X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/7c420169baa7c50428589cca7f8eda71b462eb15..0f74f7850de124626d556442d22d143d85457816:/lisp/color.el diff --git a/lisp/color.el b/lisp/color.el index 07044333c4..5b67eb58a6 100644 --- a/lisp/color.el +++ b/lisp/color.el @@ -1,9 +1,10 @@ -;;; 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) 2010-2011 Free Software Foundation, Inc. -;; Author: Julien Danjou -;; Keywords: html +;; Authors: Julien Danjou +;; Drew Adams +;; Keywords: lisp, faces, color, hex, rgb, hsv, hsl, cie-lab, background ;; This file is part of GNU Emacs. @@ -22,7 +23,13 @@ ;;; 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, luminence), sRGB, +;; CIE XYZ, and CIE L*a*b* color components. ;;; Code: @@ -34,54 +41,96 @@ (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 and 1 inclusively." +;;;###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 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))) + +(defun color-rgb-to-hex (red green blue) + "Return hexadecimal notation for the color RED GREEN BLUE. +RED GREEN BLUE must 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))) +(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 (car color)) (- 1.0 (cadr color)) (- 1.0 (caddr 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-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 radians. Saturation and values are between 0 and 1 -inclusively." - (let* ((r (float red)) +(defun color-rgb-to-hsv (red green blue) + "Convert RED, GREEN, and BLUE 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) + (if (< (- max min) 1e-8) + (list 0.0 0.0 0.0) + (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-to-hsl (red green blue) "Convert RED GREEN BLUE colors to their HSL representation. -RED, GREEN and BLUE must be between 0 and 1 inclusively." +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, +inclusive." (let* ((r red) (g green) (b blue) @@ -90,13 +139,13 @@ RED, GREEN and BLUE must be between 0 and 1 inclusively." (delta (- max min)) (l (/ (+ max min) 2.0))) (list - (if (= max min) + (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)) + (+ (/ (- b r) delta) 2)) (t (+ (/ (- r g) delta) 4))) 6))) @@ -107,9 +156,9 @@ RED, GREEN and BLUE must be between 0 and 1 inclusively." (/ delta (+ max min)))) l))) -(defun color-srgb->xyz (red green blue) - "Converts RED GREEN BLUE colors from the sRGB color space to CIE XYZ. -RED, BLUE and GREEN must be between 0 and 1 inclusively." +(defun color-srgb-to-xyz (red green blue) + "Convert RED GREEN BLUE colors from the sRGB color space to CIE XYZ. +RED, BLUE and GREEN must be between 0 and 1, inclusive." (let ((r (if (<= red 0.04045) (/ red 12.95) (expt (/ (+ red 0.055) 1.055) 2.4))) @@ -123,8 +172,8 @@ RED, BLUE and GREEN must be between 0 and 1 inclusively." (+ (* 0.21266729 r) (* 0.7151522 g) (* 0.0721750 b)) (+ (* 0.0193339 r) (* 0.1191920 g) (* 0.9503041 b))))) -(defun color-xyz->srgb (X Y Z) - "Converts CIE X Y Z colors to sRGB color space." +(defun color-xyz-to-srgb (X Y Z) + "Convert CIE X Y Z colors to sRGB color space." (let ((r (+ (* 3.2404542 X) (* -1.5371385 Y) (* -0.4985314 Z))) (g (+ (* -0.9692660 X) (* 1.8760108 Y) (* 0.0415560 Z))) (b (+ (* 0.0556434 X) (* -0.2040259 Y) (* 1.0572252 Z)))) @@ -144,10 +193,10 @@ RED, BLUE and GREEN must be between 0 and 1 inclusively." (defconst color-cie-ε (/ 216 24389.0)) (defconst color-cie-κ (/ 24389 27.0)) -(defun color-xyz->lab (X Y Z &optional white-point) - "Converts CIE XYZ to CIE L*a*b*. -WHITE-POINT can be specified as (X Y Z) white point to use. If -none is set, `color-d65-xyz' is used." +(defun color-xyz-to-lab (X Y Z &optional white-point) + "Convert CIE XYZ to CIE L*a*b*. +WHITE-POINT specifies the (X Y Z) white point for the +conversion. If omitted or nil, use `color-d65-xyz'." (destructuring-bind (Xr Yr Zr) (or white-point color-d65-xyz) (let* ((xr (/ X Xr)) (yr (/ Y Yr)) @@ -166,10 +215,10 @@ none is set, `color-d65-xyz' is used." (* 500 (- fx fy)) ; a (* 200 (- fy fz)))))) ; b -(defun color-lab->xyz (L a b &optional white-point) - "Converts CIE L*a*b* to CIE XYZ. -WHITE-POINT can be specified as (X Y Z) white point to use. If -none is set, `color-d65-xyz' is used." +(defun color-lab-to-xyz (L a b &optional white-point) + "Convert CIE L*a*b* to CIE XYZ. +WHITE-POINT specifies the (X Y Z) white point for the +conversion. If omitted or nil, use `color-d65-xyz'." (destructuring-bind (Xr Yr Zr) (or white-point color-d65-xyz) (let* ((fy (/ (+ L 16) 116.0)) (fz (- fy (/ b 200.0))) @@ -187,21 +236,18 @@ none is set, `color-d65-xyz' is used." (* yr Yr) ; Y (* zr Zr))))) ; Z -(defun color-srgb->lab (red green blue) - "Converts RGB to CIE L*a*b*." - (apply 'color-xyz->lab (color-srgb->xyz red green blue))) - -(defun color-rgb->normalize (color) - "Normalize a RGB color to values between 0 and 1 inclusively." - (mapcar (lambda (x) (/ x 65535.0)) (x-color-values color))) +(defun color-srgb-to-lab (red green blue) + "Convert RGB to CIE L*a*b*." + (apply 'color-xyz-to-lab (color-srgb-to-xyz red green blue))) -(defun color-lab->srgb (L a b) - "Converts CIE L*a*b* to RGB." - (apply 'color-xyz->srgb (color-lab->xyz L a b))) +(defun color-lab-to-srgb (L a b) + "Convert CIE L*a*b* to RGB." + (apply 'color-xyz-to-srgb (color-lab-to-xyz L a b))) (defun color-cie-de2000 (color1 color2 &optional kL kC kH) - "Computes the CIEDE2000 color distance between COLOR1 and COLOR2. -Colors must be in CIE L*a*b* format." + "Return the CIEDE2000 color distance between COLOR1 and COLOR2. +Both COLOR1 and COLOR2 should be in CIE L*a*b* format, as +returned by `color-srgb-to-lab' or `color-xyz-to-lab'." (destructuring-bind (L₁ a₁ b₁) color1 (destructuring-bind (L₂ a₂ b₂) color2 (let* ((kL (or kL 1))