Designer - Transparent Background Color

[Tommer]

This is a bit of a technical question and requires an understanding of Alpha Channels

In Affinity Designer via the Document Setup, it's possible to set the document to have a 'Transparent Background', however if you know about Alpha Channels you know that actually even on a document with a transparent background there is still a background color. Such a background color might become evident in other software such as game engines that alpha blend into the background color.

I need to be able to change that color in the alpha channel when exporting my selection, as otherwise the background color which by default appears to be black bleeds into the texture in a game engine. Is there a way to do this in Affinity Designer?

[lepr]

14 hours ago, Tommer said:

This is a bit of a technical question and requires an understanding of Alpha Channels

In Affinity Designer via the Document Setup, it's possible to set the document to have a 'Transparent Background', however if you know about Alpha Channels you know that actually even on a document with a transparent background there is still a background color. Such a background color might become evident in other software such as game engines that alpha blend into the background color.

I need to be able to change that color in the alpha channel when exporting my selection, as otherwise the background color which by default appears to be black bleeds into the texture in a game engine. Is there a way to do this in Affinity Designer?

You are facing one of the bizarre design decisions in the development of Affinity apps: the document flattening process sets R, G and B to zero wherever alpha is zero. It has rendered the app useless to thousands of potential customers who require R, G and B to be preserved for all pixels in an RGBA export. I can only surmise that this is done to increase the compressibility of data.

(This is not premultiplying. Premultiplying occurs for all alpha levels, whereas Affinitiy's behaviour strictly affects only the pixels where alpha is zero.)