BLEND_ALPHA_OVER deprecation comment: "multiply alpha" ?

Development Coding synfig
1

I was planning to develop a new blending method for my own needs – very similar to the MULTIPLY blend mode, but setting alpha to [tt]A.alpha*B.alpha[/tt].

a
But by looking at the code I saw that:

github.com/s-leroux/synfig/blob … lor.h#L294

		BLEND_ALPHA_OVER=19,		//!< \deprecated multiply alphas and then straight blends using the amount

This feels like referring to something similar to what I had in mind. But – as a SynfigStudio 1.0.2 user – I don’t understand exactly what this comment is talking about.

Any clue or pointer would be welcome;)

2

I’m not sure why it’s deprecated and the comment seems to be wrong: you can try Alpha Over blending method and it clearly does something else. It seems to be subtracting alpha or something similar.

3

Yeah, after having dig a little bit deeper into the code, that comment still seems very puzzling. I don’t see anything close to what ALPHA_OVER is supposed to do.

Lets assume for now the comments is wrong :wink: