GIMP recoloring algorithm

begueradj · **Joined:** Mar 19, 2015 **Posts:** 3

Hello every one;

I would love to know which colorization/recoloring algorithm GIMP uses in a case like this one:

On a website called digidesignresort and the tutorial namedhow-to-recolor-elements-and-papers-in-gimp/

(I can not post the link)

If someone could point me to the source code/algorithm I will be glad.

Thank you in advance

Begueradj

dinasset · **Posted:** Fri Mar 20, 2015 8:12 am **(#2)**

AFAIK the native filter Colours/Colourise first desaturates the selected area/image then applies the selected hue according to the value of the grey pixels

jontait2 · **Joined:** Dec 27, 2014 **Posts:** 508

http://fossies.org/dox/gimp-2.8.14/pain ... tml#l00501

Line 539:

Code: Select all

  dest[b] = (affect[b] ? INT_BLEND (src2[b], src1[b], opacity, tmp) : src1[b]);

INT_BLEND is a C macro defined in paint-funcs-utils.h thus:

Code: Select all

#define    INT_MULT(a, b, t)   ((t) = (a) * (b) + 0x80, ((((t) >> 8) + (t)) >> 8))
#define    INT_BLEND(a, b, alpha, tmp)   (INT_MULT((a) - (b), alpha, tmp) + (b))