textsprite.as

用于flash/flex的 as3的 2D图形图像图表的动态生成

package flare.display
{
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.DisplayObject;
	import flash.geom.Rectangle;
	import flash.text.TextField;
	import flash.text.TextFieldAutoSize;
	import flash.text.TextFormat;

	/**
	 * A Sprite representing a text label.
	 * TextSprites support multiple forms of text representation: bitmapped
	 * text, embedded font text, and standard (device font) text. This allows
	 * flexibility in how text labels are handled. For example, by default,
	 * text fields using device fonts do not support alpha blending or
	 * rotation. By using a TextSprite in BITMAP mode, the text is rendered
	 * out to a bitmap which can then be alpha blended.
	 */
	public class TextSprite extends DirtySprite
	{
		// vertical anchors
		/**
		 * Constant for vertically aligning the top of the text field
		 * to a TextSprite's y-coordinate.
		 */
		public static const TOP:int = 0;
		/**
		 * Constant for vertically aligning the middle of the text field
		 * to a TextSprite's y-coordinate.
		 */
		public static const MIDDLE:int = 1;
		/**
		 * Constant for vertically aligning the bottom of the text field
		 * to a TextSprite's y-coordinate.
		 */
		public static const BOTTOM:int = 2;

		// horizontal anchors
		/**
		 * Constant for horizontally aligning the left of the text field
		 * to a TextSprite's y-coordinate.
		 */
		public static const LEFT:int = 0;
		/**
		 * Constant for horizontally aligning the center of the text field
		 * to a TextSprite's y-coordinate.
		 */
		public static const CENTER:int = 1;
		/**
		 * Constant for horizontally aligning the right of the text field
		 * to a TextSprite's y-coordinate.
		 */
		public static const RIGHT:int = 2;
		
		// text handling modes
		/**
		 * Constant indicating that text should be rendered using a TextField
		 * instance using device fonts.
		 */
		public static const DEVICE:uint = 0;
		/**
		 * Constant indicating that text should be rendered using a TextField
		 * instance using embedded fonts. For this mode to work, the fonts
		 * used must be embedded in your application SWF file.
		 */
		public static const EMBED:uint = 1;
		/**
		 * Constant indicating that text should be rendered into a Bitmap
		 * instance.
		 */
		public static const BITMAP:uint = 2;
		
		private var _mode:int = -1;
		private var _bmap:Bitmap;
		private var _tf:TextField;
		private var _fmt:TextFormat;
		
		private var _hAnchor:int = LEFT;
		private var _vAnchor:int = TOP;
		
		/** The TextField instance backing this TextSprite. */
		public function get textField():TextField { return _tf; }
		
		/** The bitmap of the text, if in BITMAP mode. */
		public function get bitmap():Bitmap { return _bmap; }
		
		/**
		 * The text rendering mode for this TextSprite, one of BITMAP,
		 * DEVICE, or EMBED.
		 */
		public function get textMode():int { return _mode; }
		public function set textMode(mode:int):void {
			setMode(mode);
		}
		
		/** The default text format for this text sprite. */
		public function get textFormat():TextFormat { return _fmt; }
		public function set textFormat(fmt:TextFormat):void {
			_tf.defaultTextFormat = (_fmt = fmt);
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The text shown by this TextSprite.
		 */
		public function get text():String { return _tf.text; }
		public function set text(txt:String):void {
			if (_tf.text != txt) {
				_tf.text = (txt==null ? "" : txt);
				if (_fmt!=null) _tf.setTextFormat(_fmt);
				dirty();
			}
		}
		
		/**
		 * The html text shown by this TextSprite.
		 */
		public function get htmlText():String { return _tf.htmlText; }
		public function set htmlText(txt:String):void {
			if (_tf.htmlText != txt) {
				_tf.htmlText = (txt==null ? "" : txt);
				dirty();
			}
		}
		
		/**
		 * The font to the text.
		 */
		public function get font():String { return String(_fmt.font); }
		public function set font(f:String):void {
			_fmt.font = f;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The color of the text.
		 */
		public function get color():uint { return uint(_fmt.color); }
		public function set color(c:uint):void {
			_fmt.color = c;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The size of the text.
		 */
		public function get size():Number { return Number(_fmt.size); }
		public function set size(s:Number):void {
			_fmt.size = s;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The boldness of the text.
		 */
		public function get bold():Boolean { return Boolean(_fmt.bold); }
		public function set bold(b:Boolean):void {
			_fmt.bold = b;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The italics of the text.
		 */
		public function get italic():Boolean { return Boolean(_fmt.italic); }
		public function set italic(b:Boolean):void {
			_fmt.italic = b;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The underline of the text.
		 */
		public function get underline():Boolean { return Boolean(_fmt.underline); }
		public function set underline(b:Boolean):void {
			_fmt.underline = b;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The kerning of the text.
		 */
		public function get kerning():Boolean { return Boolean(_fmt.kerning); }
		public function set kerning(b:Boolean):void {
			_fmt.kerning = b;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The letter-spacing of the text.
		 */
		public function get letterSpacing():int { return int(_fmt.letterSpacing); }
		public function set letterSpacing(s:int):void {
			_fmt.letterSpacing = s;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/**
		 * The horizontal anchor for the text, one of LEFT, RIGHT, or CENTER.
		 * This setting determines how the text is horizontally aligned with
		 * respect to this TextSprite's (x,y) location.
		 */
		public function get horizontalAnchor():int { return _hAnchor; }
		public function set horizontalAnchor(a:int):void { 
			if (_hAnchor != a) { _hAnchor = a; layout(); }
		}
		
		/**
		 * The vertical anchor for the text, one of TOP, BOTTOM, or MIDDLE.
		 * This setting determines how the text is vertically aligned with
		 * respect to this TextSprite's (x,y) location.
		 */
		public function get verticalAnchor():int { return _vAnchor; }
		public function set verticalAnchor(a:int):void {
			if (_vAnchor != a) { _vAnchor = a; layout(); }
		}
		
		// --------------------------------------------------------------------
		
		/**
		 * Creates a new TextSprite instance.
		 * @param text the text string for this label
		 * @param format the TextFormat determining font family, size, and style
		 * @param mode the text rendering mode to use (BITMAP by default)
		 */
		public function TextSprite(text:String=null, format:TextFormat=null, mode:int=BITMAP) {
			_tf = new TextField();
			_tf.selectable = false; // not selectable by default
			_tf.autoSize = TextFieldAutoSize.LEFT;
			_tf.defaultTextFormat = (_fmt = format ? format : new TextFormat());
			if (text != null) _tf.text = text;
			_bmap = new Bitmap();
			setMode(mode);
			dirty();
		}
		
		protected function setMode(mode:int):void
		{
			if (mode == _mode) return; // nothing to do
			
			switch (_mode) {
				case BITMAP:
					_bmap.bitmapData = null;
					removeChild(_bmap);
					break;
				case EMBED:
					_tf.embedFonts = false;
				case DEVICE:
					removeChild(_tf);
					break;
			}
			switch (mode) {
				case BITMAP:
					rasterize();
					addChild(_bmap);
					break;
				case EMBED:
					_tf.embedFonts = true;
				case DEVICE:
					addChild(_tf);
					break;
			}
			_mode = mode;
		}
		
		/**
		 * Applies the settings of the input text format to this sprite's
		 * internal text format. This method makes a shallow copy of the
		 * input format, it does not save a reference to it.
		 * @param fmt the text format to apply
		 */
		public function applyFormat(fmt:TextFormat):void {
			_fmt.align = fmt.align;
			_fmt.blockIndent = fmt.blockIndent;
			_fmt.bold = fmt.bold;
			_fmt.bullet = fmt.bullet;
			_fmt.color = fmt.color;
			_fmt.display = fmt.display;
			_fmt.font = fmt.font;
			_fmt.indent = fmt.indent;
			_fmt.italic = fmt.italic;
			_fmt.kerning = fmt.kerning;
			_fmt.leading = fmt.leading;
			_fmt.leftMargin = fmt.leftMargin;
			_fmt.letterSpacing = fmt.letterSpacing;
			_fmt.rightMargin = fmt.rightMargin;
			_fmt.size = fmt.size;
			_fmt.tabStops = fmt.tabStops;
			_fmt.target = fmt.target;
			_fmt.underline = fmt.underline;
			_fmt.url = fmt.url;
			_tf.setTextFormat(_fmt);
			if (_mode==BITMAP) dirty();
		}
		
		/** @inheritDoc */
		public override function render():void
		{
			if (_mode == BITMAP) {
				rasterize();
			}
			layout();
		}
		
		/** @private */
		protected function layout():void
		{
			var d:DisplayObject = (_mode==BITMAP ? _bmap : _tf);
			
			// horizontal anchor
			switch (_hAnchor) {
				case LEFT:   d.x = 0; break;
				case CENTER: d.x = -d.width / 2; break;
				case RIGHT:  d.x = -d.width; break;
			}
			// vertical anchor
			switch (_vAnchor) {
				case TOP:    d.y = 0; break;
				case MIDDLE: d.y = -d.height / 2; break;
				case BOTTOM: d.y = -d.height; break;
			}
		}
		
		/** @private */
		protected function rasterize():void
		{
			var tw:Number = _tf.width + 1;
			var th:Number = _tf.height + 1;
			var bd:BitmapData = _bmap.bitmapData;
			if (bd == null || bd.width != tw || bd.height != th) {
				bd = new BitmapData(tw, th, true, 0x00ffffff);
				_bmap.bitmapData = bd;
			} else {
				bd.fillRect(new Rectangle(0,0,tw,th), 0x00ffffff);
			}
			bd.draw(_tf);
		}
		
	} // end of class TextSprite
}