java - 覆盖 JApplet 中的绘制方法

Question

我正在做一个项目，使 JApplet 的内容自动缩放到 html 中指定的大小。我意识到这是布局管理器的用途，但是由于不允许我重写整个小程序结构，所以我决定尝试覆盖绘画并简单地将图形对象的 AffineTransform 设置为适当缩放的版本，然后在顶部容器中捕获鼠标事件，并使用适当的缩放变换将它们缩小。我现在卡在绘图部分了。当在 Web 浏览器中查看时，它会正确渲染缩放版本一次，然后图像会缩小回其原始大小。此外，JApplet 中的 paint 方法似乎只被调用过一次。这是我的代码的裁剪版本，着重于该问题。任何帮助，将不胜感激。提前致谢。

import javax.swing.JApplet;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;

public class Test extends JApplet
{
        public static final int ORIGINAL_APPLET_WIDTH = 1024;
        public static final int ORIGINAL_APPLET_HEIGHT = 800;
        private AffineTransform scalingTransform;
        private AffineTransform inverseScalingTransform;
 @Override
 public void init()
 {
            double xFactor = ((double)(this.getWidth()))/((double)(Test.ORIGINAL_APPLET_WIDTH));
            double yFactor = ((double)(this.getHeight()))/((double)(Test.ORIGINAL_APPLET_HEIGHT));
            this.scalingTransform = new AffineTransform();
            this.inverseScalingTransform = new AffineTransform();
            this.scalingTransform.scale(xFactor,yFactor);
            this.inverseScalingTransform.scale(1D/xFactor,1D/yFactor);
 }
    @Override
    public void paint(Graphics g)
    {
        ((Graphics2D)g).setTransform(Test.this.scalingTransform);
        super.paint(g);
    }
}

Answer 1

经过大量研究，我发现问题在于 JApplet 的绘制方法并不经常被调用。相反，内容 Pane 有自己的绘图表面，所以我只需更换内容 Pane 即可上传。这是我做的方式:

@Override
    public void init()
    {
            double xFactor = ((double)(this.getWidth()))/((double)(qt.ORIGINAL_APPLET_WIDTH));
            double yFactor = ((double)(this.getHeight()))/((double)(qt.ORIGINAL_APPLET_HEIGHT));
            this.scalingTransform = new AffineTransform();
            this.inverseScalingTransform = new AffineTransform();
            this.scalingTransform.scale(xFactor,yFactor);
            this.inverseScalingTransform.scale(1D/xFactor,1D/yFactor);
            JPanel drawScale = new JPanel()
            {
                @Override
                public void paint(Graphics g)
                {
                    ((Graphics2D)g).setTransform(Test.this.scalingTransform);
                    super.paint(g);
                }
                @Override
                public void paintAll(Graphics g)
                {
                    ((Graphics2D)g).setTransform(Test.this.scalingTransform);
                    super.paintAll(g);
                }
                @Override
                public void paintComponents(Graphics g)
                {
                    ((Graphics2D)g).setTransform(Test.this.scalingTransform);
                    super.paintComponents(g);
                }
                @Override
                public void paintComponent(Graphics g)
                {
                    ((Graphics2D)g).setTransform(Test.this.scalingTransform);
                    super.paintComponents(g);
                }
            };
            Container oldPane = this.getContentPane();
            drawScale.setLayout(oldPane.getLayout());

            this.setContentPane(drawScale);
}

这些绘画方法当然是小程序中的方法的补充。