# BLEND\_ALPHA\_OVER deprecation comment: "multiply alpha" ?

**URL:** <https://forums.synfig.org/t/blend-alpha-over-deprecation-comment-multiply-alpha/4159>\
**Category:** Coding synfig\
**Created:** [February 26, 2017, 7:23pm UTC](https://forums.synfig.org/t/blend-alpha-over-deprecation-comment-multiply-alpha/4159 "2017-02-26T19:23:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Sylvain\_Leroux](https://forums.synfig.org/user_avatar/forums.synfig.org/sylvain_leroux/32/3870_2.png) [@Sylvain\_Leroux](https://forums.synfig.org/u/Sylvain_Leroux)\
**Post date:** [February 26, 2017, 7:23pm UTC](https://forums.synfig.org/t/blend-alpha-over-deprecation-comment-multiply-alpha/4159/1 "2017-02-26T19:23:32Z")

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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](https://github.com/s-leroux/synfig/blob/master/synfig-core/src/synfig/color/color.h#L294)

```auto
		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;)

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**Author:** ![caryoscelus](https://forums.synfig.org/user_avatar/forums.synfig.org/caryoscelus/32/182_2.png) [@caryoscelus](https://forums.synfig.org/u/caryoscelus)\
**Post date:** [February 26, 2017, 8:23pm UTC](https://forums.synfig.org/t/blend-alpha-over-deprecation-comment-multiply-alpha/4159/2 "2017-02-26T20:23:24Z")

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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.

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**Author:** ![Sylvain\_Leroux](https://forums.synfig.org/user_avatar/forums.synfig.org/sylvain_leroux/32/3870_2.png) [@Sylvain\_Leroux](https://forums.synfig.org/u/Sylvain_Leroux)\
**Post date:** [February 26, 2017, 8:28pm UTC](https://forums.synfig.org/t/blend-alpha-over-deprecation-comment-multiply-alpha/4159/3 "2017-02-26T20:28:34Z")

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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 😉