[Magick-bugs] quantize introduces black areas (confirmation ofalready posted bug)

[Till Oliver Knoll]

Till Oliver Knoll wrote:
> Till Oliver Knoll wrote:
> 
>> Peter Pimley schrieb:
>>
>>> ...
>>> With the help of a few other posters, we found that earlier versions did
>>> not show the problem.  It was only very recently introduced.  6.3.4
>>> seems to be OK, whereas 6.3.5 is not.
>>
>>
>>
>> I just downloaded the latest 6.3.4 sources for Windows (which include 
>> the "VisualMagick" subfolder), e.g. from here
>>
>>
>> ftp://ftp.fu-berlin.de/unix/X11/graphics/ImageMagick/windows/ImageMagick-6.3.4-10.zip 
>>
>>
>> and it shows the same buggy behaviour: "black areas" are also produced 
>> with the following command:
>>
>>    convert -size 256x256 gradient:blue-none -colors 16 out.png
>>
>> Am going to try the previous version(s) ...
> 
> 
> I have tried the version 6.3.2 which also shows the buggy "black area"! 

Sorry for the message traffic peak, but finally I have found a version 
which seems to work!

After digging the web for older ImageMagick sources I came up with the 
6.2.9-0, as downloaded from some (out of sync?) mirror:

 
http://gsmp.tfh-berlin.de/mirror/t2-source/6.0/I/ImageMagick-6.2.9-0.tar.bz2

which apparently is the latest in the 6.2.x series.

I compiled it on SuSE 8.2 with the usual

   %> ./configure
   %> make
   %> make install

Seems like the gradient:blue-none (the 'none' keyword) was only 
introduced in the 6.3.x series, so I could not test it with the

   convert -size 256x256 gradient:blue-none -colors 16 out.png

(which produces an all blue image without transparency)

but my test image 'alpha254.png' (some image with alpha channel set 
uniformly to 254) which fails with the 6.3.x WORKS with this version 
6.2.9-0!

Seems like the bug was introduced somewhere in the 6.3.x.


I could not find older (official) 6.2.x sources on the mirrors listed on 
www.imagemagick.org (the oldest version seems to be 6.3.2) and I am 
still lacking the "VisualMagick" Windows source files for the 6.2.x. 
which is not available on the URL given above. Does anyone have an URL 
for old 6.2.x (6.2.9) Windows sources which I could use until this issue 
is fixed in a newer version?


Thanks, Oliver