paper.js/src/path/Path.Constructors.js

/*
 * Paper.js
 *
 * This file is part of Paper.js, a JavaScript Vector Graphics Library,
 * based on Scriptographer.org and designed to be largely API compatible.
 * http://paperjs.org/
 * http://scriptographer.org/
 *
 * Copyright (c) 2011, Juerg Lehni & Jonathan Puckey
 * http://lehni.org/ & http://jonathanpuckey.com/
 *
 * Distributed under the MIT license. See LICENSE file for details.
 *
 * All rights reserved.
 */

Path.inject({ statics: new function() {
	// Kappa, see: http://www.whizkidtech.redprince.net/bezier/circle/kappa/
	var kappa = 2 * (Math.sqrt(2) - 1) / 3;

	var ovalSegments = [
		new Segment([0, 0.5], [0, kappa ], [0, -kappa]),
		new Segment([0.5, 0], [-kappa, 0], [kappa, 0 ]),
		new Segment([1, 0.5], [0, -kappa], [0, kappa ]),
		new Segment([0.5, 1], [kappa, 0 ], [-kappa, 0])
	];

	return /** @lends Path */{
		/**
		 * {@grouptitle Shaped Paths}
		 *
		 * Creates a Path Item with two anchor points forming a line.
		 *
		 * @param {Point} pt1 the first anchor point of the path
		 * @param {Point} pt2 the second anchor point of the path
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var from = new Point(20, 20);
		 * var to = new Point(100, 100);
		 * var path = new Path.Line(from, to);
		 * path.strokeColor = 'black';
		 */
		Line: function() {
			return new Path(
				Point.read(arguments),
				Point.read(arguments)
			);
		},

		/**
		 * Creates a rectangle shaped Path Item from the passed point and size.
		 *
		 * @name Path.Rectangle
		 * @param {Point} point
		 * @param {Size} size
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var point = new Point(100, 100);
		 * var size = new Size(100, 100);
		 * var rectangle = new Rectangle(point, size);
		 * var path = new Path.Rectangle(rectangle);
		 * path.strokeColor = 'black';
		 */
		/**
		 * Creates a rectangle shaped Path Item from the passed points. These do not
		 * necessarily need to be the top left and bottom right corners, the
		 * constructor figures out how to fit a rectangle between them.
		 *
		 * @name Path.Rectangle
		 * @param {Point} point1 The first point defining the rectangle
		 * @param {Point} point2 The second point defining the rectangle
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var point = new Point(100, 100);
		 * var point2 = new Point(200, 300);
		 * var path = new Path.Rectangle(point, point2);
		 * path.strokeColor = 'black';
		 */
		/**
		 * Creates a rectangle shaped Path Item from the passed abstract
		 * {@link Rectangle}.
		 *
		 * @param {Rectangle} rect
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var point = new Point(100, 100);
		 * var size = new Size(100, 100);
		 * var rectangle = new Rectangle(point, size);
		 * var path = new Path.Rectangle(rectangle);
		 * path.strokeColor = 'black';
		 */
		Rectangle: function(rect) {
			rect = Rectangle.read(arguments);
			var left = rect.x,
				top = rect.y,
				right = left + rect.width,
				bottom = top + rect.height,
				path = new Path();
			path._add([
				new Segment(Point.create(left, bottom)),
				new Segment(Point.create(left, top)),
				new Segment(Point.create(right, top)),
				new Segment(Point.create(right, bottom))
			]);
			path._closed = true;
			return path;
		},

		/**
		 * Creates a rectangular Path Item with rounded corners.
		 *
		 * @param {Rectangle} rect
		 * @param {Size} size the size of the rounded corners
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var point = new Point(100, 100);
		 * var size = new Size(100, 100);
		 * var rectangle = new Rectangle(point, size);
		 * var cornerSize = new Size(30, 30);
		 * var path = new Path.RoundRectangle(rectangle, cornerSize);
		 */
		RoundRectangle: function(rect, size) {
			var _rect = Rectangle.read(arguments),
				_size = Size.read(arguments);
			if (_size.isZero())
				// No need for new, since constructors here do so themselves.
				return Path.Rectangle(rect);
			_size = Size.min(_size, _rect.getSize(true).divide(2));
			var bl = _rect.getBottomLeft(true),
				tl = _rect.getTopLeft(true),
				tr = _rect.getTopRight(true),
				br = _rect.getBottomRight(true),
				uSize = _size.multiply(kappa * 2),
				path = new Path();
			path._add([
				new Segment(bl.add(_size.width, 0), null, [-uSize.width, 0]),
				new Segment(bl.subtract(0, _size.height), [0, uSize.height], null),

				new Segment(tl.add(0, _size.height), null, [0, -uSize.height]),
				new Segment(tl.add(_size.width, 0), [-uSize.width, 0], null),

				new Segment(tr.subtract(_size.width, 0), null, [uSize.width, 0]),
				new Segment(tr.add(0, _size.height), [0, -uSize.height], null),

				new Segment(br.subtract(0, _size.height), null, [0, uSize.height]),
				new Segment(br.subtract(_size.width, 0), [uSize.width, 0], null)
			]);
			path._closed = true;
			return path;
		},

		/**
		* Creates an oval shaped Path Item.
		 *
		 * @param {Rectangle} rect
		 * @param {Boolean} [circumscribed=false] when set to {@code true} the
		 *        oval shaped path will be created so the rectangle fits into
		 *        it. When set to {@code false} the oval path will fit within
		 *        the rectangle.
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var topLeft = new Point(100, 100);
		 * var size = new Size(150, 100);
		 * var rectangle = new Rectangle(topLeft, size);
		 * var path = new Path.Oval(rectangle);
		 * path.fillColor = 'black';
		 */
		// TODO: Shall this be called Path.Ellipse instead?
		Oval: function(rect) {
			rect = Rectangle.read(arguments);
			var path = new Path(),
				point = rect.getPoint(true),
				size = rect.getSize(true),
				segments = new Array(4);
			for (var i = 0; i < 4; i++) {
				var segment = ovalSegments[i];
				segments[i] = new Segment(
					segment._point.multiply(size).add(point),
					segment._handleIn.multiply(size),
					segment._handleOut.multiply(size)
				);
			}
			path._add(segments);
			path._closed = true;
			return path;
		},

		/**
		 * Creates a circle shaped Path Item.
		 *
		 * @param {Point} center the center point of the circle
		 * @param {Number} radius the radius of the circle
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var path = new Path.Circle(new Point(100, 100), 50);
		 */
		Circle: function(center, radius) {
			var _center = Point.read(arguments),
				_radius = Base.readValue(arguments);
			return Path.Oval(new Rectangle(_center.subtract(_radius),
					Size.create(_radius * 2, _radius * 2)));
		},

		/**
		 * Creates a circular arc shaped Path Item.
		 *
		 * @param {Point} from the starting point of the circular arc
		 * @param {Point} through the point the arc passes through
		 * @param {Point} to the end point of the arc
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var start = new Point(0, 0);
		 * var through = new Point(100, 100);
		 * var to = new Point(200, 150);
		 * var path = new Path.Arc(start, through, to);
		 * path.strokeColor = 'black';
		 */
		Arc: function(from, through, to) {
			var path = new Path();
			path.moveTo(from);
			path.arcTo(through, to);
			return path;
		},

		/**
		 * Creates a regular polygon shaped Path Item.
		 *
		 * @param {Point} center the center point of the polygon
		 * @param {Number} numSides the number of sides of the polygon
		 * @param {Number} radius the radius of the polygon
		 * @return {Path} the newly created path
		 *
		 * @example
		 * // Create a triangle shaped path
		 * var center = new Point(100, 100);
		 * var sides = 3;
		 * var radius = 50;
		 * var triangle = new Path.RegularPolygon(center, sides, radius);
		 * triangle.fillColor = 'black';
		 *
		 * @example
		 * // Create a decahedron shaped path
		 * var center = new Point(100, 100);
		 * var sides = 10;
		 * var radius = 50;
		 * var decahedron = new Path.RegularPolygon(center, sides, radius);
		 * decahedron.fillColor = 'black';
		 */
		RegularPolygon: function(center, numSides, radius) {
			var _center = Point.read(arguments),
				_numSides = Base.readValue(arguments),
				_radius = Base.readValue(arguments),
				path = new Path(),
				step = 360 / _numSides,
				three = !(_numSides % 3),
				vector = new Point(0, three ? -_radius : _radius),
				offset = three ? -1 : 0.5,
				segments = new Array(_numSides);
			for (var i = 0; i < _numSides; i++) {
				segments[i] = new Segment(_center.add(
					vector.rotate((i + offset) * step)));
			}
			path._add(segments);
			path._closed = true;
			return path;
		},

		/**
		 * Creates a star shaped Path Item.
		 *
		 * The largest of {@code radius1} and {@code radius2} will be the outer
		 * radius of the star. The smallest of radius1 and radius2 will be the
		 * inner radius.
		 *
		 * @param {Point} center the center point of the star
		 * @param {Number} numPoints the number of points of the star
		 * @param {Number} radius1
		 * @param {Number} radius2
		 * @return {Path} the newly created path
		 *
		 * @example
		 * var center = new Point(100, 100);
		 * var points = 6;
		 * var radius1 = 20;
		 * var radius2 = 50;
		 * var path = new Path.Star(center, points, radius1, radius2);
		 * path.fillColor = 'black';
		 */
		Star: function(center, numPoints, radius1, radius2) {
			var _center = Point.read(arguments),
				_numPoints = Base.readValue(arguments) * 2,
				_radius1 = Base.readValue(arguments),
				_radius2 = Base.readValue(arguments),
				path = new Path(),
				step = 360 / _numPoints,
				vector = new Point(0, -1),
				segments = new Array(_numPoints);
			for (var i = 0; i < _numPoints; i++) {
				segments[i] = new Segment(_center.add(
					vector.rotate(step * i).multiply(i % 2 ? _radius2 : _radius1)));
			}
			path._add(segments);
			path._closed = true;
			return path;
		}
	};
}});