'use strict'; // combine 2 matrixes // m1, m2 - [a, b, c, d, e, g] // function combine(m1, m2) { return [ m1[0] * m2[0] + m1[2] * m2[1], m1[1] * m2[0] + m1[3] * m2[1], m1[0] * m2[2] + m1[2] * m2[3], m1[1] * m2[2] + m1[3] * m2[3], m1[0] * m2[4] + m1[2] * m2[5] + m1[4], m1[1] * m2[4] + m1[3] * m2[5] + m1[5] ]; } function Matrix() { if (!(this instanceof Matrix)) { return new Matrix(); } this.queue = []; // list of matrixes to apply this.cache = null; // combined matrix cache } Matrix.prototype.matrix = function (m) { if (m[0] === 1 && m[1] === 0 && m[2] === 0 && m[3] === 1 && m[4] === 0 && m[5] === 0) { return this; } this.cache = null; this.queue.push(m); return this; }; Matrix.prototype.translate = function (tx, ty) { if (tx !== 0 || ty !== 0) { this.cache = null; this.queue.push([ 1, 0, 0, 1, tx, ty ]); } return this; }; Matrix.prototype.scale = function (sx, sy) { if (sx !== 1 || sy !== 1) { this.cache = null; this.queue.push([ sx, 0, 0, sy, 0, 0 ]); } return this; }; Matrix.prototype.rotate = function (angle, rx, ry) { var rad, cos, sin; if (angle !== 0) { this.translate(rx, ry); rad = angle * Math.PI / 180; cos = Math.cos(rad); sin = Math.sin(rad); this.queue.push([ cos, sin, -sin, cos, 0, 0 ]); this.cache = null; this.translate(-rx, -ry); } return this; }; Matrix.prototype.skewX = function (angle) { if (angle !== 0) { this.cache = null; this.queue.push([ 1, 0, Math.tan(angle * Math.PI / 180), 1, 0, 0 ]); } return this; }; Matrix.prototype.skewY = function (angle) { if (angle !== 0) { this.cache = null; this.queue.push([ 1, Math.tan(angle * Math.PI / 180), 0, 1, 0, 0 ]); } return this; }; // Flatten queue // Matrix.prototype.toArray = function () { if (this.cache) { return this.cache; } if (!this.queue.length) { this.cache = [ 1, 0, 0, 1, 0, 0 ]; return this.cache; } this.cache = this.queue[0]; if (this.queue.length === 1) { return this.cache; } for (var i = 1; i < this.queue.length; i++) { this.cache = combine(this.cache, this.queue[i]); } return this.cache; }; // Apply list of matrixes to (x,y) point. // If `isRelative` set, `translate` component of matrix will be skipped // Matrix.prototype.calc = function (x, y, isRelative) { var m; // Don't change point on empty transforms queue if (!this.queue.length) { return [ x, y ]; } // Calculate final matrix, if not exists // // NB. if you deside to apply transforms to point one-by-one, // they should be taken in reverse order if (!this.cache) { this.cache = this.toArray(); } m = this.cache; // Apply matrix to point return [ x * m[0] + y * m[2] + (isRelative ? 0 : m[4]), x * m[1] + y * m[3] + (isRelative ? 0 : m[5]) ]; }; module.exports = Matrix;