Cache css color parser values

lib/canvas.js

@@ -34,6 +34,12 @@ exports.version = '0.0.1';
 
 exports.cairoVersion = cairoVersion;
 
+/**
+ * Cache color string RGBA values.
+ */
+
+var cache = {};
+
 /**
  * Parse the given color `str`.
  *
@@ -62,11 +68,12 @@ exports.cairoVersion = cairoVersion;
  */
 
 exports.parseColor = function(str){
+  if (cache[str]) return cache[str];
   str = colors[str] || String(str);
   if (0 == str.indexOf('rgba')) {
     var captures = /rgba\((\d{1,3}) *, *(\d{1,3}) *, *(\d{1,3}) *, *(\d+\.\d+|\.\d+|\d+) *\)/.exec(str);
     if (!captures) return;
-    return [
+    return cache[str] = [
         parseInt(captures[1], 10)
       , parseInt(captures[2], 10)
       , parseInt(captures[3], 10)
@@ -75,7 +82,7 @@ exports.parseColor = function(str){
   } else if (0 == str.indexOf('rgb')) {
     var captures = /rgb\((\d{1,3}) *, *(\d{1,3}) *, *(\d{1,3}) *\)/.exec(str);
     if (!captures) return;
-    return [
+    return cache[str] = [
         parseInt(captures[1], 10)
       , parseInt(captures[2], 10)
       , parseInt(captures[3], 10)
@@ -84,7 +91,7 @@ exports.parseColor = function(str){
   } else if ('#' == str.charAt(0) && str.length > 4) {
     var captures = /#(\w{2})(\w{2})(\w{2})/.exec(str);
     if (!captures) return;
-    return [
+    return cache[str] = [
         parseInt(captures[1], 16)
       , parseInt(captures[2], 16)
       , parseInt(captures[3], 16)
@@ -93,7 +100,7 @@ exports.parseColor = function(str){
   } else if ('#' == str.charAt(0)) {
     var captures = /#(\w)(\w)(\w)/.exec(str);
     if (!captures) return;
-    return [
+    return cache[str] = [
         parseInt(captures[1] + captures[1], 16)
       , parseInt(captures[2] + captures[2], 16)
       , parseInt(captures[3] + captures[3], 16)