158 lines
3.2 KiB
JavaScript
158 lines
3.2 KiB
JavaScript
/**
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* RequireJS implementation of https://github.com/matthewmueller/unmatrix
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*/
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define([], function () {
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'use strict';
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/**
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* Unmatrix
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*
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* @param {Element|String} input || matrix thereof
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* @return {Object}
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*/
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function unmatrix(input) {
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return 'string' !== typeof input ?
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parse(style(input)) :
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parse(input);
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}
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/**
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* Unmatrix: parse the values of the matrix
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*
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* Algorithm from:
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*
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* - http://hg.mozilla.org/mozilla-central/file/7cb3e9795d04/layout/style/nsStyleAnimation.cpp
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*
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* @param {String} str
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* @return {Object}
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* @api public
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*/
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function parse(str) {
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if(str === 'none') {
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return {
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translateX: 0,
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translateY: 0,
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rotate: 0,
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skew: 0,
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scaleX: 1,
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scaleY: 1
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};
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}
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var m = stom(str);
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var A = m[0];
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var B = m[1];
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var C = m[2];
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var D = m[3];
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if (A * D === B * C) {
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throw new Error('transform#unmatrix: matrix is singular');
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}
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// step (3)
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var scaleX = Math.sqrt(A * A + B * B);
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A /= scaleX;
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B /= scaleX;
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// step (4)
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var skew = A * C + B * D;
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C -= A * skew;
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D -= B * skew;
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// step (5)
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var scaleY = Math.sqrt(C * C + D * D);
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C /= scaleY;
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D /= scaleY;
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skew /= scaleY;
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// step (6)
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if ( A * D < B * C ) {
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A = -A;
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B = -B;
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skew = -skew;
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scaleX = -scaleX;
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}
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return {
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translateX: m[4],
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translateY: m[5],
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rotate: rtod(Math.atan2(B, A)),
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skew: rtod(Math.atan(skew)),
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scaleX: round(scaleX),
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scaleY: round(scaleY)
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};
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}
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/**
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* Get the computed style
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*
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* @param {Element} el
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* @return {String}
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* @api private
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*/
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function style(el) {
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var _style = window.getComputedStyle(el);
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return _style.getPropertyValue('transform') ||
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_style.getPropertyValue('-webkit-transform') ||
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_style.getPropertyValue('-ms-transform');
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}
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/**
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* String to matrix
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*
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* @param {String} style
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* @return {Array}
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* @api private
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*/
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function stom(str) {
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var m = [];
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if (window.WebKitCSSMatrix) {
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m = new window.WebKitCSSMatrix(str);
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return [m.a, m.b, m.c, m.d, m.e, m.f];
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}
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var rdigit = /[\d\.\-]+/g;
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var n;
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while(n = rdigit.exec(str)) {
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m.push(+n);
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}
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return m;
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}
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/**
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* Radians to degrees
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*
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* @param {Number} radians
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* @return {Number} degrees
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* @api private
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*/
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function rtod(radians) {
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var deg = radians * 180 / Math.PI;
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return round(deg);
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}
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/**
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* Round to the nearest hundredth
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*
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* @param {Number} n
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* @return {Number}
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* @api private
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*/
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function round(n) {
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return Math.round(n * 100) / 100;
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}
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/**
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* @exports
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*/
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return unmatrix;
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});
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