小程序生成二维码--简化版
使用：
//wxml文件 <canvas id="qrcode" /> //js文件 import qrcode from '../../utils/qrcode' //引入qrcode.js文件 Page({ onLoad() { wx.createSelectorQuery().select('#qrcode').context(function(res){ let code = '111' qrcode.api.draw(code, { ctx: res.context, width:170, height:170, }) }).exec() } })
utils/qrcode.js
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 } })()
