Sakurai/pdf.js
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Improving CanvasPixelArray polyfill for Android

Browse Source
This commit is contained in:
Fabian Lange 2014-06-25 12:52:06 +02:00
parent b482393e6a
commit 54fb1f7226
1 changed files with 28 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
web/compatibility.js
View File

@ -481,7 +481,7 @@ if (typeof PDFJS === 'undefined') {
}
})();
// Support: IE<11, Chrome<21
// Support: IE<11, Chrome<21, Android<4.4
(function checkSetPresenceInImageData() {
// IE < 11 will use window.CanvasPixelArray which lacks set function.
if (window.CanvasPixelArray) {
@ -493,23 +493,37 @@ if (typeof PDFJS === 'undefined') {
};
}
} else {
// Chrome < 21 uses an inaccessible CanvasPixelArray prototype.
// Because we cannot feature detect it, we rely on user agent.
// Old Chrome and Android use an inaccessible CanvasPixelArray prototype.
// Because we cannot feature detect it, we rely on user agent parsing.
var polyfill = false;
if (navigator.userAgent.indexOf('Chrom') >= 0) {
var versionMatch = navigator.userAgent.match(/Chrom(e|ium)\/([0-9]+)\./);
if (versionMatch && parseInt(versionMatch[2]) < 21) {
var contextPrototype = window.CanvasRenderingContext2D.prototype;
contextPrototype._createImageData = contextPrototype.createImageData;
contextPrototype.createImageData = function(w, h) {
var imageData = this._createImageData(w, h);
imageData.data.set = function(arr) {
for (var i = 0, ii = this.length; i < ii; i++) {
this[i] = arr[i];
}
};
return imageData;
};
// Chrome < 21 lacks the set function.
polyfill = true;
}
} else if (navigator.userAgent.indexOf('Android') >= 0) {
// Android < 4.4 lacks the set function.
// Android >= 4.4 will contain Chrome in the user agent,
// thus pass the Chrome check above and not reach this block.
var isOldAndroid = /Android\s[0-4][^\d]/g.test(navigator.userAgent);
if (isOldAndroid) {
polyfill = true;
}
}
if (polyfill) {
var contextPrototype = window.CanvasRenderingContext2D.prototype;
contextPrototype._createImageData = contextPrototype.createImageData;
contextPrototype.createImageData = function(w, h) {
var imageData = this._createImageData(w, h);
imageData.data.set = function(arr) {
for (var i = 0, ii = this.length; i < ii; i++) {
this[i] = arr[i];
}
};
return imageData;
};
}
}
})();