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Possibly a stupid question regarding PNGs and IE

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Possibly a stupid question regarding PNGs and IE Malcolm Turnbull 04 Mar 15:20
  Possibly a stupid question regarding PNGs and IE Judy Wilson 04 Mar 23:01
   Possibly a stupid question regarding PNGs and IE Dan Nikkel 05 Mar 01:47
Malcolm Turnbull
2003-03-04 15:20:09 UTC (over 17 years ago)

Possibly a stupid question regarding PNGs and IE

I think I've figured out how to get transparent PNGs from gimp to appear OK (ish) in i.e by setting the background colour before saving and toggling the option to save background colour...

But I was wondering if it was possible for GIMP to save the background colour as transparent ? (It seems to allow only solid colours)

PhotoShop seems to be able to do this and those PNGs work fine in IE6 (not sure about others)

Ps. It would be nice if the freehand selection tool allowed you to select straight lines rather than guessing all the time, i.e. for cutting out a box shape at an angle..

I'm pretty ignorant of how to use gimp and even worse and photo shop so flame me if I'm talking rubish..

Judy Wilson
2003-03-04 23:01:41 UTC (over 17 years ago)

Possibly a stupid question regarding PNGs and IE

Don't apologize when you only want to learn!

* Malcolm Turnbull [030304 09:27]:

But I was wondering if it was possible for GIMP to save the background colour as transparent ? (It seems to allow only solid colours)

It will save as tranparent if you erase the part you want to be transparent. Open the layer dialog box and right click on the backgroud layer. Add an alpha channel. It won't work if you don't have an alpha channel. Then make your selection and be sure the part you want transparent is the selection. Use the erase tool of the selection. It should reveal the checkerboard underneath. That's transparency. Then save as a PNG. I do this all the time.

PhotoShop seems to be able to do this and those PNGs work fine in IE6 (not sure about others)

Ps. It would be nice if the freehand selection tool allowed you to select straight lines rather than guessing all the time, i.e. for cutting out a box shape at an angle..

I'll look for the answer to this one, too.

I'm pretty ignorant of how to use gimp and even worse and photo shop so flame me if I'm talking rubish..

I've actually written a tutoria for the gimp. If you'll email off-line maybe we could figure a way to get it for you.

Judy

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Dan Nikkel
2003-03-05 01:47:53 UTC (over 17 years ago)

Possibly a stupid question regarding PNGs and IE

On Tue, 4 Mar 2003 16:01:41 -0600, Judy Wilson wrote:

* Malcolm Turnbull [030304 09:27]:

But I was wondering if it was possible for GIMP to save the background colour as transparent ? (It seems to allow only solid colours)

It will save as tranparent if you erase the part you want to be transparent. Open the layer dialog box and right click on the backgroud layer. Add an alpha channel. It won't work if you don't have an alpha channel. Then make your selection and be sure the part you want transparent is the selection. Use the erase tool of the selection. It should reveal the checkerboard underneath. That's transparency. Then save as a PNG. I do this all the time.

There's something else to keep in mind with respect to the PNG format. PNG supports transparency (both binary or full alpha channel), but can also support a default background color (through the bKGD chunk) for use when the application viewing the image doesn't have a natural background over which to lay the image. I believe this is what's being saved when you toggle "save background color".

If your image has transparency and it's being overlayed on a background (like on a web page), and the browser supports transparent PNGs, then this background color is ignored (as the web page's background is used). But if you're just viewing this image standalone in some application, or you're using an older browser on a web page which doesn't fully support PNGs transparency (e.g. Netscape 4.7x), then this background color you specify can be used instead of having the application pick it's own background for the image (e.g. black).

You can also tweak the background color of a PNG image with the netpbm utilities after you've created it in the gimp.