diff options
Diffstat (limited to 'dom/canvas/test/webgl-conf/checkout/js/pnglib.js')
| -rw-r--r-- | dom/canvas/test/webgl-conf/checkout/js/pnglib.js | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/dom/canvas/test/webgl-conf/checkout/js/pnglib.js b/dom/canvas/test/webgl-conf/checkout/js/pnglib.js new file mode 100644 index 000000000..d2a9b99e0 --- /dev/null +++ b/dom/canvas/test/webgl-conf/checkout/js/pnglib.js @@ -0,0 +1,207 @@ +/** +* A handy class to calculate color values. +* +* @version 1.0 +* @author Robert Eisele <robert@xarg.org> +* @copyright Copyright (c) 2010, Robert Eisele +* @link http://www.xarg.org/2010/03/generate-client-side-png-files-using-javascript/ +* @license http://www.opensource.org/licenses/bsd-license.php BSD License +* +*/ + +(function() { + + // helper functions for that ctx + function write(buffer, offs) { + for (var i = 2; i < arguments.length; i++) { + for (var j = 0; j < arguments[i].length; j++) { + buffer[offs++] = arguments[i].charAt(j); + } + } + } + + function byte2(w) { + return String.fromCharCode((w >> 8) & 255, w & 255); + } + + function byte4(w) { + return String.fromCharCode((w >> 24) & 255, (w >> 16) & 255, (w >> 8) & 255, w & 255); + } + + function byte2lsb(w) { + return String.fromCharCode(w & 255, (w >> 8) & 255); + } + + window.PNGlib = function(width,height,depth) { + + this.width = width; + this.height = height; + this.depth = depth; + + // pixel data and row filter identifier size + this.pix_size = height * (width + 1); + + // deflate header, pix_size, block headers, adler32 checksum + this.data_size = 2 + this.pix_size + 5 * Math.floor((0xfffe + this.pix_size) / 0xffff) + 4; + + // offsets and sizes of Png chunks + this.ihdr_offs = 0; // IHDR offset and size + this.ihdr_size = 4 + 4 + 13 + 4; + this.plte_offs = this.ihdr_offs + this.ihdr_size; // PLTE offset and size + this.plte_size = 4 + 4 + 3 * depth + 4; + this.trns_offs = this.plte_offs + this.plte_size; // tRNS offset and size + this.trns_size = 4 + 4 + depth + 4; + this.idat_offs = this.trns_offs + this.trns_size; // IDAT offset and size + this.idat_size = 4 + 4 + this.data_size + 4; + this.iend_offs = this.idat_offs + this.idat_size; // IEND offset and size + this.iend_size = 4 + 4 + 4; + this.buffer_size = this.iend_offs + this.iend_size; // total PNG size + + this.buffer = new Array(); + this.palette = new Object(); + this.pindex = 0; + + var _crc32 = new Array(); + + // initialize buffer with zero bytes + for (var i = 0; i < this.buffer_size; i++) { + this.buffer[i] = "\x00"; + } + + // initialize non-zero elements + write(this.buffer, this.ihdr_offs, byte4(this.ihdr_size - 12), 'IHDR', byte4(width), byte4(height), "\x08\x03"); + write(this.buffer, this.plte_offs, byte4(this.plte_size - 12), 'PLTE'); + write(this.buffer, this.trns_offs, byte4(this.trns_size - 12), 'tRNS'); + write(this.buffer, this.idat_offs, byte4(this.idat_size - 12), 'IDAT'); + write(this.buffer, this.iend_offs, byte4(this.iend_size - 12), 'IEND'); + + // initialize deflate header + var header = ((8 + (7 << 4)) << 8) | (3 << 6); + header+= 31 - (header % 31); + + write(this.buffer, this.idat_offs + 8, byte2(header)); + + // initialize deflate block headers + for (var i = 0; (i << 16) - 1 < this.pix_size; i++) { + var size, bits; + if (i + 0xffff < this.pix_size) { + size = 0xffff; + bits = "\x00"; + } else { + size = this.pix_size - (i << 16) - i; + bits = "\x01"; + } + write(this.buffer, this.idat_offs + 8 + 2 + (i << 16) + (i << 2), bits, byte2lsb(size), byte2lsb(~size)); + } + + /* Create crc32 lookup table */ + for (var i = 0; i < 256; i++) { + var c = i; + for (var j = 0; j < 8; j++) { + if (c & 1) { + c = -306674912 ^ ((c >> 1) & 0x7fffffff); + } else { + c = (c >> 1) & 0x7fffffff; + } + } + _crc32[i] = c; + } + + // compute the index into a png for a given pixel + this.index = function(x,y) { + var i = y * (this.width + 1) + x + 1; + var j = this.idat_offs + 8 + 2 + 5 * Math.floor((i / 0xffff) + 1) + i; + return j; + } + + // convert a color and build up the palette + this.color = function(red, green, blue, alpha) { + + alpha = alpha >= 0 ? alpha : 255; + var color = (((((alpha << 8) | red) << 8) | green) << 8) | blue; + + if (typeof this.palette[color] == "undefined") { + if (this.pindex == this.depth) return "\x00"; + + var ndx = this.plte_offs + 8 + 3 * this.pindex; + + this.buffer[ndx + 0] = String.fromCharCode(red); + this.buffer[ndx + 1] = String.fromCharCode(green); + this.buffer[ndx + 2] = String.fromCharCode(blue); + this.buffer[this.trns_offs+8+this.pindex] = String.fromCharCode(alpha); + + this.palette[color] = String.fromCharCode(this.pindex++); + } + return this.palette[color]; + } + + // output a PNG string, Base64 encoded + this.getBase64 = function() { + + var s = this.getDump(); + + var ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; + var c1, c2, c3, e1, e2, e3, e4; + var l = s.length; + var i = 0; + var r = ""; + + do { + c1 = s.charCodeAt(i); + e1 = c1 >> 2; + c2 = s.charCodeAt(i+1); + e2 = ((c1 & 3) << 4) | (c2 >> 4); + c3 = s.charCodeAt(i+2); + if (l < i+2) { e3 = 64; } else { e3 = ((c2 & 0xf) << 2) | (c3 >> 6); } + if (l < i+3) { e4 = 64; } else { e4 = c3 & 0x3f; } + r+= ch.charAt(e1) + ch.charAt(e2) + ch.charAt(e3) + ch.charAt(e4); + } while ((i+= 3) < l); + return r; + } + + // output a PNG string + this.getDump = function() { + + // compute adler32 of output pixels + row filter bytes + var BASE = 65521; /* largest prime smaller than 65536 */ + var NMAX = 5552; /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ + var s1 = 1; + var s2 = 0; + var n = NMAX; + + for (var y = 0; y < this.height; y++) { + for (var x = -1; x < this.width; x++) { + s1+= this.buffer[this.index(x, y)].charCodeAt(0); + s2+= s1; + if ((n-= 1) == 0) { + s1%= BASE; + s2%= BASE; + n = NMAX; + } + } + } + s1%= BASE; + s2%= BASE; + write(this.buffer, this.idat_offs + this.idat_size - 8, byte4((s2 << 16) | s1)); + + // compute crc32 of the PNG chunks + function crc32(png, offs, size) { + var crc = -1; + for (var i = 4; i < size-4; i += 1) { + crc = _crc32[(crc ^ png[offs+i].charCodeAt(0)) & 0xff] ^ ((crc >> 8) & 0x00ffffff); + } + write(png, offs+size-4, byte4(crc ^ -1)); + } + + crc32(this.buffer, this.ihdr_offs, this.ihdr_size); + crc32(this.buffer, this.plte_offs, this.plte_size); + crc32(this.buffer, this.trns_offs, this.trns_size); + crc32(this.buffer, this.idat_offs, this.idat_size); + crc32(this.buffer, this.iend_offs, this.iend_size); + + // convert PNG to string + return "\211PNG\r\n\032\n"+this.buffer.join(''); + } + } + +})(); |