Add color helper plugin, it might be better to host it elsewhere, but

for now it's available here


git-svn-id: https://flot.googlecode.com/svn/trunk@219 1e0a6537-2640-0410-bfb7-f154510ff394

jquery.colorhelpers.js

+/* Plugin for jQuery for working with colors.
+ * 
+ * Version 1.0.
+ * 
+ * Inspiration from jQuery color animation plugin by John Resig.
+ *
+ * Released under the MIT license by Ole Laursen, October 2009.
+ *
+ * Examples:
+ *
+ *   $.color.parse("#fff").scale('rgb', 0.25).add('a', -0.5).toString()
+ *   var c = $.color.extract($("#mydiv"), 'background-color');
+ *   console.log(c.r, c.g, c.b, c.a);
+ *   $.color.make(100, 50, 25, 0.4).toString() // returns "rgba(100,50,25,0.4)"
+ *
+ * Note that .scale() and .add() work in-place instead of returning
+ * new objects.
+ */ 
+
+(function() {
+    jQuery.color = {};
+
+    // construct color object with some convenient chainable helpers
+    jQuery.color.make = function (r, g, b, a) {
+        var o = {};
+        o.r = r || 0;
+        o.g = g || 0;
+        o.b = b || 0;
+        o.a = a != null ? a : 1;
+
+        o.add = function (c, d) {
+            for (var i = 0; i < c.length; ++i)
+                o[c.charAt(i)] += d;
+            return o.normalize();
+        };
+        
+        o.scale = function (c, f) {
+            for (var i = 0; i < c.length; ++i)
+                o[c.charAt(i)] *= f;
+            return o.normalize();
+        };
+        
+        o.toString = function () {
+            if (o.a >= 1.0) {
+                return "rgb("+[o.r, o.g, o.b].join(",")+")";
+            } else {
+                return "rgba("+[o.r, o.g, o.b, o.a].join(",")+")";
+            }
+        };
+
+        o.normalize = function () {
+            function clamp(min, value, max) {
+                return value < min ? min: (value > max ? max: value);
+            }
+            
+            o.r = clamp(0, parseInt(o.r), 255);
+            o.g = clamp(0, parseInt(o.g), 255);
+            o.b = clamp(0, parseInt(o.b), 255);
+            o.a = clamp(0, o.a, 1);
+            return o;
+        };
+
+        o.clone = function () {
+            return jQuery.color.make(o.r, o.b, o.g, o.a);
+        };
+
+        return o.normalize();
+    }
+
+    // extract CSS color property from element, going up in the DOM
+    // if it's "transparent"
+    jQuery.color.extract = function (elem, css) {
+        var c;
+        do {
+            c = elem.css(css).toLowerCase();
+            // keep going until we find an element that has color, or
+            // we hit the body
+            if (c != '' && c != 'transparent')
+                break;
+            elem = elem.parent();
+        } while (!jQuery.nodeName(elem.get(0), "body"));
+
+        // catch Safari's way of signalling transparent
+        if (c == "rgba(0, 0, 0, 0)")
+            c = "transparent";
+        
+        return jQuery.color.parse(c);
+    }
+    
+    // parse CSS color string (like "rgb(10, 32, 43)" or "#fff"),
+    // returns color object
+    jQuery.color.parse = function (str) {
+        var res, m = jQuery.color.make;
+
+        // Look for rgb(num,num,num)
+        if (res = /rgb\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*\)/.exec(str))
+            return m(parseInt(res[1], 10), parseInt(res[2], 10), parseInt(res[3], 10));
+        
+        // Look for rgba(num,num,num,num)
+        if (res = /rgba\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]+(?:\.[0-9]+)?)\s*\)/.exec(str))
+            return m(parseInt(res[1], 10), parseInt(res[2], 10), parseInt(res[3], 10), parseFloat(res[4]));
+            
+        // Look for rgb(num%,num%,num%)
+        if (res = /rgb\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*\)/.exec(str))
+            return m(parseFloat(res[1])*2.55, parseFloat(res[2])*2.55, parseFloat(res[3])*2.55);
+
+        // Look for rgba(num%,num%,num%,num)
+        if (res = /rgba\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\s*\)/.exec(str))
+            return m(parseFloat(res[1])*2.55, parseFloat(res[2])*2.55, parseFloat(res[3])*2.55, parseFloat(res[4]));
+        
+        // Look for #a0b1c2
+        if (res = /#([a-fA-F0-9]{2})([a-fA-F0-9]{2})([a-fA-F0-9]{2})/.exec(str))
+            return m(parseInt(res[1], 16), parseInt(res[2], 16), parseInt(res[3], 16));
+
+        // Look for #fff
+        if (res = /#([a-fA-F0-9])([a-fA-F0-9])([a-fA-F0-9])/.exec(str))
+            return m(parseInt(res[1]+res[1], 16), parseInt(res[2]+res[2], 16), parseInt(res[3]+res[3], 16));
+
+        // Otherwise, we're most likely dealing with a named color
+        var name = jQuery.trim(str).toLowerCase();
+        if (name == "transparent")
+            return m(255, 255, 255, 0);
+        else {
+            res = lookupColors[name];
+            return m(res[0], res[1], res[2]);
+        }
+    }
+    
+    var lookupColors = {
+        aqua:[0,255,255],
+        azure:[240,255,255],
+        beige:[245,245,220],
+        black:[0,0,0],
+        blue:[0,0,255],
+        brown:[165,42,42],
+        cyan:[0,255,255],
+        darkblue:[0,0,139],
+        darkcyan:[0,139,139],
+        darkgrey:[169,169,169],
+        darkgreen:[0,100,0],
+        darkkhaki:[189,183,107],
+        darkmagenta:[139,0,139],
+        darkolivegreen:[85,107,47],
+        darkorange:[255,140,0],
+        darkorchid:[153,50,204],
+        darkred:[139,0,0],
+        darksalmon:[233,150,122],
+        darkviolet:[148,0,211],
+        fuchsia:[255,0,255],
+        gold:[255,215,0],
+        green:[0,128,0],
+        indigo:[75,0,130],
+        khaki:[240,230,140],
+        lightblue:[173,216,230],
+        lightcyan:[224,255,255],
+        lightgreen:[144,238,144],
+        lightgrey:[211,211,211],
+        lightpink:[255,182,193],
+        lightyellow:[255,255,224],
+        lime:[0,255,0],
+        magenta:[255,0,255],
+        maroon:[128,0,0],
+        navy:[0,0,128],
+        olive:[128,128,0],
+        orange:[255,165,0],
+        pink:[255,192,203],
+        purple:[128,0,128],
+        violet:[128,0,128],
+        red:[255,0,0],
+        silver:[192,192,192],
+        white:[255,255,255],
+        yellow:[255,255,0]
+    };    
+})();