Index: conformance/resources/pnglib.js |
=================================================================== |
--- conformance/resources/pnglib.js (revision 0) |
+++ conformance/resources/pnglib.js (revision 0) |
@@ -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(''); |
+ } |
+ } |
+ |
+})(); |
Property changes on: conformance/resources/pnglib.js |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |