/*!
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* Ext JS Library 3.1.0
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* Copyright(c) 2006-2009 Ext JS, LLC
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* licensing@extjs.com
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* http://www.extjs.com/license
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*/
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/**
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* @class Ext.util.TextMetrics
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* Provides precise pixel measurements for blocks of text so that you can determine exactly how high and
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* wide, in pixels, a given block of text will be. Note that when measuring text, it should be plain text and
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* should not contain any HTML, otherwise it may not be measured correctly.
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* @singleton
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*/
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Ext.util.TextMetrics = function(){
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var shared;
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return {
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/**
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* Measures the size of the specified text
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* @param {String/HTMLElement} el The element, dom node or id from which to copy existing CSS styles
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* that can affect the size of the rendered text
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* @param {String} text The text to measure
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* @param {Number} fixedWidth (optional) If the text will be multiline, you have to set a fixed width
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* in order to accurately measure the text height
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* @return {Object} An object containing the text's size {width: (width), height: (height)}
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*/
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measure : function(el, text, fixedWidth){
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if(!shared){
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shared = Ext.util.TextMetrics.Instance(el, fixedWidth);
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}
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shared.bind(el);
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shared.setFixedWidth(fixedWidth || 'auto');
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return shared.getSize(text);
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},
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/**
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* Return a unique TextMetrics instance that can be bound directly to an element and reused. This reduces
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* the overhead of multiple calls to initialize the style properties on each measurement.
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* @param {String/HTMLElement} el The element, dom node or id that the instance will be bound to
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* @param {Number} fixedWidth (optional) If the text will be multiline, you have to set a fixed width
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* in order to accurately measure the text height
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* @return {Ext.util.TextMetrics.Instance} instance The new instance
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*/
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createInstance : function(el, fixedWidth){
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return Ext.util.TextMetrics.Instance(el, fixedWidth);
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}
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};
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}();
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Ext.util.TextMetrics.Instance = function(bindTo, fixedWidth){
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var ml = new Ext.Element(document.createElement('div'));
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document.body.appendChild(ml.dom);
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ml.position('absolute');
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ml.setLeftTop(-1000, -1000);
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ml.hide();
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if(fixedWidth){
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ml.setWidth(fixedWidth);
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}
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var instance = {
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/**
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* <p><b>Only available on the instance returned from {@link #createInstance}, <u>not</u> on the singleton.</b></p>
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* Returns the size of the specified text based on the internal element's style and width properties
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* @param {String} text The text to measure
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* @return {Object} An object containing the text's size {width: (width), height: (height)}
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*/
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getSize : function(text){
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ml.update(text);
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var s = ml.getSize();
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ml.update('');
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return s;
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},
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/**
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* <p><b>Only available on the instance returned from {@link #createInstance}, <u>not</u> on the singleton.</b></p>
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* Binds this TextMetrics instance to an element from which to copy existing CSS styles
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* that can affect the size of the rendered text
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* @param {String/HTMLElement} el The element, dom node or id
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*/
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bind : function(el){
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ml.setStyle(
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Ext.fly(el).getStyles('font-size','font-style', 'font-weight', 'font-family','line-height', 'text-transform', 'letter-spacing')
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);
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},
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/**
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* <p><b>Only available on the instance returned from {@link #createInstance}, <u>not</u> on the singleton.</b></p>
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* Sets a fixed width on the internal measurement element. If the text will be multiline, you have
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* to set a fixed width in order to accurately measure the text height.
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* @param {Number} width The width to set on the element
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*/
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setFixedWidth : function(width){
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ml.setWidth(width);
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},
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/**
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* <p><b>Only available on the instance returned from {@link #createInstance}, <u>not</u> on the singleton.</b></p>
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* Returns the measured width of the specified text
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* @param {String} text The text to measure
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* @return {Number} width The width in pixels
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*/
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getWidth : function(text){
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ml.dom.style.width = 'auto';
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return this.getSize(text).width;
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},
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/**
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* <p><b>Only available on the instance returned from {@link #createInstance}, <u>not</u> on the singleton.</b></p>
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* Returns the measured height of the specified text. For multiline text, be sure to call
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* {@link #setFixedWidth} if necessary.
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* @param {String} text The text to measure
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* @return {Number} height The height in pixels
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*/
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getHeight : function(text){
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return this.getSize(text).height;
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}
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};
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instance.bind(bindTo);
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return instance;
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};
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Ext.Element.addMethods({
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/**
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* Returns the width in pixels of the passed text, or the width of the text in this Element.
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* @param {String} text The text to measure. Defaults to the innerHTML of the element.
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* @param {Number} min (Optional) The minumum value to return.
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* @param {Number} max (Optional) The maximum value to return.
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* @return {Number} The text width in pixels.
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* @member Ext.Element getTextWidth
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*/
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getTextWidth : function(text, min, max){
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return (Ext.util.TextMetrics.measure(this.dom, Ext.value(text, this.dom.innerHTML, true)).width).constrain(min || 0, max || 1000000);
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}
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});
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