Changes

287 bytes added ,  04:03, 5 August 2014
make use of Template:warning, and recommend quantum depth of 16
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To solve the problem, GraphicsMagick needs to be rebuilt with the appropriate settings. See below for tracking dependencies and the reasoning behind each flag. Once done, the following commands should work to build GraphicsMagick.
 
To solve the problem, GraphicsMagick needs to be rebuilt with the appropriate settings. See below for tracking dependencies and the reasoning behind each flag. Once done, the following commands should work to build GraphicsMagick.
 
<pre>
 
<pre>
./configure  --with-quantum-depth=32 --enable-shared --disable-static --with-magick-plus-plus=yes
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./configure  --with-quantum-depth=16 --enable-shared --disable-static --with-magick-plus-plus=yes
 
make
 
make
 
make check
 
make check
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As versions with higher values are not available on the repositories, the solution is to compile it. Octave needs then to be recompiled to use the freshly compiled Magick++ library.
 
As versions with higher values are not available on the repositories, the solution is to compile it. Octave needs then to be recompiled to use the freshly compiled Magick++ library.
   −
=== Warning ===
+
{{warning|Increasing quantum depth may have a dramatic increase in memory usage. If you use QuantumDepth 32, all images will be read with that precision even if they were saved with 8bit. This means that a 100MB 8bit image will temporarly take 400MB memory, or more if the image was compressed and they usually are, before Octave resizes it back down to 100MB. Because of this, because 32 bit integers images are rare, and because GraphicsMagick does not handle floating point, it's recommended to use QuantumDepth of 16.}}
If you use QuantumDepth 32, all images will be read with that precision even if they were saved with 8bit. This means that a 100MB 8bit image will temporarly take 400MB memory before Octave resizes it back down to 100MB.
      
== Magick++ ==
 
== Magick++ ==