1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/canvas/test/webgl-conformance/conformance/resources/pnglib.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,207 @@
1.4 +/**
1.5 +* A handy class to calculate color values.
1.6 +*
1.7 +* @version 1.0
1.8 +* @author Robert Eisele <robert@xarg.org>
1.9 +* @copyright Copyright (c) 2010, Robert Eisele
1.10 +* @link http://www.xarg.org/2010/03/generate-client-side-png-files-using-javascript/
1.11 +* @license http://www.opensource.org/licenses/bsd-license.php BSD License
1.12 +*
1.13 +*/
1.14 +
1.15 +(function() {
1.16 +
1.17 + // helper functions for that ctx
1.18 + function write(buffer, offs) {
1.19 + for (var i = 2; i < arguments.length; i++) {
1.20 + for (var j = 0; j < arguments[i].length; j++) {
1.21 + buffer[offs++] = arguments[i].charAt(j);
1.22 + }
1.23 + }
1.24 + }
1.25 +
1.26 + function byte2(w) {
1.27 + return String.fromCharCode((w >> 8) & 255, w & 255);
1.28 + }
1.29 +
1.30 + function byte4(w) {
1.31 + return String.fromCharCode((w >> 24) & 255, (w >> 16) & 255, (w >> 8) & 255, w & 255);
1.32 + }
1.33 +
1.34 + function byte2lsb(w) {
1.35 + return String.fromCharCode(w & 255, (w >> 8) & 255);
1.36 + }
1.37 +
1.38 + window.PNGlib = function(width,height,depth) {
1.39 +
1.40 + this.width = width;
1.41 + this.height = height;
1.42 + this.depth = depth;
1.43 +
1.44 + // pixel data and row filter identifier size
1.45 + this.pix_size = height * (width + 1);
1.46 +
1.47 + // deflate header, pix_size, block headers, adler32 checksum
1.48 + this.data_size = 2 + this.pix_size + 5 * Math.floor((0xfffe + this.pix_size) / 0xffff) + 4;
1.49 +
1.50 + // offsets and sizes of Png chunks
1.51 + this.ihdr_offs = 0; // IHDR offset and size
1.52 + this.ihdr_size = 4 + 4 + 13 + 4;
1.53 + this.plte_offs = this.ihdr_offs + this.ihdr_size; // PLTE offset and size
1.54 + this.plte_size = 4 + 4 + 3 * depth + 4;
1.55 + this.trns_offs = this.plte_offs + this.plte_size; // tRNS offset and size
1.56 + this.trns_size = 4 + 4 + depth + 4;
1.57 + this.idat_offs = this.trns_offs + this.trns_size; // IDAT offset and size
1.58 + this.idat_size = 4 + 4 + this.data_size + 4;
1.59 + this.iend_offs = this.idat_offs + this.idat_size; // IEND offset and size
1.60 + this.iend_size = 4 + 4 + 4;
1.61 + this.buffer_size = this.iend_offs + this.iend_size; // total PNG size
1.62 +
1.63 + this.buffer = new Array();
1.64 + this.palette = new Object();
1.65 + this.pindex = 0;
1.66 +
1.67 + var _crc32 = new Array();
1.68 +
1.69 + // initialize buffer with zero bytes
1.70 + for (var i = 0; i < this.buffer_size; i++) {
1.71 + this.buffer[i] = "\x00";
1.72 + }
1.73 +
1.74 + // initialize non-zero elements
1.75 + write(this.buffer, this.ihdr_offs, byte4(this.ihdr_size - 12), 'IHDR', byte4(width), byte4(height), "\x08\x03");
1.76 + write(this.buffer, this.plte_offs, byte4(this.plte_size - 12), 'PLTE');
1.77 + write(this.buffer, this.trns_offs, byte4(this.trns_size - 12), 'tRNS');
1.78 + write(this.buffer, this.idat_offs, byte4(this.idat_size - 12), 'IDAT');
1.79 + write(this.buffer, this.iend_offs, byte4(this.iend_size - 12), 'IEND');
1.80 +
1.81 + // initialize deflate header
1.82 + var header = ((8 + (7 << 4)) << 8) | (3 << 6);
1.83 + header+= 31 - (header % 31);
1.84 +
1.85 + write(this.buffer, this.idat_offs + 8, byte2(header));
1.86 +
1.87 + // initialize deflate block headers
1.88 + for (var i = 0; (i << 16) - 1 < this.pix_size; i++) {
1.89 + var size, bits;
1.90 + if (i + 0xffff < this.pix_size) {
1.91 + size = 0xffff;
1.92 + bits = "\x00";
1.93 + } else {
1.94 + size = this.pix_size - (i << 16) - i;
1.95 + bits = "\x01";
1.96 + }
1.97 + write(this.buffer, this.idat_offs + 8 + 2 + (i << 16) + (i << 2), bits, byte2lsb(size), byte2lsb(~size));
1.98 + }
1.99 +
1.100 + /* Create crc32 lookup table */
1.101 + for (var i = 0; i < 256; i++) {
1.102 + var c = i;
1.103 + for (var j = 0; j < 8; j++) {
1.104 + if (c & 1) {
1.105 + c = -306674912 ^ ((c >> 1) & 0x7fffffff);
1.106 + } else {
1.107 + c = (c >> 1) & 0x7fffffff;
1.108 + }
1.109 + }
1.110 + _crc32[i] = c;
1.111 + }
1.112 +
1.113 + // compute the index into a png for a given pixel
1.114 + this.index = function(x,y) {
1.115 + var i = y * (this.width + 1) + x + 1;
1.116 + var j = this.idat_offs + 8 + 2 + 5 * Math.floor((i / 0xffff) + 1) + i;
1.117 + return j;
1.118 + }
1.119 +
1.120 + // convert a color and build up the palette
1.121 + this.color = function(red, green, blue, alpha) {
1.122 +
1.123 + alpha = alpha >= 0 ? alpha : 255;
1.124 + var color = (((((alpha << 8) | red) << 8) | green) << 8) | blue;
1.125 +
1.126 + if (typeof this.palette[color] == "undefined") {
1.127 + if (this.pindex == this.depth) return "\x00";
1.128 +
1.129 + var ndx = this.plte_offs + 8 + 3 * this.pindex;
1.130 +
1.131 + this.buffer[ndx + 0] = String.fromCharCode(red);
1.132 + this.buffer[ndx + 1] = String.fromCharCode(green);
1.133 + this.buffer[ndx + 2] = String.fromCharCode(blue);
1.134 + this.buffer[this.trns_offs+8+this.pindex] = String.fromCharCode(alpha);
1.135 +
1.136 + this.palette[color] = String.fromCharCode(this.pindex++);
1.137 + }
1.138 + return this.palette[color];
1.139 + }
1.140 +
1.141 + // output a PNG string, Base64 encoded
1.142 + this.getBase64 = function() {
1.143 +
1.144 + var s = this.getDump();
1.145 +
1.146 + var ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
1.147 + var c1, c2, c3, e1, e2, e3, e4;
1.148 + var l = s.length;
1.149 + var i = 0;
1.150 + var r = "";
1.151 +
1.152 + do {
1.153 + c1 = s.charCodeAt(i);
1.154 + e1 = c1 >> 2;
1.155 + c2 = s.charCodeAt(i+1);
1.156 + e2 = ((c1 & 3) << 4) | (c2 >> 4);
1.157 + c3 = s.charCodeAt(i+2);
1.158 + if (l < i+2) { e3 = 64; } else { e3 = ((c2 & 0xf) << 2) | (c3 >> 6); }
1.159 + if (l < i+3) { e4 = 64; } else { e4 = c3 & 0x3f; }
1.160 + r+= ch.charAt(e1) + ch.charAt(e2) + ch.charAt(e3) + ch.charAt(e4);
1.161 + } while ((i+= 3) < l);
1.162 + return r;
1.163 + }
1.164 +
1.165 + // output a PNG string
1.166 + this.getDump = function() {
1.167 +
1.168 + // compute adler32 of output pixels + row filter bytes
1.169 + var BASE = 65521; /* largest prime smaller than 65536 */
1.170 + var NMAX = 5552; /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
1.171 + var s1 = 1;
1.172 + var s2 = 0;
1.173 + var n = NMAX;
1.174 +
1.175 + for (var y = 0; y < this.height; y++) {
1.176 + for (var x = -1; x < this.width; x++) {
1.177 + s1+= this.buffer[this.index(x, y)].charCodeAt(0);
1.178 + s2+= s1;
1.179 + if ((n-= 1) == 0) {
1.180 + s1%= BASE;
1.181 + s2%= BASE;
1.182 + n = NMAX;
1.183 + }
1.184 + }
1.185 + }
1.186 + s1%= BASE;
1.187 + s2%= BASE;
1.188 + write(this.buffer, this.idat_offs + this.idat_size - 8, byte4((s2 << 16) | s1));
1.189 +
1.190 + // compute crc32 of the PNG chunks
1.191 + function crc32(png, offs, size) {
1.192 + var crc = -1;
1.193 + for (var i = 4; i < size-4; i += 1) {
1.194 + crc = _crc32[(crc ^ png[offs+i].charCodeAt(0)) & 0xff] ^ ((crc >> 8) & 0x00ffffff);
1.195 + }
1.196 + write(png, offs+size-4, byte4(crc ^ -1));
1.197 + }
1.198 +
1.199 + crc32(this.buffer, this.ihdr_offs, this.ihdr_size);
1.200 + crc32(this.buffer, this.plte_offs, this.plte_size);
1.201 + crc32(this.buffer, this.trns_offs, this.trns_size);
1.202 + crc32(this.buffer, this.idat_offs, this.idat_size);
1.203 + crc32(this.buffer, this.iend_offs, this.iend_size);
1.204 +
1.205 + // convert PNG to string
1.206 + return "\211PNG\r\n\032\n"+this.buffer.join('');
1.207 + }
1.208 + }
1.209 +
1.210 +})();
