fb-layer-modes
Simple demo to show how to implement layer blending modes such as the ones found in the GIMP.
There are 31 of them implemented, shown here in alphabetic order: Addition Alpha Average Brighten Brightness Burn Darken DarkenOnly Desaturate Difference Dissolve Divide Dodge Exclusion Freeze Glow GrainExtract GrainMerge GrayScale HardLight Heat LightenOnly Multiply Negative Overlay Reflect Screen SoftLight Stamp Substract Tint
The 'layer modes.bas' contains a simple demo showing all of them (see the comments in the code for the keybindings) And 'benchmark.bas' does a simple test to compare the blitter with the equivalent functionality implemented using FB's PUT statement with the custom mode. Only 'Alpha' blending mode is compared, which is the basic alpha compositing with support for opacity.
Have fun!