Generates partial
transparency information for the current image
procedure CreateAlpha;
Description
Use CreateAlpha to convert the current image into a
partial transparency image.
When
the current image color type is:
-
COLOR_RGB, it is transformed into COLOR_RGBALPHA and
AlphaScanline becomes valid.
-
COLOR_GRAYSCALE is transformed into COLOR_GRAYSCALEALPHA and also
AlphaScanline becomes valid.
-
COLOR_PALETTE, the tRNS chunk is created
containg alpha information for the current image.
Components
> TPNGObject > Methods > CreateAlpha