/*
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* Optimized version of PerspectiveTransform.js
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* by Edan Kwan
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* website: http://www.edankwan.com/
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* twitter: https://twitter.com/#!/edankwan
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* Lab: www.edankwan.com/lab
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*
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* The original PerspectiveTransform.js is created by Israel Pastrana
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* http://www.is-real.net/experiments/css3/wonder-webkit/js/real/display/PerspectiveTransform.js
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*
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* Matrix Libraries from a Java port of JAMA: A Java Matrix Package, http://math.nist.gov/javanumerics/jama/
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* Developed by Dr Peter Coxhead: http://www.cs.bham.ac.uk/~pxc/
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* Available here: http://www.cs.bham.ac.uk/~pxc/js/
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*
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* I simply removed some irrelevant variables and functions and merge everything into a smaller function. I also added some error checking functions and bug fixing things.
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*/
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(function (define) {
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define(function(){
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function PerspectiveTransform(element, width, height, useBackFacing){
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this.element = element;
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this.style = element.style;
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this.computedStyle = window.getComputedStyle(element);
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this.width = width;
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this.height = height;
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this.useBackFacing = !!useBackFacing;
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this.topLeft = {x: 0, y: 0};
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this.topRight = {x: width, y: 0};
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this.bottomLeft = {x: 0, y: height};
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this.bottomRight = {x: width, y: height};
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this.calcStyle = '';
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}
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PerspectiveTransform.useDPRFix = false;
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PerspectiveTransform.dpr = 1;
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PerspectiveTransform.prototype = (function(){
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var app = {
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stylePrefix: ''
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};
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var aM = [[0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0]];
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var bM = [0, 0, 0, 0, 0, 0, 0, 0];
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function _setTransformStyleName(){
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var testStyle = document.createElement('div').style;
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app.stylePrefix =
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'webkitTransform' in testStyle ? 'webkit' :
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'MozTransform' in testStyle ? 'Moz' :
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'msTransform' in testStyle ? 'ms' :
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'';
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PerspectiveTransform.transformStyleName = app.stylePrefix + (app.stylePrefix.length>0?'Transform':'transform');
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PerspectiveTransform.transformDomStyleName = '-'+app.stylePrefix.toLowerCase()+'-transform';
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PerspectiveTransform.transformOriginStyleName = app.stylePrefix + (app.stylePrefix.length>0?'TransformOrigin':'transformOrigin');
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PerspectiveTransform.transformOriginDomStyleName = '-'+app.stylePrefix.toLowerCase()+'-transform-origin';
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}
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// Check the distances between each points and if there is some points with the distance lequal to or less than 1 pixel, then return true. Otherwise return false;
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function _hasDistancesError(){
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var lenX = this.topLeft.x - this.topRight.x;
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var lenY = this.topLeft.y - this.topRight.y;
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if(Math.sqrt(lenX * lenX + lenY * lenY)<=1) return true;
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lenX = this.bottomLeft.x - this.bottomRight.x;
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lenY = this.bottomLeft.y - this.bottomRight.y;
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if(Math.sqrt(lenX * lenX + lenY * lenY)<=1) return true;
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lenX = this.topLeft.x - this.bottomLeft.x;
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lenY = this.topLeft.y - this.bottomLeft.y;
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if(Math.sqrt(lenX * lenX + lenY * lenY)<=1) return true;
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lenX = this.topRight.x - this.bottomRight.x;
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lenY = this.topRight.y - this.bottomRight.y;
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if( Math.sqrt(lenX * lenX + lenY * lenY)<=1) return true;
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lenX = this.topLeft.x - this.bottomRight.x;
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lenY = this.topLeft.y - this.bottomRight.y;
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if( Math.sqrt(lenX * lenX + lenY * lenY)<=1) return true;
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lenX = this.topRight.x - this.bottomLeft.x;
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lenY = this.topRight.y - this.bottomLeft.y;
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if( Math.sqrt(lenX * lenX + lenY * lenY)<=1) return true;
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return false;
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}
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// Get the determinant of given 3 points
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function _getDeterminant(p0, p1, p2){
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return p0.x * p1.y + p1.x * p2.y + p2.x * p0.y - p0.y * p1.x - p1.y * p2.x - p2.y * p0.x;
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}
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// Return true if it is a concave polygon or if it is backfacing when the useBackFacing property is false. Otehrwise return true;
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function _hasPolyonError(){
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var det1 = _getDeterminant(this.topLeft, this.topRight, this.bottomRight);
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var det2 = _getDeterminant(this.bottomRight, this.bottomLeft, this.topLeft);
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if(this.useBackFacing){
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if(det1*det2<=0) return true;
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}else{
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if(det1<=0||det2<=0) return true;
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}
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var det1 = _getDeterminant(this.topRight, this.bottomRight, this.bottomLeft);
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var det2 = _getDeterminant(this.bottomLeft, this.topLeft, this.topRight);
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if(this.useBackFacing){
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if(det1*det2<=0) return true;
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}else{
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if(det1<=0||det2<=0) return true;
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}
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return false;
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}
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function checkError(){
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if(_hasDistancesError.apply(this)) return 1; // Points are too close to each other.
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if(_hasPolyonError.apply(this)) return 2; // Concave or backfacing if the useBackFacing property is false
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return 0; // no error
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}
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function calc() {
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var width = this.width;
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var height = this.height;
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// get the offset from the transfrom origin of the element
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var offsetX = 0;
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var offsetY = 0;
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var offset = this.computedStyle.getPropertyValue(PerspectiveTransform.transformOriginDomStyleName);
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if(offset.indexOf('px')>-1){
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offset = offset.split('px');
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offsetX = -parseFloat(offset[0]);
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offsetY = -parseFloat(offset[1]);
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}else if(offset.indexOf('%')>-1){
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offset = offset.split('%');
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offsetX = -parseFloat(offset[0]) * width / 100;
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offsetY = -parseFloat(offset[1]) * height / 100;
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}
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// magic here:
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var dst = [this.topLeft, this.topRight, this.bottomLeft, this.bottomRight];
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var arr = [0, 1, 2, 3, 4, 5, 6, 7];
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for(var i = 0; i < 4; i++) {
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aM[i][0] = aM[i+4][3] = i & 1 ? width + offsetX : offsetX;
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aM[i][1] = aM[i+4][4] = (i > 1 ? height + offsetY : offsetY);
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aM[i][6] = (i & 1 ? -offsetX-width : -offsetX) * (dst[i].x + offsetX);
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aM[i][7] = (i > 1 ? -offsetY-height : -offsetY) * (dst[i].x + offsetX);
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aM[i+4][6] = (i & 1 ? -offsetX-width : -offsetX) * (dst[i].y + offsetY);
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aM[i+4][7] = (i > 1 ? -offsetY-height : -offsetY) * (dst[i].y + offsetY);
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bM[i] = (dst[i].x + offsetX);
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bM[i + 4] = (dst[i].y + offsetY);
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aM[i][2] = aM[i+4][5] = 1;
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aM[i][3] = aM[i][4] = aM[i][5] = aM[i+4][0] = aM[i+4][1] = aM[i+4][2] = 0;
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}
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var kmax, sum;
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var row;
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var col = [];
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var i, j, k, tmp;
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for(var j = 0; j < 8; j++) {
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for(var i = 0; i < 8; i++) col[i] = aM[i][j];
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for(i = 0; i < 8; i++) {
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row = aM[i];
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kmax = i<j?i:j;
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sum = 0.0;
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for(var k = 0; k < kmax; k++) sum += row[k] * col[k];
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row[j] = col[i] -= sum;
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}
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var p = j;
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for(i = j + 1; i < 8; i++) {
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if(Math.abs(col[i]) > Math.abs(col[p])) p = i;
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}
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if(p != j) {
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for(k = 0; k < 8; k++) {
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tmp = aM[p][k];
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aM[p][k] = aM[j][k];
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aM[j][k] = tmp;
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}
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tmp = arr[p];
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arr[p] = arr[j];
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arr[j] = tmp;
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}
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if(aM[j][j] != 0.0) for(i = j + 1; i < 8; i++) aM[i][j] /= aM[j][j];
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}
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for(i = 0; i < 8; i++) arr[i] = bM[arr[i]];
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for(k = 0; k < 8; k++) {
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for(i = k + 1; i < 8; i++) arr[i] -= arr[k] * aM[i][k];
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}
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for(k = 7; k > -1; k--) {
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arr[k] /= aM[k][k];
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for(i = 0; i < k; i++) arr[i] -= arr[k] * aM[i][k];
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}
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return this.calcStyle = 'matrix3d(' + arr[0].toFixed(9) + ',' + arr[3].toFixed(9) + ', 0,' + arr[6].toFixed(9) + ',' + arr[1].toFixed(9) + ',' + arr[4].toFixed(9) + ', 0,' + arr[7].toFixed(9) + ',0, 0, 1, 0,' + arr[2].toFixed(9) + ',' + arr[5].toFixed(9) + ', 0, 1)';
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}
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function update(style) {
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style = style || this.calcStyle;
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if(PerspectiveTransform.useDPRFix) {
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var dpr = PerspectiveTransform.dpr;
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style = 'scale(' + dpr + ',' + dpr + ')perspective(1000px)' + style + 'translateZ('+ ((1 - dpr) * 1000) + 'px)';
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}
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// use toFixed() just in case the Number became something like 3.10000001234e-9
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return this.style[PerspectiveTransform.transformStyleName] = style;
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}
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_setTransformStyleName();
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app.calc = calc;
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app.update = update;
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app.checkError = checkError;
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return app;
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})();
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return PerspectiveTransform;
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});
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}(typeof define === "function" && define.amd ? define : function (app) {
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window["PerspectiveTransform"] = app();
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}));
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