rotation.js-e

## Copyright (c) 2015, Empirical Modelling Group
## All rights reserved.
##
## See LICENSE.txt

${{

	Rotation = function (angle, centre, origin, angle2, radius, items) {
		this.angle = angle;
		this.centre = centre;
		this.origin = origin;
		this.angle2 = angle2;
		this.radius = radius;
		this.items = items;

		var radiansPerUnit = Math.PI / root.lookup("semicircleAngle").value();
		if (angle2 === undefined) {
			this.radians2 = 0;
		} else {
			this.radians2 = -angle2 * radiansPerUnit;
		}
		if (angle === undefined) {
			this.radians = 0;
		} else {
			this.radians = -angle * radiansPerUnit - this.radians2;
		}
	}

	Rotation.prototype = new EdenUI.plugins.Canvas2D.Transform();
	
	Rotation.prototype.transform = function (context) {
		var origin = this.origin;
		var centre = this.centre;
		var radius = this.radius;

		context.translate(origin.x, origin.y);

		if (radius !== undefined) {
			context.rotate(this.radians2);
			context.translate(radius, 0);
		}
		context.rotate(this.radians);

		if (centre !== undefined) {
			context.translate(-centre.x, -centre.y);
		}
	}

	Rotation.prototype.getCSS = function (scale) {
		var origin = this.origin;
		var centre = this.centre;
		var radius = this.radius;

		var css, x, y, theta;

		x = origin.x * scale;
		y = origin.y * scale;
		css = "translate(" + x + "px, " + y + "px) ";

		if (radius !== undefined) {
			theta = this.radians2;
			x = radius * scale;
			css = css +  "rotate(" + theta + "rad) translateX(" + x + "px) ";
		}

		theta = this.radians;
		css = css + "rotate(" + theta + "rad) ";

		if (centre !== undefined) {
			x = -centre.x * scale;
			y = -centre.y * scale;
			css = css + "translate(" + x + "px, " + y + "px)";
		}

		return css;
	}

	Rotation.prototype.inverse = function (x, y) {
		var origin = this.origin;
		var centre = this.centre;
		var radius = this.radius;

		var invX = x - origin.x;
		var invY = y - origin.y;
		var temp, sin, cos;

		if (radius !== undefined) {
			sin = Math.sin(-this.radians2);
			cos = Math.cos(-this.radians2);
			temp = invX;
			invX = cos * invX - sin * invY;
			invY = sin * temp + cos * invY;
			invX = invX - radius;
		}

		sin = Math.sin(-this.radians);
		cos = Math.cos(-this.radians);
		temp = invX;
		invX = cos * invX - sin * invY;
		invY = sin * temp + cos * invY;

		if (centre !== undefined) {
			invX = invX + centre.x;
			invY = invY + centre.y;
		}
		return new Point(invX, invY);
	}

	Rotation.prototype.toString = function() {
		if (this.radius !== undefined && this.centre !== undefined) {
			return "CombinedRotation(" + Eden.edenCodeForValues(this.angle, this.centre, this.origin, this.angle2, this.radius, this.items) + ")";
		} else if (this.radius !== undefined) {
			return "RotateAboutPoint(" + Eden.edenCodeForValues(this.angle2, this.origin, this.radius, this.items) + ")";
		} else {
			return "RotateAboutCentre(" + Eden.edenCodeForValues(this.angle, this.centre, this.origin, this.items) + ")";
		}
	}

	Rotation.prototype.getEdenCode = Rotation.prototype.toString;

}}$;

func Rotate {
	para item, angle;
	
	${{
		if (item instanceof CanvasImage) {
			return new Rotation(angle, new Point(item.dx + item.dWidth/2, item.dy + item.dHeight/2), new Point(item.dx,item.dy), 0, undefined, [item]);
		}
	}}$;
}

func CombinedRotation {
	${{
		if (arguments[0] instanceof Folder) {
			//Probably not an actual function call but semicircleAngle observable changed.
			return undefined;
		}

		var angle, centre, origin, angle2, radius, items;
		angle = arguments[0];
		centre = arguments[1];
		origin = arguments[2];

		if (arguments.length == 6) {
			angle2 = arguments[3];
			radius = arguments[4];
			items = arguments[5];
		} else {
			angle2 = angle;
			radius = arguments[3];
			items = arguments[4];		
		}

		if (!(centre instanceof Point)) {
			eden.error(new Error("CombinedRotation: The centre of rotation must be a Point, not a " + typeof(centre)), "error");
			return undefined;
		}
		if (!(origin instanceof Point)) {
			eden.error(new Error("CombinedRotation: The centre of the circular orbit must be a Point, not a " + typeof(origin)), "error");
			return undefined;
		}
		return new Rotation(angle, centre, origin, angle2, radius, items);
	}}$;
}

func RotateAboutCentre {
	${{
		if (arguments[0] instanceof Folder) {
			//Probably not an actual function call but semicircleAngle observable changed.
			return undefined;
		}

		var angle = arguments[0];
		var centre = arguments[1];
		var origin = arguments[2];
		var items = arguments[3];

		if (!(centre instanceof Point)) {
			eden.error(new Error("RotateAboutCentre: The centre of rotation must be a Point, not a " + typeof(centre)), "error");
			return undefined;
		}
		if (!(origin instanceof Point)) {
			eden.error(new Error("RotateAboutCentre: The destination position must be a Point, not a " + typeof(origin)), "error");
			return undefined;
		}
		return new Rotation(angle, centre, origin, 0, undefined, items);
	}}$;
}

func RotateAboutPoint {
	${{
		if (arguments[0] instanceof Folder) {
			//Probably not an actual function call but semicircleAngle observable changed.
			return undefined;
		}

		var angle, origin, radius, centre, items;
		angle = arguments[0];
		origin = arguments[1];
		radius = arguments[2];

		if (arguments.length == 5) {
			centre = arguments[3];
			items = arguments[4];
			if (!(centre instanceof Point)) {
				eden.error(new Error("RotateAboutPoint: The centre point of the source picture must be a Point, not a " + typeof(centre)), "error");
				return undefined;
			}
		} else {
			items = arguments[3];
		}

		if (!(origin instanceof Point)) {
			eden.error(new Error("RotateAboutPoint: The centre of the circle must be a Point, not a " + typeof(origin)), "error");
			return undefined;
		}
		return new Rotation(0, centre, origin, angle, radius, items);
	}}$;
}

semicircleAngle ~> [CombinedRotation, RotateAboutCentre, RotateAboutPoint];