Red Hat Bugzilla – Bug 996411
GraphicsMagick: support 32 bits per pixel
Last modified: 2014-08-20 08:40:55 EDT
When I use the imread() function in Octave appears the following message: warning: your version of GraphicsMagick limits images to 16 bits per pixel For a optimal use of image processing in Octave there is the need of 32 bit per pixel but the image quality gonna be poor after the call of the imshow() function. How reproducible: - Open QtOctave. - Use the imread() function with some image. - Use the imshow() function with the same image called with the imread() function. - Watch the quality of the image.
http://wiki.octave.org/GraphicsMagick mentions 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. We are already using 16 If that wiki entry is not current, please clarify and re-open.