BitmapText.js

/*
* BitmapText
* Visit http://createjs.com/ for window.documentation, updates and examples.
*
* Copyright (c) 2010 gskinner.com, inc.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated window.documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/

this.createjs = this.createjs || {};

(function () {
	"use strict";


// constructor:
	/**
	 * Displays text using bitmap glyphs defined in a sprite sheet. Multi-line text is supported
	 * using new line characters, but automatic wrapping is not supported. See the 
	 * {{#crossLink "BitmapText/spriteSheet:property"}}{{/crossLink}}
	 * property for more information on defining glyphs.
	 * 
	 * <strong>Important:</strong> BitmapText extends Container, but is not designed to be used as one.
	 * As such, methods like addChild and removeChild are disabled.
	 * @class BitmapText
	 * @extends DisplayObject
	 * @param {String} [text=""] The text to display.
	 * @param {SpriteSheet} [spriteSheet=null] The spritesheet that defines the character glyphs.
	 * @constructor
	 **/
	function BitmapText(text, spriteSheet) {
		this.Container_constructor();
		
		
	// public properties:
		/**
		 * The text to display.
		 * @property text
		 * @type String
		 * @default ""
		 **/
		this.text = text||"";
		
		/**
		 * A SpriteSheet instance that defines the glyphs for this bitmap text. Each glyph/character
		 * should have a single frame animation defined in the sprite sheet named the same as
		 * corresponding character. For example, the following animation definition:
		 *
		 * 		"A": {frames: [0]}
		 *
		 * would indicate that the frame at index 0 of the spritesheet should be drawn for the "A" character. The short form
		 * is also acceptable:
		 * 
		 * 		"A": 0
		 *
		 * Note that if a character in the text is not found in the sprite sheet, it will also
		 * try to use the alternate case (upper or lower).
		 *
		 * See SpriteSheet for more information on defining sprite sheet data.
		 * @property spriteSheet
		 * @type SpriteSheet
		 * @default null
		 **/
		this.spriteSheet = spriteSheet;
	
		/**
		 * The height of each line of text. If 0, then it will use a line height calculated
		 * by checking for the height of the "1", "T", or "L" character (in that order). If
		 * those characters are not defined, it will use the height of the first frame of the
		 * sprite sheet.
		 * @property lineHeight
		 * @type Number
		 * @default 0
		 **/
		this.lineHeight = 0;
	
		/**
		 * This spacing (in pixels) will be added after each character in the output.
		 * @property letterSpacing
		 * @type Number
		 * @default 0
		 **/
		this.letterSpacing = 0;
	
		/**
		 * If a space character is not defined in the sprite sheet, then empty pixels equal to
		 * spaceWidth will be inserted instead. If 0, then it will use a value calculated
		 * by checking for the width of the "1", "l", "E", or "A" character (in that order). If
		 * those characters are not defined, it will use the width of the first frame of the
		 * sprite sheet.
		 * @property spaceWidth
		 * @type Number
		 * @default 0
		 **/
		this.spaceWidth = 0;
		
		
	// private properties:
	 	/**
		 * @property _oldProps
		 * @type Object
		 * @protected
		 **/
		this._oldProps = {text:0,spriteSheet:0,lineHeight:0,letterSpacing:0,spaceWidth:0};
	}
	var p = createjs.extend(BitmapText, createjs.Container);

	/**
	 * <strong>REMOVED</strong>. Removed in favor of using `MySuperClass_constructor`.
	 * See {{#crossLink "Utility Methods/extend"}}{{/crossLink}} and {{#crossLink "Utility Methods/promote"}}{{/crossLink}}
	 * for details.
	 *
	 * There is an inheritance tutorial distributed with EaselJS in /tutorials/Inheritance.
	 *
	 * @method initialize
	 * @protected
	 * @deprecated
	 */
	// p.initialize = function() {}; // searchable for devs wondering where it is.

// static properties:
	/**
	 * BitmapText uses Sprite instances to draw text. To reduce the creation and destruction of instances (and thus garbage collection), it maintains
	 * an internal object pool of sprite instances to reuse. Increasing this value can cause more sprites to be
	 * retained, slightly increasing memory use, but reducing instantiation.
	 * @property maxPoolSize
	 * @type Number
	 * @static
	 * @default 100
	 **/
	BitmapText.maxPoolSize = 100;
	
	/**
	 * Sprite object pool.
	 * @type {Array}
	 * @static
	 * @private
	 */
	BitmapText._spritePool = [];

	
// public methods:
	/**
	 * Docced in superclass.
	 **/
	p.draw = function(ctx, ignoreCache) {
		if (this.DisplayObject_draw(ctx, ignoreCache)) { return; }
		this._updateText();
		this.Container_draw(ctx, ignoreCache);
	};
	
	/**
	 * Docced in superclass.
	 **/
	p.getBounds = function() {
		this._updateText();
		return this.Container_getBounds();
	};
	
	/**
	 * Returns true or false indicating whether the display object would be visible if drawn to a canvas.
	 * This does not account for whether it would be visible within the boundaries of the stage.
	 * NOTE: This method is mainly for internal use, though it may be useful for advanced uses.
	 * @method isVisible
	 * @return {Boolean} Boolean indicating whether the display object would be visible if drawn to a canvas
	 **/
	p.isVisible = function() {
		var hasContent = this.cacheCanvas || (this.spriteSheet && this.spriteSheet.complete && this.text);
		return !!(this.visible && this.alpha > 0 && this.scaleX !== 0 && this.scaleY !== 0 && hasContent);
	};
	
	p.clone = function() {
		return this._cloneProps(new BitmapText(this.text, this.spriteSheet));
	};
	
	/**
	 * <strong>Disabled in BitmapText.</strong>
	 * @method addChild
	 **/
	/**
	 * <strong>Disabled in BitmapText.</strong>
	 * @method addChildAt
	 **/
	/**
	 * <strong>Disabled in BitmapText.</strong>
	 * @method removeChild
	 **/
	/**
	 * <strong>Disabled in BitmapText.</strong>
	 * @method removeChildAt
	 **/
	/**
	 * <strong>Disabled in BitmapText.</strong>
	 * @method removeAllChildren
	 **/
	p.addChild = p.addChildAt = p.removeChild = p.removeChildAt = p.removeAllChildren = function() {};


// private methods:
 	/**
	 * @method _cloneProps
	 * @param {BitmapText} o
	 * @return {BitmapText} o
	 * @protected
	 **/
	p._cloneProps = function(o) {
		this.Container__cloneProps(o);
		o.lineHeight = this.lineHeight;
		o.letterSpacing = this.letterSpacing;
		o.spaceWidth = this.spaceWidth;
		return o;
	};
	
	/**
	 * @method _getFrameIndex
	 * @param {String} character
	 * @param {SpriteSheet} spriteSheet
	 * @return {Number}
	 * @protected
	 **/
	p._getFrameIndex = function(character, spriteSheet) {
		var c, o = spriteSheet.getAnimation(character);
		if (!o) {
			(character != (c = character.toUpperCase())) || (character != (c = character.toLowerCase())) || (c=null);
			if (c) { o = spriteSheet.getAnimation(c); }
		}
		return o && o.frames[0];
	};
	
	/**
	 * @method _getFrame
	 * @param {String} character
	 * @param {SpriteSheet} spriteSheet
	 * @return {Object}
	 * @protected
	 **/
	p._getFrame = function(character, spriteSheet) {
		var index = this._getFrameIndex(character, spriteSheet);
		return index == null ? index : spriteSheet.getFrame(index);
	};
	
	/**
	 * @method _getLineHeight
	 * @param {SpriteSheet} ss
	 * @return {Number}
	 * @protected
	 **/
	p._getLineHeight = function(ss) {
		var frame = this._getFrame("1",ss) || this._getFrame("T",ss) || this._getFrame("L",ss) || ss.getFrame(0);
		return frame ? frame.rect.height : 1;
	};
	/**
	 * @method _getSpaceWidth
	 * @param {SpriteSheet} ss
	 * @return {Number}
	 * @protected
	 **/
	p._getSpaceWidth = function(ss) {
		var frame = this._getFrame("1",ss) || this._getFrame("l",ss) || this._getFrame("e",ss) || this._getFrame("a",ss) || ss.getFrame(0);
		return frame ? frame.rect.width : 1;
	};
	
	/**
	 * @method _drawText
	 * @protected
	 **/
	p._updateText = function() {
		var x=0, y=0, o=this._oldProps, change=false, spaceW=this.spaceWidth, lineH=this.lineHeight, ss=this.spriteSheet;
		var pool=BitmapText._spritePool, kids=this.children, childIndex=0, numKids=kids.length, sprite;
		
		for (var n in o) {
			if (o[n] != this[n]) {
				o[n] = this[n];
				change = true;
			}
		}
		if (!change) { return; }
		
		var hasSpace = !!this._getFrame(" ", ss);
		if (!hasSpace && !spaceW) { spaceW = this._getSpaceWidth(ss); }
		if (!lineH) { lineH = this._getLineHeight(ss); }
		
		for(var i=0, l=this.text.length; i<l; i++) {
			var character = this.text.charAt(i);
			if (character == " " && !hasSpace) {
				x += spaceW;
				continue;
			} else if (character=="\n" || character=="\r") {
				if (character=="\r" && this.text.charAt(i+1) == "\n") { i++; } // crlf
				x = 0;
				y += lineH;
				continue;
			}

			var index = this._getFrameIndex(character, ss);
			if (index == null) { continue; }
			
			if (childIndex < numKids) {
				sprite = kids[childIndex];
			} else {
				kids.push(sprite = pool.length ? pool.pop() : new createjs.Sprite());
				sprite.parent = this;
				numKids++;
			}
			sprite.spriteSheet = ss;
			sprite.gotoAndStop(index);
			sprite.x = x;
			sprite.y = y;
			childIndex++;
			
			x += sprite.getBounds().width + this.letterSpacing;
		}
		while (numKids > childIndex) {
			 // faster than removeChild.
			pool.push(sprite = kids.pop());
			sprite.parent = null;
			numKids--;
		}
		if (pool.length > BitmapText.maxPoolSize) { pool.length = BitmapText.maxPoolSize; }
	};


	createjs.BitmapText = createjs.promote(BitmapText, "Container");
}());