drawrect.as

AS3的画图功能一些源码

/*-------------------------------------------------------------
	mc.drawRect is a method for drawing rectangles and
	rounded rectangles. Regular rectangles are
	sufficiently easy that I often just rebuilt the
	method in any file I needed it in, but the rounded
	rectangle was something I was needing more often,
	hence the method. The rounding is very much like
	that of the rectangle tool in Flash where if the
	rectangle is smaller in either dimension than the
	rounding would permit, the rounding scales down to
	fit.
-------------------------------------------------------------*/
MovieClip.prototype.drawRect = function(x, y, w, h, cornerRadius) {
	// ==============
	// mc.drawRect() - by Ric Ewing ([e-mail]) - version 1.1 - 4.7.2002
	// 
	// x, y = top left corner of rect
	// w = width of rect
	// h = height of rect
	// cornerRadius = [optional] radius of rounding for corners (defaults to 0)
	// ==============
	if (arguments.length<4) {
		return;
	}
	// if the user has defined cornerRadius our task is a bit more complex. :)
	if (cornerRadius>0) {
		// init vars
		var theta, angle, cx, cy, px, py;
		// make sure that w + h are larger than 2*cornerRadius
		if (cornerRadius>Math.min(w, h)/2) {
			cornerRadius = Math.min(w, h)/2;
		}
		// theta = 45 degrees in radians
		theta = Math.PI/4;
		// draw top line
		this.moveTo(x+cornerRadius, y);
		this.lineTo(x+w-cornerRadius, y);
		//angle is currently 90 degrees
		angle = -Math.PI/2;
		// draw tr corner in two parts
		cx = x+w-cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+w-cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		angle += theta;
		cx = x+w-cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+w-cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		// draw right line
		this.lineTo(x+w, y+h-cornerRadius);
		// draw br corner
		angle += theta;
		cx = x+w-cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+h-cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+w-cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+h-cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		angle += theta;
		cx = x+w-cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+h-cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+w-cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+h-cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		// draw bottom line
		this.lineTo(x+cornerRadius, y+h);
		// draw bl corner
		angle += theta;
		cx = x+cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+h-cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+h-cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		angle += theta;
		cx = x+cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+h-cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+h-cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		// draw left line
		this.lineTo(x, y+cornerRadius);
		// draw tl corner
		angle += theta;
		cx = x+cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
		angle += theta;
		cx = x+cornerRadius+(Math.cos(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		cy = y+cornerRadius+(Math.sin(angle+(theta/2))*cornerRadius/Math.cos(theta/2));
		px = x+cornerRadius+(Math.cos(angle+theta)*cornerRadius);
		py = y+cornerRadius+(Math.sin(angle+theta)*cornerRadius);
		this.curveTo(cx, cy, px, py);
	} else {
		// cornerRadius was not defined or = 0. This makes it easy.
		this.moveTo(x, y);
		this.lineTo(x+w, y);
		this.lineTo(x+w, y+h);
		this.lineTo(x, y+h);
		this.lineTo(x, y);
	}
};