如何制作透明组件。

如何制作透明组件。

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--- 如何制作透明组件。 (http://www.webasp.net/article/7/6589.htm)

-- 作者：未知
-- 发布日期： 2003-07-26

懒得写说明了，大家应该能看懂。这是一个透明面板的例子，可仿此法制作其它透明组件。有问题给我来信。8-）

希望与大家分享经验。

package com.borland.samples.welcome;

import java.awt.*;
public class MyPanel extends Panel {
  private Image bi; // offscreen image
  private Graphics big; // Graphics for the offscreen image
  public void update(Graphics g) {
    paint(g);
  }
  public void paint(Graphics g) {
    if (bi == null) { // you can't do this from the constructor
      bi = createImage(getSize().width,getSize().height);
      big = bi.getGraphics();
    }
    Rectangle area = g.getClipBounds(); // this is the area that needs to be (re)painted (no need to repaint everything)
    big.setClip(area);
    big.clearRect(area.x, area.y, area.width, area.height); // fills the area with the background color        // the next statement will call the paint methods for the other panels/components you have added to this panel        // and draw them to the offscreen image
    super.paint(big);// now draw the offscreen image to the panel
    g.drawImage(bi,area.x, area.y, area.x+area.width, area.y+area.height,area.x, area.y, area.x+area.width, area.y+area.height,this);
}
}

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