From:	"Andrew Francis" <lpontiac AT bigpond DOT com>
Newsgroups:	comp.os.msdos.djgpp
References:	<385747AE DOT E8045C3 AT wanadoo DOT fr>
Subject:	Re: problem with bitmaps & optimized palette under allegro
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Date:	Thu, 16 Dec 1999 18:12:22 +0800
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To:	djgpp AT delorie DOT com
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The reason Allegro does this is that for standard paletted modes, VGA cards
(and VESA modes) use a gradient of 0-63 to specify colors. The only real way
around it is not to use 8-bit-mode, as far as I know.

If you're really determined, try storing the files in your own native file
format, etc...


lolo wrote in message <385747AE DOT E8045C3 AT wanadoo DOT fr>...
>
>I use Allegro library to to display bitmaps that I previously store in a
>.dat file ... my bitmaps are in 256 colors file format but with
>optimized palette, in the dat file I store the bitmap and the palette
>under my main program I initialise my screen in 16milions colors and
>when I try to render my bitmaps with their own optimized palette the
>colors are not matching exactly... I've seen in the source code of
>allegro that for palette it make an approximation of the color by
>reducing the value stored in the palette (so the values are from 0 to
>63)... How can I avoid this so I will have full gradients on my screen..
>I can of course use 16milions colors bitmaps to avoid palette
>manipulations, but I'm short of space....
>
>If anybody know how to manage this .... thank's by advance...
>

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