445 lines
13 KiB
JavaScript
445 lines
13 KiB
JavaScript
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(function (root, factory) {
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if (typeof define === 'function' && define.amd) {
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define([], factory);
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} else if (typeof module === 'object' && module.exports) {
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module.exports = factory();
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} else {
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// generic browser usage
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let ex = factory();
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for (let id in ex) {
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root[id] = ex[id];
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}
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}
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}(typeof self !== 'undefined' ? self : this, function () {
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const zlib = typeof process == 'object' && typeof process.release == 'object' &&
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process.release.name == 'node' ? require('zlib') : null;
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const hexmap = (()=> {
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let arr = Array(256);
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for (let i = 0; i < 16; i++) {
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arr[i] = '0' + i.toString(16);
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}
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for (let i = 16; i < 256; i++) {
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arr[i] = i.toString(16);
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}
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return arr;
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})();
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// DOM-specialized version for browsers.
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function imageToZ64(img, opts) {
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// Draw the image to a temp canvas so we can access its RGBA data
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let cvs = document.createElement('canvas');
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let ctx = cvs.getContext('2d');
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cvs.width = +img.width || img.offsetWidth;
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cvs.height = +img.height || img.offsetHeight;
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ctx.imageSmoothingQuality = 'high'; // in case canvas needs to scale image
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ctx.drawImage(img, 0, 0, cvs.width, cvs.height);
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let pixels = ctx.getImageData(0, 0, cvs.width, cvs.height);
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return rgbaToZ64(pixels.data, pixels.width, opts);
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}
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// DOM-specialized version for browsers.
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function imageToACS(img, opts) {
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// Draw the image to a temp canvas so we can access its RGBA data
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let cvs = document.createElement('canvas');
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let ctx = cvs.getContext('2d');
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cvs.width = +img.width || img.offsetWidth;
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cvs.height = +img.height || img.offsetHeight;
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ctx.imageSmoothingQuality = 'high'; // in case canvas needs to scale image
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ctx.drawImage(img, 0, 0, cvs.width, cvs.height);
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let pixels = ctx.getImageData(0, 0, cvs.width, cvs.height);
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return rgbaToACS(pixels.data, pixels.width, opts);
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}
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// Uses zlib on node.js, pako.js in the browser.
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//
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// `rgba` can be a Uint8Array or Buffer, or an Array of integers between 0 and 255.
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// `width` is the image width, in pixels
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// `opts` is an options object:
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// `black` is the blackness percent between 1..99, default 50.
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// `rotate` is one of:
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// 'N' no rotation (default)
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// 'L' rotate 90 degrees counter-clockwise
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// 'R' rotate 90 degrees clockwise
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// 'I' rotate 180 degrees (inverted)
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// 'B' same as 'L'
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function rgbaToZ64(rgba, width, opts) {
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opts = opts || {};
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width = width|0;
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if (!width || width < 0) {
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throw new Error('Invalid width');
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}
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let height = ~~(rgba.length / width / 4);
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// Create a monochome image, cropped to remove padding.
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// The return is a Uint8Array with extra properties width and height.
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let mono = monochrome(rgba, width, height, +opts.black || 50, opts.notrim);
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let buf;
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switch (opts.rotate) {
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case 'R': buf = right(mono); break;
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case 'B':
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case 'L': buf = left(mono); break;
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case 'I': buf = invert(mono); break;
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default: buf = normal(mono); break;
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}
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// Compress and base64 encode
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let imgw = buf.width;
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let imgh = buf.height;
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let rowl = ~~((imgw + 7) / 8);
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let b64;
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if (zlib) {
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b64 = zlib.deflateSync(buf).toString('base64');
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} else {
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b64 = u8tob64(pako.deflate(buf));
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}
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// Example usage of the return value `rv`:
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// '^GFA,' + rv.length + ',' + rv.length + ',' + rv.rowlen + ',' + rv.z64
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return {
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length: buf.length, // uncompressed number of bytes
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rowlen: rowl, // number of packed bytes per row
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width: imgw, // rotated image width in pixels
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height: imgh, // rotated image height in pixels
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z64: ':Z64:' + b64 + ':' + crc16(b64),
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};
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}
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// Implements the Alternative Data Compression Scheme as described in the ref manual.
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//
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// `rgba` can be a Uint8Array or Buffer, or an Array of integers between 0 and 255.
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// `width` is the image width, in pixels
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// `opts` is an options object:
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// `black` is the blackness percent between 1..99, default 50.
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// `rotate` is one of:
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// 'N' no rotation (default)
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// 'L' rotate 90 degrees counter-clockwise
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// 'R' rotate 90 degrees clockwise
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// 'I' rotate 180 degrees (inverted)
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// 'B' same as 'L'
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function rgbaToACS(rgba, width, opts) {
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opts = opts || {};
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width = width|0;
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if (!width || width < 0) {
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throw new Error('Invalid width');
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}
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let height = ~~(rgba.length / width / 4);
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// Create a monochome image, cropped to remove padding.
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// The return is a Uint8Array with extra properties width and height.
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let mono = monochrome(rgba, width, height, +opts.black || 50, opts.notrim);
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let buf;
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switch (opts.rotate) {
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case 'R': buf = right(mono); break;
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case 'B':
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case 'L': buf = left(mono); break;
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case 'I': buf = invert(mono); break;
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default: buf = normal(mono); break;
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}
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// Encode in hex and apply the "Alternative Data Compression Scheme"
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//
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// G H I J K L M N O P Q R S T U V W X Y
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// 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
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//
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// g h i j k l m n o p q r s t u v w x y z
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// 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
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//
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let imgw = buf.width;
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let imgh = buf.height;
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let rowl = ~~((imgw + 7) / 8);
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let hex = '';
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for (let i = 0, l = buf.length; i < l; i++) {
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hex += hexmap[buf[i]];
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}
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let acs = '';
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let re = /([0-9a-fA-F])\1{2,}/g;
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let match = re.exec(hex);
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let offset = 0;
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while (match) {
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acs += hex.substring(offset, match.index);
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let l = match[0].length;
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while (l >= 400) {
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acs += 'z';
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l -= 400;
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}
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if (l >= 20) {
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acs += '_ghijklmnopqrstuvwxy'[((l / 20)|0)];
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l = l % 20;
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}
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if (l) {
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acs += '_GHIJKLMNOPQRSTUVWXY'[l];
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}
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acs += match[1];
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offset = re.lastIndex;
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match = re.exec(hex);
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}
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acs += hex.substr(offset);
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// Example usage of the return value `rv`:
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// '^GFA,' + rv.length + ',' + rv.length + ',' + rv.rowlen + ',' + rv.acs
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return {
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length: buf.length, // uncompressed number of bytes
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rowlen: rowl, // number of packed bytes per row
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width: imgw, // rotated image width in pixels
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height: imgh, // rotated image height in pixels
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acs: acs,
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};
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}
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// Normal, unrotated case
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function normal(mono) {
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let width = mono.width;
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let height = mono.height;
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let buf = new Uint8Array(~~((width + 7) / 8) * height);
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let idx = 0; // index into buf
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let byte = 0; // current byte of image data
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let bitx = 0; // bit index
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for (let i = 0, n = mono.length; i < n; i++) {
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byte |= mono[i] << (7 - (bitx++ & 7));
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if (bitx == width || !(bitx & 7)) {
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buf[idx++] = byte;
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byte = 0;
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if (bitx == width) {
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bitx = 0;
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}
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}
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}
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buf.width = width;
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buf.height = height;
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return buf;
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}
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// Inverted 180 degrees
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function invert(mono) {
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let width = mono.width;
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let height = mono.height;
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let buf = new Uint8Array(~~((width + 7) / 8) * height);
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let idx = 0; // index into buf
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let byte = 0; // current byte of image data
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let bitx = 0; // bit index
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for (let i = mono.length-1; i >= 0; i--) {
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byte |= mono[i] << (7 - (bitx++ & 7));
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if (bitx == width || !(bitx & 7)) {
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buf[idx++] = byte;
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byte = 0;
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if (bitx == width) {
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bitx = 0;
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}
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}
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}
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buf.width = width;
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buf.height = height;
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return buf;
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}
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// Rotate 90 degrees counter-clockwise
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function left(mono) {
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let width = mono.width;
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let height = mono.height;
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let buf = new Uint8Array(~~((height + 7) / 8) * width);
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let idx = 0; // index into buf
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let byte = 0; // current byte of image data
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for (let x = width - 1; x >= 0; x--) {
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let bitx = 0; // bit index
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for (let y = 0; y < height; y++) {
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byte |= mono[y * width + x] << (7 - (bitx++ & 7));
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if (y == height-1 || !(bitx & 7)) {
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buf[idx++] = byte;
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byte = 0;
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}
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}
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}
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buf.width = height;
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buf.height = width;
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return buf;
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}
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// Rotate 90 degrees clockwise
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function right(mono) {
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let width = mono.width;
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let height = mono.height;
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let buf = new Uint8Array(~~((height + 7) / 8) * width);
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let idx = 0; // index into buf
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let byte = 0; // current byte of image data
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for (let x = 0; x < width; x++) {
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let bitx = 0; // bit index
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for (let y = height - 1; y >= 0; y--) {
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byte |= mono[y * width + x] << (7 - (bitx++ & 7));
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if (y == 0 || !(bitx & 7)) {
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buf[idx++] = byte;
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byte = 0;
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}
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}
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}
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buf.width = height;
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buf.height = width;
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return buf;
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}
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// Convert the RGBA to monochrome, 1-bit-per-byte. Crops
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// empty space around the edges of the image if !notrim.
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function monochrome(rgba, width, height, black, notrim) {
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// Convert black from percent to 0..255 value
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black = 255 * black / 100;
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let minx, maxx, miny, maxy;
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if (notrim) {
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minx = miny = 0;
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maxx = width-1;
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maxy = height-1;
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} else {
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// Run through the image and determine bounding box
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maxx = maxy = 0;
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minx = width;
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miny = height;
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let x = 0, y = 0;
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for (let i = 0, n = width * height * 4; i < n; i += 4) {
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// Alpha blend with white.
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let a = rgba[i+3] / 255;
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let r = rgba[i] * .3 * a + 255 * (1 - a);
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let g = rgba[i+1] * .59 * a + 255 * (1 - a);
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let b = rgba[i+2] * .11 * a + 255 * (1 - a);
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let gray = r + g + b;
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if (gray <= black) {
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if (minx > x) minx = x;
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if (miny > y) miny = y;
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if (maxx < x) maxx = x;
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if (maxy < y) maxy = y;
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}
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if (++x == width) {
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x = 0;
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y++;
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}
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}
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}
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// One more time through the data, this time we create the cropped image.
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let cx = maxx - minx + 1;
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let cy = maxy - miny + 1;
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let buf = new Uint8Array(cx * cy);
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let idx = 0;
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for (y = miny; y <= maxy; y++) {
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let i = (y * width + minx) * 4;
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for (x = minx; x <= maxx; x++) {
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// Alpha blend with white.
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let a = rgba[i+3] / 255;
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let r = rgba[i] * .3 * a + 255 * (1 - a);
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let g = rgba[i+1] * .59 * a + 255 * (1 - a);
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let b = rgba[i+2] * .11 * a + 255 * (1 - a);
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let gray = r + g + b;
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buf[idx++] = gray <= black ? 1 : 0;
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i += 4;
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}
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}
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// Return the monochrome image
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buf.width = cx;
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buf.height = cy;
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return buf;
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}
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// Cannot use btoa() with Uint8Arrays. Used only by the browser.
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function u8tob64(a) {
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let s = '';
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let i = 0;
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for (let l = a.length & 0xfffffff0; i < l; i += 16) {
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s += String.fromCharCode(a[i],a[i+1],a[i+2],a[i+3],a[i+4],a[i+5],
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a[i+6],a[i+7],a[i+8],a[i+9],a[i+10],
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a[i+11],a[i+12],a[i+13],a[i+14],a[i+15]);
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}
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while (i < a.length) {
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s += String.fromCharCode(a[i++]);
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}
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return btoa(s);
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}
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// CRC16 used by zebra
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const crcTable = [
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0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5,
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0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b,
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0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210,
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0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
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0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c,
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0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401,
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0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b,
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0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
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0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6,
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0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738,
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0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5,
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0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
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0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969,
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0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96,
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0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc,
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0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
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0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03,
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0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd,
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0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6,
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0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
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0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a,
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0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb,
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0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1,
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0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
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0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c,
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0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2,
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0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb,
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0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
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0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447,
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0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8,
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0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2,
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0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
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0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9,
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0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827,
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0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c,
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0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
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0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0,
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0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d,
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0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07,
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0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
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0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba,
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0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74,
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0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
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];
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function crc16(s) {
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// This is not an accumlating crc routine. Normally, the acc is intialized to
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// 0xffff then inverted on each call. We just start with 0.
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let crc = 0;
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let j, i;
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for (i = 0; i < s.length; i++) {
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c = s.charCodeAt(i);
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if (c > 255) {
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throw new RangeError();
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}
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j = (c ^ (crc >> 8)) & 0xFF;
|
|
crc = crcTable[j] ^ (crc << 8);
|
|
}
|
|
|
|
crc = (crc & 0xffff).toString(16).toLowerCase();
|
|
return '0000'.substr(crc.length) + crc;
|
|
}
|
|
|
|
return zlib ? { rgbaToZ64, rgbaToACS } : { rgbaToZ64, rgbaToACS, imageToZ64, imageToACS };
|
|
}));
|