设置Shell的透明度

Eclipse3.4中setAlpha方法详解

最新推荐文章于 2022-12-25 16:09:47 发布

原创最新推荐文章于 2022-12-25 16:09:47 发布 · 678 阅读

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#shell #thread #exception #eclipse #access #system

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本文介绍了Eclipse3.4及以上版本中提供的setAlpha方法，该方法允许设置透明度范围从0（完全透明）到255（完全不透明）。文章详细解释了如何使用此方法调整窗口透明度，并提供了实现这一功能的具体代码示例。

publicc void setAlpha(int alpha)
alpha范围为0~255

从eclipse3.4开始支持此方法

/**
* Sets the receiver's alpha value which must be
* between 0 (transparent) and 255 (opaque).
* <p>
* This operation requires the operating system's advanced
* widgets subsystem which may not be available on some
* platforms.
* </p>
* @param alpha the alpha value
*
* @exception SWTException <ul>
*    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
*    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @since 3.4
*/
public void setAlpha (int alpha) {
checkWidget ();
if (!OS.IsWinCE && OS.WIN32_VERSION >= OS.VERSION (5, 1)) {
  alpha &= 0xFF;
  int bits = OS.GetWindowLong (handle, OS.GWL_EXSTYLE);
  if (alpha == 0xFF) {
   OS.SetWindowLong (handle, OS.GWL_EXSTYLE, bits & ~OS.WS_EX_LAYERED);
   int flags = OS.RDW_ERASE | OS.RDW_INVALIDATE | OS.RDW_FRAME | OS.RDW_ALLCHILDREN;
   OS.RedrawWindow (handle, null, 0, flags);
  } else {
   OS.SetWindowLong (handle, OS.GWL_EXSTYLE, bits | OS.WS_EX_LAYERED);
   OS.SetLayeredWindowAttributes (handle, 0, (byte)alpha, OS.LWA_ALPHA);
  }
}
}