Draws contents of this canvas onto another canvas with pixel blending.

public procedure DrawBlend(const SrcRect: TRect; 
                           DestCanvas: TImagingCanvas; 
                           DestX: Integer; 
                           DestY: Integer; 
                           SrcFactor: TBlendingFactor; 
                           DestFactor: TBlendingFactor);

Blending factors are chosen using TBlendingFactor parameters. Resulting destination pixel color is: SrcColor * SrcFactor + DstColor * DstFactor