/**
+ * @class Ext.util.TextMetrics
+ * Provides precise pixel measurements for blocks of text so that you can determine exactly how high and
+ * wide, in pixels, a given block of text will be. Note that when measuring text, it should be plain text and
+ * should not contain any HTML, otherwise it may not be measured correctly.
+ * @singleton
+ */
+Ext.util.TextMetrics = function(){
+ var shared;
+ return {
+ /**
+ * Measures the size of the specified text
+ * @param {String/HTMLElement} el The element, dom node or id from which to copy existing CSS styles
+ * that can affect the size of the rendered text
+ * @param {String} text The text to measure
+ * @param {Number} fixedWidth (optional) If the text will be multiline, you have to set a fixed width
+ * in order to accurately measure the text height
+ * @return {Object} An object containing the text's size {width: (width), height: (height)}
+ */
+ measure : function(el, text, fixedWidth){
+ if(!shared){
+ shared = Ext.util.TextMetrics.Instance(el, fixedWidth);
+ }
+ shared.bind(el);
+ shared.setFixedWidth(fixedWidth || 'auto');
+ return shared.getSize(text);
+ },
+
+ /**
+ * Return a unique TextMetrics instance that can be bound directly to an element and reused. This reduces
+ * the overhead of multiple calls to initialize the style properties on each measurement.
+ * @param {String/HTMLElement} el The element, dom node or id that the instance will be bound to
+ * @param {Number} fixedWidth (optional) If the text will be multiline, you have to set a fixed width
+ * in order to accurately measure the text height
+ * @return {Ext.util.TextMetrics.Instance} instance The new instance
+ */
+ createInstance : function(el, fixedWidth){
+ return Ext.util.TextMetrics.Instance(el, fixedWidth);
+ }
+ };
+}();
+
+Ext.util.TextMetrics.Instance = function(bindTo, fixedWidth){
+ var ml = new Ext.Element(document.createElement('div'));
+ document.body.appendChild(ml.dom);
+ ml.position('absolute');
+ ml.setLeftTop(-1000, -1000);
+ ml.hide();
+
+ if(fixedWidth){
+ ml.setWidth(fixedWidth);
+ }
+
+ var instance = {
+ /**
+ * Returns the size of the specified text based on the internal element's style and width properties
+ * @param {String} text The text to measure
+ * @return {Object} An object containing the text's size {width: (width), height: (height)}
+ */
+ getSize : function(text){
+ ml.update(text);
+ var s = ml.getSize();
+ ml.update('');
+ return s;
+ },
+
+ /**
+ * Binds this TextMetrics instance to an element from which to copy existing CSS styles
+ * that can affect the size of the rendered text
+ * @param {String/HTMLElement} el The element, dom node or id
+ */
+ bind : function(el){
+ ml.setStyle(
+ Ext.fly(el).getStyles('font-size','font-style', 'font-weight', 'font-family','line-height', 'text-transform', 'letter-spacing')
+ );
+ },
+
+ /**
+ * Sets a fixed width on the internal measurement element. If the text will be multiline, you have
+ * to set a fixed width in order to accurately measure the text height.
+ * @param {Number} width The width to set on the element
+ */
+ setFixedWidth : function(width){
+ ml.setWidth(width);
+ },
+
+ /**
+ * Returns the measured width of the specified text
+ * @param {String} text The text to measure
+ * @return {Number} width The width in pixels
+ */
+ getWidth : function(text){
+ ml.dom.style.width = 'auto';
+ return this.getSize(text).width;
+ },
+
+ /**
+ * Returns the measured height of the specified text. For multiline text, be sure to call
+ * {@link #setFixedWidth} if necessary.
+ * @param {String} text The text to measure
+ * @return {Number} height The height in pixels
+ */
+ getHeight : function(text){
+ return this.getSize(text).height;
+ }
+ };
+
+ instance.bind(bindTo);
+
+ return instance;
+};
+
+Ext.Element.addMethods({
+ /**
+ * Returns the width in pixels of the passed text, or the width of the text in this Element.
+ * @param {String} text The text to measure. Defaults to the innerHTML of the element.
+ * @param {Number} min (Optional) The minumum value to return.
+ * @param {Number} max (Optional) The maximum value to return.
+ * @return {Number} The text width in pixels.
+ * @member Ext.Element getTextWidth
+ */
+ getTextWidth : function(text, min, max){
+ return (Ext.util.TextMetrics.measure(this.dom, Ext.value(text, this.dom.innerHTML, true)).width).constrain(min || 0, max || 1000000);
+ }
+});
+