-;;; color.el --- Color manipulation laboratory routines -*- coding: utf-8; -*-
+;;; color.el --- Color manipulation library -*- coding: utf-8; -*-
-;; Copyright (C) 2010 Free Software Foundation, Inc.
+;; Copyright (C) 2010-2014 Free Software Foundation, Inc.
-;; Author: Julien Danjou <julien@danjou.info>
-;; Keywords: html
+;; Authors: Julien Danjou <julien@danjou.info>
+;; Drew Adams <drew.adams@oracle.com>
+;; Keywords: lisp, faces, color, hex, rgb, hsv, hsl, cie-lab, background
;; This file is part of GNU Emacs.
;;; Commentary:
-;; This package provides color manipulation functions.
+;; This package provides functions for manipulating colors, including
+;; converting between color representations, computing color
+;; complements, and computing CIEDE2000 color distances.
+;;
+;; Supported color representations include RGB (red, green, blue), HSV
+;; (hue, saturation, value), HSL (hue, saturation, luminance), sRGB,
+;; CIE XYZ, and CIE L*a*b* color components.
;;; Code:
-(eval-when-compile
- (require 'cl))
-
;; Emacs < 23.3
(eval-and-compile
(unless (boundp 'float-pi)
(defconst float-pi (* 4 (atan 1)) "The value of Pi (3.1415926...).")))
-(defun color-rgb->hex (red green blue)
- "Return hexadecimal notation for RED GREEN BLUE color.
-RED GREEN BLUE must be values between [0,1]."
+;;;###autoload
+(defun color-name-to-rgb (color &optional frame)
+ "Convert COLOR string to a list of normalized RGB components.
+COLOR should be a color name (e.g. \"white\") or an RGB triplet
+string (e.g. \"#ff12ec\").
+
+Normally the return value is a list of three floating-point
+numbers, (RED GREEN BLUE), each between 0.0 and 1.0 inclusive.
+
+Optional argument 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."
+ ;; `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.
+RED, GREEN, and BLUE should be numbers between 0.0 and 1.0, inclusive."
(format "#%02x%02x%02x"
(* red 255) (* green 255) (* blue 255)))
-(defun color-complement (color)
- "Return the color that is the complement of COLOR."
- (let ((color (color-rgb->normalize color)))
- (list (- 1.0 (car color))
- (- 1.0 (cadr color))
- (- 1.0 (caddr color)))))
+(defun color-complement (color-name)
+ "Return the color that is the complement of COLOR-NAME.
+COLOR-NAME should be a string naming a color (e.g. \"white\"), or
+a string specifying a color's RGB components (e.g. \"#ff12ec\")."
+ (let ((color (color-name-to-rgb color-name)))
+ (list (- 1.0 (nth 0 color))
+ (- 1.0 (nth 1 color))
+ (- 1.0 (nth 2 color)))))
+
+(defun color-gradient (start stop step-number)
+ "Return a list with STEP-NUMBER colors from START to STOP.
+The color list builds a color gradient starting at color START to
+color STOP. It does not include the START and STOP color in the
+resulting list."
+ (let* ((r (nth 0 start))
+ (g (nth 1 start))
+ (b (nth 2 start))
+ (r-step (/ (- (nth 0 stop) r) (1+ step-number)))
+ (g-step (/ (- (nth 1 stop) g) (1+ step-number)))
+ (b-step (/ (- (nth 2 stop) b) (1+ step-number)))
+ result)
+ (dotimes (n step-number)
+ (push (list (setq r (+ r r-step))
+ (setq g (+ g g-step))
+ (setq b (+ b b-step)))
+ result))
+ (nreverse result)))
+
+(defun color-hue-to-rgb (v1 v2 h)
+ "Compute hue from V1 and V2 H.
+Used internally 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 hue, saturation and luminance to their RGB representation.
+H, S, and L should each be numbers between 0.0 and 1.0, inclusive.
+Return a list (RED GREEN BLUE), where each element is 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 (mod (+ H (/ 1.0 3)) 1))
+ (color-hue-to-rgb m1 m2 H)
+ (color-hue-to-rgb m1 m2 (mod (- H (/ 1.0 3)) 1))))))
(defun color-complement-hex (color)
"Return the color that is the complement of COLOR, in hexadecimal format."
- (apply 'color-rgb->hex (color-complement color)))
+ (apply 'color-rgb-to-hex (color-complement color)))
-(defun color-rgb->hsv (red green blue)
- "Convert RED GREEN BLUE values to HSV representation.
-Hue is in radian. Saturation and values are between [0,1]."
- (let* ((r (float red))
+(defun color-rgb-to-hsv (red green blue)
+ "Convert RGB color components to HSV.
+RED, GREEN, and BLUE should each be numbers between 0.0 and 1.0,
+inclusive. Return a list (HUE SATURATION VALUE), where HUE is
+in radians and both SATURATION and VALUE are between 0.0 and 1.0,
+inclusive."
+ (let* ((r (float red))
(g (float green))
(b (float blue))
(max (max r g b))
(min (min r g b)))
- (list
- (/ (* 2 float-pi
- (cond ((and (= r g) (= g b)) 0)
- ((and (= r max)
- (>= g b))
- (* 60 (/ (- g b) (- max min))))
- ((and (= r max)
- (< g b))
- (+ 360 (* 60 (/ (- g b) (- max min)))))
- ((= max g)
- (+ 120 (* 60 (/ (- b r) (- max min)))))
- ((= max b)
- (+ 240 (* 60 (/ (- r g) (- max min)))))))
- 360)
- (if (= max 0)
- 0
- (- 1 (/ min max)))
- (/ max 255.0))))
-
-(defun color-rgb->hsl (red green blue)
- "Convert RED GREEN BLUE colors to their HSL representation.
-RED, GREEN and BLUE must be between [0,1]."
+ (if (< (- max min) 1e-8)
+ (list 0.0 0.0 min)
+ (list
+ (/ (* 2 float-pi
+ (cond ((and (= r g) (= g b)) 0)
+ ((and (= r max)
+ (>= g b))
+ (* 60 (/ (- g b) (- max min))))
+ ((and (= r max)
+ (< g b))
+ (+ 360 (* 60 (/ (- g b) (- max min)))))
+ ((= max g)
+ (+ 120 (* 60 (/ (- b r) (- max min)))))
+ ((= max b)
+ (+ 240 (* 60 (/ (- r g) (- max min)))))))
+ &nbs
projects / gnus / blobdiff