;;; color.el --- Color manipulation library -*- coding: utf-8; -*-
-;; Copyright (C) 2010-2011 Free Software Foundation, Inc.
+;; Copyright (C) 2010-2012 Free Software Foundation, Inc.
;; Authors: Julien Danjou <julien@danjou.info>
;; Drew Adams <drew.adams@oracle.com>
;; complements, and computing CIEDE2000 color distances.
;;
;; Supported color representations include RGB (red, green, blue), HSV
-;; (hue, saturation, value), HSL (hue, saturation, luminence), sRGB,
+;; (hue, saturation, value), HSL (hue, saturation, luminance), sRGB,
;; CIE XYZ, and CIE L*a*b* color components.
;;; Code:
Optional arg FRAME specifies the frame where the color is to be
displayed. If FRAME is omitted or nil, use the selected frame.
If FRAME cannot display COLOR, return nil."
- (mapcar (lambda (x) (/ x 65535.0)) (color-values color frame)))
+ ;; `colors-values' maximum value is either 65535 or 65280 depending on the
+ ;; display system. So we use a white conversion to get the max value.
+ (let ((valmax (float (car (color-values "#ffffff")))))
+ (mapcar (lambda (x) (/ x valmax)) (color-values color frame))))
(defun color-rgb-to-hex (red green blue)
"Return hexadecimal notation for the color RED GREEN BLUE.
result))
(nreverse result)))
+(defun color-hue-to-rgb (v1 v2 h)
+ "Compute hue from V1 and V2 H. Internally used by
+`color-hsl-to-rgb'."
+ (cond
+ ((< h (/ 1.0 6)) (+ v1 (* (- v2 v1) h 6.0)))
+ ((< h 0.5) v2)
+ ((< h (/ 2.0 3)) (+ v1 (* (- v2 v1) (- (/ 2.0 3) h) 6.0)))
+ (t v1)))
+
+(defun color-hsl-to-rgb (H S L)
+ "Convert H S L (HUE, SATURATION, LUMINANCE) , where HUE is in
+radians and both SATURATION and LUMINANCE are between 0.0 and
+1.0, inclusive to their RGB representation.
+
+Return a list (RED, GREEN, BLUE) which each be numbers between
+0.0 and 1.0, inclusive."
+
+ (if (= S 0.0)
+ (list L L L)
+ (let* ((m2 (if (<= L 0.5)
+ (* L (+ 1.0 S))
+ (- (+ L S) (* L S))))
+ (m1 (- (* 2.0 L) m2)))
+ (list
+ (color-hue-to-rgb m1 m2 (+ H (/ 1.0 3)))
+ (color-hue-to-rgb m1 m2 H)
+ (color-hue-to-rgb m1 m2 (- H (/ 1.0 3)))))))
+
(defun color-complement-hex (color)
"Return the color that is the complement of COLOR, in hexadecimal format."
(apply 'color-rgb-to-hex (color-complement color)))
RED, GREEN, and BLUE should each be numbers between 0.0 and 1.0,
inclusive.
-Return a list (HUE, SATURATION, LUMINENCE), where HUE is in radians
-and both SATURATION and LUMINENCE are between 0.0 and 1.0,
+Return a list (HUE, SATURATION, LUMINANCE), where HUE is in radians
+and both SATURATION and LUMINANCE are between 0.0 and 1.0,
inclusive."
(let* ((r red)
(g green)
(min (min r g b))
(delta (- max min))
(l (/ (+ max min) 2.0)))
- (list
- (if (< (- max min) 1e-8)
- 0
- (* 2 float-pi
- (/ (cond ((= max r)
- (+ (/ (- g b) delta) (if (< g b) 6 0)))
- ((= max g)
- (+ (/ (- b r) delta) 2))
- (t
- (+ (/ (- r g) delta) 4)))
- 6)))
- (if (= max min)
- 0
- (if (> l 0.5)
- (/ delta (- 2 (+ max min)))
- (/ delta (+ max min))))
- l)))
+ (if (= delta 0)
+ (list 0.0 0.0 l)
+ (let* ((s (if (<= l 0.5) (/ delta (+ max min))
+ (/ delta (- 2.0 max min))))
+ (rc (/ (- max r) delta))
+ (gc (/ (- max g) delta))
+ (bc (/ (- max b) delta))
+ (h (mod
+ (/
+ (cond
+ ((= r max) (- bc gc))
+ ((= g max) (+ 2.0 rc (- bc)))
+ (t (+ 4.0 gc (- rc))))
+ 6.0) 1.0)))
+ (list h s l)))))
(defun color-srgb-to-xyz (red green blue)
"Convert RED GREEN BLUE colors from the sRGB color space to CIE XYZ.
(expt (/ ΔH′ (* Sh kH)) 2.0)
(* Rt (/ ΔC′ (* Sc kC)) (/ ΔH′ (* Sh kH)))))))))
+(defun color-clamp (value)
+ "Make sure VALUE is a number between 0.0 and 1.0 inclusive."
+ (min 1.0 (max 0.0 value)))
+
+(defun color-saturate-hsl (H S L percent)
+ "Return a color PERCENT more saturated than the one defined in
+H S L color-space.
+
+Return a list (HUE, SATURATION, LUMINANCE), where HUE is in radians
+and both SATURATION and LUMINANCE are between 0.0 and 1.0,
+inclusive."
+ (list H (color-clamp (+ S (/ percent 100.0))) L))
+
+(defun color-saturate-name (name percent)
+ "Short hand to saturate COLOR by PERCENT.
+
+See `color-saturate-hsl'."
+ (apply 'color-rgb-to-hex
+ (apply 'color-hsl-to-rgb
+ (apply 'color-saturate-hsl
+ (append
+ (apply 'color-rgb-to-hsl
+ (color-name-to-rgb name))
+ (list percent))))))
+
+(defun color-desaturate-hsl (H S L percent)
+ "Return a color PERCENT less saturated than the one defined in
+H S L color-space.
+
+Return a list (HUE, SATURATION, LUMINANCE), where HUE is in radians
+and both SATURATION and LUMINANCE are between 0.0 and 1.0,
+inclusive."
+ (color-saturate-hsl H S L (- percent)))
+
+(defun color-desaturate-name (name percent)
+ "Short hand to desaturate COLOR by PERCENT.
+
+See `color-desaturate-hsl'."
+ (color-saturate-name name (- percent)))
+
+(defun color-lighten-hsl (H S L percent)
+ "Return a color PERCENT lighter than the one defined in
+H S L color-space.
+
+Return a list (HUE, SATURATION, LUMINANCE), where HUE is in radians
+and both SATURATION and LUMINANCE are between 0.0 and 1.0,
+inclusive."
+ (list H S (color-clamp (+ L (/ percent 100.0)))))
+
+(defun color-lighten-name (name percent)
+ "Short hand to saturate COLOR by PERCENT.
+
+See `color-lighten-hsl'."
+ (apply 'color-rgb-to-hex
+ (apply 'color-hsl-to-rgb
+ (apply 'color-lighten--hsl
+ (append
+ (apply 'color-rgb-to-hsl
+ (color-name-to-rgb name))
+ (list percent))))))
+
+(defun color-darken-hsl (H S L percent)
+ "Return a color PERCENT darker than the one defined in
+H S L color-space.
+
+Return a list (HUE, SATURATION, LUMINANCE), where HUE is in radians
+and both SATURATION and LUMINANCE are between 0.0 and 1.0,
+inclusive."
+ (color-lighten-hsl H S L (- percent)))
+
+(defun color-darken-name (name percent)
+ "Short hand to saturate COLOR by PERCENT.
+
+See `color-darken-hsl'."
+ (color-lighten-name name (- percent)))
+
(provide 'color)
;;; color.el ends here
projects / gnus / blobdiff