能用gdi+ 将一jpg或bmp图片显示成半透明吗？

Question

rt

Answer 1

http://msdn.microsoft.com/msdnmag/issues/05/12/catwork/default.aspx

Answer 2

var  G:TGPGraphics;
     image:TGPImage;
     imageArr:TGPImageAttributes;
const 
  ColorMatrix: TColorMatrix =
   ((1.0, 0.0, 0.0, 0.0, 0.0),
    (0.0, 1.0, 0.0, 0.0, 0.0),
    (0.0, 0.0, 1.0, 0.0, 0.0),
    (0.0, 0.0, 0.0, 0.5, 0.0),
    (0.0, 0.0, 0.0, 0.0, 1.0));
begin
    G:=TGpGraphics.Create(Self.Canvas.Handle);
    Image:=TGpimage.Create('c:\1.bmp') 
    imageArr:=TGPImageAttributes.Create;
    imageArr.SetColorMatrix(colorMatrix, ColorMatrixFlagsDefault,ColorAdjustTypeBitmap);
    g.DrawImage(
      image,
      MakeRect(30, Height, Width, Height), // Destination rectangle
      0,                                   // Source rectangle X
      0,                                   // Source rectangle Y
      Width,                               // Source rectangle width
      Height,                              // Source rectangle height
      UnitPixel,
      imageArr
    );    
    G.free ;
    image.free ;
    imageArr.free;   
end;

Answer 3

MakeRect(30, Height, Width, Height),//////MakeRect(0,0,Width,Height);