arc.js-e

## Copyright (c) 2013, Empirical Modelling Group
## All rights reserved.
##
## See LICENSE.txt

${{
Arc = function(x, y, r, sAngle, eAngle, colour, drawingOptions) {
	this.x = x;
	this.y = y;
	this.r = r;
	this.sAngle = sAngle;
	this.eAngle = eAngle;
	var radiansPerUnit = Math.PI / root.lookup("semicircleAngle").value();
	var sRadians = sAngle * radiansPerUnit;
	var eRadians = eAngle * radiansPerUnit;
	var twoPI = 2 * Math.PI;
	sRadians = sRadians % twoPI;
	if (sRadians < 0) {
		sRadians = sRadians + twoPI;
	}
	eRadians = eRadians % twoPI;
	if (eRadians < 0) {
		eRadians = eRadians + twoPI;
	}
	this.sRadians = sRadians;
	this.eRadians = eRadians;
	
	this.colour = colour
	this.drawingOptions = drawingOptions;
}
}}$;

#! Draw an Arc. See [drawing options](@external CanvasExamples > drawingoptions) to control appearance.
#
# ##Usage Example
#  `Arc(x, y, radius, startAngle, endAngle);`
#  `Arc(x, y, radius, startAngle, endAngle, "red");`
#
# @param x X position
# @param y Y position
# @param r Radius
# @param sAngle Start angle in degrees
# @param eAngle End angle in degrees
# @param [colour] Default is black
# @param [drawingOptions] Drawing Options object
#
#  #canvas #arc #drawingOptions
func Arc {
${{
	var x = arguments[0];
	var y = arguments[1];
	var r = arguments[2];
	var sAngle = arguments[3];
	var eAngle = arguments[4];
	var colour, drawingOptions;
	if (arguments.length == 6 && typeof(arguments[5]) == "object" && !(arguments[5] instanceof EdenUI.plugins.Canvas2D.FillStyle)) {
		colour = "black";
		drawingOptions = arguments[5];
	} else {
		colour = arguments[5];
		drawingOptions = arguments[6];
		if (colour === undefined) { colour = "black"; }
	}
	return new Arc(x, y, r, sAngle, eAngle, colour, drawingOptions);
}}$; };
semicircleAngle ~> [Arc];

${{

Arc.prototype.draw = function(context, scale) {
	var anticlockwise;
	if (this.drawingOptions !== undefined && "direction" in this.drawingOptions) {
		var directionName = this.drawingOptions.direction;
		var turnedThroughAC = this.eRadians - this.sRadians;
		if (this.eRadians < this.sRadians) {
			turnedThroughAC = turnedThroughAC + 2 * Math.PI;
		}
		switch (directionName) {
		case "anticlockwise":
		case "acw":
		case "ccw":
			anticlockwise = true;
			break;
		case "auto":
			anticlockwise = this.sAngle < this.eAngle;
			break;
		case "clockwise":
		case "cw":
			anticlockwise = false;
			break;
		case "major":
			anticlockwise = turnedThroughAC > Math.PI;
			break;
		case "minor":
			anticlockwise = turnedThroughAC <= Math.PI;
			break;
		default:
			//Invalid value specified.
			anticlockwise = true;
		}
	} else {
		//Default to "auto" 
		anticlockwise = this.sAngle < this.eAngle;
	}
	var sRadians = this.sRadians;
	var eRadians = this.eRadians;
	if (scale < 0) {
		sRadians = -sRadians;
		eRadians = -eRadians;
		anticlockwise = !anticlockwise;
	}
	var r = this.r - context.lineWidth / 2;
	context.beginPath();
	context.arc(this.x, this.y, r, -sRadians, -eRadians, anticlockwise);
	context.strokeStyle = this.colour;
	context.stroke();

	if (this.drawingOptions !== undefined && this.drawingOptions.arrowhead instanceof Arrowhead) {
		var cos1 = Math.cos(-sRadians);
		var sin1 = Math.sin(-sRadians);
		var cos2 = Math.cos(-eRadians);
		var sin2 = Math.sin(-eRadians);
		var x1 = this.x + r * cos1;
		var y1 = this.y + r * sin1;
		var x2 = this.x + r * cos2;
		var y2 = this.y + r * sin2;
		var gradient1 = -cos1 / sin1;
		var gradient2 = -cos2 / sin2;
		var reverse1, reverse2;
		if (anticlockwise) {
			reverse1 = sRadians <= Math.PI;
			reverse2 = eRadians <= Math.PI;
		} else {
			reverse1 = sRadians > Math.PI;
			reverse2 = eRadians > Math.PI;
		}
		this.drawingOptions.arrowhead.draw(context, scale, x1, y1, gradient1, reverse1, x2, y2,
			gradient2, reverse2);
	}
};

Arc.prototype.toString = function() {
	var s = "Arc(" + Eden.edenCodeForValues(this.x, this.y, this.r, this.sAngle, this.eAngle, this.colour);

	if (this.drawingOptions !== undefined) {
		s = s + ", " + Eden.edenCodeForValue(this.drawingOptions);
	}
	
	s = s + ")";
	return s;
}

Arc.prototype.getEdenCode = Arc.prototype.toString;

}}$;