public static extern Boolean AlphaBlend( IntPtr hdcDest, Int32 nXOriginDest, Int32 nYOriginDest, Int32 nWdithDest, Int32 nHeightDest, IntPtr hdcSrc, Int32 nXOriginSrc, Int32 nYOriginSrc, Int32 nWidthSrc, Int32 nHeightSrc, BLENDFUNCTION blendFunction );
public static extern bool AlphaBlend( IntPtr hdcDest, int nXOriginDest, int nYOriginDest, int nWdithDest, int nHeightDest, IntPtr hdcSrc, int nXOriginSrc, int nYOriginSrc, int nWidthSrc, int nHeightSrc, BLENDFUNCTION blendFunction );
public static extern Boolean UpdateLayeredWindow( IntPtr hWnd, IntPtr hdcDst, ref POINT pptDst, ref SIZE psize, IntPtr hdcSrc, ref POINT pptSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags );
private new void Invalidate(Rectangle rect)
{
Bitmap memoryBitmap = new Bitmap(
rect.Size.Width,
rect.Size.Height,
PixelFormat.Format32bppArgb
);
using (Graphics g = Graphics.FromImage(memoryBitmap))
{
Rectangle area = new Rectangle(0, 0, rect.Size.Width, rect.Size.Height);
this.RaisePaintEvent(g, area);
IntPtr hDC = User32.GetDC(IntPtr.Zero);
IntPtr memoryDC = Gdi32.CreateCompatibleDC(hDC);
IntPtr hBitmap = memoryBitmap.GetHbitmap(Color.FromArgb(0));
IntPtr oldBitmap = Gdi32.SelectObject(memoryDC, hBitmap);
SIZE size;
size.cx = rect.Size.Width;
size.cy = rect.Size.Height;
POINT location;
location.x = rect.Location.X;
location.y = rect.Location.Y;
POINT sourcePoint;
sourcePoint.x = 0;
sourcePoint.y = 0;
BLENDFUNCTION blend = new BLENDFUNCTION();
blend.AlphaFormat = (byte)WinGdi.AC_SRC_ALPHA;
blend.BlendFlags = 0;
blend.BlendOp = (byte)WinGdi.AC_SRC_OVER;
blend.SourceConstantAlpha = (byte)(255 - ((this.Opacity * 255) / 100));
User32.UpdateLayeredWindow(
this.Handle,
hDC,
ref location,
ref size,
memoryDC,
ref sourcePoint,
0,
ref blend,
WinUser.ULW_ALPHA
);
Gdi32.SelectObject(memoryDC, oldBitmap);
User32.ReleaseDC(IntPtr.Zero, hDC);
Gdi32.DeleteObject(hBitmap);
Gdi32.DeleteDC(memoryDC);
}
}
