Question

我正在尝试使用swingx中的ShadowRenderer为面板创建阴影。这是我到目前为止所做的：

在面板构造函数中创建一次阴影渲染器。

public CustomPanel() {
    super();
    renderer = new ShadowRenderer(20, 0.5f, Color.RED);
}

每次调整面板大小时，我都会重新计算新阴影。

@Override
public void setBounds(int x, int y, int width, int height) {
    super.setBounds(x, y, width, height);
    shadow = renderer.createShadow(GraphicsUtilities.createCompatibleTranslucentImage(width, height));
}

然后我覆盖我的面板的paintComponent方法来绘制生成的图像：

protected void paintComponent(Graphics g) {
    Graphics2D g2 = (Graphics2D) g.create();

    g2.drawImage(shadow, 0, 0, null);
    //super.paintComponent(g);
}

但shadow图片从未显示过。为什么？我阅读了this和我除了我的代码以绘制阴影渲染器生成的一种“阴影”图像。

Answer 1

这里是shortened example of DropShadowDemo

JXPanel panel = new JXPanel() {
    int shadowSize = 40;
    ShadowRenderer renderer = new ShadowRenderer(shadowSize/ 2, 0.5f, Color.RED); 
    BufferedImage imageA = 
            XTestUtils.loadDefaultImage("moon.jpg");
    BufferedImage shadow;

    @Override
    public void setBounds(int x, int y, int width, int height) {
        super.setBounds(x, y, width, height);
        // not really needed here - the base image size is fixed
        shadow = renderer.createShadow(imageA); 
    }

    @Override
    protected void paintComponent(Graphics g) {
        int x = (getWidth() - imageA.getWidth()) / 2;
        int y = (getHeight() - imageA.getHeight()) / 2;

        Graphics2D g2 = (Graphics2D) g;
        Composite c = g2.getComposite();
        g2.setComposite(AlphaComposite.SrcOver.derive(renderer.getOpacity()));
        g.drawImage(shadow, x - shadowSize / 2, y - shadowSize / 2, null);
        g2.setComposite(c);
        g.drawImage(imageA, x, y, null);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(imageA.getWidth() + shadowSize, imageA.getHeight()+ shadowSize);
    }

};
panel.setOpaque(false);

为什么我看不到使用此ShadowRenderer生成的阴影？

1 个答案: