From 634e9ac890a1f31aa7fdd36ea69a30e0f2c5de69 Mon Sep 17 00:00:00 2001
From: Fabian Jakobs <fabian.jakobs@web.de>
Date: Wed, 15 Dec 2010 14:13:44 +0100
Subject: [PATCH] optimize text size measurement code and fix ugly off by one
 error

---
 lib/ace/layer/text.js | 42 ++++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/lib/ace/layer/text.js b/lib/ace/layer/text.js
index c8f60391..7af4c7aa 100644
--- a/lib/ace/layer/text.js
+++ b/lib/ace/layer/text.js
@@ -39,6 +39,7 @@ define(function(require, exports, module) {
 
 var oop = require("pilot/oop");
 var dom = require("pilot/dom");
+var lang = require("pilot/lang");
 var EventEmitter = require("pilot/event_emitter").EventEmitter;
 
 var Text = function(parentEl) {
@@ -79,7 +80,7 @@ var Text = function(parentEl) {
                 self.$characterSize = size;
                 self._dispatchEvent("changeCharaterSize", {data: size});
             }
-        }, 1000);
+        }, 500);
     };
 
     this.$fontStyles = {
@@ -91,32 +92,37 @@ var Text = function(parentEl) {
     },
 
     this.$measureSizes = function() {
-        var measureNode = document.createElement("div");
-        var style = measureNode.style;
-
-        style.width = style.height = "auto";
-        style.left = style.top = "-1000px";
-        style.visibility = "hidden";
-        style.position = "absolute";
-        style.overflow = "visible";
+        if (!this.$measureNode) {
+	        var measureNode = this.$measureNode = document.createElement("div");
+	        var style = measureNode.style;
+	
+	        style.width = style.height = "auto";
+	        style.left = style.top = "-1000px";
+	        
+	        style.visibility = "hidden";
+	        style.position = "absolute";
+	        style.overflow = "visible";
+	        style.whiteSpace = "nowrap";
+	
+	        // in FF 3.6 monospace fonts can have a fixed sub pixel width.
+	        // that's why we have to measure many characters
+	        // Note: characterWidth can be a float!
+	        var n = 1000;
+	        measureNode.innerHTML = lang.stringRepeat("Xy", n);
+	        document.body.insertBefore(measureNode, document.body.firstChild);
+        }
 
+        var style = this.$measureNode;
         for (var prop in this.$fontStyles) {
             var value = dom.computedStyle(this.element, prop);
             style[prop] = value;
         }
 
-        // in FF 3.6 monospace fonts can have a fixed sub pixel width.
-        // that's why we have to measure many characters
-        // Note: characterWidth can be a float!
-        measureNode.innerHTML = new Array(10000).join("Xy");
-        document.body.insertBefore(measureNode, document.body.firstChild);
-
         var size = {
-            height: measureNode.offsetHeight,
-            width: measureNode.offsetWidth / 20000
+            height: this.$measureNode.offsetHeight,
+            width: this.$measureNode.offsetWidth / (n * 2)
         };
 
-        document.body.removeChild(measureNode);
         return size;
     };