121 lines
3.3 KiB
JavaScript
121 lines
3.3 KiB
JavaScript
|
/* canvas-toBlob.js
|
||
|
* A canvas.toBlob() implementation.
|
||
|
* 2013-12-27
|
||
|
*
|
||
|
* By Eli Grey, http://eligrey.com and Devin Samarin, https://github.com/eboyjr
|
||
|
* License: X11/MIT
|
||
|
* See LICENSE.md
|
||
|
*/
|
||
|
|
||
|
/*global self */
|
||
|
/*jslint bitwise: true, regexp: true, confusion: true, es5: true, vars: true, white: true,
|
||
|
plusplus: true */
|
||
|
|
||
|
/*! @source http://purl.eligrey.com/github/canvas-toBlob.js/blob/master/canvas-toBlob.js */
|
||
|
|
||
|
(function(view) {
|
||
|
"use strict";
|
||
|
var
|
||
|
Uint8Array = view.Uint8Array
|
||
|
, HTMLCanvasElement = view.HTMLCanvasElement
|
||
|
, canvas_proto = HTMLCanvasElement && HTMLCanvasElement.prototype
|
||
|
, is_base64_regex = /\s*;\s*base64\s*(?:;|$)/i
|
||
|
, to_data_url = "toDataURL"
|
||
|
, base64_ranks
|
||
|
, decode_base64 = function(base64) {
|
||
|
var
|
||
|
len = base64.length
|
||
|
, buffer = new Uint8Array(len / 4 * 3 | 0)
|
||
|
, i = 0
|
||
|
, outptr = 0
|
||
|
, last = [0, 0]
|
||
|
, state = 0
|
||
|
, save = 0
|
||
|
, rank
|
||
|
, code
|
||
|
, undef
|
||
|
;
|
||
|
while (len--) {
|
||
|
code = base64.charCodeAt(i++);
|
||
|
rank = base64_ranks[code-43];
|
||
|
if (rank !== 255 && rank !== undef) {
|
||
|
last[1] = last[0];
|
||
|
last[0] = code;
|
||
|
save = (save << 6) | rank;
|
||
|
state++;
|
||
|
if (state === 4) {
|
||
|
buffer[outptr++] = save >>> 16;
|
||
|
if (last[1] !== 61 /* padding character */) {
|
||
|
buffer[outptr++] = save >>> 8;
|
||
|
}
|
||
|
if (last[0] !== 61 /* padding character */) {
|
||
|
buffer[outptr++] = save;
|
||
|
}
|
||
|
state = 0;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
// 2/3 chance there's going to be some null bytes at the end, but that
|
||
|
// doesn't really matter with most image formats.
|
||
|
// If it somehow matters for you, truncate the buffer up outptr.
|
||
|
return buffer;
|
||
|
}
|
||
|
;
|
||
|
if (Uint8Array) {
|
||
|
base64_ranks = new Uint8Array([
|
||
|
62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1
|
||
|
, -1, -1, 0, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
|
||
|
, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25
|
||
|
, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35
|
||
|
, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
|
||
|
]);
|
||
|
}
|
||
|
if (HTMLCanvasElement && !canvas_proto.toBlob) {
|
||
|
canvas_proto.toBlob = function(callback, type /*, ...args*/) {
|
||
|
if (!type) {
|
||
|
type = "image/png";
|
||
|
} if (this.mozGetAsFile) {
|
||
|
callback(this.mozGetAsFile("canvas", type));
|
||
|
return;
|
||
|
}
|
||
|
var
|
||
|
args = Array.prototype.slice.call(arguments, 1)
|
||
|
, dataURI = this[to_data_url].apply(this, args)
|
||
|
, header_end = dataURI.indexOf(",")
|
||
|
, data = dataURI.substring(header_end + 1)
|
||
|
, is_base64 = is_base64_regex.test(dataURI.substring(0, header_end))
|
||
|
, blob
|
||
|
;
|
||
|
if (Blob.fake) {
|
||
|
// no reason to decode a data: URI that's just going to become a data URI again
|
||
|
blob = new Blob
|
||
|
if (is_base64) {
|
||
|
blob.encoding = "base64";
|
||
|
} else {
|
||
|
blob.encoding = "URI";
|
||
|
}
|
||
|
blob.data = data;
|
||
|
blob.size = data.length;
|
||
|
} else if (Uint8Array) {
|
||
|
if (is_base64) {
|
||
|
blob = new Blob([decode_base64(data)], {type: type});
|
||
|
} else {
|
||
|
blob = new Blob([decodeURIComponent(data)], {type: type});
|
||
|
}
|
||
|
}
|
||
|
callback(blob);
|
||
|
};
|
||
|
|
||
|
if (canvas_proto.toDataURLHD) {
|
||
|
canvas_proto.toBlobHD = function() {
|
||
|
to_data_url = "toDataURLHD";
|
||
|
var blob = this.toBlob();
|
||
|
to_data_url = "toDataURL";
|
||
|
return blob;
|
||
|
}
|
||
|
} else {
|
||
|
canvas_proto.toBlobHD = canvas_proto.toBlob;
|
||
|
}
|
||
|
}
|
||
|
}(typeof self !== "undefined" && self || typeof window !== "undefined" && window || this.content || this));
|