ts3java/ts3-client/swing/src/main/java/com/ts3client/ui/AvatarView.java

package com.ts3client.ui;

import javax.swing.JComponent;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.Toolkit;

/**
 * Paints an avatar scaled to fit, keeping its aspect ratio. The image is a Toolkit
 * image drawn with this component as its observer, so an animated GIF keeps playing:
 * each decoded frame triggers a repaint.
 */
final class AvatarView extends JComponent {

    private final int boxSize;
    private Image image;
    private int imageWidth = -1;
    private int imageHeight = -1;

    AvatarView(int boxSize) {
        this.boxSize = boxSize;
        setPreferredSize(new Dimension(boxSize, boxSize));
        setMinimumSize(getPreferredSize());
    }

    /** @param data the encoded image, or {@code null} to show nothing */
    void setImage(byte[] data) {
        if (image != null) image.flush();
        image = data == null ? null : Toolkit.getDefaultToolkit().createImage(data);
        imageWidth = imageHeight = -1;
        repaint();
    }

    boolean hasImage() {
        return image != null;
    }

    @Override
    protected void paintComponent(Graphics g) {
        if (image == null) return;
        if (imageWidth < 0 || imageHeight < 0) {
            // Unknown until the header is decoded; the observer repaints once it is.
            imageWidth = image.getWidth(this);
            imageHeight = image.getHeight(this);
            if (imageWidth < 0 || imageHeight < 0) return;
        }
        double scale = Math.min(1.0, 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();
        try {
            g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g2.drawImage(image, (getWidth() - w) / 2, (getHeight() - h) / 2, w, h, this);
        } finally {
            g2.dispose();
        }
    }

    int boxSize() {
        return boxSize;
    }
}