Re: [AL] libjpeg no longer works

[Elias P. <el...@us...>]

On Sun, 2003-06-29 at 05:52, Gillius wrote:
> I'm using Allegro, I believe version 4.1.9, and a user e-mailed me saying 
> that libjpeg doesn't work anymore.
> 
> When the library dissapeared some 4-5 years ago I put it up on my site 
> since it didn't have a home page.  Until recently it compiled perfectly on 
> Windows without a single warning.  Amazing since it was written for Allegro 
> 3, and the JPEG code written in 1996 and the library in 1998, that it 
> lasted so long!
> 
> But alas now it doesn't compile, there is only one error -- the symbol 
> _color_depth is no longer defined.  I figure this is some internal symbol 
> undocumented in Allegro.
> 
> Why this is, I'm not sure.  From a brief glance in the code it appears that 
> it uses _color_depth to discover the bit depth of the bitmap created in 
> create_bitmap, but it uses it lots of times, both before and after the 
> create_bitmap call.
> 
> With some effort I might be able to use bitmap_color_depth can 
> create_bitmap to simulate a get_color_depth() Allegro call, since 
> create_bitmap uses the current color depth, I can create a dummy bitmap to 
> find the depth set by set_color_depth.
> 
> Any comments?  Is my guess on the symbol wrong?  Am I right in saying it 
> doesn't exist anymore, but used to be an internal Allegro symbol?
> 

I think it still exists, but you have to include:
allegro/internal/aintern.h. At least grep shows me that file if I look
for it.

Also note that there's a new function get_color_depth() in the unstable
branch now.

My advice would be to use this instead:
http://www.allegro.cc/depot/project.php?_id=522
It is a very recently written library, by Angelo Mottola himself - so it
is sure to work, and also is maintained in case a bug is found. I think
the comments on allegro.cc are about an old version, and it can decode
every .jpg out there now, as well as encode. (But I never used it myself
yet)

-- 
Elias Pschernig <el...@us...>