save image with mask layer to file with transparency

[bitrat]

How? Seems like something that should be straight forward.

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Answering my own question here.

mask -> active layer
right click menu -> Mask to Selection
delete mask layer
image -> active layer
fill selection with key color
colors -> color to alpha [select key color]
file -> export as png

Is there a way to do this directly, without the step using color to alpha?
It would be nice if it could all be accomplished in one step.

[bitrat]

(01-24-2021, 02:36 AM)bitrat Wrote: ...

Maybe I'll try some script-fu.

[Ofnuts]

I can't wrap my head around what you are trying to do but it looks way too complicated anyway. If you use a layer mask (which you don't seem to be doing) you would skip most of this.

[bitrat]

(01-24-2021, 08:57 PM)Ofnuts Wrote: I can't wrap my head around what you are trying to do but it looks way too complicated anyway. If you use a layer mask (which you don't seem to be doing) you would skip most of this.

I am using a layer mask. That's fine inside GIMP using the native .xcf format, but I want to export a .png file with transparency, with the alpha channel matching the mask.

This seems so obvious and basic I can't believe it's not a built in command. Maybe it is, but I haven't found it.

[Ofnuts]

(01-24-2021, 09:06 PM)bitrat Wrote:

(01-24-2021, 08:57 PM)Ofnuts Wrote: I can't wrap my head around what you are trying to do but it looks way too complicated anyway. If you use a layer mask (which you don't seem to be doing) you would skip most of this.

I am using a layer mask.  That's fine inside GIMP using the native .xcf format, but I want to export a .png file with transparency, with the alpha channel matching the mask.

This seems so obvious and basic I can't believe it's not a built in command.  Maybe it is, but I haven't found it.

That works for me. If I export the attached XCF to PNG, I get the expected result. Maybe you have to force the pixel format in the PNG dialog.

   

[bitrat]

Hmm, thanks! Yes that works. I was doing the layer mask wrong, so a big help all round! :-)