GNOME Bugzilla – Bug 356354
Colormap Dialog documentation refers to 'Dithering' instead of 'Quantization'
Last modified: 2006-09-28 20:46:22 UTC
"for example, in a pattern fill, GIMP will usually not be able to find exactly the right colors in the colormap, so it will approximate them by Dithering." Dithering is not performed when pattern filling, cloning, or most other situations where it could be applied. Instead, the pixel colors are matched to the nearest color in the colormap (which is normally referred to as quantization) There is no operation that works on an indexed image that performs dithering. Ironically, operations that only work on RGB images are the only ones producing dithering: Blend tool (if the dithering option is enabled) and Convert to Indexed.
So is this sentence just plain wrong when it comes to dithering for pattern fill? Or should this paragraph elaborate this case more like you explained? --> assign
I think the right thing to do is to add a 'quantizing' item to the glossary and refer to that instead of dithering. "for example, in a pattern fill or clone operation, GIMP will usually not be able to find exactly the right colors in the colormap, so it will approximate them by Quantization." might be a good wording.
I have changed the English for this paragraph to read: It is important to realize that the colors in the colormap are the <emphasis>only colors available</emphasis> for an indexed image (that is, unless you add new colors to the colormap). This has a major effect on many gimp operations: for example, in a pattern fill, GIMP will usually not be able to find exactly the right colors in the colormap, so it will approximate them by using the nearest color available. If the colormap is too limited or poorly chosen, this can easily produce very poor image quality. 2006-09-28 Bill Skaggs <weskaggs@primate.ucdavis.edu> * src/dialogs/indexed-palette-dialog.xml: Change incorrect statement about dithering. Fixes bug #356354 for en, still incorrect for other linguas. (I don't think we need to hit users with technical terminology for this.)