[linux-help] Re: GIMP & transparant GIFs

[Steven Saner <ssaner@xxxxxxxxxxxxxxx>]

Actually I learned an additional (better?) way of doing this. It
involves the use of a Layer mask. If you right click on a layer in the
Layers/Channels dialog box, you can choose to create a mask. You can
then copy and paste an image into that mask position. If the mask is a
black and white image, anyplace that is white will allow the image
that you are masking to show through. Anyplace that is black will be
masked out and will be transparent.

For example, I had a black image on a white background, and I wanted
to make the black image be on a transparent background. What I did was
duplicate that layer, so I had two layers with the black on white
image. I then inverted the values on one of them (creating a white on
black image). On the other layer I created a mask and copied the
inverted layer to the mask. I then could delete that inverted layer
and I was left with a layer that had the original layer, but was
masked such that it was a black image on a transparent background.

Layer masks allow you to do all kinds of things. I just didn't know
they existed until I looked at some of the tutorials on the gimp web
site.


On Wed, May 24, 2000 at 12:52:11AM -0500, Jonathan Hall wrote:
> Someone was asking how to save transparant GIFs in GIMP... here's the only
> way I've found to do it... (it's a pain in the butt!)
> 
> 1. Open/create the image...
> 2. Open the Layers/Channels dialog box (Ctrl-L)
> 3. Create at least one extra layer.  If you're gonna actually use layers,
>    create one more layer than you need--and make sure it's the BOTTOM (i.e. 
>    "Background") layer.
> 4. Edit/modify your image as you like... leaving the bottom/background layer
>    unused.  Leave "holes" in the above layer(s) where you want the
>    transparancy to be.
> 5. When you're ready to save the image, on the Layers/Channel dialog,
>    highlight the bottom/background layer, and delete it.  This leaves the
>    top layer(s) unmodified, with its transparant spots actually
>    transparant...  Then save the image as normal.
> 
> In my experience, this is the only way to create an unlayered image with
> transparancy... Why you (I?) cannot delete stuff on an image with only one
> layer, and it be transparant (and not just WHITE) is beyond me...
> 
> If there's an easier way to do this, please let me know :-)
> 
> 
> --
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> Reina de los Angeles de Porciuncula"- and can be abbreviated to 3.63% of its
> size: "L.A."
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