POV-Ray : Newsgroups : povray.bugreports : GIF interlaced are not properly recognized Server Time
28 Mar 2024 18:06:37 EDT (-0400)
  GIF interlaced are not properly recognized (Message 1 to 3 of 3)  
From: GioSeregni
Subject: GIF interlaced are not properly recognized
Date: 3 Mar 2020 01:05:00
Message: <web.5e5df36678fbb0062c923fbd0@news.povray.org>
Hi all.
I went crazy with the code because with "ONCE" activated I kept seeing GIF
images strechted and repeated 4 times.
The same images, which I hadn't saved recently, were regular.
Then I understand, now Irfanview has the INTERLACED option by default, but this
is not recognized and the decoding of the image is wrong.
Regards
G.


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From: Le Forgeron
Subject: Re: GIF interlaced are not properly recognized
Date: 3 Mar 2020 14:50:59
Message: <5e5eb523$1@news.povray.org>
Le 03/03/2020 à 07:04, GioSeregni a écrit :
> Hi all.
> I went crazy with the code because with "ONCE" activated I kept seeing GIF
> images strechted and repeated 4 times.
> The same images, which I hadn't saved recently, were regular.
> Then I understand, now Irfanview has the INTERLACED option by default, but this
> is not recognized and the decoding of the image is wrong.
> Regards
> G.
> 
> 

Well, the problem should be handled in povray,
since FS#314, but seems the correction did not make it in the official
code. (not the 3.7 stable anyway)

But it is already fixed on the official master.

For the curious, in source/base/image/gif.cpp, the check for interlaced
gif should look at buffer[8] and not buffer[9] (for & 0x40)

Now, you won't be happy with the correction either, because interlaced
gif are not supported but you will get an interruption at parse time
instead of rendering (so it will save you time).


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From: GioSeregni
Subject: Re: GIF interlaced are not properly recognized
Date: 3 Mar 2020 16:45:01
Message: <web.5e5ecf9cd65511d02c923fbd0@news.povray.org>
Le_Forgeron <jgr### [at] freefr> wrote:
> Le 03/03/2020 à 07:04, GioSeregni a écrit :
> > Hi all.
> > I went crazy with the code because with "ONCE" activated I kept seeing GIF
> > images strechted and repeated 4 times.
> > The same images, which I hadn't saved recently, were regular.
> > Then I understand, now Irfanview has the INTERLACED option by default, but this
> > is not recognized and the decoding of the image is wrong.
> > Regards
> > G.
> >
> >
>
> Well, the problem should be handled in povray,
> since FS#314, but seems the correction did not make it in the official
> code. (not the 3.7 stable anyway)
>
> But it is already fixed on the official master.
>
> For the curious, in source/base/image/gif.cpp, the check for interlaced
> gif should look at buffer[8] and not buffer[9] (for & 0x40)
>
> Now, you won't be happy with the correction either, because interlaced
> gif are not supported but you will get an interruption at parse time
> instead of rendering (so it will save you time).


Thanks for your kind reply, it's ok, in my opinion the problem arises if the
user doesn't know it, because if he thinks it's his code's fault he can work
hours without finding a solution.Best Regards and thanks again!
G.


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