Blending
Blending functions combine the colors of two visual sources.
add() — Addition
Adds the color values. The result is usually brighter.
mult() — Multiplication
Multiplies the color values. The result is usually darker.
diff() — Difference
Computes the absolute difference between colors.
blend() — Smooth blending
Linearly interpolates between two sources.
layer() — Layering
Puts one source on top of another using the alpha channel.
mask() — Masking
Uses the second source as a transparency mask.