
             }
         } else {
             Rectangle line = insertLine(loc);
             if (line != null) {
-                g2.fillRect(line.x, line.y - 1, line.width, 2);
+                int dot = UIScale.scale(7);
-                g2.fillOval(line.x - 3, line.y - 4, 7, 7);
+                g2.fillRect(line.x, line.y - line.height / 2, line.width, line.height);
+                g2.fillOval(line.x - dot / 2, line.y - dot / 2 - 1, dot, dot);
             }
         }
         g2.dispose();
@@ -210,19 +213,19 @@ final class DropIndicatorTree extends JTree {
         return obj instanceof ChannelNode && Spacers.isSpacer(((ChannelNode) obj).name);
     }
 
-    /** The 1px-tall strip where the insertion line goes, in tree coordinates. */
+    /** The strip where the insertion line goes, in tree coordinates. */
     private Rectangle insertLine(JTree.DropLocation loc) {
         DefaultMutableTreeNode parent = (DefaultMutableTreeNode) loc.getPath().getLastPathComponent();
         int index = loc.getChildIndex();
         if (index < parent.getChildCount()) {
             Rectangle r = getPathBounds(loc.getPath().pathByAddingChild(parent.getChildAt(index)));
-            return r == null ? null : new Rectangle(r.x, r.y, getWidth() - r.x, 2);
+            return r == null ? null : new Rectangle(r.x, r.y, getWidth() - r.x, UIScale.scale(2));
         }
         if (parent.getChildCount() == 0) {
             Rectangle r = getPathBounds(loc.getPath());
             if (r == null) return null;
             int x = r.x + getRowHeight();
-            return new Rectangle(x, r.y + r.height, getWidth() - x, 2);
+            return new Rectangle(x, r.y + r.height, getWidth() - x, UIScale.scale(2));
         }
         // Past the last child: below that child's whole (expanded) subtree.
         TreePath lastChild = loc.getPath().pathByAddingChild(parent.getChildAt(parent.getChildCount() - 1));
@@ -250,7 +253,7 @@ final class DropIndicatorTree extends JTree {
      */
     private void paintBadges(Graphics g) {
         Rectangle visible = getVisibleRect();
-        int right = visible.x + visible.width - BADGE_MARGIN;
+        int right = visible.x + visible.width - UIScale.scale(BADGE_MARGIN);
         for (int row = 0; row < getRowCount(); row++) {
             Rectangle bounds = getRowBounds(row);
             if (bounds == null || bounds.y + bounds.height < visible.y) continue;
@@ -262,7 +265,7 @@ final class DropIndicatorTree extends JTree {
             if (icons.isEmpty()) continue;
 
             GroupIcons.Row strip = new GroupIcons.Row(icons);
-            int x = Math.max(bounds.x + bounds.width + BADGE_GAP, right - strip.getIconWidth());
+            int x = Math.max(bounds.x + bounds.width + UIScale.scale(BADGE_GAP), right - strip.getIconWidth());
             strip.paintIcon(this, g, x, bounds.y + (bounds.height - strip.getIconHeight()) / 2);
         }
     }

ts3-client/swing/src/main/java/com/ts3client/ui/FileBrowserDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ChannelNode;
 import com.ts3client.net.TeamspeakConnection;
 import com.ts3client.net.filetransfer.FileTransfer;
@@ -65,15 +67,15 @@ public final class FileBrowserDialog extends JDialog {
         this.channelId = channel.id;
         this.channelPassword = "";
 
-        JPanel content = new JPanel(new BorderLayout(0, 8));
+        JPanel content = new JPanel(new BorderLayout(0, UIScale.scale(8)));
         content.setBackground(Theme.windowBg());
-        content.setBorder(BorderFactory.createEmptyBorder(10, 12, 10, 12));
+        content.setBorder(new ScaledEmptyBorder(10, 12, 10, 12));
         content.add(buildToolbar(), BorderLayout.NORTH);
         content.add(buildTable(), BorderLayout.CENTER);
         content.add(buildTransfers(), BorderLayout.SOUTH);
         setContentPane(content);
 
-        setPreferredSize(new Dimension(640, 480));
+        setPreferredSize(UIScale.scale(new Dimension(640, 480)));
         pack();
         setLocationRelativeTo(owner);
 
@@ -98,17 +100,17 @@ public final class FileBrowserDialog extends JDialog {
         deleteButton.addActionListener(e -> deleteSelected());
 
         bar.add(upButton);
-        bar.add(Box.createHorizontalStrut(6));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(6)));
         bar.add(refresh);
-        bar.add(Box.createHorizontalStrut(16));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(16)));
         bar.add(pathLabel);
         bar.add(Box.createHorizontalGlue());
         bar.add(mkdir);
-        bar.add(Box.createHorizontalStrut(6));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(6)));
         bar.add(upload);
-        bar.add(Box.createHorizontalStrut(6));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(6)));
         bar.add(downloadButton);
-        bar.add(Box.createHorizontalStrut(6));
+        bar.add(Box.createHorizontalStrut(UIScale.scale(6)));
         bar.add(deleteButton);
 
         pathLabel.setFont(Theme.uiFont());
@@ -118,14 +120,14 @@ public final class FileBrowserDialog extends JDialog {
 
     private JScrollPane buildTable() {
         table.setFont(Theme.uiFont());
-        table.setRowHeight(20);
+        table.setRowHeight(UIScale.scale(20));
         table.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
         table.setFillsViewportHeight(true);
-        table.getColumnModel().getColumn(0).setPreferredWidth(300);
+        table.getColumnModel().getColumn(0).setPreferredWidth(UIScale.scale(300));
         table.getColumnModel().getColumn(0).setCellRenderer(new NameRenderer());
-        table.getColumnModel().getColumn(1).setPreferredWidth(90);
+        table.getColumnModel().getColumn(1).setPreferredWidth(UIScale.scale(90));
-        table.getColumnModel().getColumn(2).setPreferredWidth(70);
+        table.getColumnModel().getColumn(2).setPreferredWidth(UIScale.scale(70));
-        table.getColumnModel().getColumn(3).setPreferredWidth(150);
+        table.getColumnModel().getColumn(3).setPreferredWidth(UIScale.scale(150));
         table.getSelectionModel().addListSelectionListener(e -> updateButtons());
         table.addMouseListener(new MouseAdapter() {
             @Override
@@ -146,7 +148,7 @@ public final class FileBrowserDialog extends JDialog {
         transfersPanel.setBackground(Theme.windowBg());
         JScrollPane scroll = new JScrollPane(transfersPanel);
         scroll.setBorder(BorderFactory.createTitledBorder("Transfers"));
-        scroll.setPreferredSize(new Dimension(10, 120));
+        scroll.setPreferredSize(UIScale.scale(new Dimension(10, 120)));
         scroll.getViewport().setBackground(Theme.windowBg());
         return scroll;
     }
@@ -325,10 +327,10 @@ public final class FileBrowserDialog extends JDialog {
         private FileTransfer transfer;
 
         TransferRow() {
-            setLayout(new BorderLayout(8, 0));
+            setLayout(new BorderLayout(UIScale.scale(8), 0));
             setBackground(Theme.windowBg());
-            setBorder(BorderFactory.createEmptyBorder(3, 2, 3, 2));
+            setBorder(new ScaledEmptyBorder(3, 2, 3, 2));
-            setMaximumSize(new Dimension(Integer.MAX_VALUE, 44));
+            setMaximumSize(new Dimension(Integer.MAX_VALUE, UIScale.scale(44)));
             label.setFont(Theme.uiFont());
             bar.setStringPainted(true);
             add(label, BorderLayout.NORTH);

ts3-client/swing/src/main/java/com/ts3client/ui/FormPanel.java

@@ -1,6 +1,8 @@
 package com.ts3client.ui;
 
-import javax.swing.BorderFactory;
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.JComponent;
 import javax.swing.JLabel;
 import javax.swing.JPanel;
@@ -27,7 +29,7 @@ class FormPanel extends JPanel implements Scrollable {
 
     FormPanel() {
         super(new GridBagLayout());
-        setBorder(BorderFactory.createEmptyBorder(12, 12, 12, 12));
+        setBorder(new ScaledEmptyBorder(12, 12, 12, 12));
     }
 
     @Override
@@ -57,7 +59,7 @@ class FormPanel extends JPanel implements Scrollable {
 
     static GridBagConstraints gbc() {
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(4, 4, 4, 4);
+        c.insets = UIScale.scale(new Insets(4, 4, 4, 4));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
         return c;
@@ -81,8 +83,8 @@ class FormPanel extends JPanel implements Scrollable {
      */
     static void limitWidth(JComponent comp, int preferredWidth) {
         int height = comp.getPreferredSize().height;
-        comp.setPreferredSize(new Dimension(preferredWidth, height));
+        comp.setPreferredSize(new Dimension(UIScale.scale(preferredWidth), height));
-        comp.setMinimumSize(new Dimension(MIN_FIELD_WIDTH, height));
+        comp.setMinimumSize(new Dimension(UIScale.scale(MIN_FIELD_WIDTH), height));
     }
 
     static JPanel sliderWithLabel(JSlider slider, JLabel valueLabel) {
@@ -94,7 +96,7 @@ class FormPanel extends JPanel implements Scrollable {
      * the longest value so the slider does not jump around as it is dragged.
      */
     static JPanel sliderWithLabel(JSlider slider, JLabel valueLabel, int labelWidth) {
-        JPanel panel = new JPanel(new BorderLayout(6, 0));
+        JPanel panel = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         limitWidth(slider, SLIDER_WIDTH);
         panel.add(slider, BorderLayout.CENTER);
         valueLabel.setPreferredSize(new Dimension(labelWidth, valueLabel.getPreferredSize().height));

ts3-client/swing/src/main/java/com/ts3client/ui/GroupIcons.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.Group;
 import com.ts3client.net.IconRepository;
 
@@ -42,7 +43,7 @@ public final class GroupIcons {
         // its own style; only server-uploaded icons come off the wire. The theme keeps
         // its own cache, so those are not cached again here.
         if (iconId > 0 && iconId <= IconRepository.MAX_BUNDLED_ID) {
-            ImageIcon themed = IconTheme.icon("GROUP_" + iconId, SIZE);
+            ImageIcon themed = IconTheme.icon("GROUP_" + iconId, UIScale.scale(SIZE));
             if (themed != null) return themed;
         }
 
@@ -54,8 +55,9 @@ public final class GroupIcons {
 
         ImageIcon icon = new ImageIcon(data);
         if (icon.getIconWidth() <= 0) return null;
-        if (icon.getIconWidth() != SIZE || icon.getIconHeight() != SIZE) {
+        int size = UIScale.scale(SIZE);
-            icon = new ImageIcon(icon.getImage().getScaledInstance(SIZE, SIZE, Image.SCALE_SMOOTH));
+        if (icon.getIconWidth() != size || icon.getIconHeight() != size) {
+            icon = new ImageIcon(icon.getImage().getScaledInstance(size, size, Image.SCALE_SMOOTH));
         }
         decoded.put(iconId, icon);
         return icon;
@@ -89,15 +91,16 @@ public final class GroupIcons {
             int offset = x;
             for (Icon icon : icons) {
                 icon.paintIcon(c, g, offset, y + (getIconHeight() - icon.getIconHeight()) / 2);
-                offset += icon.getIconWidth() + GAP;
+                offset += icon.getIconWidth() + UIScale.scale(GAP);
             }
         }
 
         @Override
         public int getIconWidth() {
             int width = 0;
-            for (Icon icon : icons) width += icon.getIconWidth() + GAP;
+            int gap = UIScale.scale(GAP);
-            return Math.max(0, width - GAP);
+            for (Icon icon : icons) width += icon.getIconWidth() + gap;
+            return Math.max(0, width - gap);
         }
 
         @Override

ts3-client/swing/src/main/java/com/ts3client/ui/HotkeyDialog.java

@@ -1,11 +1,12 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.hotkey.Hotkey;
 import com.ts3client.hotkey.HotkeyAction;
 import com.ts3client.hotkey.HotkeyCombo;
 import com.ts3client.hotkey.HotkeyEngine;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.DefaultListCellRenderer;
 import javax.swing.JButton;
@@ -120,8 +121,8 @@ final class HotkeyDialog extends JDialog {
         argumentField.setText(hotkey.argument == null ? "" : hotkey.argument);
         hint.setFont(hint.getFont().deriveFont(Font.ITALIC, hint.getFont().getSize2D() - 1f));
 
-        getContentPane().setLayout(new BorderLayout(8, 8));
+        getContentPane().setLayout(new BorderLayout(UIScale.scale(8), UIScale.scale(8)));
-        ((JComponent) getContentPane()).setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        ((JComponent) getContentPane()).setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
         getContentPane().add(buildActionPane(), BorderLayout.CENTER);
         getContentPane().add(buildForm(), BorderLayout.SOUTH);
 
@@ -129,12 +130,12 @@ final class HotkeyDialog extends JDialog {
         updateForAction();
         Dialogs.closeOnEscape(this, this::cancel);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
-        setSize(new Dimension(470, 560));
+        setSize(UIScale.scale(new Dimension(470, 560)));
         setLocationRelativeTo(owner);
     }
 
     private JPanel buildActionPane() {
-        JPanel p = new JPanel(new BorderLayout(0, 4));
+        JPanel p = new JPanel(new BorderLayout(0, UIScale.scale(4)));
         p.add(new JLabel("Action:"), BorderLayout.NORTH);
         p.add(new JScrollPane(tree), BorderLayout.CENTER);
         p.add(advancedCheck, BorderLayout.SOUTH);
@@ -144,7 +145,7 @@ final class HotkeyDialog extends JDialog {
     private JPanel buildForm() {
         JPanel p = new JPanel(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(3, 3, 3, 3);
+        c.insets = UIScale.scale(new Insets(3, 3, 3, 3));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 

ts3-client/swing/src/main/java/com/ts3client/ui/HotkeysPanel.java

@@ -1,8 +1,9 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.hotkey.Hotkey;
 
-import javax.swing.BorderFactory;
 import javax.swing.JButton;
 import javax.swing.JLabel;
 import javax.swing.JPanel;
@@ -34,18 +35,18 @@ final class HotkeysPanel extends JPanel {
     private final JTable table = new JTable(model);
 
     HotkeysPanel(HotkeyService service) {
-        super(new BorderLayout(6, 6));
+        super(new BorderLayout(UIScale.scale(6), UIScale.scale(6)));
         this.service = service;
-        setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
 
         synchronized (service.all()) {
             for (Hotkey h : service.all()) working.add(h.copy());
         }
 
         table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
-        table.setRowHeight(table.getRowHeight() + 4);
+        table.setRowHeight(table.getRowHeight() + UIScale.scale(4));
-        table.getColumnModel().getColumn(0).setPreferredWidth(240);
+        table.getColumnModel().getColumn(0).setPreferredWidth(UIScale.scale(240));
-        table.getColumnModel().getColumn(1).setPreferredWidth(150);
+        table.getColumnModel().getColumn(1).setPreferredWidth(UIScale.scale(150));
         table.addMouseListener(new MouseAdapter() {
             @Override
             public void mouseClicked(MouseEvent e) {

ts3-client/swing/src/main/java/com/ts3client/ui/HtmlStyles.java

@@ -1,13 +1,16 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.text.BBCode;
 
 import javax.swing.JEditorPane;
 import javax.swing.JViewport;
 import javax.swing.SwingUtilities;
 import javax.swing.text.html.HTMLEditorKit;
+import javax.swing.text.AttributeSet;
 import javax.swing.text.html.StyleSheet;
 import java.awt.Color;
+import java.awt.Font;
 
 /**
  * The HTML panes showing TeamSpeak text — chat logs, client and channel information —
@@ -70,7 +73,7 @@ final class HtmlStyles {
 
     private static void installKit(JEditorPane pane, String html, boolean atEnd) {
         HTMLEditorKit kit = new HTMLEditorKit();
-        StyleSheet css = new StyleSheet();
+        StyleSheet css = new ScaledStyleSheet();
         css.addStyleSheet(kit.getStyleSheet());
 
         Object bodyStyle = pane.getClientProperty(BODY_STYLE);
@@ -102,7 +105,24 @@ final class HtmlStyles {
         }
     }
 
+    /** A CSS length of {@code px} at the interface scale. */
+    static String px(int px) {
+        return UIScale.scale(px) + "px";
+    }
+
     private static String hex(Color c) {
         return String.format("#%02x%02x%02x", c.getRed(), c.getGreen(), c.getBlue());
     }
+
+    /**
+     * Scales every font size, the way a browser scales CSS pixels: Swing takes a
+     * {@code font-size} in pixels literally, and the text is written in unscaled ones.
+     */
+    private static final class ScaledStyleSheet extends StyleSheet {
+        @Override
+        public Font getFont(AttributeSet a) {
+            Font font = super.getFont(a);
+            return UIScale.getUserScaleFactor() == 1f ? font : font.deriveFont(UIScale.scale(font.getSize2D()));
+        }
+    }
 }

ts3-client/swing/src/main/java/com/ts3client/ui/IconChooserDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.IconRepository;
 import com.ts3client.net.TeamspeakConnection;
 
@@ -69,7 +71,7 @@ final class IconChooserDialog extends JDialog {
                 group("Local", localList, localFooter()));
         split.setResizeWeight(0.6);
 
-        status.setBorder(BorderFactory.createEmptyBorder(2, 8, 2, 8));
+        status.setBorder(new ScaledEmptyBorder(2, 8, 2, 8));
         status.setForeground(Theme.chatSystem());
 
         getContentPane().setLayout(new BorderLayout());
@@ -81,7 +83,7 @@ final class IconChooserDialog extends JDialog {
 
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
-        setSize(new Dimension(520, 360));
+        setSize(UIScale.scale(new Dimension(520, 360)));
         setLocationRelativeTo(owner);
 
         loadRemoteIcons();
@@ -101,8 +103,8 @@ final class IconChooserDialog extends JDialog {
         list.setLayoutOrientation(JList.HORIZONTAL_WRAP);
         list.setVisibleRowCount(-1);
         list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
-        list.setFixedCellWidth(32);
+        list.setFixedCellWidth(UIScale.scale(32));
-        list.setFixedCellHeight(32);
+        list.setFixedCellHeight(UIScale.scale(32));
         list.setCellRenderer(new IconCellRenderer());
         list.addListSelectionListener(e -> onSelectionChanged(list));
         list.addMouseListener(new MouseAdapter() {
@@ -129,7 +131,7 @@ final class IconChooserDialog extends JDialog {
     }
 
     private JPanel group(String title, JList<Long> list, Component footer) {
-        JPanel panel = new JPanel(new BorderLayout(0, 4));
+        JPanel panel = new JPanel(new BorderLayout(0, UIScale.scale(4)));
         panel.setBorder(BorderFactory.createTitledBorder(title));
         panel.add(new JScrollPane(list), BorderLayout.CENTER);
         panel.add(footer, BorderLayout.SOUTH);
@@ -150,7 +152,7 @@ final class IconChooserDialog extends JDialog {
     private Component localFooter() {
         com.ts3client.gfx.IconPack active = IconTheme.get().activePack();
         JLabel pack = new JLabel("Icon Pack: " + (active == null ? "none" : active.name()));
-        pack.setBorder(BorderFactory.createEmptyBorder(0, 4, 0, 4));
+        pack.setBorder(new ScaledEmptyBorder(0, 4, 0, 4));
         return pack;
     }
 

ts3-client/swing/src/main/java/com/ts3client/ui/IconTheme.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.github.weisj.jsvg.SVGDocument;
 import com.github.weisj.jsvg.parser.LoaderContext;
 import com.github.weisj.jsvg.parser.SVGLoader;
@@ -33,6 +34,7 @@ import java.util.concurrent.CopyOnWriteArrayList;
  *
  * <p>Rendering is cached per key and size: vector art is rasterised at the size it
  * is asked for, bitmaps are scaled from the closest resolution the pack ships.
+ * {@link #SIZE} and {@link #TOOLBAR_SIZE} are unscaled; sizes passed in are pixels.
  */
 public final class IconTheme {
 
@@ -86,12 +88,12 @@ public final class IconTheme {
         listeners.add(listener);
     }
 
-    /** @return the icon for a TeamSpeak icon key at 16&times;16, or {@code null} if no pack has it */
+    /** @return the icon for a TeamSpeak icon key at tree-row size, or {@code null} if no pack has it */
     public static ImageIcon icon(String key) {
-        return icon(key, SIZE);
+        return icon(key, UIScale.scale(SIZE));
     }
 
-    /** @return the icon for a TeamSpeak icon key, or {@code null} if no pack has it */
+    /** @return the icon for a TeamSpeak icon key at {@code size} pixels, or {@code null} if no pack has it */
     public static ImageIcon icon(String key, int size) {
         return INSTANCE.lookup(key, size);
     }

ts3-client/swing/src/main/java/com/ts3client/ui/Icons.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.ImageIcon;
 import java.awt.BasicStroke;
 import java.awt.Color;
@@ -15,14 +17,25 @@ import java.awt.image.BufferedImage;
  * so a machine with no icon pack installed still gets a complete (if plain) set.
  * Everything else — menu and dialog decoration — simply stays blank without a pack,
  * which is why {@link #of(String)} may return {@code null}.
+ *
+ * <p>Icons come at the interface's scale; the variants taking a size take it in pixels.
  */
 public final class Icons {
 
+    /** The box the built-in painters draw in. */
     private static final int SZ = IconTheme.SIZE;
 
     private Icons() {
     }
 
+    private static int small() {
+        return UIScale.scale(IconTheme.SIZE);
+    }
+
+    private static int large() {
+        return UIScale.scale(IconTheme.TOOLBAR_SIZE);
+    }
+
     private interface Painter {
         void paint(Graphics2D g);
     }
@@ -44,13 +57,13 @@ public final class Icons {
         return null;
     }
 
-    /** @return the pack's icon at a given size, or {@code null} when it has none */
+    /** @return the pack's icon at {@code size} pixels, or {@code null} when it has none */
     public static ImageIcon of(String key, int size) {
         return IconTheme.icon(key, size);
     }
 
     private static ImageIcon themed(String key, Painter fallback) {
-        return themed(key, SZ, fallback);
+        return themed(key, small(), fallback);
     }
 
     private static ImageIcon themed(String key, int size, Painter fallback) {
@@ -64,14 +77,14 @@ public final class Icons {
      */
     private static ImageIcon themed(String[] keys, Painter fallback) {
         for (String key : keys) {
-            ImageIcon icon = IconTheme.icon(key, SZ);
+            ImageIcon icon = IconTheme.icon(key, small());
             if (icon != null) return icon;
         }
         return make(fallback);
     }
 
     private static ImageIcon make(Painter p) {
-        return make(SZ, p);
+        return make(small(), p);
     }
 
     /** Runs a painter (which draws in a 16&times;16 box) scaled to {@code size}. */
@@ -129,7 +142,7 @@ public final class Icons {
     // ---- client status icons ----
 
     public static ImageIcon clientIdle() {
-        return clientIdle(SZ);
+        return clientIdle(small());
     }
 
     public static ImageIcon clientIdle(int size) {
@@ -137,7 +150,7 @@ public final class Icons {
     }
 
     public static ImageIcon clientTalking() {
-        return clientTalking(SZ);
+        return clientTalking(small());
     }
 
     public static ImageIcon clientTalking(int size) {
@@ -145,7 +158,7 @@ public final class Icons {
     }
 
     public static ImageIcon clientAway() {
-        return clientAway(SZ);
+        return clientAway(small());
     }
 
     public static ImageIcon clientAway(int size) {
@@ -154,12 +167,12 @@ public final class Icons {
 
     /** A channel commander that is not talking. */
     public static ImageIcon clientCommander() {
-        return clientCommander(SZ);
+        return clientCommander(small());
     }
 
     /** A channel commander that is talking. */
     public static ImageIcon clientCommanderTalking() {
-        return clientCommanderTalking(SZ);
+        return clientCommanderTalking(small());
     }
 
     public static ImageIcon clientQuery() {
@@ -167,7 +180,7 @@ public final class Icons {
     }
 
     public static ImageIcon micMuted() {
-        return micMuted(SZ);
+        return micMuted(small());
     }
 
     public static ImageIcon micMuted(int size) {
@@ -175,7 +188,7 @@ public final class Icons {
     }
 
     public static ImageIcon speakerMuted() {
-        return speakerMuted(SZ);
+        return speakerMuted(small());
     }
 
     public static ImageIcon speakerMuted(int size) {
@@ -184,7 +197,7 @@ public final class Icons {
 
     /** The capture device is unavailable (another tab holds it), as opposed to muted. */
     public static ImageIcon micDisabled() {
-        return micDisabled(SZ);
+        return micDisabled(small());
     }
 
     public static ImageIcon micDisabled(int size) {
@@ -193,7 +206,7 @@ public final class Icons {
 
     /** The playback device is unavailable, as opposed to muted/deafened. */
     public static ImageIcon speakerDisabled() {
-        return speakerDisabled(SZ);
+        return speakerDisabled(small());
     }
 
     public static ImageIcon speakerDisabled(int size) {
@@ -202,7 +215,7 @@ public final class Icons {
 
     /** TS3's "Local Mic Mute": silenced, but not reported as muted. */
     public static ImageIcon micLocalMuted() {
-        return micLocalMuted(SZ);
+        return micLocalMuted(small());
     }
 
     public static ImageIcon micLocalMuted(int size) {
@@ -222,32 +235,32 @@ public final class Icons {
     // ---- toolbar / action icons ----
 
     public static ImageIcon connect() {
-        return themed("CONNECT", IconTheme.TOOLBAR_SIZE, Icons::paintConnect);
+        return themed("CONNECT", large(), Icons::paintConnect);
     }
 
     public static ImageIcon disconnect() {
-        return themed("DISCONNECT", IconTheme.TOOLBAR_SIZE, Icons::paintDisconnect);
+        return themed("DISCONNECT", large(), Icons::paintDisconnect);
     }
 
     public static ImageIcon mic() {
-        return themed("CAPTURE", IconTheme.TOOLBAR_SIZE, Icons::paintMic);
+        return themed("CAPTURE", large(), Icons::paintMic);
     }
 
     public static ImageIcon speaker() {
-        return themed("PLAYBACK", IconTheme.TOOLBAR_SIZE, Icons::paintSpeaker);
+        return themed("PLAYBACK", large(), Icons::paintSpeaker);
     }
 
     public static ImageIcon micMutedLarge() {
-        return themed("INPUT_MUTED", IconTheme.TOOLBAR_SIZE, Icons::paintMicMuted);
+        return themed("INPUT_MUTED", large(), Icons::paintMicMuted);
     }
 
     public static ImageIcon speakerMutedLarge() {
-        return themed("OUTPUT_MUTED", IconTheme.TOOLBAR_SIZE, Icons::paintSpeakerMuted);
+        return themed("OUTPUT_MUTED", large(), Icons::paintSpeakerMuted);
     }
 
     /** Marks the server that currently owns the microphone. */
     public static ImageIcon micActive() {
-        return themed("ACTIVATE_MICROPHONE", IconTheme.TOOLBAR_SIZE, Icons::paintMicActive);
+        return themed("ACTIVATE_MICROPHONE", large(), Icons::paintMicActive);
     }
 
     /** The same marker at tab-label size. */
@@ -262,7 +275,7 @@ public final class Icons {
     public static ImageIcon channelClientPair() {
         ImageIcon channel = channel(true);
         ImageIcon edit = themed("EDIT", Icons::paintEdit);
-        int gap = 8;
+        int gap = UIScale.scale(8);
         int width = channel.getIconWidth() + gap + edit.getIconWidth();
         int height = Math.max(channel.getIconHeight(), edit.getIconHeight());
         BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
@@ -282,15 +295,15 @@ public final class Icons {
 
     /** The toolbar's away marker. */
     public static ImageIcon away() {
-        return themed("AWAY", IconTheme.TOOLBAR_SIZE, g -> paintPerson(g, Theme.away()));
+        return themed("AWAY", large(), g -> paintPerson(g, Theme.away()));
     }
 
     public static ImageIcon settings() {
-        return themed("SETTINGS", IconTheme.TOOLBAR_SIZE, Icons::paintSettings);
+        return themed("SETTINGS", large(), Icons::paintSettings);
     }
 
     public static ImageIcon app() {
-        return app(SZ);
+        return app(small());
     }
 
     public static ImageIcon app(int size) {

ts3-client/swing/src/main/java/com/ts3client/ui/IdentitiesDialog.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Bookmarks;
 import com.ts3client.config.IdentityEntry;
 import com.ts3client.config.IdentityStore;
@@ -7,7 +9,6 @@ import com.ts3client.config.Settings;
 import com.ts3client.teamspeak.TeamSpeakImporter;
 import com.ts3client.teamspeak.TeamSpeakSettingsDb;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.DefaultListCellRenderer;
@@ -73,12 +74,12 @@ public final class IdentitiesDialog extends JDialog {
         list.setVisibleRowCount(10);
 
         JScrollPane scroll = new JScrollPane(list);
-        scroll.setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
+        scroll.setBorder(new ScaledEmptyBorder(8, 8, 8, 8));
-        scroll.setPreferredSize(new Dimension(220, 260));
+        scroll.setPreferredSize(UIScale.scale(new Dimension(220, 260)));
 
         JPanel buttons = new JPanel();
         buttons.setLayout(new BoxLayout(buttons, BoxLayout.Y_AXIS));
-        buttons.setBorder(BorderFactory.createEmptyBorder(8, 0, 8, 8));
+        buttons.setBorder(new ScaledEmptyBorder(8, 0, 8, 8));
         addButton(buttons, "New…", this::newIdentity);
         addButton(buttons, "Import…", this::importIdentity);
         if (TeamSpeakSettingsDb.locate() != null) {
@@ -103,15 +104,15 @@ public final class IdentitiesDialog extends JDialog {
         Dialogs.closeOnEscape(this);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
         pack();
-        setMinimumSize(new Dimension(640, 320));
+        setMinimumSize(UIScale.scale(new Dimension(640, 320)));
         setLocationRelativeTo(owner);
     }
 
     private JPanel buildDetails() {
         JPanel form = new JPanel(new GridBagLayout());
-        form.setBorder(BorderFactory.createEmptyBorder(12, 4, 12, 8));
+        form.setBorder(new ScaledEmptyBorder(12, 4, 12, 8));
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(4, 4, 4, 4);
+        c.insets = UIScale.scale(new Insets(4, 4, 4, 4));
         c.anchor = GridBagConstraints.NORTHWEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -149,7 +150,7 @@ public final class IdentitiesDialog extends JDialog {
         b.setMaximumSize(new Dimension(Integer.MAX_VALUE, b.getPreferredSize().height));
         b.addActionListener(e -> action.run());
         panel.add(b);
-        panel.add(Box.createVerticalStrut(4));
+        panel.add(Box.createVerticalStrut(UIScale.scale(4)));
     }
 
     private String label(IdentityEntry e) {
@@ -335,8 +336,8 @@ public final class IdentitiesDialog extends JDialog {
 
         JDialog progress = new JDialog(this, "Please wait", true);
         JLabel status = new JLabel(message);
-        JPanel panel = new JPanel(new BorderLayout(8, 8));
+        JPanel panel = new JPanel(new BorderLayout(UIScale.scale(8), UIScale.scale(8)));
-        panel.setBorder(BorderFactory.createEmptyBorder(16, 16, 12, 16));
+        panel.setBorder(new ScaledEmptyBorder(16, 16, 12, 16));
         panel.add(status, BorderLayout.CENTER);
         if (cancellable) {
             JButton cancel = new JButton("Stop");

ts3-client/swing/src/main/java/com/ts3client/ui/InfoPanel.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.contacts.Contact;
 import com.ts3client.net.ChannelNode;
 import com.ts3client.net.ClientEntry;
@@ -65,7 +67,7 @@ public final class InfoPanel extends JPanel {
 
     public InfoPanel() {
         super(new BorderLayout());
-        pane.setBorder(BorderFactory.createEmptyBorder(6, 8, 6, 8));
+        pane.setBorder(new ScaledEmptyBorder(6, 8, 6, 8));
         pane.addHyperlinkListener(e -> {
             if (e.getEventType() != javax.swing.event.HyperlinkEvent.EventType.ACTIVATED) return;
             Links.open(e.getDescription(), this);
@@ -82,7 +84,7 @@ public final class InfoPanel extends JPanel {
         toggle.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
         toggle.setToolTipText("Show these details in a chat tab instead");
         toggle.setOpaque(true);
-        toggle.setBorder(BorderFactory.createEmptyBorder(1, 4, 1, 4));
+        toggle.setBorder(new ScaledEmptyBorder(1, 4, 1, 4));
         toggle.addMouseListener(new MouseAdapter() {
             @Override
             public void mousePressed(MouseEvent e) {
@@ -188,7 +190,7 @@ public final class InfoPanel extends JPanel {
     private String body() {
         if (shownChannel != null) return channelBody(shownChannel);
         if (shownClient != null) {
-            renderedAvatarBox = inChatTab ? AvatarHtml.MAX_SIZE : avatarBox();
+            renderedAvatarBox = inChatTab ? UIScale.scale(AvatarHtml.MAX_SIZE) : avatarBox();
             return clientBody(shownClient, shownModel, shownIcons, shownContact, shownAvatar, renderedAvatarBox);
         }
         return "<i class='muted'>Select a channel or client to see details.</i>";
@@ -201,9 +203,11 @@ public final class InfoPanel extends JPanel {
      */
     private int avatarBox() {
         int width = scroll.getViewport().getWidth();
-        if (width <= 0) return AvatarHtml.MAX_SIZE;
+        int max = UIScale.scale(AvatarHtml.MAX_SIZE);
-        int box = width * 2 / 5 / AVATAR_BOX_STEP * AVATAR_BOX_STEP;
+        if (width <= 0) return max;
-        return Math.max(AVATAR_MIN_SIZE, Math.min(AvatarHtml.MAX_SIZE, box));
+        int step = UIScale.scale(AVATAR_BOX_STEP);
+        int box = width * 2 / 5 / step * step;
+        return Math.max(UIScale.scale(AVATAR_MIN_SIZE), Math.min(max, box));
     }
 
     private static String channelBody(ChannelNode ch) {
@@ -231,7 +235,7 @@ public final class InfoPanel extends JPanel {
         // The avatar sits top-right beside the details, like the official client's info frame.
         return "<table width='100%' cellpadding='0' cellspacing='0'><tr>"
                 + "<td valign='top'>" + details + "</td>"
-                + "<td valign='top' align='right' style='padding-left:8px'>" + picture + "</td>"
+                + "<td valign='top' align='right' style='padding-left:" + HtmlStyles.px(8) + "'>" + picture + "</td>"
                 + "</tr></table>";
     }
 
@@ -297,11 +301,11 @@ public final class InfoPanel extends JPanel {
         if (group.iconId == 0) return "";
         File file = icons.file(group.iconId);
         if (file == null) return "";
-        return "<img src='" + file.toURI() + "' width='14' height='14'> ";
+        return "<img src='" + file.toURI() + "' width='" + UIScale.scale(14) + "' height='" + UIScale.scale(14) + "'> ";
     }
 
     private static String heading(String text) {
-        return "<div style='font-weight:bold;font-size:13px;margin-bottom:4px'>" + text + "</div>";
+        return "<div style='font-weight:bold;font-size:13px;margin-bottom:" + HtmlStyles.px(4) + "'>" + text + "</div>";
     }
 
     private static void row(StringBuilder sb, String label, String value) {

ts3-client/swing/src/main/java/com/ts3client/ui/LevelMeter.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.JComponent;
 import java.awt.Color;
 import java.awt.Dimension;
@@ -25,11 +27,11 @@ public final class LevelMeter extends JComponent {
     private volatile boolean transmitting;
 
     public LevelMeter() {
-        setPreferredSize(new Dimension(240, 18));
+        setPreferredSize(UIScale.scale(new Dimension(240, 18)));
         // A bare JComponent reports no minimum of its own, so a layout tight on space
         // collapses the bar to nothing. Keep the height and let only the width give.
-        setMinimumSize(new Dimension(60, 18));
+        setMinimumSize(UIScale.scale(new Dimension(60, 18)));
-        setMaximumSize(new Dimension(Integer.MAX_VALUE, 18));
+        setMaximumSize(new Dimension(Integer.MAX_VALUE, UIScale.scale(18)));
     }
 
     public void setLevel(double db) {
@@ -70,16 +72,17 @@ public final class LevelMeter extends JComponent {
         int h = getHeight();
 
         g.setColor(new Color(0x2B2B2B));
-        g.fillRoundRect(0, 0, w - 1, h - 1, 6, 6);
+        int arc = UIScale.scale(6);
+        g.fillRoundRect(0, 0, w - 1, h - 1, arc, arc);
 
         int level = dbToX(levelDb, w - 2);
         g.setColor(transmitting ? Theme.talking() : new Color(0x5A9BD4));
-        g.fillRoundRect(1, 1, Math.max(0, level), h - 3, 5, 5);
+        g.fillRoundRect(1, 1, Math.max(0, level), h - 3, arc - 1, arc - 1);
 
         if (showThreshold) {
             int tx = dbToX(thresholdDb, w - 2);
             g.setColor(new Color(0xF0C419));
-            g.fillRect(tx, 1, 2, h - 3);
+            g.fillRect(tx, 1, UIScale.scale(2), h - 3);
         }
     }
 }

ts3-client/swing/src/main/java/com/ts3client/ui/MainFrame.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.audio.AudioBackend;
 import com.ts3client.audio.desktop.DesktopAudioBackend;
 import com.ts3client.config.AwayMessages;
@@ -14,7 +15,6 @@ import com.ts3client.net.ChannelNode;
 import com.ts3client.sound.SoundNotifier;
 import com.ts3client.sound.SoundPlayer;
 
-import javax.swing.BorderFactory;
 import javax.swing.JCheckBox;
 import javax.swing.JCheckBoxMenuItem;
 import javax.swing.JFrame;
@@ -104,7 +104,7 @@ public final class MainFrame extends JFrame implements ServerTabPane.Listener {
         });
         // Catches Ctrl+C / SIGTERM so we still leave the servers cleanly.
         Runtime.getRuntime().addShutdownHook(shutdownHook);
-        setMinimumSize(new Dimension(720, 480));
+        setMinimumSize(UIScale.scale(new Dimension(720, 480)));
 
         tray = new TrayController(this, this::quit);
         menuBar = buildMenuBar();
@@ -128,7 +128,7 @@ public final class MainFrame extends JFrame implements ServerTabPane.Listener {
 
         statusTimer = new javax.swing.Timer(3000, e -> updateConnectionStatus());
         statusTimer.start();
-        setSize(880, 560);
+        setSize(UIScale.scale(new Dimension(880, 560)));
         setLocationRelativeTo(null);
 
         // Deferred so the window is on screen before we start connecting.
@@ -639,7 +639,7 @@ public final class MainFrame extends JFrame implements ServerTabPane.Listener {
 
         JTextField labelField = new JTextField(selected.title());
         JCheckBox joinChannel = new JCheckBox("Join \"" + channelPath + "\" on connect", !channelPath.isEmpty());
-        JPanel form = new JPanel(new GridLayout(0, 1, 0, 2));
+        JPanel form = new JPanel(new GridLayout(0, 1, 0, UIScale.scale(2)));
         form.add(new JLabel("Bookmark label:"));
         form.add(labelField);
         if (!channelPath.isEmpty()) form.add(joinChannel);

ts3-client/swing/src/main/java/com/ts3client/ui/MainToolbar.java

@@ -1,8 +1,9 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 
-import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.JButton;
 import javax.swing.JCheckBoxMenuItem;
@@ -74,7 +75,7 @@ final class MainToolbar extends JToolBar {
 
         setFloatable(false);
         setBackground(Theme.toolbarBg());
-        setBorder(BorderFactory.createEmptyBorder(4, 6, 4, 6));
+        setBorder(new ScaledEmptyBorder(4, 6, 4, 6));
         setComponentPopupMenu(buildContextMenu());
 
         connectButton = new JButton(Icons.connect());
@@ -152,7 +153,7 @@ final class MainToolbar extends JToolBar {
 
     /** The Master Volume slider: multiplies both voice and notification volume. */
     private JComponent buildMasterVolumeControl() {
-        JPanel panel = new JPanel(new FlowLayout(FlowLayout.RIGHT, 4, 0));
+        JPanel panel = new JPanel(new FlowLayout(FlowLayout.RIGHT, UIScale.scale(4), 0));
         panel.setOpaque(false);
         panel.setAlignmentY(Component.CENTER_ALIGNMENT);
 
@@ -164,7 +165,7 @@ final class MainToolbar extends JToolBar {
         slider.setOpaque(false);
         slider.setToolTipText("Master volume (voice + notifications) — scroll to adjust");
         slider.setAlignmentY(Component.CENTER_ALIGNMENT);
-        slider.setPreferredSize(new Dimension(135, slider.getPreferredSize().height));
+        slider.setPreferredSize(new Dimension(UIScale.scale(135), slider.getPreferredSize().height));
         slider.addChangeListener(e -> {
             settings.masterVolume = slider.getValue() / 100.0;
             listener.onMasterVolumeChanged();

ts3-client/swing/src/main/java/com/ts3client/ui/NicknameCellEditor.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ClientEntry;
 
 import javax.swing.DefaultCellEditor;
@@ -103,7 +104,7 @@ final class NicknameCellEditor extends DefaultTreeCellEditor {
         if (!(c instanceof JLabel)) return;
         editingIcon = ((JLabel) c).getIcon();
         offset = editingIcon == null ? 0
-                : editingIcon.getIconWidth() + renderer.getIconTextGap() - FIELD_NUDGE;
+                : editingIcon.getIconWidth() + renderer.getIconTextGap() - UIScale.scale(FIELD_NUDGE);
     }
 
     /** The edited nickname, trimmed; empty when nothing usable was typed. */

ts3-client/swing/src/main/java/com/ts3client/ui/NotificationsPanel.java

@@ -1,12 +1,13 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 import com.ts3client.sound.NotificationSettings;
 import com.ts3client.sound.SoundEvent;
 import com.ts3client.sound.SoundNotifier;
 import com.ts3client.sound.SoundPack;
 
-import javax.swing.BorderFactory;
 import javax.swing.JButton;
 import javax.swing.JComboBox;
 import javax.swing.JComponent;
@@ -79,7 +80,7 @@ final class NotificationsPanel extends JPanel {
     private final EventTableModel tableModel = new EventTableModel();
 
     NotificationsPanel(Settings settings, SoundNotifier sounds) {
-        super(new BorderLayout(0, 8));
+        super(new BorderLayout(0, UIScale.scale(8)));
         this.settings = settings;
         this.sounds = sounds;
         this.working = settings.notifications.copy();
@@ -91,7 +92,7 @@ final class NotificationsPanel extends JPanel {
         buildRows();
         this.table = buildTable();
 
-        setBorder(BorderFactory.createEmptyBorder(12, 12, 12, 12));
+        setBorder(new ScaledEmptyBorder(12, 12, 12, 12));
         add(buildHeader(), BorderLayout.NORTH);
         add(new JScrollPane(table), BorderLayout.CENTER);
         add(buildFooter(), BorderLayout.SOUTH);
@@ -122,7 +123,7 @@ final class NotificationsPanel extends JPanel {
     private JComponent buildHeader() {
         JPanel p = new JPanel(new GridBagLayout());
         GridBagConstraints c = new GridBagConstraints();
-        c.insets = new Insets(2, 2, 2, 2);
+        c.insets = UIScale.scale(new Insets(2, 2, 2, 2));
         c.anchor = GridBagConstraints.WEST;
         c.fill = GridBagConstraints.HORIZONTAL;
 
@@ -132,7 +133,7 @@ final class NotificationsPanel extends JPanel {
         test.setToolTipText("Play this pack's test sound");
         test.addActionListener(e -> sounds.preview(SoundEvent.SPECIAL_SOUND_TEST));
 
-        JPanel packRow = new JPanel(new BorderLayout(6, 0));
+        JPanel packRow = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         packRow.add(packCombo, BorderLayout.CENTER);
         packRow.add(test, BorderLayout.EAST);
 
@@ -146,7 +147,7 @@ final class NotificationsPanel extends JPanel {
         volume.setToolTipText("Volume of the notification sounds");
         addRow(p, c, row++, new JLabel("Sound volume:"), volume);
 
-        JPanel dirRow = new JPanel(new BorderLayout(6, 0));
+        JPanel dirRow = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         JButton browse = new JButton("Browse…");
         browse.addActionListener(e -> browseForPackFolder());
         dirRow.add(packDirField, BorderLayout.CENTER);
@@ -157,10 +158,10 @@ final class NotificationsPanel extends JPanel {
     }
 
     private JComponent buildFooter() {
-        JPanel p = new JPanel(new BorderLayout(6, 0));
+        JPanel p = new JPanel(new BorderLayout(UIScale.scale(6), 0));
         JLabel hint = new JLabel("<html><b>Bold</b> actions are important: they are still played "
                 + "while your speakers are muted.</html>");
-        hint.setBorder(BorderFactory.createEmptyBorder(4, 0, 0, 0));
+        hint.setBorder(new ScaledEmptyBorder(4, 0, 0, 0));
 
         JPanel buttons = new JPanel();
         JButton important = new JButton("Toggle important");
@@ -187,12 +188,12 @@ final class NotificationsPanel extends JPanel {
         t.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
         t.setShowGrid(false);
         t.setTableHeader(null);
-        t.setRowHeight(Math.max(t.getRowHeight(), t.getFontMetrics(t.getFont()).getHeight() + 6));
+        t.setRowHeight(Math.max(t.getRowHeight(), t.getFontMetrics(t.getFont()).getHeight() + UIScale.scale(6)));
-        t.getColumnModel().getColumn(0).setMaxWidth(TOGGLE_COLUMN_WIDTH);
+        t.getColumnModel().getColumn(0).setMaxWidth(UIScale.scale(TOGGLE_COLUMN_WIDTH));
-        t.getColumnModel().getColumn(0).setMinWidth(TOGGLE_COLUMN_WIDTH);
+        t.getColumnModel().getColumn(0).setMinWidth(UIScale.scale(TOGGLE_COLUMN_WIDTH));
         t.getColumnModel().getColumn(0).setCellRenderer(new ToggleRenderer(t.getDefaultRenderer(Boolean.class)));
         t.getColumnModel().getColumn(1).setCellRenderer(new ActionRenderer());
-        t.setPreferredScrollableViewportSize(new Dimension(360, 260));
+        t.setPreferredScrollableViewportSize(UIScale.scale(new Dimension(360, 260)));
 
         t.addMouseListener(new MouseAdapter() {
             @Override
@@ -381,11 +382,11 @@ final class NotificationsPanel extends JPanel {
             if (row.isHeading()) {
                 setFont(base.deriveFont(Font.BOLD));
                 setForeground(selected ? table.getSelectionForeground() : table.getForeground());
-                setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
+                setBorder(new ScaledEmptyBorder(2, 2, 2, 2));
                 setToolTipText(null);
                 return this;
             }
-            setBorder(BorderFactory.createEmptyBorder(2, 18, 2, 2));
+            setBorder(new ScaledEmptyBorder(2, 18, 2, 2));
             setFont(base.deriveFont(working.isImportant(row.event) ? Font.BOLD : Font.PLAIN));
             boolean silent = !sounds.hasSound(row.event);
             setForeground(selected ? table.getSelectionForeground()

ts3-client/swing/src/main/java/com/ts3client/ui/ReasonDialog.java

@@ -1,6 +1,7 @@
 package com.ts3client.ui;
 
-import javax.swing.BorderFactory;
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+
 import javax.swing.BoxLayout;
 import javax.swing.JComponent;
 import javax.swing.JLabel;
@@ -54,7 +55,7 @@ final class ReasonDialog {
     static JLabel label(String text) {
         JLabel label = new JLabel(text);
         label.setAlignmentX(Component.LEFT_ALIGNMENT);
-        label.setBorder(BorderFactory.createEmptyBorder(0, 0, 4, 0));
+        label.setBorder(new ScaledEmptyBorder(0, 0, 4, 0));
         return label;
     }
 

ts3-client/swing/src/main/java/com/ts3client/ui/ServerGroupsDialog.java

@@ -1,10 +1,11 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.net.ClientEntry;
 import com.ts3client.net.Group;
 import com.ts3client.net.TeamspeakConnection;
 
-import javax.swing.BorderFactory;
 import javax.swing.BoxLayout;
 import javax.swing.GrayFilter;
 import javax.swing.ImageIcon;
@@ -48,10 +49,10 @@ final class ServerGroupsDialog extends JDialog {
 
         list.setLayout(new BoxLayout(list, BoxLayout.Y_AXIS));
         JScrollPane scroll = new JScrollPane(list);
-        scroll.setPreferredSize(new Dimension(280, 360));
+        scroll.setPreferredSize(UIScale.scale(new Dimension(280, 360)));
         scroll.getVerticalScrollBar().setUnitIncrement(16);
 
-        header.setBorder(BorderFactory.createEmptyBorder(8, 10, 4, 10));
+        header.setBorder(new ScaledEmptyBorder(8, 10, 4, 10));
         header.setHorizontalAlignment(SwingConstants.LEFT);
 
         JButton close = new JButton("Close");

ts3-client/swing/src/main/java/com/ts3client/ui/ServerTabPane.java

@@ -1,5 +1,8 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.BorderFactory;
 import javax.swing.JButton;
 import javax.swing.JComponent;
@@ -150,9 +153,9 @@ final class ServerTabPane extends JPanel {
 
     /** A tab's label: title, microphone marker and a close button. */
     private JComponent buildTabComponent(ServerTab tab, boolean hasMic) {
-        JPanel cell = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 0));
+        JPanel cell = new JPanel(new FlowLayout(FlowLayout.LEFT, UIScale.scale(4), 0));
         cell.setOpaque(false);
-        cell.setBorder(BorderFactory.createEmptyBorder(1, 0, 1, 0));
+        cell.setBorder(new ScaledEmptyBorder(1, 0, 1, 0));
 
         JLabel label = new JLabel(tab.title(), hasMic ? Icons.micActiveSmall() : null, JLabel.LEADING);
         label.setFont(Theme.uiFont());
@@ -175,7 +178,7 @@ final class ServerTabPane extends JPanel {
         close.setContentAreaFilled(false);
         close.setMargin(new Insets(0, 0, 0, 0));
         close.setForeground(Theme.chatSystem());
-        close.setPreferredSize(new Dimension(14, 14));
+        close.setPreferredSize(UIScale.scale(new Dimension(14, 14)));
         close.setToolTipText("Close this connection");
         close.addActionListener(e -> listener.closeTab(tab));
         cell.add(close);

ts3-client/swing/src/main/java/com/ts3client/ui/ServerTreePanel.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.config.Settings;
 import com.ts3client.contacts.ContactStore;
 import com.ts3client.contacts.ContactType;
@@ -168,7 +169,7 @@ public final class ServerTreePanel extends JScrollPane {
             ui.setLeftChildIndent(4);
             ui.setRightChildIndent(10);
         }
-        tree.setRowHeight(20);
+        tree.setRowHeight(UIScale.scale(20));
         tree.setBackground(Theme.treeBg());
         tree.setFont(Theme.uiFont());
         ServerTreeCellRenderer renderer = new ServerTreeCellRenderer(id -> id == selfClientId, contacts, settings);

ts3-client/swing/src/main/java/com/ts3client/ui/SettingsDialog.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.audio.OpusParameters;
 import com.ts3client.audio.VoiceInput;
 import com.ts3client.audio.VoiceOutput;
@@ -92,8 +93,8 @@ public final class SettingsDialog extends JDialog {
         });
 
         pack();
-        setSize(new Dimension(480, 540));
+        setSize(UIScale.scale(new Dimension(480, 540)));
-        setMinimumSize(new Dimension(420, 360));
+        setMinimumSize(UIScale.scale(new Dimension(420, 360)));
         setLocationRelativeTo(owner);
     }
 

ts3-client/swing/src/main/java/com/ts3client/ui/Spinners.java

@@ -1,5 +1,7 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
+
 import javax.swing.JSpinner;
 import java.awt.Dimension;
 
@@ -19,7 +21,7 @@ final class Spinners {
     static JSpinner compact(JSpinner spinner) {
         JSpinner.NumberEditor editor = new JSpinner.NumberEditor(spinner, "#");
         spinner.setEditor(editor);
-        Dimension size = new Dimension(WIDTH, spinner.getPreferredSize().height);
+        Dimension size = new Dimension(UIScale.scale(WIDTH), spinner.getPreferredSize().height);
         spinner.setPreferredSize(size);
         spinner.setMaximumSize(size);
         return spinner;

ts3-client/swing/src/main/java/com/ts3client/ui/StatusBar.java

@@ -1,6 +1,7 @@
 package com.ts3client.ui;
 
-import javax.swing.BorderFactory;
+import com.formdev.flatlaf.util.ScaledEmptyBorder;
+
 import javax.swing.JLabel;
 import javax.swing.JPanel;
 import java.awt.BorderLayout;
@@ -14,7 +15,7 @@ final class StatusBar extends JPanel {
     StatusBar() {
         super(new BorderLayout());
         setBackground(Theme.statusBg());
-        setBorder(BorderFactory.createEmptyBorder(3, 8, 3, 8));
+        setBorder(new ScaledEmptyBorder(3, 8, 3, 8));
         statusLabel.setFont(Theme.uiFont());
         codecLabel.setFont(Theme.uiFont());
         codecLabel.setForeground(Theme.chatSystem());

ts3-client/swing/src/main/java/com/ts3client/ui/Theme.java

@@ -1,6 +1,7 @@
 package com.ts3client.ui;
 
 import com.formdev.flatlaf.ui.FlatUIUtils;
+import com.formdev.flatlaf.util.UIScale;
 
 import javax.swing.UIManager;
 import java.awt.Color;
@@ -36,7 +37,7 @@ public final class Theme {
 
     public static Font uiFont() {
         Font f = UIManager.getFont("Label.font");
-        return f != null ? f : new Font("SansSerif", Font.PLAIN, 12);
+        return f != null ? f : new Font("SansSerif", Font.PLAIN, UIScale.scale(12));
     }
 
     public static Font uiBold() {

ts3-client/swing/src/main/java/com/ts3client/ui/VoiceActivationPanel.java

@@ -1,5 +1,6 @@
 package com.ts3client.ui;
 
+import com.formdev.flatlaf.util.UIScale;
 import com.ts3client.audio.InputLevel;
 import com.ts3client.audio.OpusParameters;
 import com.ts3client.audio.VoiceInput;
@@ -105,11 +106,11 @@ final class VoiceActivationPanel extends FormPanel {
         c.gridx = 0;
         c.gridy = row;
         c.gridwidth = 2;
-        c.insets = new Insets(10, 4, 2, 4);
+        c.insets = UIScale.scale(new Insets(10, 4, 2, 4));
         add(new JLabel("Input level:"), c);
         c.gridy = ++row;
         add(meter, c);
-        c.insets = new Insets(4, 4, 4, 4);
+        c.insets = UIScale.scale(new Insets(4, 4, 4, 4));
         c.gridy = ++row;
         add(buildTestControls(), c);
         c.gridwidth = 1;

ts3-client/swing/src/test/java/com/ts3client/ui/DisplayScaleTest.java

@@ -0,0 +1,32 @@
+package com.ts3client.ui;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+class DisplayScaleTest {
+
+    private static final List<String> KWINRC = List.of(
+            "[Plugins]",
+            "Scale=9",
+            "",
+            "[Xwayland]",
+            "Scale = 1.5",
+            "",
+            "[Xwayland][Extra]",
+            "Scale=2");
+
+    @Test
+    void readsTheKeyFromItsOwnGroupOnly() {
+        assertEquals("1.5", DisplayScale.iniValue(KWINRC, "Xwayland", "Scale"));
+    }
+
+    @Test
+    void missingKeyIsNull() {
+        assertNull(DisplayScale.iniValue(KWINRC, "Xwayland", "Other"));
+        assertNull(DisplayScale.iniValue(KWINRC, "Compositing", "Scale"));
+    }
+}