#

API Documentation for: 0.8.1
Show: Inherited Protected Private Deprecated

# File:Matrix2D.js

    /*
    * Matrix2D
    * Visit http://createjs.com/ for documentation, updates and examples.
    *
    * Copyright (c) 2010 gskinner.com, inc.
    *
    * Permission is hereby granted, free of charge, to any person
    * obtaining a copy of this software and associated documentation
    * files (the "Software"), to deal in the Software without
    * restriction, including without limitation the rights to use,
    * copy, modify, merge, publish, distribute, sublicense, and/or sell
    * copies of the Software, and to permit persons to whom the
    * Software is furnished to do so, subject to the following
    * conditions:
    *
    * The above copyright notice and this permission notice shall be
    * included in all copies or substantial portions of the Software.
    *
    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    * OTHER DEALINGS IN THE SOFTWARE.
    */

    /**
     * @module EaselJS
     */

    // namespace:
    //this.createjs = this.createjs||{};

    (function() {
    	"use strict";

    // constructor:
    	/**
    	 * Represents an affine transformation matrix, and provides tools for constructing and concatenating matrices.
    	 *
    	 * This matrix can be visualized as:
    	 *
    	 * 	[ a  c  tx
    	 * 	  b  d  ty
    	 * 	  0  0  1  ]
    	 *
    	 * Note the locations of b and c.
    	 *
    	 * @class Matrix2D
    	 * @param {Number} [a=1] Specifies the a property for the new matrix.
    	 * @param {Number} [b=0] Specifies the b property for the new matrix.
    	 * @param {Number} [c=0] Specifies the c property for the new matrix.
    	 * @param {Number} [d=1] Specifies the d property for the new matrix.
    	 * @param {Number} [tx=0] Specifies the tx property for the new matrix.
    	 * @param {Number} [ty=0] Specifies the ty property for the new matrix.
    	 * @constructor
    	 **/
    	function Matrix2D(a, b, c, d, tx, ty) {
    		this.setValues(a,b,c,d,tx,ty);

    	// public properties:
    		// assigned in the setValues method.
    		/**
    		 * Position (0, 0) in a 3x3 affine transformation matrix.
    		 * @property a
    		 * @type Number
    		 **/

    		/**
    		 * Position (0, 1) in a 3x3 affine transformation matrix.
    		 * @property b
    		 * @type Number
    		 **/

    		/**
    		 * Position (1, 0) in a 3x3 affine transformation matrix.
    		 * @property c
    		 * @type Number
    		 **/

    		/**
    		 * Position (1, 1) in a 3x3 affine transformation matrix.
    		 * @property d
    		 * @type Number
    		 **/

    		/**
    		 * Position (2, 0) in a 3x3 affine transformation matrix.
    		 * @property tx
    		 * @type Number
    		 **/

    		/**
    		 * Position (2, 1) in a 3x3 affine transformation matrix.
    		 * @property ty
    		 * @type Number
    		 **/
    	}
    	var p = Matrix2D.prototype;

    	/**
    	 * <strong>REMOVED</strong>. Removed in favor of using `MySuperClass_constructor`.
    	 * See {{#crossLink "Utility Methods/extend"}}{{/crossLink}} and {{#crossLink "Utility Methods/promote"}}{{/crossLink}}
    	 * for details.
    	 *
    	 * There is an inheritance tutorial distributed with EaselJS in /tutorials/Inheritance.
    	 *
    	 * @method initialize
    	 * @protected
    	 * @deprecated
    	 */
    	// p.initialize = function() {}; // searchable for devs wondering where it is.

    // constants:
    	/**
    	 * Multiplier for converting degrees to radians. Used internally by Matrix2D.
    	 * @property DEG_TO_RAD
    	 * @static
    	 * @final
    	 * @type Number
    	 * @readonly
    	 **/
    	Matrix2D.DEG_TO_RAD = Math.PI/180;

    // static public properties:
    	/**
    	 * An identity matrix, representing a null transformation.
    	 * @property identity
    	 * @static
    	 * @type Matrix2D
    	 * @readonly
    	 **/
    	Matrix2D.identity = null; // set at bottom of class definition.

    // public methods:
    	/**
    	 * Sets the specified values on this instance.
    	 * @method setValues
    	 * @param {Number} [a=1] Specifies the a property for the new matrix.
    	 * @param {Number} [b=0] Specifies the b property for the new matrix.
    	 * @param {Number} [c=0] Specifies the c property for the new matrix.
    	 * @param {Number} [d=1] Specifies the d property for the new matrix.
    	 * @param {Number} [tx=0] Specifies the tx property for the new matrix.
    	 * @param {Number} [ty=0] Specifies the ty property for the new matrix.
    	 * @return {Matrix2D} This instance. Useful for chaining method calls.
    	*/
    	p.setValues = function(a, b, c, d, tx, ty) {
    		// don't forget to update docs in the constructor if these change:
    		this.a = (a == null) ? 1 : a;
    		this.b = b || 0;
    		this.c = c || 0;
    		this.d = (d == null) ? 1 : d;
    		this.tx = tx || 0;
    		this.ty = ty || 0;
    		return this;
    	};

    	/**
    	 * Appends the specified matrix properties to this matrix. All parameters are required.
    	 * This is the equivalent of multiplying `(this matrix) * (specified matrix)`.
    	 * @method append
    	 * @param {Number} a
    	 * @param {Number} b
    	 * @param {Number} c
    	 * @param {Number} d
    	 * @param {Number} tx
    	 * @param {Number} ty
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.append = function(a, b, c, d, tx, ty) {
    		var a1 = this.a;
    		var b1 = this.b;
    		var c1 = this.c;
    		var d1 = this.d;
    		if (a != 1 || b != 0 || c != 0 || d != 1) {
    			this.a  = a1*a+c1*b;
    			this.b  = b1*a+d1*b;
    			this.c  = a1*c+c1*d;
    			this.d  = b1*c+d1*d;
    		}
    		this.tx = a1*tx+c1*ty+this.tx;
    		this.ty = b1*tx+d1*ty+this.ty;
    		return this;
    	};

    	/**
    	 * Prepends the specified matrix properties to this matrix.
    	 * This is the equivalent of multiplying `(specified matrix) * (this matrix)`.
    	 * All parameters are required.
    	 * @method prepend
    	 * @param {Number} a
    	 * @param {Number} b
    	 * @param {Number} c
    	 * @param {Number} d
    	 * @param {Number} tx
    	 * @param {Number} ty
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.prepend = function(a, b, c, d, tx, ty) {
    		var a1 = this.a;
    		var c1 = this.c;
    		var tx1 = this.tx;

    		this.a  = a*a1+c*this.b;
    		this.b  = b*a1+d*this.b;
    		this.c  = a*c1+c*this.d;
    		this.d  = b*c1+d*this.d;
    		this.tx = a*tx1+c*this.ty+tx;
    		this.ty = b*tx1+d*this.ty+ty;
    		return this;
    	};

    	/**
    	 * Appends the specified matrix to this matrix.
    	 * This is the equivalent of multiplying `(this matrix) * (specified matrix)`.
    	 * @method appendMatrix
    	 * @param {Matrix2D} matrix
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.appendMatrix = function(matrix) {
    		return this.append(matrix.a, matrix.b, matrix.c, matrix.d, matrix.tx, matrix.ty);
    	};

    	/**
    	 * Prepends the specified matrix to this matrix.
    	 * This is the equivalent of multiplying `(specified matrix) * (this matrix)`.
    	 * For example, you could calculate the combined transformation for a child object using:
    	 *
    	 * 	var o = myDisplayObject;
    	 * 	var mtx = o.getMatrix();
    	 * 	while (o = o.parent) {
    	 * 		// prepend each parent's transformation in turn:
    	 * 		o.prependMatrix(o.getMatrix());
    	 * 	}
    	 * @method prependMatrix
    	 * @param {Matrix2D} matrix
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.prependMatrix = function(matrix) {
    		return this.prepend(matrix.a, matrix.b, matrix.c, matrix.d, matrix.tx, matrix.ty);
    	};

    	/**
    	 * Generates matrix properties from the specified display object transform properties, and appends them to this matrix.
    	 * For example, you can use this to generate a matrix representing the transformations of a display object:
    	 *
    	 * 	var mtx = new Matrix2D();
    	 * 	mtx.appendTransform(o.x, o.y, o.scaleX, o.scaleY, o.rotation);
    	 * @method appendTransform
    	 * @param {Number} x
    	 * @param {Number} y
    	 * @param {Number} scaleX
    	 * @param {Number} scaleY
    	 * @param {Number} rotation
    	 * @param {Number} skewX
    	 * @param {Number} skewY
    	 * @param {Number} regX Optional.
    	 * @param {Number} regY Optional.
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.appendTransform = function(x, y, scaleX, scaleY, rotation, skewX, skewY, regX, regY) {
    		if (rotation%360) {
    			var r = rotation*Matrix2D.DEG_TO_RAD;
    			var cos = Math.cos(r);
    			var sin = Math.sin(r);
    		} else {
    			cos = 1;
    			sin = 0;
    		}

    		if (skewX || skewY) {
    			// TODO: can this be combined into a single append operation?
    			skewX *= Matrix2D.DEG_TO_RAD;
    			skewY *= Matrix2D.DEG_TO_RAD;
    			this.append(Math.cos(skewY), Math.sin(skewY), -Math.sin(skewX), Math.cos(skewX), x, y);
    			this.append(cos*scaleX, sin*scaleX, -sin*scaleY, cos*scaleY, 0, 0);
    		} else {
    			this.append(cos*scaleX, sin*scaleX, -sin*scaleY, cos*scaleY, x, y);
    		}

    		if (regX || regY) {
    			// append the registration offset:
    			this.tx -= regX*this.a+regY*this.c;
    			this.ty -= regX*this.b+regY*this.d;
    		}
    		return this;
    	};

    	/**
    	 * Generates matrix properties from the specified display object transform properties, and prepends them to this matrix.
    	 * For example, you could calculate the combined transformation for a child object using:
    	 *
    	 * 	var o = myDisplayObject;
    	 * 	var mtx = new createjs.Matrix2D();
    	 * 	do  {
    	 * 		// prepend each parent's transformation in turn:
    	 * 		mtx.prependTransform(o.x, o.y, o.scaleX, o.scaleY, o.rotation, o.skewX, o.skewY, o.regX, o.regY);
    	 * 	} while (o = o.parent);
    	 *
    	 * 	Note that the above example would not account for {{#crossLink "DisplayObject/transformMatrix:property"}}{{/crossLink}}
    	 * 	values. See {{#crossLink "Matrix2D/prependMatrix"}}{{/crossLink}} for an example that does.
    	 * @method prependTransform
    	 * @param {Number} x
    	 * @param {Number} y
    	 * @param {Number} scaleX
    	 * @param {Number} scaleY
    	 * @param {Number} rotation
    	 * @param {Number} skewX
    	 * @param {Number} skewY
    	 * @param {Number} regX Optional.
    	 * @param {Number} regY Optional.
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.prependTransform = function(x, y, scaleX, scaleY, rotation, skewX, skewY, regX, regY) {
    		if (rotation%360) {
    			var r = rotation*Matrix2D.DEG_TO_RAD;
    			var cos = Math.cos(r);
    			var sin = Math.sin(r);
    		} else {
    			cos = 1;
    			sin = 0;
    		}

    		if (regX || regY) {
    			// prepend the registration offset:
    			this.tx -= regX; this.ty -= regY;
    		}
    		if (skewX || skewY) {
    			// TODO: can this be combined into a single prepend operation?
    			skewX *= Matrix2D.DEG_TO_RAD;
    			skewY *= Matrix2D.DEG_TO_RAD;
    			this.prepend(cos*scaleX, sin*scaleX, -sin*scaleY, cos*scaleY, 0, 0);
    			this.prepend(Math.cos(skewY), Math.sin(skewY), -Math.sin(skewX), Math.cos(skewX), x, y);
    		} else {
    			this.prepend(cos*scaleX, sin*scaleX, -sin*scaleY, cos*scaleY, x, y);
    		}
    		return this;
    	};

    	/**
    	 * Applies a clockwise rotation transformation to the matrix.
    	 * @method rotate
    	 * @param {Number} angle The angle to rotate by, in degrees. To use a value in radians, multiply it by `180/Math.PI`.
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.rotate = function(angle) {
    		angle = angle*Matrix2D.DEG_TO_RAD;
    		var cos = Math.cos(angle);
    		var sin = Math.sin(angle);

    		var a1 = this.a;
    		var b1 = this.b;

    		this.a = a1*cos+this.c*sin;
    		this.b = b1*cos+this.d*sin;
    		this.c = -a1*sin+this.c*cos;
    		this.d = -b1*sin+this.d*cos;
    		return this;
    	};

    	/**
    	 * Applies a skew transformation to the matrix.
    	 * @method skew
    	 * @param {Number} skewX The amount to skew horizontally in degrees. To use a value in radians, multiply it by `180/Math.PI`.
    	 * @param {Number} skewY The amount to skew vertically in degrees.
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	*/
    	p.skew = function(skewX, skewY) {
    		skewX = skewX*Matrix2D.DEG_TO_RAD;
    		skewY = skewY*Matrix2D.DEG_TO_RAD;
    		this.append(Math.cos(skewY), Math.sin(skewY), -Math.sin(skewX), Math.cos(skewX), 0, 0);
    		return this;
    	};

    	/**
    	 * Applies a scale transformation to the matrix.
    	 * @method scale
    	 * @param {Number} x The amount to scale horizontally. E.G. a value of 2 will double the size in the X direction, and 0.5 will halve it.
    	 * @param {Number} y The amount to scale vertically.
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.scale = function(x, y) {
    		this.a *= x;
    		this.b *= x;
    		this.c *= y;
    		this.d *= y;
    		//this.tx *= x;
    		//this.ty *= y;
    		return this;
    	};

    	/**
    	 * Translates the matrix on the x and y axes.
    	 * @method translate
    	 * @param {Number} x
    	 * @param {Number} y
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.translate = function(x, y) {
    		this.tx += this.a*x + this.c*y;
    		this.ty += this.b*x + this.d*y;
    		return this;
    	};

    	/**
    	 * Sets the properties of the matrix to those of an identity matrix (one that applies a null transformation).
    	 * @method identity
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.identity = function() {
    		this.a = this.d = 1;
    		this.b = this.c = this.tx = this.ty = 0;
    		return this;
    	};

    	/**
    	 * Inverts the matrix, causing it to perform the opposite transformation.
    	 * @method invert
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	 **/
    	p.invert = function() {
    		var a1 = this.a;
    		var b1 = this.b;
    		var c1 = this.c;
    		var d1 = this.d;
    		var tx1 = this.tx;
    		var n = a1*d1-b1*c1;

    		this.a = d1/n;
    		this.b = -b1/n;
    		this.c = -c1/n;
    		this.d = a1/n;
    		this.tx = (c1*this.ty-d1*tx1)/n;
    		this.ty = -(a1*this.ty-b1*tx1)/n;
    		return this;
    	};

    	/**
    	 * Returns true if the matrix is an identity matrix.
    	 * @method isIdentity
    	 * @return {Boolean}
    	 **/
    	p.isIdentity = function() {
    		return this.tx === 0 && this.ty === 0 && this.a === 1 && this.b === 0 && this.c === 0 && this.d === 1;
    	};

    	/**
    	 * Returns true if this matrix is equal to the specified matrix (all property values are equal).
    	 * @method equals
    	 * @param {Matrix2D} matrix The matrix to compare.
    	 * @return {Boolean}
    	 **/
    	p.equals = function(matrix) {
    		return this.tx === matrix.tx && this.ty === matrix.ty && this.a === matrix.a && this.b === matrix.b && this.c === matrix.c && this.d === matrix.d;
    	};

    	/**
    	 * Transforms a point according to this matrix.
    	 * @method transformPoint
    	 * @param {Number} x The x component of the point to transform.
    	 * @param {Number} y The y component of the point to transform.
    	 * @param {Point | Object} [pt] An object to copy the result into. If omitted a generic object with x/y properties will be returned.
    	 * @return {Point} This matrix. Useful for chaining method calls.
    	 **/
    	p.transformPoint = function(x, y, pt) {
    		pt = pt||{};
    		pt.x = x*this.a+y*this.c+this.tx;
    		pt.y = x*this.b+y*this.d+this.ty;
    		return pt;
    	};

    	/**
    	 * Decomposes the matrix into transform properties (x, y, scaleX, scaleY, and rotation). Note that these values
    	 * may not match the transform properties you used to generate the matrix, though they will produce the same visual
    	 * results.
    	 * @method decompose
    	 * @param {Object} target The object to apply the transform properties to. If null, then a new object will be returned.
    	 * @return {Object} The target, or a new generic object with the transform properties applied.
    	*/
    	p.decompose = function(target) {
    		// TODO: it would be nice to be able to solve for whether the matrix can be decomposed into only scale/rotation even when scale is negative
    		if (target == null) { target = {}; }
    		target.x = this.tx;
    		target.y = this.ty;
    		target.scaleX = Math.sqrt(this.a * this.a + this.b * this.b);
    		target.scaleY = Math.sqrt(this.c * this.c + this.d * this.d);

    		var skewX = Math.atan2(-this.c, this.d);
    		var skewY = Math.atan2(this.b, this.a);

    		var delta = Math.abs(1-skewX/skewY);
    		if (delta < 0.00001) { // effectively identical, can use rotation:
    			target.rotation = skewY/Matrix2D.DEG_TO_RAD;
    			if (this.a < 0 && this.d >= 0) {
    				target.rotation += (target.rotation <= 0) ? 180 : -180;
    			}
    			target.skewX = target.skewY = 0;
    		} else {
    			target.skewX = skewX/Matrix2D.DEG_TO_RAD;
    			target.skewY = skewY/Matrix2D.DEG_TO_RAD;
    		}
    		return target;
    	};

    	/**
    	 * Copies all properties from the specified matrix to this matrix.
    	 * @method copy
    	 * @param {Matrix2D} matrix The matrix to copy properties from.
    	 * @return {Matrix2D} This matrix. Useful for chaining method calls.
    	*/
    	p.copy = function(matrix) {
    		return this.setValues(matrix.a, matrix.b, matrix.c, matrix.d, matrix.tx, matrix.ty);
    	};

    	/**
    	 * Returns a clone of the Matrix2D instance.
    	 * @method clone
    	 * @return {Matrix2D} a clone of the Matrix2D instance.
    	 **/
    	p.clone = function() {
    		return new Matrix2D(this.a, this.b, this.c, this.d, this.tx, this.ty);
    	};

    	/**
    	 * Returns a string representation of this object.
    	 * @method toString
    	 * @return {String} a string representation of the instance.
    	 **/
    	p.toString = function() {
    		return "[Matrix2D (a="+this.a+" b="+this.b+" c="+this.c+" d="+this.d+" tx="+this.tx+" ty="+this.ty+")]";
    	};

    	// this has to be populated after the class is defined:
    	Matrix2D.identity = new Matrix2D();

    	createjs.Matrix2D = Matrix2D;
    }());