/usr/share/gimp/2.0/scripts/alfaro-color-temperature.scm is in gimp-plugin-registry 7.20140602ubuntu3.
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; The GIMP -- an image manipulation program
; Copyright (C) 1995 Spencer Kimball and Peter Mattis
;
; Colortemp script for GIMP 2.4
; Copyright (C) 2006 Luca de Alfaro <lda@dealfaro.com>
;
; Tags: photo, color correction, color temperature
;
; Author statement:
; Converts the color temperature of an image
;
; --------------------------------------------------------------------
; Distributed by Gimp FX Foundry project
; --------------------------------------------------------------------
; - Changelog -
;
; --------------------------------------------------------------------
;
; This program is free software: you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 3 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program. If not, see <http://www.gnu.org/licenses/>.
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (script-fu-colortemp image drawable sourcemod sourcetemp desttemp intensmult satura)
(define (floor x) (- x (fmod x 1)))
; Linear interpolations, used by the table lookup below
(define (interpolate xlow xhi ylow yhi x)
(let* ((deltax (- xhi xlow))
(deltap (- x xlow))
(deltay (- yhi ylow))
(inc (* deltay (/ deltap deltax)))
)
(+ ylow inc)))
; Interpolates colors
(define (interpolate-rows low high temp)
(let* ((t_low (car low))
(r_low (cadr low))
(g_low (caddr low))
(b_low (nth 3 low))
(t_hi (car high))
(r_hi (cadr high))
(g_hi (caddr high))
(b_hi (nth 3 high)))
(list
(interpolate t_low t_hi r_low r_hi temp)
(interpolate t_low t_hi g_low g_hi temp)
(interpolate t_low t_hi b_low b_hi temp))))
; Given the colortable and color temperature in K, finds
; r, g, b values in the linear space.
(define (findcolors colortable temp)
(let* ((l colortable)
(low (car colortable)))
(while (> temp (car (car l)))
(set! low (car l))
(set! l (cdr l)))
(interpolate-rows low (car l) temp)))
; Converts from linear to gamma-corrected sRGB [0,1]
(define (togamma x)
(if (<= x 0.00304)
(* x 12.92)
(let* ((exponent (/ 1 2.4)))
(- (* 1.055 (pow x exponent)) 0.055))))
; Converts from linear to gamma-corrected sRGB [0,255]
(define (togamma255 x)
(max (min (floor (* 256 (togamma x))) 255) 0))
; Converts from gamma-corrected sRGB [0,1] to linear
(define (tolinear y)
(if (<= y 0.0392768)
(/ y 12.92)
(let* ((ratio (/ (+ y 0.055) 1.055)))
(pow ratio 2.4))))
; Converts from gamma-corrected sRGB [0,255] to linear
(define (to255linear y)
(tolinear (/ y 255)))
; Applies a ratio (in linear space) to sRGB values, where the sRGB
; values are scaled 0..255.
(define (lin-mult-in-gamma-space y255 r)
(togamma255 (* r (to255linear y255))))
; Finds the colors (in linear space) of the temperature whose color
; best matches the foreground. It uses a least-square fit (any better ideas?).
(define (sourcecolors-from-bestmatch colortable fg)
(let* ((fg-red (to255linear (car fg)))
(fg-green (to255linear (cadr fg)))
(fg-blue (to255linear (caddr fg)))
(m (max fg-red (max fg-green fg-blue))))
(if (< m 0.000001)
(list 1 1 1)
(let* ((nr (min 1 (/ fg-red m)))
(ng (min 1 (/ fg-green m)))
(nb (min 1 (/ fg-blue m)))
(t 1000)
(d 4)
(best (list 1 1 1)))
(while (<= t 12000)
(let* ((c (findcolors colortable t))
(cr (car c))
(cg (cadr c))
(cb (caddr c))
(dr (- cr nr))
(dg (- cg ng))
(db (- cb nb))
(d1 (+ (* dr dr) (+ (* dg dg) (* db db)))))
(if (< d1 d)
(set! best c))
(if (< d1 d)
(set! d d1)))
(set! t (+ t 50))) ; we compute the temp within 50K; should be enough
best))))
; Finds the colors (in linear space) of the foreground.
(define (sourcecolors-from-fg fg)
(let* ((fg-red (to255linear (car fg)))
(fg-green (to255linear (cadr fg)))
(fg-blue (to255linear (caddr fg)))
(m (max fg-red (max fg-green fg-blue))))
(if (< m 0.000001)
(list 1 1 1)
(let* ((nr (min 1 (/ fg-red m)))
(ng (min 1 (/ fg-green m)))
(nb (min 1 (/ fg-blue m))))
(list nr ng nb)))))
; This is the color table, taken from
; http://www.vendian.org/mncharity/dir3/blackbody/UnstableURLs/bbr_color.html
(let* (
(colortemp (list
(list 1000 1.0000 0.0401 0.0000)
(list 1100 1.0000 0.0631 0.0000)
(list 1200 1.0000 0.0860 0.0000)
(list 1300 1.0000 0.1085 0.0000)
(list 1400 1.0000 0.1303 0.0000)
(list 1500 1.0000 0.1515 0.0000)
(list 1600 1.0000 0.1718 0.0000)
(list 1700 1.0000 0.1912 0.0000)
(list 1800 1.0000 0.2097 0.0000)
(list 1900 1.0000 0.2272 0.0000)
(list 2000 1.0000 0.2484 0.0061)
(list 2100 1.0000 0.2709 0.0153)
(list 2200 1.0000 0.2930 0.0257)
(list 2300 1.0000 0.3149 0.0373)
(list 2400 1.0000 0.3364 0.0501)
(list 2500 1.0000 0.3577 0.0640)
(list 2600 1.0000 0.3786 0.0790)
(list 2700 1.0000 0.3992 0.0950)
(list 2800 1.0000 0.4195 0.1119)
(list 2900 1.0000 0.4394 0.1297)
(list 3000 1.0000 0.4589 0.1483)
(list 3100 1.0000 0.4781 0.1677)
(list 3200 1.0000 0.4970 0.1879)
(list 3300 1.0000 0.5155 0.2087)
(list 3400 1.0000 0.5336 0.2301)
(list 3500 1.0000 0.5515 0.2520)
(list 3600 1.0000 0.5689 0.2745)
(list 3700 1.0000 0.5860 0.2974)
(list 3800 1.0000 0.6028 0.3207)
(list 3900 1.0000 0.6193 0.3444)
(list 4000 1.0000 0.6354 0.3684)
(list 4100 1.0000 0.6511 0.3927)
(list 4200 1.0000 0.6666 0.4172)
(list 4300 1.0000 0.6817 0.4419)
(list 4400 1.0000 0.6966 0.4668)
(list 4500 1.0000 0.7111 0.4919)
(list 4600 1.0000 0.7253 0.5170)
(list 4700 1.0000 0.7392 0.5422)
(list 4800 1.0000 0.7528 0.5675)
(list 4900 1.0000 0.7661 0.5928)
(list 5000 1.0000 0.7792 0.6180)
(list 5100 1.0000 0.7919 0.6433)
(list 5200 1.0000 0.8044 0.6685)
(list 5300 1.0000 0.8167 0.6937)
(list 5400 1.0000 0.8286 0.7187)
(list 5500 1.0000 0.8403 0.7437)
(list 5600 1.0000 0.8518 0.7686)
(list 5700 1.0000 0.8630 0.7933)
(list 5800 1.0000 0.8740 0.8179)
(list 5900 1.0000 0.8847 0.8424)
(list 6000 1.0000 0.8952 0.8666)
(list 6100 1.0000 0.9055 0.8907)
(list 6200 1.0000 0.9156 0.9147)
(list 6300 1.0000 0.9254 0.9384)
(list 6400 1.0000 0.9351 0.9619)
(list 6500 1.0000 0.9445 0.9853)
(list 6600 0.9917 0.9458 1.0000)
(list 6700 0.9696 0.9336 1.0000)
(list 6800 0.9488 0.9219 1.0000)
(list 6900 0.9290 0.9107 1.0000)
(list 7000 0.9102 0.9000 1.0000)
(list 7100 0.8923 0.8897 1.0000)
(list 7200 0.8753 0.8799 1.0000)
(list 7300 0.8591 0.8704 1.0000)
(list 7400 0.8437 0.8614 1.0000)
(list 7500 0.8289 0.8527 1.0000)
(list 7600 0.8149 0.8443 1.0000)
(list 7700 0.8014 0.8363 1.0000)
(list 7800 0.7885 0.8285 1.0000)
(list 7900 0.7762 0.8211 1.0000)
(list 8000 0.7644 0.8139 1.0000)
(list 8100 0.7531 0.8069 1.0000)
(list 8200 0.7423 0.8002 1.0000)
(list 8300 0.7319 0.7938 1.0000)
(list 8400 0.7219 0.7875 1.0000)
(list 8500 0.7123 0.7815 1.0000)
(list 8600 0.7030 0.7757 1.0000)
(list 8700 0.6941 0.7700 1.0000)
(list 8800 0.6856 0.7645 1.0000)
(list 8900 0.6773 0.7593 1.0000)
(list 9000 0.6693 0.7541 1.0000)
(list 9100 0.6617 0.7492 1.0000)
(list 9200 0.6543 0.7444 1.0000)
(list 9300 0.6471 0.7397 1.0000)
(list 9400 0.6402 0.7352 1.0000)
(list 9500 0.6335 0.7308 1.0000)
(list 9600 0.6271 0.7265 1.0000)
(list 9700 0.6208 0.7224 1.0000)
(list 9800 0.6148 0.7183 1.0000)
(list 9900 0.6089 0.7144 1.0000)
(list 10000 0.6033 0.7106 1.0000)
(list 10100 0.5978 0.7069 1.0000)
(list 10200 0.5925 0.7033 1.0000)
(list 10300 0.5873 0.6998 1.0000)
(list 10400 0.5823 0.6964 1.0000)
(list 10500 0.5774 0.6930 1.0000)
(list 10600 0.5727 0.6898 1.0000)
(list 10700 0.5681 0.6866 1.0000)
(list 10800 0.5637 0.6836 1.0000)
(list 10900 0.5593 0.6806 1.0000)
(list 11000 0.5551 0.6776 1.0000)
(list 11100 0.5510 0.6748 1.0000)
(list 11200 0.5470 0.6720 1.0000)
(list 11300 0.5432 0.6693 1.0000)
(list 11400 0.5394 0.6666 1.0000)
(list 11500 0.5357 0.6640 1.0000)
(list 11600 0.5322 0.6615 1.0000)
(list 11700 0.5287 0.6590 1.0000)
(list 11800 0.5253 0.6566 1.0000)
(list 11900 0.5220 0.6542 1.0000)
(list 12000 0.5187 0.6519 1.0000)
))
; Foreground
(fg (car (gimp-context-get-foreground)))
; Finds the linear source colors
; The colors are taken from slider temperature
(sourcecolors (cond ((= sourcemod 0) (findcolors colortemp sourcetemp))
; The colors are taken from foreground best-match
((= sourcemod 1) (sourcecolors-from-bestmatch colortemp fg))))
; and the target colors
(targetcolors (findcolors colortemp desttemp))
; computes the ratios
(rr (/ (car targetcolors) (car sourcecolors)))
(rg (/ (cadr targetcolors) (cadr sourcecolors)))
(rb (/ (caddr targetcolors) (caddr sourcecolors)))
; Multiplies them by the intensity modification
(m (/ intensmult 100))
; And these are the real ratios
(rratio (* rr m))
(gratio (* rg m))
(bratio (* rb m))
(i 0)
(num_bytes 256)
(red-curve (cons-array num_bytes 'byte))
(green-curve (cons-array num_bytes 'byte))
(blue-curve (cons-array num_bytes 'byte)))
(gimp-image-undo-group-start image)
(while (< i num_bytes)
(aset red-curve i (lin-mult-in-gamma-space i rratio))
(aset green-curve i (lin-mult-in-gamma-space i gratio))
(aset blue-curve i (lin-mult-in-gamma-space i bratio))
(set! i (+ i 1)))
(gimp-curves-explicit drawable RED-LUT num_bytes red-curve )
(gimp-curves-explicit drawable GREEN-LUT num_bytes green-curve)
(gimp-curves-explicit drawable BLUE-LUT num_bytes blue-curve )
(gimp-hue-saturation drawable 0 0.0 0.0 satura)
(gimp-image-undo-group-end image)
(gimp-displays-flush)
))
(script-fu-register
"script-fu-colortemp"
_"Convert Color Temperat_ure"
_"Convert Color Temperature 2.0\n\nFor help, go to http://www.dealfaro.org/home/code/colortemp.html\n"
"Luca de Alfaro <lda@dealfaro.com>"
"Luca de Alfaro"
"December 2006"
"RGB*"
SF-IMAGE "Image" 0
SF-DRAWABLE "Drawable" 0
SF-OPTION "Obtain original temperature" '("From slider below" "From foreground color")
SF-ADJUSTMENT _"Original temperature (K)" '(6500 1000 12000 25 250 0 0)
SF-ADJUSTMENT _"Target temperature (K)" '(6500 1000 12000 25 250 0 0)
SF-ADJUSTMENT _"Intensity (%)" '(100 0 200 1 10 0 0)
SF-ADJUSTMENT _"Saturation change (%)" '(0 -100 100 1 10 0 0)
)
(script-fu-menu-register "script-fu-colortemp"
_"<Image>/FX-Foundry/Color")
|