//dirtyRect是绝对坐标（在多屏的情况下）
public virtual void SetHBitmap(IntPtr hBitmap, Rectangle newWindowBounds, Point drawAt, Rectangle dirtyRect,byte opacity)
{
// IntPtr screenDc = Win32.GDI32.GetDC(IntPtr.Zero);
IntPtr memDc = Win32.GDI32.CreateCompatibleDC(IntPtr.Zero);
IntPtr oldBitmap = IntPtr.Zero;
try
{
oldBitmap = Win32.GDI32.SelectObject(memDc, hBitmap);
var winSize = new Native.Size(newWindowBounds.Width, newWindowBounds.Height);
var winPos = new Native.Point(newWindowBounds.X, newWindowBounds.Y);
var drawBmpAt = new Native.Point(drawAt.X, drawAt.Y);
var blend = new Native.BLENDFUNCTION { BlendOp = GDI32.AC_SRC_OVER, BlendFlags = 0, SourceConstantAlpha = opacity, AlphaFormat = GDI32.AC_SRC_ALPHA };
var updateInfo = new Native.UPDATELAYEREDWINDOWINFO();
updateInfo.cbSize = (uint) Marshal.SizeOf(typeof (Native.UPDATELAYEREDWINDOWINFO));
updateInfo.dwFlags = GDI32.ULW_ALPHA;
updateInfo.hdcDst = IntPtr.Zero;//Native.GetDC(IntPtr.Zero);//IntPtr.Zero; //ScreenDC
updateInfo.hdcSrc = memDc;
// dirtyRect.X -= _bounds.X;
// dirtyRect.Y -= _bounds.Y;
//dirtyRect.Offset(-_bounds.X, -_bounds.Y);
var dirRect = new GDI32.RECT(dirtyRect.X,dirtyRect.Y,dirtyRect.Right,dirtyRect.Bottom);
unsafe
{
updateInfo.pblend = &blend;
updateInfo.pptDst = &winPos;
updateInfo.psize = &winSize;
updateInfo.pptSrc = &drawBmpAt;
updateInfo.prcDirty = &dirRect;
}
Native.UpdateLayeredWindowIndirect(Handle, ref updateInfo);
// Debug.Assert(Native.GetLastError() == 0);
//Native.UpdateLayeredWindow(Handle, IntPtr.Zero, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, GDI32.ULW_ALPHA);
}
finally
{
//GDI32.ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
GDI32.SelectObject(memDc, oldBitmap);
//Windows.DeleteObject(hBitmap); // The documentation says that we have to use the Windows.DeleteObject... but since there is no such method I use the normal DeleteObject from Win32 GDI and it's working fine without any resource leak.
//Win32.DeleteObject(hBitmap);
}
GDI32.DeleteDC(memDc);
}
}