nanogui: PNG support
Subject:
RE: [nanogui] PNG Support
From:
Fabrice Gautier ####@####.####
Date:
19 Sep 2002 04:48:07 -0000
Message-Id: <B1F6452C89AFD411AE0800A0CC734C239DBD2D@EMAIL1>
I've not done a thorought investigation, but i think there is a bug.
In the current code, if i try to display an 8bit PNG image, the output is
compressed toward the left. I would says its compressed by a factor of 3. So
my guess is that somehow the decoding onl output 8 bit samples but nanoX
think its 24bits sample...
If i change pimage->bpp=24 to pimage->bpp=8 in LoadPNG then the size is
okay.
--
Fabrice Gautier,
####@####.####
> -----Original Message-----
> From: Jordan Crouse ####@####.####
> Sent: Wednesday, September 18, 2002 12:36 PM
> To: Fabrice Gautier
> Cc: ####@####.####
> Subject: Re: [nanogui] PNG Support
>
>
> The image will be appropriately converted to the correct bit
> depth when it is written to the screen, so we maintain an
> internal representation of 24 bits for simplicity.
>
> In your case, you may see an issue, depending on how well
> Microwindows and the PNG library match your colors. The PNG
> library is intelligent enough to understand the palletized
> entries, so even though we are in 24 bit mode, the colors
> should still stay true. However, when we actually draw the
> image, the colors will be matched to the internal
> Microwindows palette which may or may not have the correct
> colors. At 8 bit depth, you should be OK, but be prepared
> for colors to be a bit off from what you expected.
>
> Jordan
>
> On Wed, 18 Sep 2002 11:57:03 -0700
> Fabrice Gautier ####@####.#### wrote:
>
> > Hi,
> >
> > It seems that PNG images are always decoded as 24bpp
> images. Am i right or
> > did i missed something?
> >
> > Since I only have 8 bit display, and I use only 8bpp
> palletized PNG I'd
> > rather have then as 8bpp images...
> >
> >
> > --
> > Fabrice Gautier,
> > ####@####.####
> >
> >
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