Transparency and PNG format

Peter T. Evensen pevensen at
Tue Nov 29 17:17:58 CST 2005

I use transparent pngs all the time.  I think you do have to use an alpha 
channel, which Revolution just uses.

If GraphicConverter isn't creating a PNG with an alpha channel, that could 
be why they aren't showing up as transparent in Revolution.

The nice thing about alpha channels is that you can have semi-transparencies.

At 04:05 PM 11/29/2005, you wrote:
>Folks, I've got a number of small GIFs in an app, representing human
>figures - therefore not rectangular. I managed to give each one a
>transparent background and RR honours this when I import the GIFs as
>images (i.e. the background information on the card shows up around
>the shape of the figure).
>I've now started to using PNGs rather than GIFS, and I can give them
>transparent backgrounds in exactly the same way as the GIFs
>(GraphicConverter on the Mac is really good for this - a lot simpler
>than Photoshop Elements... but I digress). However when I import a
>PNG as an image, the transparency disappears and the figure therefore
>appears in a white rectangle. I can fix this with inks, but only on
>the Mac, and this app is destined for PC users mostly.
>I've looked at the docs, but I can't see a way of telling RR to use
>the transparency in a PNG. I see a bit about Alpha Channels, but I
>don't know if I'm using an Alpha Channel or not, and anyway I can't
>understand how RR deals with them. I can of course convert all my
>PNGs to GIFs, but is this the only solution? (This leads me to ask if
>is there any disadvantage to using GIFs over PNGs - I kind of thought
>there was, but I'm no longer sure why).
>Can anyone clarify this for me?
>Graham Samuel / The Living Fossil Co. / UK and France
>use-revolution mailing list
>use-revolution at
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Peter T. Evensen
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