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Bug #12618 unable to select colors using palette of (loaded ) pngs or gifs
Submitted: 2001-08-07 09:06 UTC Modified: 2002-06-02 13:42 UTC
From: frank dot loeffler at uni-jena dot de Assigned:
Status: Not a bug Package: GD related
PHP Version: 4.0.4pl1 OS: Debian Woody
Private report: No CVE-ID: None
 [2001-08-07 09:06 UTC] frank dot loeffler at uni-jena dot de
Hi,

It maybe is a problem of concept. I do not have any knowledge about the inside, but think of following problem:

Imagine a image, saved as png and loaded with ImageCreateFromPNG. The image has maybe 2 different colors (to be simple), but with the same RGB-value. Ok, this does not seem to make sense, but think of a more complicated situation.
You can get a color handle from a loaded image only with imagecolorexact or imagecolorclosest. Both functions would maybe return the unwanted color.

So, the problem of concept as I said is maybe the kind of 'save' the image. In a GIF I think you have a palette, so to say a table with an index and for each index you have the RGB-values. In the image itself only the index of a color is saved. If you now 'save' the image in the way, that you save for each pixel the RGB-values and so do not need a palette, you loose information. If this is the case here, I do not know a solution to the problem that is simple. Then maybe close this bug, but please confirm it.
If it is not, then a function ImageColorExtractByIndex or something similar would be fine.

Thanks for work on PHP, Frank



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 [2002-06-02 13:42 UTC] derick@php.net
This has nothing to do with PHP itself, but with the GD library thta is used by PHP, make this one bugus.
 
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