TITLE:JPopupMenuを半透明にする
#navi(../)
#tags(JPopupMenu, JMenuItem, JWindow, Translucent)
RIGHT:Posted by &author(aterai); at 2012-02-27
*JPopupMenuを半透明にする [#gcc0b988]
``JPopupMenu``を半透明にします。

-&jnlp;
-&jar;
-&zip;

//#screenshot
#ref(https://lh3.googleusercontent.com/-SKQis3B-SmY/T0dd531MovI/AAAAAAAABJk/fWIZIAeE3oE/s800/TranslucentPopupMenu.png)

**サンプルコード [#yd15f03c]
#code(link){{
class TranslucentPopupMenu extends JPopupMenu{
  private static final Color ALPHA_ZERO = new Color(0, true);
  private static final Color POPUP_BACK = new Color(250,250,250,200);
  private static final Color POPUP_LEFT = new Color(230,230,230,200);
  private static final int LEFT_WIDTH = 24;
  @Override public boolean isOpaque() {
    return false;
  }
  @Override public void updateUI() {
    super.updateUI();
    boolean isNimbus = UIManager.getBorder("PopupMenu.border")==null;
    if(isNimbus) {
      setBorder(new BorderUIResource(BorderFactory.createLineBorder(Color.GRAY)));
    }
  }
  @Override public JMenuItem add(JMenuItem menuItem) {
    menuItem.setOpaque(false);
    return super.add(menuItem);
  }
  @Override public void show(Component c, int x, int y) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        Window p = SwingUtilities.getWindowAncestor(TranslucentPopupMenu.this);
        if(p!=null && p instanceof JWindow) {
          System.out.println("Heavy weight");
          JWindow w = (JWindow)p;
          if(System.getProperty("java.version").startsWith("1.6.0")) {
            w.dispose();
            if(com.sun.awt.AWTUtilities.isWindowOpaque(w)) {
              com.sun.awt.AWTUtilities.setWindowOpaque(w, false);
            }
            w.setVisible(true);
          }else{
            w.setBackground(ALPHA_ZERO);
          }
        }else{
          System.out.println("Light weight");
        }
      }
    });
    super.show(c, x, y);
  }
  @Override protected void paintComponent(Graphics g) {
    Graphics2D g2 = (Graphics2D)g.create();
    g2.setPaint(POPUP_LEFT);
    g2.fillRect(0,0,LEFT_WIDTH,getHeight());
    g2.setPaint(POPUP_BACK);
    g2.fillRect(LEFT_WIDTH,0,getWidth(),getHeight());
    g2.dispose();
    //super.paintComponent(g);
  }
}
}}

**解説 [#z80cf3e7]
上記のサンプルでは、JPopupMenuは、isOpaque()メソッドをオーバーライド、JMenuItemはsetOpaque(false) として、それぞれ透明に設定し、JPopupMenu#paintComponent(...)で、半透明の背景を描画しています。

``JPopupMenu``が親フレームの外にはみ出す場合は、``Heavyweight``の``JWindow``を使って``JPopupMenu``が表示されるので、``JWindow#setBackground(new Color(0, true))``で(``JDK 1.6.0_10``では、``com.sun.awt.AWTUtilities.setWindowOpaque(w, false)``)、``JPopupMenu#show(...)``が呼ばれるたびに、毎回(親フレームの透明度を引き継がないように?)``JWindow``自体を透明にしています。

----
- メモ: ``JPopupMenu``(ルート)が``Light weight``で、その``JMenu``から開く``JPopupMenu``(サブメニュー) が``Heavy weight``のときに半透明にならない
-- [http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7156657 Bug ID: 7156657 Version 7 doesn't support translucent popup menus against a translucent window]
-- ``JDK 1.7.0_06``などで修正された

**参考リンク [#dcc353c1]
- [http://today.java.net/pub/a/today/2008/03/18/translucent-and-shaped-swing-windows.html Translucent and Shaped Swing Windows | Java.net]
- [[JMenuなどから開くPopupMenuを半透明化>Swing/TranslucentSubMenu]]

**コメント [#bd72dc66]
- メモ: [http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7156657 Bug ID: 7156657 Version 7 doesn't support translucent popup menus against a translucent window]、[http://hg.openjdk.java.net/jdk8/jdk8/jdk/rev/4acd0211f48b jdk8/jdk8/jdk: changeset 5453:4acd0211f48b] -- [[aterai]] &new{2012-08-10 (金) 19:22:39};
-- ``JDK 1.7.0_06``で修正されている? [http://www.oracle.com/technetwork/java/javase/2col/7u6-bugfixes-1733378.html Java™ SE Development Kit 7 Update 6 Bug Fixes] -- [[aterai]] &new{2012-08-15 (水) 13:55:37};

#comment