This demonstration compares interpolation in RGB, HSL, CIE Lab and CIE LCH color spaces.
The code is available as the d3.cie plugin.
-
-
Save fgassert/11304263 to your computer and use it in GitHub Desktop.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| (function(d3) { | |
| var cie = d3.cie = {}; | |
| cie.lab = function(l, a, b) { | |
| return arguments.length === 1 | |
| ? (l instanceof Lab ? lab(l.l, l.a, l.b) | |
| : (l instanceof Lch ? lch_lab(l.l, l.c, l.h) | |
| : rgb_lab((l = d3.rgb(l)).r, l.g, l.b))) | |
| : lab(+l, +a, +b); | |
| }; | |
| cie.lch = function(l, c, h) { | |
| return arguments.length === 1 | |
| ? (l instanceof Lch ? lch(l.l, l.c, l.h) | |
| : (l instanceof Lab ? lab_lch(l.l, l.a, l.b) | |
| : lab_lch((l = rgb_lab((l = d3.rgb(l)).r, l.g, l.b)).l, l.a, l.b))) | |
| : lch(+l, +c, +h); | |
| }; | |
| cie.interpolateLab = function(a, b) { | |
| a = cie.lab(a); | |
| b = cie.lab(b); | |
| var al = a.l, | |
| aa = a.a, | |
| ab = a.b, | |
| bl = b.l - al, | |
| ba = b.a - aa, | |
| bb = b.b - ab; | |
| return function(t) { | |
| return lab_rgb(al + bl * t, aa + ba * t, ab + bb * t) + ""; | |
| }; | |
| }; | |
| cie.interpolateLch = function(a, b) { | |
| a = cie.lch(a); | |
| b = cie.lch(b); | |
| var al = a.l, | |
| ac = a.c, | |
| ah = a.h, | |
| bl = b.l - al, | |
| bc = b.c - ac, | |
| bh = b.h - ah; | |
| return function(t) { | |
| return lch_lab(al + bl * t, ac + bc * t, ah + bh * t) + ""; | |
| }; | |
| }; | |
| function lab(l, a, b) { | |
| return new Lab(l, a, b); | |
| } | |
| function Lab(l, a, b) { | |
| this.l = l; | |
| this.a = a; | |
| this.b = b; | |
| } | |
| Lab.prototype.brighter = function(k) { | |
| return lab(Math.min(100, this.l + K * (arguments.length ? k : 1)), this.a, this.b); | |
| }; | |
| Lab.prototype.darker = function(k) { | |
| return lab(Math.max(0, this.l - K * (arguments.length ? k : 1)), this.a, this.b); | |
| }; | |
| Lab.prototype.rgb = function() { | |
| return lab_rgb(this.l, this.a, this.b); | |
| }; | |
| Lab.prototype.toString = function() { | |
| return this.rgb() + ""; | |
| }; | |
| function lch(l, c, h) { | |
| return new Lch(l, c, h); | |
| } | |
| function Lch(l, c, h) { | |
| this.l = l; | |
| this.c = c; | |
| this.h = h; | |
| } | |
| Lch.prototype.brighter = function(k) { | |
| return lch(Math.min(100, this.l + K * (arguments.length ? k : 1)), this.c, this.h); | |
| }; | |
| Lch.prototype.darker = function(k) { | |
| return lch(Math.max(0, this.l - K * (arguments.length ? k : 1)), this.c, this.h); | |
| }; | |
| Lch.prototype.rgb = function() { | |
| return lch_lab(this.l, this.c, this.h).rgb(); | |
| }; | |
| Lch.prototype.toString = function() { | |
| return this.rgb() + ""; | |
| }; | |
| // Corresponds roughly to RGB brighter/darker | |
| var K = 18; | |
| // D65 standard referent | |
| var X = 0.950470, Y = 1, Z = 1.088830; | |
| function lab_rgb(l, a, b) { | |
| var y = (l + 16) / 116, x = y + a / 500, z = y - b / 200; | |
| x = lab_xyz(x) * X; | |
| y = lab_xyz(y) * Y; | |
| z = lab_xyz(z) * Z; | |
| return d3.rgb( | |
| xyz_rgb( 3.2404542 * x - 1.5371385 * y - 0.4985314 * z), | |
| xyz_rgb(-0.9692660 * x + 1.8760108 * y + 0.0415560 * z), | |
| xyz_rgb( 0.0556434 * x - 0.2040259 * y + 1.0572252 * z) | |
| ); | |
| } | |
| function rgb_lab(r, g, b) { | |
| r = rgb_xyz(r); | |
| g = rgb_xyz(g); | |
| b = rgb_xyz(b); | |
| var x = xyz_lab((0.4124564 * r + 0.3575761 * g + 0.1804375 * b) / X), | |
| y = xyz_lab((0.2126729 * r + 0.7151522 * g + 0.0721750 * b) / Y), | |
| z = xyz_lab((0.0193339 * r + 0.1191920 * g + 0.9503041 * b) / Z); | |
| return lab(116 * y - 16, 500 * (x - y), 200 * (y - z)); | |
| } | |
| function lab_lch(l, a, b) { | |
| var c = Math.sqrt(a * a + b * b), | |
| h = Math.atan2(b, a) / Math.PI * 180; | |
| return lch(l, c, h); | |
| } | |
| function lch_lab(l, c, h) { | |
| h = h * Math.PI / 180; | |
| return lab(l, Math.cos(h) * c, Math.sin(h) * c); | |
| } | |
| function lab_xyz(x) { | |
| return x > 0.206893034 ? x * x * x : (x - 4 / 29) / 7.787037; | |
| } | |
| function xyz_lab(x) { | |
| return x > 0.008856 ? Math.pow(x, 1 / 3) : 7.787037 * x + 4 / 29; | |
| } | |
| function xyz_rgb(r) { | |
| return Math.round(255 * (r <= 0.00304 ? 12.92 * r : 1.055 * Math.pow(r, 1 / 2.4) - 0.055)); | |
| } | |
| function rgb_xyz(r) { | |
| return (r /= 255) <= 0.04045 ? r / 12.92 : Math.pow((r + 0.055) / 1.055, 2.4); | |
| } | |
| })(d3); |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| body { | |
| font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; | |
| } | |
| </style> | |
| <body> | |
| <script src="http://d3js.org/d3.v2.min.js?2.9.5"></script> | |
| <script src="cie.js"></script> | |
| <script> | |
| var values = d3.range(960); | |
| var interpolators = { | |
| "hsl": d3.interpolateHsl, | |
| "rgb": d3.interpolateRgb, | |
| "lab": d3.cie.interpolateLab, | |
| "lch": d3.cie.interpolateLch | |
| }; | |
| var width = 960, | |
| height = 500; | |
| var y = d3.scale.ordinal() | |
| .domain(d3.keys(interpolators)) | |
| .rangeRoundBands([0, height], .1); | |
| var x = d3.scale.ordinal() | |
| .domain(values) | |
| .rangeRoundBands([0, width]); | |
| var color = d3.scale.linear() | |
| .domain([0, values.length - 1]) | |
| .range(["#ffc", "#232842"]); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var g = svg.selectAll("g") | |
| .data(d3.entries(interpolators)) | |
| .enter().append("g") | |
| .attr("transform", function(d) { return "translate(0," + y(d.key) + ")"; }); | |
| g.each(function(d) { | |
| color.interpolate(d.value); | |
| d3.select(this).selectAll("rect") | |
| .data(values) | |
| .enter().append("rect") | |
| .attr("x", x) | |
| .attr("width", x.rangeBand()) | |
| .attr("height", y.rangeBand) | |
| .style("fill", color); | |
| }); | |
| g.append("text") | |
| .attr("x", 16) | |
| .attr("y", y.rangeBand() / 2) | |
| .attr("dy", ".35em") | |
| .text(function(d) { return d.key; }); | |
| </script> |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment