New rule: similar colors

2015-09-20 01:06:42 +02:00
parent bdbd1a0f08
commit d0257fea8f
9 changed files with 235 additions and 3 deletions
@@ -0,0 +1,90 @@
+var debug   = require('debug')('ylt:colorDiff');
+var diff    = require('color-diff');
+var parse   = require('parse-color');
+
+
+var colorDiff = function() {
+
+    var COLOR_DIFF_THRESHOLD = 0.9;
+
+    this.compareAllColors = function(data) {
+        debug('Starting to compare all colors...');
+
+        var offenders = data.toolsResults.phantomas.offenders.cssColors;
+        var colors = (offenders) ? this.parseAllColors(offenders) : [];
+        var result = [];
+
+        // Compare colors to each other
+        for (var i = 0; i < colors.length - 1 ; i++) {
+            for (var j = i + 1; j < colors.length; j++) {
+                debug('Comparing color %s with color %s', colors[i].original, colors[j].original);
+                if (this.compareTwoColors(colors[i], colors[j])) {
+                    debug('Colors are similar!');
+                    result.push({
+                        color1: colors[i].original,
+                        color2: colors[j].original,
+                        isDark: (colors[i].Lab.L < 60)
+                    });
+                }
+            }
+        }
+
+        data.toolsResults.colorDiff = {
+            metrics: {
+                similarColors: result.length
+            },
+            offenders: {
+                similarColors: result
+            }
+        };
+
+        return data;
+    };
+
+    this.parseAllColors = function(offenders) {
+        var parsedOffenders = offenders.map(this.parseOffender);
+        var deduplicatedColors = {};
+
+        parsedOffenders.forEach(function(color) {
+            deduplicatedColors[color] = color;
+        });
+
+        return Object.keys(deduplicatedColors).map(this.parseColor);
+    };
+
+    this.parseOffender = function(offender) {
+        var regexResult = /^(.*) \(\d+ times\)$/.exec(offender);
+        return regexResult[1];
+    };
+
+    this.parseColor = function(color) {
+        var colorArray = parse(color).rgba;
+
+        var obj = {
+            R: colorArray[0],
+            G: colorArray[1],
+            B: colorArray[2],
+            A: colorArray[3]
+        };
+
+        obj.Lab = diff.rgb_to_lab(obj);
+        obj.original = color;
+
+        return obj;
+    };
+
+    this.compareTwoColors = function(color1, color2) {
+        if (color1.A !== color2.A) {
+            debug('Comparison not possible, because the alpha channel is different');
+            return false;
+        }
+
+        var delta = diff.diff(color1.Lab, color2.Lab);
+        debug('Delta is %d', delta);
+        
+        return delta <= COLOR_DIFF_THRESHOLD;
+    };
+
+};
+
+module.exports = new colorDiff();