Var

  Matrix: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, 0.4, 0.0),

    (0.0, 0.0, 0.0, 0.0, 1.0));

 

Procedure AlphaDraw(AFrom,AAlpha,ATo:TBitmap;AWidth,AHeight,APercent:Integer);

Var

  Graphics:GPGraphics;

  Bitmap:GPBitmap;

  Attributes:GPImageAttributes;

Begin

  Matrix[3,3]:=APercent/100;

  GdipCreateFromHDC(ATo.Canvas.Handle,Graphics);

  GdipCreateBitmapFromHBITMAP(AFrom.Handle,AFrom.Palette,Bitmap);

  GdipDrawImageRectI(Graphics,Bitmap,0,0,AWidth,AHeight);

  GdipDisposeImage(Bitmap);

  GdipCreateBitmapFromHBITMAP(AAlpha.Handle,AAlpha.Palette,Bitmap);

  GdipCreateImageAttributes(Attributes);

  GdipSetImageAttributesColorMatrix(Attributes,ColorAdjustTypeBitmap,True,@Matrix,Nil,ColorMatrixFlagsDefault);

  GdipDrawImageRectRect(Graphics,Bitmap,0,0,AWidth,AHeight,0,0,AWidth,AHeight,UnitPixel,Attributes,Nil,Nil);

  GdipDisposeImageAttributes(Attributes);

  GdipDisposeImage(Bitmap);

  GdipDeleteGraphics(Graphics);

End;

Image3.Canvas.FillRect(Image3.ClientRect); // Image3 не должен быть пустым

AlphaDraw(Image1.Picture.Bitmap,Image2.Picture.Bitmap,Image3.Picture.Bitmap,128,128,50);