!(function() {

	// alignment pattern
	var adelta = [
		0, 11, 15, 19, 23, 27, 31,
		16, 18, 20, 22, 24, 26, 28, 20, 22, 24, 24, 26, 28, 28, 22, 24, 24,
		26, 26, 28, 28, 24, 24, 26, 26, 26, 28, 28, 24, 26, 26, 26, 28, 28
	];

	// version block
	var vpat = [
		0xc94, 0x5bc, 0xa99, 0x4d3, 0xbf6, 0x762, 0x847, 0x60d,
		0x928, 0xb78, 0x45d, 0xa17, 0x532, 0x9a6, 0x683, 0x8c9,
		0x7ec, 0xec4, 0x1e1, 0xfab, 0x08e, 0xc1a, 0x33f, 0xd75,
		0x250, 0x9d5, 0x6f0, 0x8ba, 0x79f, 0xb0b, 0x42e, 0xa64,
		0x541, 0xc69
	];

	// final format bits with mask: level << 3 | mask
	var fmtword = [
		0x77c4, 0x72f3, 0x7daa, 0x789d, 0x662f, 0x6318, 0x6c41, 0x6976, //L
		0x5412, 0x5125, 0x5e7c, 0x5b4b, 0x45f9, 0x40ce, 0x4f97, 0x4aa0, //M
		0x355f, 0x3068, 0x3f31, 0x3a06, 0x24b4, 0x2183, 0x2eda, 0x2bed, //Q
		0x1689, 0x13be, 0x1ce7, 0x19d0, 0x0762, 0x0255, 0x0d0c, 0x083b //H
	];

	// 4 per version: number of blocks 1,2; data width; ecc width
	var eccblocks = [
		1, 0, 19, 7, 1, 0, 16, 10, 1, 0, 13, 13, 1, 0, 9, 17,
		1, 0, 34, 10, 1, 0, 28, 16, 1, 0, 22, 22, 1, 0, 16, 28,
		1, 0, 55, 15, 1, 0, 44, 26, 2, 0, 17, 18, 2, 0, 13, 22,
		1, 0, 80, 20, 2, 0, 32, 18, 2, 0, 24, 26, 4, 0, 9, 16,
		1, 0, 108, 26, 2, 0, 43, 24, 2, 2, 15, 18, 2, 2, 11, 22,
		2, 0, 68, 18, 4, 0, 27, 16, 4, 0, 19, 24, 4, 0, 15, 28,
		2, 0, 78, 20, 4, 0, 31, 18, 2, 4, 14, 18, 4, 1, 13, 26,
		2, 0, 97, 24, 2, 2, 38, 22, 4, 2, 18, 22, 4, 2, 14, 26,
		2, 0, 116, 30, 3, 2, 36, 22, 4, 4, 16, 20, 4, 4, 12, 24,
		2, 2, 68, 18, 4, 1, 43, 26, 6, 2, 19, 24, 6, 2, 15, 28,
		4, 0, 81, 20, 1, 4, 50, 30, 4, 4, 22, 28, 3, 8, 12, 24,
		2, 2, 92, 24, 6, 2, 36, 22, 4, 6, 20, 26, 7, 4, 14, 28,
		4, 0, 107, 26, 8, 1, 37, 22, 8, 4, 20, 24, 12, 4, 11, 22,
		3, 1, 115, 30, 4, 5, 40, 24, 11, 5, 16, 20, 11, 5, 12, 24,
		5, 1, 87, 22, 5, 5, 41, 24, 5, 7, 24, 30, 11, 7, 12, 24,
		5, 1, 98, 24, 7, 3, 45, 28, 15, 2, 19, 24, 3, 13, 15, 30,
		1, 5, 107, 28, 10, 1, 46, 28, 1, 15, 22, 28, 2, 17, 14, 28,
		5, 1, 120, 30, 9, 4, 43, 26, 17, 1, 22, 28, 2, 19, 14, 28,
		3, 4, 113, 28, 3, 11, 44, 26, 17, 4, 21, 26, 9, 16, 13, 26,
		3, 5, 107, 28, 3, 13, 41, 26, 15, 5, 24, 30, 15, 10, 15, 28,
		4, 4, 116, 28, 17, 0, 42, 26, 17, 6, 22, 28, 19, 6, 16, 30,
		2, 7, 111, 28, 17, 0, 46, 28, 7, 16, 24, 30, 34, 0, 13, 24,
		4, 5, 121, 30, 4, 14, 47, 28, 11, 14, 24, 30, 16, 14, 15, 30,
		6, 4, 117, 30, 6, 14, 45, 28, 11, 16, 24, 30, 30, 2, 16, 30,
		8, 4, 106, 26, 8, 13, 47, 28, 7, 22, 24, 30, 22, 13, 15, 30,
		10, 2, 114, 28, 19, 4, 46, 28, 28, 6, 22, 28, 33, 4, 16, 30,
		8, 4, 122, 30, 22, 3, 45, 28, 8, 26, 23, 30, 12, 28, 15, 30,
		3, 10, 117, 30, 3, 23, 45, 28, 4, 31, 24, 30, 11, 31, 15, 30,
		7, 7, 116, 30, 21, 7, 45, 28, 1, 37, 23, 30, 19, 26, 15, 30,
		5, 10, 115, 30, 19, 10, 47, 28, 15, 25, 24, 30, 23, 25, 15, 30,
		13, 3, 115, 30, 2, 29, 46, 28, 42, 1, 24, 30, 23, 28, 15, 30,
		17, 0, 115, 30, 10, 23, 46, 28, 10, 35, 24, 30, 19, 35, 15, 30,
		17, 1, 115, 30, 14, 21, 46, 28, 29, 19, 24, 30, 11, 46, 15, 30,
		13, 6, 115, 30, 14, 23, 46, 28, 44, 7, 24, 30, 59, 1, 16, 30,
		12, 7, 121, 30, 12, 26, 47, 28, 39, 14, 24, 30, 22, 41, 15, 30,
		6, 14, 121, 30, 6, 34, 47, 28, 46, 10, 24, 30, 2, 64, 15, 30,
		17, 4, 122, 30, 29, 14, 46, 28, 49, 10, 24, 30, 24, 46, 15, 30,
		4, 18, 122, 30, 13, 32, 46, 28, 48, 14, 24, 30, 42, 32, 15, 30,
		20, 4, 117, 30, 40, 7, 47, 28, 43, 22, 24, 30, 10, 67, 15, 30,
		19, 6, 118, 30, 18, 31, 47, 28, 34, 34, 24, 30, 20, 61, 15, 30
	];

	// Galois field log table
	var glog = [
		0xff, 0x00, 0x01, 0x19, 0x02, 0x32, 0x1a, 0xc6, 0x03, 0xdf, 0x33, 0xee, 0x1b, 0x68, 0xc7, 0x4b,
		0x04, 0x64, 0xe0, 0x0e, 0x34, 0x8d, 0xef, 0x81, 0x1c, 0xc1, 0x69, 0xf8, 0xc8, 0x08, 0x4c, 0x71,
		0x05, 0x8a, 0x65, 0x2f, 0xe1, 0x24, 0x0f, 0x21, 0x35, 0x93, 0x8e, 0xda, 0xf0, 0x12, 0x82, 0x45,
		0x1d, 0xb5, 0xc2, 0x7d, 0x6a, 0x27, 0xf9, 0xb9, 0xc9, 0x9a, 0x09, 0x78, 0x4d, 0xe4, 0x72, 0xa6,
		0x06, 0xbf, 0x8b, 0x62, 0x66, 0xdd, 0x30, 0xfd, 0xe2, 0x98, 0x25, 0xb3, 0x10, 0x91, 0x22, 0x88,
		0x36, 0xd0, 0x94, 0xce, 0x8f, 0x96, 0xdb, 0xbd, 0xf1, 0xd2, 0x13, 0x5c, 0x83, 0x38, 0x46, 0x40,
		0x1e, 0x42, 0xb6, 0xa3, 0xc3, 0x48, 0x7e, 0x6e, 0x6b, 0x3a, 0x28, 0x54, 0xfa, 0x85, 0xba, 0x3d,
		0xca, 0x5e, 0x9b, 0x9f, 0x0a, 0x15, 0x79, 0x2b, 0x4e, 0xd4, 0xe5, 0xac, 0x73, 0xf3, 0xa7, 0x57,
		0x07, 0x70, 0xc0, 0xf7, 0x8c, 0x80, 0x63, 0x0d, 0x67, 0x4a, 0xde, 0xed, 0x31, 0xc5, 0xfe, 0x18,
		0xe3, 0xa5, 0x99, 0x77, 0x26, 0xb8, 0xb4, 0x7c, 0x11, 0x44, 0x92, 0xd9, 0x23, 0x20, 0x89, 0x2e,
		0x37, 0x3f, 0xd1, 0x5b, 0x95, 0xbc, 0xcf, 0xcd, 0x90, 0x87, 0x97, 0xb2, 0xdc, 0xfc, 0xbe, 0x61,
		0xf2, 0x56, 0xd3, 0xab, 0x14, 0x2a, 0x5d, 0x9e, 0x84, 0x3c, 0x39, 0x53, 0x47, 0x6d, 0x41, 0xa2,
		0x1f, 0x2d, 0x43, 0xd8, 0xb7, 0x7b, 0xa4, 0x76, 0xc4, 0x17, 0x49, 0xec, 0x7f, 0x0c, 0x6f, 0xf6,
		0x6c, 0xa1, 0x3b, 0x52, 0x29, 0x9d, 0x55, 0xaa, 0xfb, 0x60, 0x86, 0xb1, 0xbb, 0xcc, 0x3e, 0x5a,
		0xcb, 0x59, 0x5f, 0xb0, 0x9c, 0xa9, 0xa0, 0x51, 0x0b, 0xf5, 0x16, 0xeb, 0x7a, 0x75, 0x2c, 0xd7,
		0x4f, 0xae, 0xd5, 0xe9, 0xe6, 0xe7, 0xad, 0xe8, 0x74, 0xd6, 0xf4, 0xea, 0xa8, 0x50, 0x58, 0xaf
	];

	// Galios field exponent table
	var gexp = [
		0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1d, 0x3a, 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26,
		0x4c, 0x98, 0x2d, 0x5a, 0xb4, 0x75, 0xea, 0xc9, 0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30, 0x60, 0xc0,
		0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35, 0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23,
		0x46, 0x8c, 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0, 0x5d, 0xba, 0x69, 0xd2, 0xb9, 0x6f, 0xde, 0xa1,
		0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f, 0x5e, 0xbc, 0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0,
		0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f, 0xfe, 0xe1, 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2,
		0xd9, 0xaf, 0x43, 0x86, 0x11, 0x22, 0x44, 0x88, 0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd, 0x67, 0xce,
		0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93, 0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc,
		0x85, 0x17, 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9, 0x4f, 0x9e, 0x21, 0x42, 0x84, 0x15, 0x2a, 0x54,
		0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4, 0x55, 0xaa, 0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73,
		0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e, 0xfc, 0xe5, 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff,
		0xe3, 0xdb, 0xab, 0x4b, 0x96, 0x31, 0x62, 0xc4, 0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57, 0xae, 0x41,
		0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e, 0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6,
		0x51, 0xa2, 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef, 0xc3, 0x9b, 0x2b, 0x56, 0xac, 0x45, 0x8a, 0x09,
		0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a, 0xf4, 0xf5, 0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16,
		0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83, 0x1b, 0x36, 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x00
	];

	// Working buffers:
	// data input and ecc append, image working buffer, fixed part of image, run lengths for badness
	var strinbuf = [],
		eccbuf = [],
		qrframe = [],
		framask = [],
		rlens = [];
	// Control values - width is based on version, last 4 are from table.
	var version, width, neccblk1, neccblk2, datablkw, eccblkwid;
	var ecclevel = 2;
	// set bit to indicate cell in qrframe is immutable.  symmetric around diagonal
	function setmask(x, y) {
		var bt;
		if (x > y) {
			bt = x;
			x = y;
			y = bt;
		}
		// y*y = 1+3+5...
		bt = y;
		bt *= y;
		bt += y;
		bt >>= 1;
		bt += x;
		framask[bt] = 1;
	}

	// enter alignment pattern - black to qrframe, white to mask (later black frame merged to mask)
	function putalign(x, y) {
		var j;

		qrframe[x + width * y] = 1;
		for (j = -2; j < 2; j++) {
			qrframe[(x + j) + width * (y - 2)] = 1;
			qrframe[(x - 2) + width * (y + j + 1)] = 1;
			qrframe[(x + 2) + width * (y + j)] = 1;
			qrframe[(x + j + 1) + width * (y + 2)] = 1;
		}
		for (j = 0; j < 2; j++) {
			setmask(x - 1, y + j);
			setmask(x + 1, y - j);
			setmask(x - j, y - 1);
			setmask(x + j, y + 1);
		}
	}

	//========================================================================
	// Reed Solomon error correction
	// exponentiation mod N
	function modnn(x) {
		while (x >= 255) {
			x -= 255;
			x = (x >> 8) + (x & 255);
		}
		return x;
	}

	var genpoly = [];

	// Calculate and append ECC data to data block.  Block is in strinbuf, indexes to buffers given.
	function appendrs(data, dlen, ecbuf, eclen) {
		var i, j, fb;

		for (i = 0; i < eclen; i++)
			strinbuf[ecbuf + i] = 0;
		for (i = 0; i < dlen; i++) {
			fb = glog[strinbuf[data + i] ^ strinbuf[ecbuf]];
			if (fb != 255) /* fb term is non-zero */
				for (j = 1; j < eclen; j++)
					strinbuf[ecbuf + j - 1] = strinbuf[ecbuf + j] ^ gexp[modnn(fb + genpoly[eclen - j])];
			else
				for (j = ecbuf; j < ecbuf + eclen; j++)
					strinbuf[j] = strinbuf[j + 1];
			strinbuf[ecbuf + eclen - 1] = fb == 255 ? 0 : gexp[modnn(fb + genpoly[0])];
		}
	}

	//========================================================================
	// Frame data insert following the path rules

	// check mask - since symmetrical use half.
	function ismasked(x, y) {
		var bt;
		if (x > y) {
			bt = x;
			x = y;
			y = bt;
		}
		bt = y;
		bt += y * y;
		bt >>= 1;
		bt += x;
		return framask[bt];
	}

	//========================================================================
	//  Apply the selected mask out of the 8.
	function applymask(m) {
		var x, y, r3x, r3y;

		switch (m) {
			case 0:
				for (y = 0; y < width; y++)
					for (x = 0; x < width; x++)
						if (!((x + y) & 1) && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
				break;
			case 1:
				for (y = 0; y < width; y++)
					for (x = 0; x < width; x++)
						if (!(y & 1) && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
				break;
			case 2:
				for (y = 0; y < width; y++)
					for (r3x = 0, x = 0; x < width; x++, r3x++) {
						if (r3x == 3)
							r3x = 0;
						if (!r3x && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
					}
				break;
			case 3:
				for (r3y = 0, y = 0; y < width; y++, r3y++) {
					if (r3y == 3)
						r3y = 0;
					for (r3x = r3y, x = 0; x < width; x++, r3x++) {
						if (r3x == 3)
							r3x = 0;
						if (!r3x && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
					}
				}
				break;
			case 4:
				for (y = 0; y < width; y++)
					for (r3x = 0, r3y = ((y >> 1) & 1), x = 0; x < width; x++, r3x++) {
						if (r3x == 3) {
							r3x = 0;
							r3y = !r3y;
						}
						if (!r3y && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
					}
				break;
			case 5:
				for (r3y = 0, y = 0; y < width; y++, r3y++) {
					if (r3y == 3)
						r3y = 0;
					for (r3x = 0, x = 0; x < width; x++, r3x++) {
						if (r3x == 3)
							r3x = 0;
						if (!((x & y & 1) + !(!r3x | !r3y)) && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
					}
				}
				break;
			case 6:
				for (r3y = 0, y = 0; y < width; y++, r3y++) {
					if (r3y == 3)
						r3y = 0;
					for (r3x = 0, x = 0; x < width; x++, r3x++) {
						if (r3x == 3)
							r3x = 0;
						if (!(((x & y & 1) + (r3x && (r3x == r3y))) & 1) && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
					}
				}
				break;
			case 7:
				for (r3y = 0, y = 0; y < width; y++, r3y++) {
					if (r3y == 3)
						r3y = 0;
					for (r3x = 0, x = 0; x < width; x++, r3x++) {
						if (r3x == 3)
							r3x = 0;
						if (!(((r3x && (r3x == r3y)) + ((x + y) & 1)) & 1) && !ismasked(x, y))
							qrframe[x + y * width] ^= 1;
					}
				}
				break;
		}
		return;
	}

	// Badness coefficients.
	var N1 = 3,
		N2 = 3,
		N3 = 40,
		N4 = 10;

	// Using the table of the length of each run, calculate the amount of bad image 
	// - long runs or those that look like finders; called twice, once each for X and Y
	function badruns(length) {
		var i;
		var runsbad = 0;
		for (i = 0; i <= length; i++)
			if (rlens[i] >= 5)
				runsbad += N1 + rlens[i] - 5;
		// BwBBBwB as in finder
		for (i = 3; i < length - 1; i += 2)
			if (rlens[i - 2] == rlens[i + 2] &&
				rlens[i + 2] == rlens[i - 1] &&
				rlens[i - 1] == rlens[i + 1] &&
				rlens[i - 1] * 3 == rlens[i]
				// white around the black pattern? Not part of spec
				&&
				(rlens[i - 3] == 0 // beginning
					||
					i + 3 > length // end
					||
					rlens[i - 3] * 3 >= rlens[i] * 4 || rlens[i + 3] * 3 >= rlens[i] * 4)
			)
				runsbad += N3;
		return runsbad;
	}

	// Calculate how bad the masked image is - blocks, imbalance, runs, or finders.
	function badcheck() {
		var x, y, h, b, b1;
		var thisbad = 0;
		var bw = 0;

		// blocks of same color.
		for (y = 0; y < width - 1; y++)
			for (x = 0; x < width - 1; x++)
				if ((qrframe[x + width * y] && qrframe[(x + 1) + width * y] &&
						qrframe[x + width * (y + 1)] && qrframe[(x + 1) + width * (y + 1)]) // all black
					||
					!(qrframe[x + width * y] || qrframe[(x + 1) + width * y] ||
						qrframe[x + width * (y + 1)] || qrframe[(x + 1) + width * (y + 1)])) // all white
					thisbad += N2;

		// X runs
		for (y = 0; y < width; y++) {
			rlens[0] = 0;
			for (h = b = x = 0; x < width; x++) {
				if ((b1 = qrframe[x + width * y]) == b)
					rlens[h]++;
				else
					rlens[++h] = 1;
				b = b1;
				bw += b ? 1 : -1;
			}
			thisbad += badruns(h);
		}

		// black/white imbalance
		if (bw < 0)
			bw = -bw;

		var big = bw;
		var count = 0;
		big += big << 2;
		big <<= 1;
		while (big > width * width)
			big -= width * width, count++;
		thisbad += count * N4;

		// Y runs
		for (x = 0; x < width; x++) {
			rlens[0] = 0;
			for (h = b = y = 0; y < width; y++) {
				if ((b1 = qrframe[x + width * y]) == b)
					rlens[h]++;
				else
					rlens[++h] = 1;
				b = b1;
			}
			thisbad += badruns(h);
		}
		return thisbad;
	}

	function genframe(instring) {
		var x, y, k, t, v, i, j, m;

		// find the smallest version that fits the string
		t = instring.length;
		version = 0;
		do {
			version++;
			k = (ecclevel - 1) * 4 + (version - 1) * 16;
			neccblk1 = eccblocks[k++];
			neccblk2 = eccblocks[k++];
			datablkw = eccblocks[k++];
			eccblkwid = eccblocks[k];
			k = datablkw * (neccblk1 + neccblk2) + neccblk2 - 3 + (version <= 9);
			if (t <= k)
				break;
		} while (version < 40);

		// FIXME - insure that it fits insted of being truncated
		width = 17 + 4 * version;

		// allocate, clear and setup data structures
		v = datablkw + (datablkw + eccblkwid) * (neccblk1 + neccblk2) + neccblk2;
		for (t = 0; t < v; t++)
			eccbuf[t] = 0;
		strinbuf = instring.slice(0);

		for (t = 0; t < width * width; t++)
			qrframe[t] = 0;

		for (t = 0; t < (width * (width + 1) + 1) / 2; t++)
			framask[t] = 0;

		// insert finders - black to frame, white to mask
		for (t = 0; t < 3; t++) {
			k = 0;
			y = 0;
			if (t == 1)
				k = (width - 7);
			if (t == 2)
				y = (width - 7);
			qrframe[(y + 3) + width * (k + 3)] = 1;
			for (x = 0; x < 6; x++) {
				qrframe[(y + x) + width * k] = 1;
				qrframe[y + width * (k + x + 1)] = 1;
				qrframe[(y + 6) + width * (k + x)] = 1;
				qrframe[(y + x + 1) + width * (k + 6)] = 1;
			}
			for (x = 1; x < 5; x++) {
				setmask(y + x, k + 1);
				setmask(y + 1, k + x + 1);
				setmask(y + 5, k + x);
				setmask(y + x + 1, k + 5);
			}
			for (x = 2; x < 4; x++) {
				qrframe[(y + x) + width * (k + 2)] = 1;
				qrframe[(y + 2) + width * (k + x + 1)] = 1;
				qrframe[(y + 4) + width * (k + x)] = 1;
				qrframe[(y + x + 1) + width * (k + 4)] = 1;
			}
		}

		// alignment blocks
		if (version > 1) {
			t = adelta[version];
			y = width - 7;
			for (;;) {
				x = width - 7;
				while (x > t - 3) {
					putalign(x, y);
					if (x < t)
						break;
					x -= t;
				}
				if (y <= t + 9)
					break;
				y -= t;
				putalign(6, y);
				putalign(y, 6);
			}
		}

		// single black
		qrframe[8 + width * (width - 8)] = 1;

		// timing gap - mask only
		for (y = 0; y < 7; y++) {
			setmask(7, y);
			setmask(width - 8, y);
			setmask(7, y + width - 7);
		}
		for (x = 0; x < 8; x++) {
			setmask(x, 7);
			setmask(x + width - 8, 7);
			setmask(x, width - 8);
		}

		// reserve mask-format area
		for (x = 0; x < 9; x++)
			setmask(x, 8);
		for (x = 0; x < 8; x++) {
			setmask(x + width - 8, 8);
			setmask(8, x);
		}
		for (y = 0; y < 7; y++)
			setmask(8, y + width - 7);

		// timing row/col
		for (x = 0; x < width - 14; x++)
			if (x & 1) {
				setmask(8 + x, 6);
				setmask(6, 8 + x);
			}
		else {
			qrframe[(8 + x) + width * 6] = 1;
			qrframe[6 + width * (8 + x)] = 1;
		}

		// version block
		if (version > 6) {
			t = vpat[version - 7];
			k = 17;
			for (x = 0; x < 6; x++)
				for (y = 0; y < 3; y++, k--)
					if (1 & (k > 11 ? version >> (k - 12) : t >> k)) {
						qrframe[(5 - x) + width * (2 - y + width - 11)] = 1;
						qrframe[(2 - y + width - 11) + width * (5 - x)] = 1;
					}
			else {
				setmask(5 - x, 2 - y + width - 11);
				setmask(2 - y + width - 11, 5 - x);
			}
		}

		// sync mask bits - only set above for white spaces, so add in black bits
		for (y = 0; y < width; y++)
			for (x = 0; x <= y; x++)
				if (qrframe[x + width * y])
					setmask(x, y);

		// convert string to bitstream
		// 8 bit data to QR-coded 8 bit data (numeric or alphanum, or kanji not supported)
		v = strinbuf.length;

		// string to array
		for (i = 0; i < v; i++)
			eccbuf[i] = strinbuf.charCodeAt(i);
		strinbuf = eccbuf.slice(0);

		// calculate max string length
		x = datablkw * (neccblk1 + neccblk2) + neccblk2;
		if (v >= x - 2) {
			v = x - 2;
			if (version > 9)
				v--;
		}

		// shift and repack to insert length prefix
		i = v;
		if (version > 9) {
			strinbuf[i + 2] = 0;
			strinbuf[i + 3] = 0;
			while (i--) {
				t = strinbuf[i];
				strinbuf[i + 3] |= 255 & (t << 4);
				strinbuf[i + 2] = t >> 4;
			}
			strinbuf[2] |= 255 & (v << 4);
			strinbuf[1] = v >> 4;
			strinbuf[0] = 0x40 | (v >> 12);
		} else {
			strinbuf[i + 1] = 0;
			strinbuf[i + 2] = 0;
			while (i--) {
				t = strinbuf[i];
				strinbuf[i + 2] |= 255 & (t << 4);
				strinbuf[i + 1] = t >> 4;
			}
			strinbuf[1] |= 255 & (v << 4);
			strinbuf[0] = 0x40 | (v >> 4);
		}
		// fill to end with pad pattern
		i = v + 3 - (version < 10);
		while (i < x) {
			strinbuf[i++] = 0xec;
			// buffer has room    if (i == x)      break;
			strinbuf[i++] = 0x11;
		}

		// calculate and append ECC

		// calculate generator polynomial
		genpoly[0] = 1;
		for (i = 0; i < eccblkwid; i++) {
			genpoly[i + 1] = 1;
			for (j = i; j > 0; j--)
				genpoly[j] = genpoly[j] ?
				genpoly[j - 1] ^ gexp[modnn(glog[genpoly[j]] + i)] : genpoly[j - 1];
			genpoly[0] = gexp[modnn(glog[genpoly[0]] + i)];
		}
		for (i = 0; i <= eccblkwid; i++)
			genpoly[i] = glog[genpoly[i]]; // use logs for genpoly[] to save calc step

		// append ecc to data buffer
		k = x;
		y = 0;
		for (i = 0; i < neccblk1; i++) {
			appendrs(y, datablkw, k, eccblkwid);
			y += datablkw;
			k += eccblkwid;
		}
		for (i = 0; i < neccblk2; i++) {
			appendrs(y, datablkw + 1, k, eccblkwid);
			y += datablkw + 1;
			k += eccblkwid;
		}
		// interleave blocks
		y = 0;
		for (i = 0; i < datablkw; i++) {
			for (j = 0; j < neccblk1; j++)
				eccbuf[y++] = strinbuf[i + j * datablkw];
			for (j = 0; j < neccblk2; j++)
				eccbuf[y++] = strinbuf[(neccblk1 * datablkw) + i + (j * (datablkw + 1))];
		}
		for (j = 0; j < neccblk2; j++)
			eccbuf[y++] = strinbuf[(neccblk1 * datablkw) + i + (j * (datablkw + 1))];
		for (i = 0; i < eccblkwid; i++)
			for (j = 0; j < neccblk1 + neccblk2; j++)
				eccbuf[y++] = strinbuf[x + i + j * eccblkwid];
		strinbuf = eccbuf;

		// pack bits into frame avoiding masked area.
		x = y = width - 1;
		k = v = 1; // up, minus
		/* inteleaved data and ecc codes */
		m = (datablkw + eccblkwid) * (neccblk1 + neccblk2) + neccblk2;
		for (i = 0; i < m; i++) {
			t = strinbuf[i];
			for (j = 0; j < 8; j++, t <<= 1) {
				if (0x80 & t)
					qrframe[x + width * y] = 1;
				do { // find next fill position
					if (v)
						x--;
					else {
						x++;
						if (k) {
							if (y != 0)
								y--;
							else {
								x -= 2;
								k = !k;
								if (x == 6) {
									x--;
									y = 9;
								}
							}
						} else {
							if (y != width - 1)
								y++;
							else {
								x -= 2;
								k = !k;
								if (x == 6) {
									x--;
									y -= 8;
								}
							}
						}
					}
					v = !v;
				} while (ismasked(x, y));
			}
		}

		// save pre-mask copy of frame
		strinbuf = qrframe.slice(0);
		t = 0; // best
		y = 30000; // demerit
		// for instead of while since in original arduino code
		// if an early mask was "good enough" it wouldn't try for a better one
		// since they get more complex and take longer.
		for (k = 0; k < 8; k++) {
			applymask(k); // returns black-white imbalance
			x = badcheck();
			if (x < y) { // current mask better than previous best?
				y = x;
				t = k;
			}
			if (t == 7)
				break; // don't increment i to a void redoing mask
			qrframe = strinbuf.slice(0); // reset for next pass
		}
		if (t != k) // redo best mask - none good enough, last wasn't t
			applymask(t);

		// add in final mask/ecclevel bytes
		y = fmtword[t + ((ecclevel - 1) << 3)];
		// low byte
		for (k = 0; k < 8; k++, y >>= 1)
			if (y & 1) {
				qrframe[(width - 1 - k) + width * 8] = 1;
				if (k < 6)
					qrframe[8 + width * k] = 1;
				else
					qrframe[8 + width * (k + 1)] = 1;
			}
		// high byte
		for (k = 0; k < 7; k++, y >>= 1)
			if (y & 1) {
				qrframe[8 + width * (width - 7 + k)] = 1;
				if (k)
					qrframe[(6 - k) + width * 8] = 1;
				else
					qrframe[7 + width * 8] = 1;
			}
		return qrframe;
	}




	var _canvas = null;

	var api = {

		get ecclevel() {
			return ecclevel;
		},

		set ecclevel(val) {
			ecclevel = val;
		},

		get size() {
			return _size;
		},

		set size(val) {
			_size = val
		},

		get canvas() {
			return _canvas;
		},

		set canvas(el) {
			_canvas = el;
		},

		getFrame: function(string) {
			return genframe(string);
		},
		//这里的utf16to8(str)是对Text中的字符串进行转码，让其支持中文
		utf16to8: function(str) {
			var out, i, len, c;

			out = "";
			len = str.length;
			for (i = 0; i < len; i++) {
				c = str.charCodeAt(i);
				if ((c >= 0x0001) && (c <= 0x007F)) {
					out += str.charAt(i);
				} else if (c > 0x07FF) {
					out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
					out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));
					out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
				} else {
					out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));
					out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
				}
			}
			return out;
		},
		/**
		 * 新增$this参数，传入组件的this,兼容在组件中生成
		 */
		draw: function(str, canvas, cavW, cavH, cavColor, haveImg, imageUrl, imageSize, $this, cb = function() {}, ecc) {
			var that = this;
			ecclevel = ecc || ecclevel;
			canvas = canvas || _canvas;
			if (!canvas) {
				console.warn('No canvas provided to draw QR code in!')
				return;
			}
			
			
			let pre_background = "#ffffff";
			var size = Math.min(cavW, cavH);
			str = that.utf16to8(str); //增加中文显示

			var frame = that.getFrame(str);
				// 组件中生成qrcode需要绑定this 
			var ctx = uni.createCanvasContext(canvas, $this);
			var px = Math.round(size / (width ));
			
			var roundedSize = px * (width);
			// var px = 1 ;
			// var roundedSize = px * (width + 8) ;
			
			//var roundedSize = 0 ;
			//var offset = Math.floor((size - roundedSize) / 2);
			var offset = 0 ;
			size = roundedSize;
			//ctx.clearRect(0, 0, cavW, cavW);
			ctx.setFillStyle(pre_background)
			ctx.fillRect(0, 0, cavW, cavW);
			ctx.setFillStyle(cavColor);
			for (var i = 0; i < width; i++) {
				for (var j = 0; j < width; j++) {
					if (frame[j * width + i]) {
						ctx.fillRect(px * ( i) + offset, px * ( j) + offset, px, px);
					}
				}
			}

			//画图片
			if (haveImg) {
				try {
					var x = Number(((cavW - imageSize - 14) / 2).toFixed(2));
					var y = Number(((cavH - imageSize -14) / 2).toFixed(2));
					drawRoundedRect(ctx, x, y, imageSize, imageSize, imageSize / 2, 6, true, true)

					let isNetImg = false;

					isNetImg = imageUrl.substr(0, 4) == 'http' ? true : false;

					if (isNetImg) {
						//网络图片下载到本地
						uni.getImageInfo({
							src: imageUrl,
							success: function(res) {
								ctx.drawImage(res.path, x, y, imageSize, imageSize);
								//--增加绘制完成回调
								ctx.draw(false, function() {
									cb();
								})
							}
						})
					} else {
						ctx.drawImage(imageUrl, x, y, imageSize, imageSize);
						//--增加绘制完成回调
						ctx.draw(false, function() {
							cb();
						})
					}




					// 画圆角矩形
					function drawRoundedRect(ctxi, x, y, width, height, r, lineWidth, fill, stroke) {
						ctxi.setLineWidth(lineWidth);
						ctxi.setFillStyle(pre_background);
						ctxi.setStrokeStyle(pre_background);
						ctxi.beginPath(); // draw top and top right corner 
						ctxi.moveTo(x + r, y);
						ctxi.arcTo(x + width, y, x + width, y + r, r); // draw right side and bottom right corner 
						ctxi.arcTo(x + width, y + height, x + width - r, y + height, r); // draw bottom and bottom left corner 
						ctxi.arcTo(x, y + height, x, y + height - r, r); // draw left and top left corner 
						ctxi.arcTo(x, y, x + r, y, r);
						ctxi.closePath();
						if (fill) {
							ctxi.fill();
						}
						if (stroke) {
							ctxi.stroke();
						}
					}
				} catch (e) {
					//TODO handle the exception
				}

			} else {
				//--增加绘制完成回调
				ctx.draw(false, function() {
					cb();
				})
			}



		}
	}
	module.exports = {
		api
	}
})();
