Zoom the text of the log, check, available and bandmap windows

Ctrl+wheel and Ctrl+plus / Ctrl+minus change the text size of the
window in front, and Ctrl+0 puts it back. Each size is kept in the
settings file.

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

src/Nonemm.App/Configuration/Settings.cs

@@ -63,6 +63,14 @@ public sealed record Settings
     /// The height of the callsigns on the bandmap, in points.
     public int BandmapTextSize { get; init; } = 12;
 
+    /// The text size of the log, check and available windows, in points. Ctrl
+    /// with the mouse wheel or plus and minus changes the one in front.
+    public int LogFontSize { get; init; } = 12;
+
+    public int CheckFontSize { get; init; } = 14;
+
+    public int AvailableFontSize { get; init; } = 13;
+
     /// Moves each incoming CW spot by a few tens of hertz, so the operator has
     /// to find the station by ear. N1MM calls it randomising.
     public bool RandomizeSpots { get; init; }

src/Nonemm.App/Windows/AvailableWindow.axaml.cs

@@ -1,3 +1,4 @@
+using Nonemm.App.Configuration;
 using Nonemm.App.Theming;
 using Avalonia.Controls;
 using Avalonia.Input;
@@ -23,6 +24,11 @@ public sealed partial class AvailableWindow : RefreshableWindow
         this.session = session;
         this.tune = tune;
         InitializeComponent();
+        _ = new FontZoom(this, new Settings().AvailableFontSize, () => session.Settings.AvailableFontSize, size =>
+        {
+            session.Save(session.Settings with { AvailableFontSize = size });
+            Refresh();
+        });
         MultsOnlyBox.IsCheckedChanged += (_, _) => Refresh();
         session.Bandmap.Changed += (_, _) => Dispatcher.UIThread.Post(Refresh);
         Refresh();
@@ -70,7 +76,7 @@ public sealed partial class AvailableWindow : RefreshableWindow
         panel.Children.Add(new TextBlock
         {
             Text = $"{band.Name} {stations.Count}",
-            FontSize = 11,
+            FontSize = session.Settings.AvailableFontSize - 2,
             Opacity = 0.7,
             Margin = new Avalonia.Thickness(0, 0, 0, 4),
         });
@@ -87,7 +93,7 @@ public sealed partial class AvailableWindow : RefreshableWindow
         {
             Text = Label(station),
             FontFamily = Fonts.Mono,
-            FontSize = 13,
+            FontSize = session.Settings.AvailableFontSize,
             Foreground = Verdicts.Colour(station.Verdict),
             HorizontalAlignment = HorizontalAlignment.Left,
             Cursor = new Cursor(StandardCursorType.Hand),

src/Nonemm.App/Windows/BandmapWindow.axaml.cs

@@ -1,3 +1,4 @@
+using Nonemm.App.Configuration;
 using Avalonia.Media;
 using Avalonia.Threading;
 using Nonemm.Contests;
@@ -25,9 +26,6 @@ public sealed partial class BandmapWindow : RefreshableWindow
         ("whole band", Frequency.Zero),
     ];
 
-    private const int MinTextSize = 8;
-    private const int MaxTextSize = 24;
-
     private readonly AppSession session;
     private readonly Action<Frequency, string> tune;
 
@@ -46,6 +44,11 @@ public sealed partial class BandmapWindow : RefreshableWindow
             Array.FindIndex(Spans, s => s.Span.Hertz == session.Settings.BandmapSpanHertz));
         CentreBox.IsChecked = session.Settings.BandmapCentred;
         View.TextSize = session.Settings.BandmapTextSize;
+        _ = new FontZoom(this, new Settings().BandmapTextSize, () => (int)View.TextSize, size =>
+        {
+            View.TextSize = size;
+            SaveView();
+        });
         SmallerButton.Click += (_, _) => ResizeText(-1);
         LargerButton.Click += (_, _) => ResizeText(1);
         SpanBox.SelectionChanged += (_, _) => SaveView();
@@ -60,7 +63,7 @@ public sealed partial class BandmapWindow : RefreshableWindow
 
     private void ResizeText(int by)
     {
-        View.TextSize = Math.Clamp(View.TextSize + by, MinTextSize, MaxTextSize);
+        View.TextSize = Math.Clamp(View.TextSize + by, FontZoom.Smallest, FontZoom.Largest);
         SaveView();
     }
 

src/Nonemm.App/Windows/CheckWindow.axaml.cs

@@ -1,3 +1,4 @@
+using Nonemm.App.Configuration;
 using Nonemm.App.Theming;
 using Avalonia.Controls;
 using Avalonia.Layout;
@@ -17,6 +18,11 @@ public sealed partial class CheckWindow : RefreshableWindow
     {
         this.session = session;
         InitializeComponent();
+        _ = new FontZoom(this, new Settings().CheckFontSize, () => session.Settings.CheckFontSize, size =>
+        {
+            session.Save(session.Settings with { CheckFontSize = size });
+            Refresh();
+        });
         Refresh();
     }
 
@@ -37,19 +43,19 @@ public sealed partial class CheckWindow : RefreshableWindow
         int at = 0;
         foreach (CheckColumn column in columns)
         {
-            Control panel = BuildColumn(column);
+            Control panel = BuildColumn(column, session.Settings.CheckFontSize);
             Grid.SetColumn(panel, at++);
             Columns.Children.Add(panel);
         }
     }
 
-    private static Control BuildColumn(CheckColumn column)
+    private static Control BuildColumn(CheckColumn column, int fontSize)
     {
         StackPanel panel = new() { Margin = new Avalonia.Thickness(0, 0, 8, 0) };
         panel.Children.Add(new TextBlock
         {
             Text = $"{Heading(column.Source)} {Count(column)}",
-            FontSize = 11,
+            FontSize = fontSize - 3,
             Opacity = 0.7,
             Margin = new Avalonia.Thickness(0, 0, 0, 4),
         });
@@ -59,7 +65,7 @@ public sealed partial class CheckWindow : RefreshableWindow
             {
                 Text = candidate.Text,
                 FontFamily = Fonts.Mono,
-                FontSize = 14,
+                FontSize = fontSize,
                 Foreground = Verdicts.Colour(candidate.Verdict),
                 HorizontalAlignment = HorizontalAlignment.Left,
             });

src/Nonemm.App/Windows/FontZoom.cs

@@ -0,0 +1,70 @@
+using Avalonia.Input;
+using Avalonia.Interactivity;
+
+namespace Nonemm.App.Windows;
+
+/// Ctrl+wheel and Ctrl+plus / Ctrl+minus on a window change the size of its
+/// text, and Ctrl+0 puts it back to `normal`. The handlers run before the controls inside get the event, so a grid
+/// or a scroll viewer does not take the wheel first.
+public sealed class FontZoom
+{
+    public const int Smallest = 8;
+    public const int Largest = 32;
+
+    private readonly int normal;
+    private readonly Func<int> size;
+    private readonly Action<int> apply;
+
+    public FontZoom(InputElement target, int normal, Func<int> size, Action<int> apply)
+    {
+        this.normal = normal;
+        this.size = size;
+        this.apply = apply;
+        target.AddHandler(InputElement.PointerWheelChangedEvent, OnWheel, RoutingStrategies.Tunnel);
+        target.AddHandler(InputElement.KeyDownEvent, OnKeyDown, RoutingStrategies.Tunnel);
+    }
+
+    private void OnWheel(object? sender, PointerWheelEventArgs e)
+    {
+        if (e.KeyModifiers.HasFlag(KeyModifiers.Control) && e.Delta.Y != 0)
+        {
+            Step(e.Delta.Y > 0 ? 1 : -1);
+            e.Handled = true;
+        }
+    }
+
+    private void OnKeyDown(object? sender, KeyEventArgs e)
+    {
+        if (!e.KeyModifiers.HasFlag(KeyModifiers.Control))
+        {
+            return;
+        }
+        if (e.Key is Key.D0 or Key.NumPad0)
+        {
+            Set(normal);
+            e.Handled = true;
+            return;
+        }
+        int by = e.Key switch
+        {
+            Key.OemPlus or Key.Add => 1,
+            Key.OemMinus or Key.Subtract => -1,
+            _ => 0,
+        };
+        if (by != 0)
+        {
+            Step(by);
+            e.Handled = true;
+        }
+    }
+
+    private void Step(int by) => Set(Math.Clamp(size() + by, Smallest, Largest));
+
+    private void Set(int wanted)
+    {
+        if (wanted != size())
+        {
+            apply(wanted);
+        }
+    }
+}

src/Nonemm.App/Windows/LogWindow.axaml

@@ -11,7 +11,7 @@
              columns are sized from the width of the text in this font -->
         <Style Selector="DataGridCell TextBlock">
           <Setter Property="FontFamily" Value="{x:Static theming:Fonts.Mono}" />
-          <Setter Property="FontSize" Value="12" />
+          <Setter Property="FontSize" Value="{DynamicResource LogFontSize}" />
           <!-- half of what the theme leaves either side of the text, so more
                columns fit across the window -->
           <Setter Property="Margin" Value="6,0" />
@@ -44,7 +44,7 @@
              sideways as the box opens -->
         <Style Selector="DataGridCell TextBox">
           <Setter Property="FontFamily" Value="{x:Static theming:Fonts.Mono}" />
-          <Setter Property="FontSize" Value="12" />
+          <Setter Property="FontSize" Value="{DynamicResource LogFontSize}" />
           <Setter Property="MinHeight" Value="0" />
           <Setter Property="Margin" Value="0" />
           <Setter Property="Padding" Value="6,0" />
@@ -53,11 +53,11 @@
         </Style>
       </Grid.Styles>
       <DataGrid Name="Rows" Grid.Row="0" GridLinesVisibility="Horizontal" CanUserSortColumns="True"
-                CanUserReorderColumns="True" FontSize="12" FontFamily="{x:Static theming:Fonts.Mono}" />
+                CanUserReorderColumns="True" FontFamily="{x:Static theming:Fonts.Mono}" />
       <GridSplitter Grid.Row="1" Height="5" ResizeDirection="Rows" Background="{DynamicResource DataGridGridLinesBrush}" />
       <DataGrid Name="Earlier" Grid.Row="2" IsReadOnly="True" GridLinesVisibility="Horizontal"
                 CanUserSortColumns="False" HeadersVisibility="None"
-                FontSize="12" FontFamily="{x:Static theming:Fonts.Mono}" />
+                FontFamily="{x:Static theming:Fonts.Mono}" />
     </Grid>
   </DockPanel>
 </local:RefreshableWindow>

src/Nonemm.App/Windows/LogWindow.axaml.cs

@@ -1,3 +1,4 @@
+using Nonemm.App.Configuration;
 using System.Collections.ObjectModel;
 using Avalonia;
 using Avalonia.Collections;
@@ -63,7 +64,25 @@ public sealed partial class LogWindow : RefreshableWindow
         };
         Colour(Rows);
         Colour(Earlier);
+        ApplyFontSize();
+        _ = new FontZoom(this, new Settings().LogFontSize, () => session.Settings.LogFontSize, size =>
+        {
+            session.Save(session.Settings with { LogFontSize = size });
+            ApplyFontSize();
+            builtFor = "";
             Refresh();
+        });
+        Refresh();
+    }
+
+    /// The cells take their size from the `LogFontSize` resource, and the
+    /// grids need it too because the column widths are measured from it.
+    private void ApplyFontSize()
+    {
+        double size = session.Settings.LogFontSize;
+        Resources["LogFontSize"] = size;
+        Rows.FontSize = size;
+        Earlier.FontSize = size;
     }
 
     /// What the operator picked. The grid raises this for the picks this window