multipliers to the color components of the source
multipliers to the color components of the destination
operation to perform on the multiplied color components of the source and destination
multiplier to the alpha component of the source
multiplier to the color component of the destination
operation to perform on the multiplied alpha components of the source and destination
dsdl2.SDLException if impossible to compose the dsdl2.BlendMode
Composes a custom dsdl2.BlendMode based on certain attributes for blending which wraps SDL_ComposeCustomBlendMode (from SDL 2.0.6)