[Gimp-developer] Doing an action for each color in an indexed color-palette

[saulgoode at flashingtwelve.brickfilms.com]

Quoting Roberto Uhlig <Roberto.Uhlig at web.de>:

> Hello,
> has/knows anyone a script/plugin (an idea) to go color by color   
> through an indexed color-palette and doing an action for each color?
> I'd like to create from a picture with an optimized color-palette   
> with ca. 5-10 (may be 1-256) colors new layers or new pictures for   
> each color in palette.
> Layer(s) or pictures must have the same extensions like the original picture.
> The new picture must be a black and white (1-bit) palette binary   
> tiff for using in geo information systems as visible and invisible.

I have written a script  
(http://flashingtwelve.brickfilms.com/GIMP/Scripts/Temp/save-as-map-masks.scm)  
which attempts to address your problem. I do not know how to save  
1-bit TIFFs and so my script saves the files as RGB-mode  
black-and-white PNGs (I know Indexed would be smaller, but I was lazy).

 From the comments in the script:

;; Saves a PNG file for each color of an Indexed image where that
;; color is replaced by white and the rest of the image is black.
;; The PNG's filename is derived from the name of the bottom
;; layer of the original Indexed image. The RGB colors are
;; appended to this name, separated by hyphens.
;; An example of an output filename would be
;; "Background-10-242-79.png".
;;
;; The files (one for each indexed color) are saved in the same directory as
;; the original image (or to the GIMP invocation directory if a
;; new image).