shapes.as

用于flash/flex的 as3的 2D图形图像图表的动态生成

package flare.util
{	
	import flash.display.Graphics;
	
	/**
	 * Utility class defining shape types and shape drawing routines. All shape
	 * drawing functions take two arguments: a <code>Graphics</code> context
	 * to draw with and a size parameter determining the radius of the shape
	 * (i.e., the height and width of the shape are twice the size parameter).
	 * 
	 * <p>All shapes are indicated by a name. This class registers these names
	 * with drawing functions, allowing the lookup of shape rendering routines
	 * by the shapes name. For example, these shape names may be assigned using
	 * a <code>flare.vis.operator.encoder.ShapeEncoder</code> and then later
	 * rendered by looking up the shape with this class, as done by the
	 * <code>flare.vis.data.render.ShapeRenderer</code> class. The set of 
	 * available shapes can be extended by using the static
	 * <code>setShape</code> method to register a new shape name and
	 * drawing function.</p>
	 */
	public class Shapes
	{
		/** Constant indicating a straight line shape. */
		public static const LINE:String = "line";
		/** Constant indicating a Bezier curve. */
		public static const BEZIER:String = "bezier";
		/** Constant indicating a cardinal spline. */
		public static const CARDINAL:String = "cardinal";
		/** Constant indicating a B-spline. */
		public static const BSPLINE:String = "bspline";
		
		/** Constant indicating a rectangular block shape. */
		public static const BLOCK:String = "block";
		/** Constant indicating a polygon shape. */
		public static const POLYGON:String = "polygon";
		/** Constant indicating a "polyblob" shape, a polygon whose
		 *  edges are interpolated with a cardinal spline. */
		public static const POLYBLOB:String = "polyblob";
		/** Constant indicating a vertical bar shape. */
		public static const VERTICAL_BAR:String = "verticalBar";
		/** Constant indicating a horizontal bar shape. */
		public static const HORIZONTAL_BAR:String = "horizontalBar";
		/** Constant indicating a wedge shape. */
		public static const WEDGE:String = "wedge";
		
		/** Constant indicating a circle shape. */
		public static const CIRCLE:String = "circle";
		/** Constant indicating a square shape. */
		public static const SQUARE:String = "square";
		/** Constant indicating a cross shape. */
		public static const CROSS:String = "cross";
		/** Constant indicating an 'X' shape. */
		public static const X:String = "x";
		/** Constant indicating a diamond shape. */
		public static const DIAMOND:String = "diamond";
		/** Constant indicating a upward-pointing triangle shape. */
		public static const TRIANGLE_UP:String = "triangleUp";
		/** Constant indicating a downward-pointing triangle shape. */
		public static const TRIANGLE_DOWN:String = "triangleDown";
		/** Constant indicating a rightward-pointing triangle shape. */
		public static const TRIANGLE_RIGHT:String = "triangleRight";
		/** Constant indicating a leftward-pointing triangle shape. */
		public static const TRIANGLE_LEFT:String = "triangleLeft";
		
		private static var _shapes:Object = {
			circle: drawCircle,
			square: drawSquare,
			cross: drawCross,
			x: drawX,
			diamond: drawDiamond,
			triangleUp: drawTriangleUp,
			triangleDown: drawTriangleDown,
			triangleRight: drawTriangleRight,
			triangleLeft: drawTriangleLeft
		};
		
		/**
		 * Gets the shape drawing function with the given name. 
		 * @param name the name of the shape to draw
		 * @return a function for drawing the shape or null if the shape name
		 *  is not found. The returned function takes two parameters:
		 *  a graphics object and a numerical size value. The size value
		 *  indicates the radius of the shape.
		 */
		public static function getShape(name:String):Function
		{
			return _shapes[name];
		}
		
		/**
		 * Sets the shape drawing function for a given shape name. 
		 * @param name the name of the shape to draw
		 * @param draw a function for drawing the shape. This function must
		 *  take two parameters: a graphics object and a numerical size value.
		 *  The size value indicates the radius of the shape.
		 */
		public static function setShape(name:String, draw:Function):void
		{
			_shapes[name] = draw;
		}
		
		/**
		 * Resets all shape drawing functions to the default settings. 
		 */
		public static function resetShapes():void
		{
			_shapes = {
				circle: drawCircle,
				square: drawSquare,
				cross: drawCross,
				x: drawX,
				diamond: drawDiamond,
				triangleUp: drawTriangleUp,
				triangleDown: drawTriangleDown,
				triangleRight: drawTriangleRight,
				triangleLeft: drawTriangleLeft
			};
		}
		
		// --------------------------------------------------------------------
		
		/**
		 * Draws a circle shape.
		 * @param g the graphics context to draw with
		 * @param size the radius of the circle
		 */
		public static function drawCircle(g:Graphics, size:Number):void
		{
			g.drawCircle(0, 0, size);
		}
		
		/**
		 * Draws a square shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the square. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawSquare(g:Graphics, size:Number):void
		{
			g.drawRect(-size, -size, 2*size, 2*size);
		}
		
		/**
		 * Draws a cross shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the cross. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawCross(g:Graphics, size:Number):void
		{
			g.moveTo(0, -size);
			g.lineTo(0, size);
			g.moveTo(-size, 0);
			g.lineTo(size, 0);
		}
		
		/**
		 * Draws an "x" shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the "x". The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawX(g:Graphics, size:Number):void
		{
			g.moveTo(-size, -size);
			g.lineTo(size, size);
			g.moveTo(size, -size);
			g.lineTo(-size, size);
		}
		
		/**
		 * Draws a diamond shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the diamond. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawDiamond(g:Graphics, size:Number):void
		{
			g.moveTo(0, size);
			g.lineTo(-size, 0);
			g.lineTo(0, -size);
			g.lineTo(size, 0);
			g.lineTo(0, size);	
		}
		
		/**
		 * Draws an upward-pointing triangle shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the triangle. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawTriangleUp(g:Graphics, size:Number):void
		{
			g.moveTo(-size, size);
			g.lineTo(size, size);
			g.lineTo(0, -size);
			g.lineTo(-size, size);
		}
		
		/**
		 * Draws a downward-pointing triangle shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the triangle. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawTriangleDown(g:Graphics, size:Number):void
		{
			g.moveTo(-size, -size);
			g.lineTo(size, -size);
			g.lineTo(0, size);
			g.lineTo(-size, -size);
		}
		
		/**
		 * Draws a right-pointing triangle shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the triangle. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawTriangleRight(g:Graphics, size:Number):void
		{
			g.moveTo(-size, -size);
			g.lineTo(size, 0);
			g.lineTo(-size, size);
			g.lineTo(-size, -size);
		}
		
		/**
		 * Draws a left-pointing triangle shape.
		 * @param g the graphics context to draw with
		 * @param size the (half-)size of the triangle. The height and width of
		 *  the shape will both be exactly twice the size parameter.
		 */
		public static function drawTriangleLeft(g:Graphics, size:Number):void
		{
			g.moveTo(size, -size);
			g.lineTo(-size, 0);
			g.lineTo(size, size);
			g.lineTo(size, -size);
		}
		
		// --------------------------------------------------------------------
		
		/**
		 * Draws an arc (a segment of a circle's circumference)
		 * @param g the graphics context to draw with
		 * @param x the center x-coordinate of the arc
		 * @param y the center y-coorindate of the arc
		 * @param radius the radius of the arc
		 * @param a0 the starting angle of the arc (in radians)
		 * @param a1 the ending angle of the arc (in radians)
		 */
		public static function drawArc(g:Graphics, x:Number, y:Number, 
									radius:Number, a0:Number, a1:Number) : void
		{
			var slices:Number = (Math.abs(a1-a0) * radius) / 4;
			var a:Number, cx:Number = x, cy:Number = y;
			
			for (var i:uint = 0; i <= slices; ++i) {
				a = a0 + i*(a1-a0)/slices;
				x = cx + radius * Math.cos(a);
				y = cy + -radius * Math.sin(a);
				if (i==0) {
					g.moveTo(x, y);
				} else {
					g.lineTo(x,y);
				}
			}
		}
		
		/**
		 * Draws a wedge defined by an angular range and inner and outer radii.
		 * An inner radius of zero results in a pie-slice shape.
		 * @param g the graphics context to draw with
		 * @param x the center x-coordinate of the wedge
		 * @param y the center y-coorindate of the wedge