ImageEn, unit iexBitmaps

TIEBitmap.DrawToCanvasWithAlpha

TIEBitmap.DrawToCanvasWithAlpha


Declaration


procedure DrawToCanvasWithAlpha(DestCanvas: TCanvas; xDst, yDst : integer; Transparency: integer; Opacity: double);


Description


Draws the whole bitmap to the specified DestCanvas canvas, at coordinates xDst, yDst with parameters:
Transparency specifies the transparency value (0 to 255).
Opacity specifies the opacity (0 to 1.0).

This functions reads the destination canvas pixels and merges them with image using the alpha channel mask.

Note: This is a simplified version of RenderToCanvasWithAlpha


Opacity vs Transparency


Both the Opacity and Transparency parameters provide the same functionality. Transparency is the traditional ImageEn value, whereas Opacity provides easier PSD compatibility.
While they can be used in combination, generally only one will be used, i.e. leave Opacity=1 and make use of transparency, or alternatively, leave Transparency=255 and make use of Opacity. For example, for 50% opacity: Transparency = 255 and Opacity = 0.5, or Transparency = 128 and Opacity = 1.0


See Also


- RenderToCanvasWithAlpha
- DrawToCanvas