rescode
Version:
Generate Codes (EAN13, QRCODE ..)
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JavaScript
// file: lib/canvas.js
//
// Copyright (c) 2011-2013 Mark Warren
//
// See the COPYRIGHT file in the bwip.js root directory
// for the extended copyright notice.
// With embedding in the browser, we load the symbols externally
// Encapsulate the bitmap interface
// bwip-js bitmap interface
function Bitmap() {
var _clr = 0; // currently active color
var _clrs = {}; // color map
var _nclr = 0; // color count
var _bits = []; // the x,y,c bits
var _minx = Infinity;
var _miny = Infinity;
var _maxx = 0;
var _maxy = 0;
this.color = function(r,g,b) {
var rgb = (r<<16) | (g<<8) | b;
if (!_clrs[rgb])
_clrs[rgb] = { n:_nclr++ };
_clr = rgb;
};
this.set = function(x, y, b) {
// postscript graphics work with floating-pt numbers
x = Math.floor(x);
y = Math.floor(y);
if (_minx > x) _minx = x;
if (_maxx < x) _maxx = x;
if (_miny > y) _miny = y;
if (_maxy < y) _maxy = y;
_bits.push([x,y,_clr]);
};
this.create = function(rot) {
var h, w;
// determine image width and height
if (rot == 'R' || rot == 'L') {
h = _maxx-_minx+1;
w = _maxy-_miny+1;
} else {
w = _maxx-_minx+1;
h = _maxy-_miny+1;
}
var png = new PNGlib(w, h, 256);
// make sure the default color (index 0) is white
png.color(255,255,255,255);
// map the colors
var cmap = [];
for (rgb in _clrs)
cmap[rgb] = png.color(rgb>>16, (rgb>>8)&0xff, (rgb&0xff), 255);
for (var i = 0; i < _bits.length; i++) {
// PostScript builds bottom-up, we build top-down.
var x = _bits[i][0] - _minx;
var y = _bits[i][1] - _miny;
var c = cmap[_bits[i][2]];
if (rot == 'N') {
y = h - y - 1; // Invert y
} else if (rot == 'I') {
x = w - x - 1; // Invert x
} else {
y = w - y; // Invert y
if (rot == 'L') {
var t = y;
y = h - x - 1;
x = t - 1;
} else {
var t = x;
x = w - y;
y = t;
}
}
png.set(x, y, c);
}
return new Buffer( png.render(), "binary" );
};
}
module.exports = Bitmap;
/**
* pnglib.js
* @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
*/
// Modified by MRW for use with bwip-js.
function PNGlib(width,height,depth) {
// 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);
}
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;
this.ihdr_size = 4 + 4 + 13 + 4;
this.plte_offs = this.ihdr_offs + this.ihdr_size;
this.plte_size = 4 + 4 + 3 * depth + 4;
this.trns_offs = this.plte_offs + this.plte_size;
this.trns_size = 4 + 4 + depth + 4;
this.idat_offs = this.trns_offs + this.trns_size;
this.idat_size = 4 + 4 + this.data_size + 4;
this.iend_offs = this.idat_offs + this.idat_size;
this.iend_size = 4 + 4 + 4;
this.buffer_size = this.iend_offs + this.iend_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;
}
// used internally
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;
}
// set a pixel to the given color
this.set = function(x,y,c) {
var i = y * (this.width + 1) + x + 1;
var j = this.idat_offs + 8+2+5 * Math.floor((i / 0xffff) + 1)+i;
this.buffer[j] = c;
}
// 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
this.render = function() {
// compute adler32 of output pixels + row filter bytes
// NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <=
// 2^32-1.
var BASE = 65521; /* largest prime smaller than 65536 */
var NMAX = 5552;
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('');
};
}