原因是code128C是纯数字条码，但是必须是偶数位。当出现奇数位是，需要在最后一位前用code128B进行转码声明，但是js中却错误的插入了chr2也就是-1对应的codeValue：62，也就是code128B中62对应的码字_，导致出现奇数位最后一位的错误。
修改代码为：
if (shifter != -1) {
result.push(shifter);
result.push(codeValue(chr1));//把这里的chr2改成chr1即可。
}barcode.js源码（生成一维码）：
var CHAR_TILDE = 126;
var CODE_FNC1 = 102;
var SET_STARTA = 103;
var SET_STARTB = 104;
var SET_STARTC = 105;
var SET_SHIFT = 98;
var SET_CODEA = 101;
var SET_CODEB = 100;
var SET_STOP = 106;
var REPLACE_CODES = {
CHAR_TILDE: CODE_FNC1 //~ corresponds to FNC1 in GS1-128 standard
}
var CODESET = {
ANY: 1,
AB: 2,
A: 3,
B: 4,
C: 5
};
function getBytes(str) {
var bytes = [];
for (var i = 0; i < str.length; i++) {
bytes.push(str.charCodeAt(i));
}
return bytes;
}
exports.code128 = function (ctx, text, width, height) {
width = parseInt(width);
height = parseInt(height);
var codes = stringToCode128(text);
var g = new Graphics(ctx, width, height);
var barWeight = g.area.width / ((codes.length - 3) * 11 + 35);
var x = g.area.left;
var y = g.area.top;
for (var i = 0; i < codes.length; i++) {
var c = codes[i];
//two bars at a time: 1 black and 1 white
for (var bar = 0; bar < 8; bar += 2) {
var barW = PATTERNS[c][bar] * barWeight;
// var barH = height - y - this.border;
var barH = height - y;
var spcW = PATTERNS[c][bar + 1] * barWeight;
//no need to draw if 0 width
if (barW > 0) {
g.fillFgRect(x, y, barW, barH);
}
x += barW + spcW;
}
}
ctx.draw();
}
function stringToCode128(text) {
var barc = {
currcs: CODESET.C
};
var bytes = getBytes(text);
//decide starting codeset
var index = bytes[0] == CHAR_TILDE ? 1 : 0;
var csa1 = bytes.length > 0 ? codeSetAllowedFor(bytes[index++]) : CODESET.AB;
var csa2 = bytes.length > 0 ? codeSetAllowedFor(bytes[index++]) : CODESET.AB;
barc.currcs = getBestStartSet(csa1, csa2);
barc.currcs = perhapsCodeC(bytes, barc.currcs);
//if no codeset changes this will end up with bytes.length+3
//start, checksum and stop
var codes = new Array();
switch (barc.currcs) {
case CODESET.A:
codes.push(SET_STARTA);
break;
case CODESET.B:
codes.push(SET_STARTB);
break;
default:
codes.push(SET_STARTC);
break;
}
for (var i = 0; i < bytes.length; i++) {
var b1 = bytes[i]; //get the first of a pair
//should we translate/replace
if (b1 in REPLACE_CODES) {
codes.push(REPLACE_CODES[b1]);
i++ //jump to next
b1 = bytes[i];
}
//get the next in the pair if possible
var b2 = bytes.length > (i + 1) ? bytes[i + 1] : -1;
codes = codes.concat(codesForChar(b1, b2, barc.currcs));
//code C takes 2 chars each time
if (barc.currcs == CODESET.C) i++;
}
//calculate checksum according to Code 128 standards
var checksum = codes[0];
for (var weight = 1; weight < codes.length; weight++) {
checksum += (weight * codes[weight]);
}
codes.push(checksum % 103);
codes.push(SET_STOP);
//encoding should now be complete
return codes;
function getBestStartSet(csa1, csa2) {
//tries to figure out the best codeset
//to start with to get the most compact code
var vote = 0;
vote += csa1 == CODESET.A ? 1 : 0;
vote += csa1 == CODESET.B ? -1 : 0;
vote += csa2 == CODESET.A ? 1 : 0;
vote += csa2 == CODESET.B ? -1 : 0;
//tie goes to B due to my own predudices
return vote > 0 ? CODESET.A : CODESET.B;
}
function perhapsCodeC(bytes, codeset) {
for (var i = 0; i < bytes.length; i++) {
var b = bytes[i]
if ((b < 48 || b > 57) && b != CHAR_TILDE)
return codeset;
}
return CODESET.C;
}
//chr1 is current byte
//chr2 is the next byte to process. looks ahead.
function codesForChar(chr1, chr2, currcs) {
var result = [];
var shifter = -1;
if (charCompatible(chr1, currcs)) {
if (currcs == CODESET.C) {
if (chr2 == -1) {
shifter = SET_CODEB;
currcs = CODESET.B;
}
else if ((chr2 != -1) && !charCompatible(chr2, currcs)) {
//need to check ahead as well
if (charCompatible(chr2, CODESET.A)) {
shifter = SET_CODEA;
currcs = CODESET.A;
}
else {
shifter = SET_CODEB;
currcs = CODESET.B;
}
}
}
}
else {
//if there is a next char AND that next char is also not compatible
if ((chr2 != -1) && !charCompatible(chr2, currcs)) {
//need to switch code sets
switch (currcs) {
case CODESET.A:
shifter = SET_CODEB;
currcs = CODESET.B;
break;
case CODESET.B:
shifter = SET_CODEA;
currcs = CODESET.A;
break;
}
}
else {
//no need to shift code sets, a temporary SHIFT will suffice
shifter = SET_SHIFT;
}
}
//ok some type of shift is nessecary
if (shifter != -1) {
result.push(shifter);
result.push(codeValue(chr1));
}
else {
if (currcs == CODESET.C) {
//include next as well
result.push(codeValue(chr1, chr2));
}
else {
result.push(codeValue(chr1));
}
}
barc.currcs = currcs;
return result;
}
}
//reduce the ascii code to fit into the Code128 char table
function codeValue(chr1, chr2) {
if (typeof chr2 == "undefined") {
return chr1 >= 32 ? chr1 - 32 : chr1 + 64;
}
else {
return parseInt(String.fromCharCode(chr1) + String.fromCharCode(chr2));
}
}
function charCompatible(chr, codeset) {
var csa = codeSetAllowedFor(chr);
if (csa == CODESET.ANY) return true;
//if we need to change from current
if (csa == CODESET.AB) return true;
if (csa == CODESET.A && codeset == CODESET.A) return true;
if (csa == CODESET.B && codeset == CODESET.B) return true;
return false;
}
function codeSetAllowedFor(chr) {
if (chr >= 48 && chr <= 57) {
//0-9
return CODESET.ANY;
}
else if (chr >= 32 && chr <= 95) {
//0-9 A-Z
return CODESET.AB;
}
else {
//if non printable
return chr < 32 ? CODESET.A : CODESET.B;
}
}
var Graphics = function(ctx, width, height) {
this.width = width;
this.height = height;
this.quiet = Math.round(this.width / 40);
this.border_size = 0;
this.padding_width = 0;
this.area = {
width : width - this.padding_width * 2 - this.quiet * 2,
height: height - this.border_size * 2,
top : this.border_size - 4,
left : this.padding_width + this.quiet
};
this.ctx = ctx;
this.fg = "#000000";
this.bg = "#ffffff";
// fill background
this.fillBgRect(0,0, width, height);
// fill center to create border
this.fillBgRect(0, this.border_size, width, height - this.border_size * 2);
}
//use native color
Graphics.prototype._fillRect = function(x, y, width, height, color) {
this.ctx.setFillStyle(color)
this.ctx.fillRect(x, y, width, height)
}
Graphics.prototype.fillFgRect = function(x,y, width, height) {
this._fillRect(x, y, width, height, this.fg);
}
Graphics.prototype.fillBgRect = function(x,y, width, height) {
this._fillRect(x, y, width, height, this.bg);
}
var PATTERNS = [
[2, 1, 2, 2, 2, 2, 0, 0], // 0
[2, 2, 2, 1, 2, 2, 0, 0], // 1
[2, 2, 2, 2, 2, 1, 0, 0], // 2
[1, 2, 1, 2, 2, 3, 0, 0], // 3
[1, 2, 1, 3, 2, 2, 0, 0], // 4
[1, 3, 1, 2, 2, 2, 0, 0], // 5
[1, 2, 2, 2, 1, 3, 0, 0], // 6
[1, 2, 2, 3, 1, 2, 0, 0], // 7
[1, 3, 2, 2, 1, 2, 0, 0], // 8
[2, 2, 1, 2, 1, 3, 0, 0], // 9
[2, 2, 1, 3, 1, 2, 0, 0], // 10
[2, 3, 1, 2, 1, 2, 0, 0], // 11
[1, 1, 2, 2, 3, 2, 0, 0], // 12
[1, 2, 2, 1, 3, 2, 0, 0], // 13
[1, 2, 2, 2, 3, 1, 0, 0], // 14
[1, 1, 3, 2, 2, 2, 0, 0], // 15
[1, 2, 3, 1, 2, 2, 0, 0], // 16
[1, 2, 3, 2, 2, 1, 0, 0], // 17
[2, 2, 3, 2, 1, 1, 0, 0], // 18
[2, 2, 1, 1, 3, 2, 0, 0], // 19
[2, 2, 1, 2, 3, 1, 0, 0], // 20
[2, 1, 3, 2, 1, 2, 0, 0], // 21
[2, 2, 3, 1, 1, 2, 0, 0], // 22
[3, 1, 2, 1, 3, 1, 0, 0], // 23
[3, 1, 1, 2, 2, 2, 0, 0], // 24
[3, 2, 1, 1, 2, 2, 0, 0], // 25
[3, 2, 1, 2, 2, 1, 0, 0], // 26
[3, 1, 2, 2, 1, 2, 0, 0], // 27
[3, 2, 2, 1, 1, 2, 0, 0], // 28
[3, 2, 2, 2, 1, 1, 0, 0], // 29
[2, 1, 2, 1, 2, 3, 0, 0], // 30
[2, 1, 2, 3, 2, 1, 0, 0], // 31
[2, 3, 2, 1, 2, 1, 0, 0], // 32
[1, 1, 1, 3, 2, 3, 0, 0], // 33
[1, 3, 1, 1, 2, 3, 0, 0], // 34
[1, 3, 1, 3, 2, 1, 0, 0], // 35
[1, 1, 2, 3, 1, 3, 0, 0], // 36
[1, 3, 2, 1, 1, 3, 0, 0], // 37
[1, 3, 2, 3, 1, 1, 0, 0], // 38
[2, 1, 1, 3, 1, 3, 0, 0], // 39
[2, 3, 1, 1, 1, 3, 0, 0], // 40
[2, 3, 1, 3, 1, 1, 0, 0], // 41
[1, 1, 2, 1, 3, 3, 0, 0], // 42
[1, 1, 2, 3, 3, 1, 0, 0], // 43
[1, 3, 2, 1, 3, 1, 0, 0], // 44
[1, 1, 3, 1, 2, 3, 0, 0], // 45
[1, 1, 3, 3, 2, 1, 0, 0], // 46
[1, 3, 3, 1, 2, 1, 0, 0], // 47
[3, 1, 3, 1, 2, 1, 0, 0], // 48
[2, 1, 1, 3, 3, 1, 0, 0], // 49
[2, 3, 1, 1, 3, 1, 0, 0], // 50
[2, 1, 3, 1, 1, 3, 0, 0], // 51
[2, 1, 3, 3, 1, 1, 0, 0], // 52
[2, 1, 3, 1, 3, 1, 0, 0], // 53
[3, 1, 1, 1, 2, 3, 0, 0], // 54
[3, 1, 1, 3, 2, 1, 0, 0], // 55
[3, 3, 1, 1, 2, 1, 0, 0], // 56
[3, 1, 2, 1, 1, 3, 0, 0], // 57
[3, 1, 2, 3, 1, 1, 0, 0], // 58
[3, 3, 2, 1, 1, 1, 0, 0], // 59
[3, 1, 4, 1, 1, 1, 0, 0], // 60
[2, 2, 1, 4, 1, 1, 0, 0], // 61
[4, 3, 1, 1, 1, 1, 0, 0], // 62
[1, 1, 1, 2, 2, 4, 0, 0], // 63
[1, 1, 1, 4, 2, 2, 0, 0], // 64
[1, 2, 1, 1, 2, 4, 0, 0], // 65
[1, 2, 1, 4, 2, 1, 0, 0], // 66
[1, 4, 1, 1, 2, 2, 0, 0], // 67
[1, 4, 1, 2, 2, 1, 0, 0], // 68
[1, 1, 2, 2, 1, 4, 0, 0], // 69
[1, 1, 2, 4, 1, 2, 0, 0], // 70
[1, 2, 2, 1, 1, 4, 0, 0], // 71
[1, 2, 2, 4, 1, 1, 0, 0], // 72
[1, 4, 2, 1, 1, 2, 0, 0], // 73
[1, 4, 2, 2, 1, 1, 0, 0], // 74
[2, 4, 1, 2, 1, 1, 0, 0], // 75
[2, 2, 1, 1, 1, 4, 0, 0], // 76
[4, 1, 3, 1, 1, 1, 0, 0], // 77
[2, 4, 1, 1, 1, 2, 0, 0], // 78
[1, 3, 4, 1, 1, 1, 0, 0], // 79
[1, 1, 1, 2, 4, 2, 0, 0], // 80
[1, 2, 1, 1, 4, 2, 0, 0], // 81
[1, 2, 1, 2, 4, 1, 0, 0], // 82
[1, 1, 4, 2, 1, 2, 0, 0], // 83
[1, 2, 4, 1, 1, 2, 0, 0], // 84
[1, 2, 4, 2, 1, 1, 0, 0], // 85
[4, 1, 1, 2, 1, 2, 0, 0], // 86
[4, 2, 1, 1, 1, 2, 0, 0], // 87
[4, 2, 1, 2, 1, 1, 0, 0], // 88
[2, 1, 2, 1, 4, 1, 0, 0], // 89
[2, 1, 4, 1, 2, 1, 0, 0], // 90
[4, 1, 2, 1, 2, 1, 0, 0], // 91
[1, 1, 1, 1, 4, 3, 0, 0], // 92
[1, 1, 1, 3, 4, 1, 0, 0], // 93
[1, 3, 1, 1, 4, 1, 0, 0], // 94
[1, 1, 4, 1, 1, 3, 0, 0], // 95
[1, 1, 4, 3, 1, 1, 0, 0], // 96
[4, 1, 1, 1, 1, 3, 0, 0], // 97
[4, 1, 1, 3, 1, 1, 0, 0], // 98
[1, 1, 3, 1, 4, 1, 0, 0], // 99
[1, 1, 4, 1, 3, 1, 0, 0], // 100
[3, 1, 1, 1, 4, 1, 0, 0], // 101
[4, 1, 1, 1, 3, 1, 0, 0], // 102
[2, 1, 1, 4, 1, 2, 0, 0], // 103
[2, 1, 1, 2, 1, 4, 0, 0], // 104
[2, 1, 1, 2, 3, 2, 0, 0], // 105
[2, 3, 3, 1, 1, 1, 2, 0] // 106
]
qrcode.js源码（生成二维码）：
var QR = (function () {
// alignment pattern
var adelta = [
0, 11, 15, 19, 23, 27, 31, // force 1 pat
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 image
return qrframe;
}
var _canvas = null,
_size = 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);
},
draw: function (string, canvas, size, ecc) {
ecclevel = ecc || ecclevel;
canvas = canvas || _canvas;
if (!canvas) {
console.warn('No canvas provided to draw QR code in!')
return;
}
size = size || _size || Math.min(canvas.width, canvas.height);
var frame = genframe(string),
ctx = canvas.ctx,
px = Math.round(size / (width + 8));
var roundedSize = px * (width + 8),
offset = Math.floor((size - roundedSize) / 2);
size = roundedSize;
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.setFillStyle('#000000');
for (var i = 0; i < width; i++) {
for (var j = 0; j < width; j++) {
if (frame[j * width + i]) {
ctx.fillRect(px * (4 + i) + offset, px * (4 + j) + offset, px, px);
}
}
}
ctx.draw();
}
}
module.exports = {
api: api
}
})()注意：使用二维码生成的时候不能传入纯数字，需要传入string，否则会报错！
index.js(公共的调用js）：
var barcode = require('./barcode');
var qrcode = require('./qrcode');
function convert_length(length) {
return Math.round(wx.getSystemInfoSync().windowWidth * length / 750);
}
function barc(id, code, width, height) {
barcode.code128(wx.createCanvasContext(id), code, convert_length(width), convert_length(height))
}
function qrc(id, code, width, height) {
qrcode.api.draw(code, {
ctx: wx.createCanvasContext(id),
width: convert_length(width),
height: convert_length(height)
})
}
module.exports = {
barcode: barc,
qrcode: qrc
}wxml页面调用：
<view class="container page">
<view class="panel">
<view class="header">
</view>
<view class="barcode">
<view class="barnum">{{code}}</view>
<canvas canvas-id="barcode" />
</view>
<view class="qrcode">
<canvas canvas-id="qrcode" />
</view>
</view>
</view>js页面：
//index.js
var wxbarcode = require('../../utils/index.js');
Page({
data: {
code: '123456789'
},
onLoad: function() {
wxbarcode.barcode('barcode', '123456789', 680, 200);
wxbarcode.qrcode('qrcode', '123456789', 420, 420);
}
})