'use strict';
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exports.type = 'perItem';
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exports.active = true;
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exports.description = 'collapses multiple transformations and optimizes it';
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exports.params = {
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convertToShorts: true,
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// degPrecision: 3, // transformPrecision (or matrix precision) - 2 by default
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floatPrecision: 3,
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transformPrecision: 5,
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matrixToTransform: true,
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shortTranslate: true,
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shortScale: true,
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shortRotate: true,
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removeUseless: true,
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collapseIntoOne: true,
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leadingZero: true,
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negativeExtraSpace: false
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};
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var cleanupOutData = require('../lib/svgo/tools').cleanupOutData,
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transform2js = require('./_transforms.js').transform2js,
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transformsMultiply = require('./_transforms.js').transformsMultiply,
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matrixToTransform = require('./_transforms.js').matrixToTransform,
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degRound,
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floatRound,
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transformRound;
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/**
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* Convert matrices to the short aliases,
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* convert long translate, scale or rotate transform notations to the shorts ones,
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* convert transforms to the matrices and multiply them all into one,
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* remove useless transforms.
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*
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* @see http://www.w3.org/TR/SVG/coords.html#TransformMatrixDefined
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*
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* @param {Object} item current iteration item
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* @param {Object} params plugin params
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* @return {Boolean} if false, item will be filtered out
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*
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* @author Kir Belevich
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*/
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exports.fn = function(item, params) {
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if (item.elem) {
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// transform
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if (item.hasAttr('transform')) {
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convertTransform(item, 'transform', params);
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}
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// gradientTransform
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if (item.hasAttr('gradientTransform')) {
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convertTransform(item, 'gradientTransform', params);
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}
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// patternTransform
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if (item.hasAttr('patternTransform')) {
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convertTransform(item, 'patternTransform', params);
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}
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}
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};
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/**
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* Main function.
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*
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* @param {Object} item input item
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* @param {String} attrName attribute name
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* @param {Object} params plugin params
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*/
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function convertTransform(item, attrName, params) {
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var data = transform2js(item.attr(attrName).value);
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params = definePrecision(data, params);
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if (params.collapseIntoOne && data.length > 1) {
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data = [transformsMultiply(data)];
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}
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if (params.convertToShorts) {
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data = convertToShorts(data, params);
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} else {
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data.forEach(roundTransform);
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}
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if (params.removeUseless) {
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data = removeUseless(data);
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}
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if (data.length) {
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item.attr(attrName).value = js2transform(data, params);
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} else {
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item.removeAttr(attrName);
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}
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}
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/**
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* Defines precision to work with certain parts.
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* transformPrecision - for scale and four first matrix parameters (needs a better precision due to multiplying),
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* floatPrecision - for translate including two last matrix and rotate parameters,
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* degPrecision - for rotate and skew. By default it's equal to (rougly)
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* transformPrecision - 2 or floatPrecision whichever is lower. Can be set in params.
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*
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* @param {Array} transforms input array
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* @param {Object} params plugin params
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* @return {Array} output array
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*/
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function definePrecision(data, params) {
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/* jshint validthis: true */
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var matrixData = data.reduce(getMatrixData, []),
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significantDigits = params.transformPrecision;
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// Clone params so it don't affect other elements transformations.
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params = Object.assign({}, params);
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// Limit transform precision with matrix one. Calculating with larger precision doesn't add any value.
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if (matrixData.length) {
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params.transformPrecision = Math.min(params.transformPrecision,
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Math.max.apply(Math, matrixData.map(floatDigits)) || params.transformPrecision);
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significantDigits = Math.max.apply(Math, matrixData.map(function(n) {
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return String(n).replace(/\D+/g, '').length; // Number of digits in a number. 123.45 → 5
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}));
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}
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// No sense in angle precision more then number of significant digits in matrix.
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if (!('degPrecision' in params)) {
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params.degPrecision = Math.max(0, Math.min(params.floatPrecision, significantDigits - 2));
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}
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floatRound = params.floatPrecision >= 1 && params.floatPrecision < 20 ?
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smartRound.bind(this, params.floatPrecision) :
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round;
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degRound = params.degPrecision >= 1 && params.floatPrecision < 20 ?
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smartRound.bind(this, params.degPrecision) :
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round;
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transformRound = params.transformPrecision >= 1 && params.floatPrecision < 20 ?
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smartRound.bind(this, params.transformPrecision) :
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round;
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return params;
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}
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/**
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* Gathers four first matrix parameters.
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*
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* @param {Array} a array of data
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* @param {Object} transform
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* @return {Array} output array
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*/
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function getMatrixData(a, b) {
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return b.name == 'matrix' ? a.concat(b.data.slice(0, 4)) : a;
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}
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/**
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* Returns number of digits after the point. 0.125 → 3
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*/
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function floatDigits(n) {
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return (n = String(n)).slice(n.indexOf('.')).length - 1;
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}
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/**
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* Convert transforms to the shorthand alternatives.
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*
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* @param {Array} transforms input array
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* @param {Object} params plugin params
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* @return {Array} output array
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*/
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function convertToShorts(transforms, params) {
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for(var i = 0; i < transforms.length; i++) {
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var transform = transforms[i];
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// convert matrix to the short aliases
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if (
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params.matrixToTransform &&
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transform.name === 'matrix'
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) {
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var decomposed = matrixToTransform(transform, params);
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if (decomposed != transform &&
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js2transform(decomposed, params).length <= js2transform([transform], params).length) {
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transforms.splice.apply(transforms, [i, 1].concat(decomposed));
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}
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transform = transforms[i];
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}
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// fixed-point numbers
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// 12.754997 → 12.755
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roundTransform(transform);
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// convert long translate transform notation to the shorts one
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// translate(10 0) → translate(10)
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if (
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params.shortTranslate &&
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transform.name === 'translate' &&
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transform.data.length === 2 &&
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!transform.data[1]
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) {
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transform.data.pop();
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}
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// convert long scale transform notation to the shorts one
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// scale(2 2) → scale(2)
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if (
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params.shortScale &&
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transform.name === 'scale' &&
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transform.data.length === 2 &&
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transform.data[0] === transform.data[1]
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) {
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transform.data.pop();
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}
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// convert long rotate transform notation to the short one
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// translate(cx cy) rotate(a) translate(-cx -cy) → rotate(a cx cy)
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if (
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params.shortRotate &&
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transforms[i - 2] &&
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transforms[i - 2].name === 'translate' &&
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transforms[i - 1].name === 'rotate' &&
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transforms[i].name === 'translate' &&
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transforms[i - 2].data[0] === -transforms[i].data[0] &&
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transforms[i - 2].data[1] === -transforms[i].data[1]
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) {
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transforms.splice(i - 2, 3, {
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name: 'rotate',
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data: [
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transforms[i - 1].data[0],
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transforms[i - 2].data[0],
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transforms[i - 2].data[1]
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]
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});
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// splice compensation
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i -= 2;
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transform = transforms[i];
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}
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}
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return transforms;
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}
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/**
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* Remove useless transforms.
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*
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* @param {Array} transforms input array
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* @return {Array} output array
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*/
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function removeUseless(transforms) {
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return transforms.filter(function(transform) {
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// translate(0), rotate(0[, cx, cy]), skewX(0), skewY(0)
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if (
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['translate', 'rotate', 'skewX', 'skewY'].indexOf(transform.name) > -1 &&
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(transform.data.length == 1 || transform.name == 'rotate') &&
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!transform.data[0] ||
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// translate(0, 0)
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transform.name == 'translate' &&
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!transform.data[0] &&
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!transform.data[1] ||
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// scale(1)
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transform.name == 'scale' &&
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transform.data[0] == 1 &&
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(transform.data.length < 2 || transform.data[1] == 1) ||
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// matrix(1 0 0 1 0 0)
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transform.name == 'matrix' &&
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transform.data[0] == 1 &&
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transform.data[3] == 1 &&
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!(transform.data[1] || transform.data[2] || transform.data[4] || transform.data[5])
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) {
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return false;
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}
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return true;
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});
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}
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/**
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* Convert transforms JS representation to string.
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*
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* @param {Array} transformJS JS representation array
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* @param {Object} params plugin params
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* @return {String} output string
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*/
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function js2transform(transformJS, params) {
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var transformString = '';
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// collect output value string
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transformJS.forEach(function(transform) {
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roundTransform(transform);
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transformString += (transformString && ' ') + transform.name + '(' + cleanupOutData(transform.data, params) + ')';
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});
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return transformString;
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}
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function roundTransform(transform) {
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switch (transform.name) {
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case 'translate':
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transform.data = floatRound(transform.data);
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break;
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case 'rotate':
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transform.data = degRound(transform.data.slice(0, 1)).concat(floatRound(transform.data.slice(1)));
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break;
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case 'skewX':
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case 'skewY':
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transform.data = degRound(transform.data);
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break;
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case 'scale':
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transform.data = transformRound(transform.data);
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break;
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case 'matrix':
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transform.data = transformRound(transform.data.slice(0, 4)).concat(floatRound(transform.data.slice(4)));
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break;
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}
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return transform;
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}
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/**
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* Rounds numbers in array.
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*
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* @param {Array} data input data array
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* @return {Array} output data array
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*/
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function round(data) {
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return data.map(Math.round);
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}
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/**
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* Decrease accuracy of floating-point numbers
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* in transforms keeping a specified number of decimals.
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* Smart rounds values like 2.349 to 2.35.
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*
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* @param {Number} fixed number of decimals
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* @param {Array} data input data array
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* @return {Array} output data array
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*/
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function smartRound(precision, data) {
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for (var i = data.length, tolerance = +Math.pow(.1, precision).toFixed(precision); i--;) {
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if (data[i].toFixed(precision) != data[i]) {
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var rounded = +data[i].toFixed(precision - 1);
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data[i] = +Math.abs(rounded - data[i]).toFixed(precision + 1) >= tolerance ?
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+data[i].toFixed(precision) :
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rounded;
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}
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}
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return data;
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}
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