tesseract.js/worker_src/worker.js

var Tesseract304 = require('tesseract.js-core')
var leveljs = require('level-js')
var db;
if (typeof indexedDB === 'undefined'){
	db = { open: function(opts, cb){ cb(true) /*err = true*/ } }
}
else {
	db = leveljs('./tessdata')
}

console.log('hallo')

var filesizes = {"afr": 1079573, "ara": 1701536, "aze": 1420865, "bel": 1276820, "ben": 6772012, "bul": 1605615, "cat": 1652368, "ces": 1035441, "chi_sim": 17710414, "chi_tra": 24717749, "chr": 320649, "dan-frak": 677656, "dan": 1972936, "deu-frak": 822644, "deu": 991656, "ell": 859719, "eng": 9453554, "enm": 619254, "epo": 1241212, "equ": 821130, "est": 1905040, "eus": 1641190, "fin": 979418, "fra": 1376221, "frk": 5912963, "frm": 5147082, "glg": 1674938, "grc": 3012615, "heb": 1051501, "hin": 6590065, "hrv": 1926995, "hun": 3074473, "ind": 1874776, "isl": 1634041, "ita": 948593, "ita_old": 3436571, "jpn": 13507168, "kan": 4390317, "kor": 5353098, "lav": 1843944, "lit": 1779240, "mal": 5966263, "meme": 88453, "mkd": 1163087, "mlt": 1463001, "msa": 1665427, "nld": 1134708, "nor": 2191610, "osd": 4274649, "pol": 7024662, "por": 909359, "ron": 915680, "rus": 5969957, "slk-frak": 289885, "slk": 2217342, "slv": 1611338, "spa": 883170, "spa_old": 5647453, "sqi": 1667041, "srp": 1770244, "swa": 757916, "swe": 2451917, "tam": 3498763, "tel": 5795246, "tgl": 1496256, "tha": 3811136, "tur": 3563264, "ukr": 937566, "vie": 2195922}

var pako = require('pako')

var T;

var tesseractinit = (function createTesseractInstance(memory){

	curindex = 0

	var Module = Tesseract304({
		TOTAL_MEMORY: memory, //must be a multiple of 10 megabytes
		TesseractProgress: function(percent){
			postMessage({
				index: curindex,
				'progress': {
					'recognized': Math.max(0,(percent-30)/70)
				}
			})
		}//,
		// onRuntimeInitialized: function(){
		// 	console.log('wau')
		// }
	})

	var base = new Module.TessBaseAPI()
	var loaded_langs = []
	var loadLanguage = function(lang, index, cb){ // NodeJS style callback
		if(loaded_langs.indexOf(lang) != -1){
			cb(null, lang)		
		}
		else{
			Module.FS_createPath("/","tessdata",true,true)

			var downloadlang = function(shouldcache){
				postMessage({
					index: index,
					'progress': {
						'loaded_lang_model': 0,
						cached: false,
						requesting: true
					}
				})
				var xhr = new XMLHttpRequest();
				xhr.open('GET', 'https://cdn.rawgit.com/naptha/tessdata/gh-pages/3.02/'+lang+'.traineddata.gz', true);
				xhr.responseType = 'arraybuffer';
				xhr.onerror = function(){ cb(xhr, null) }
				xhr.onprogress = function(e){
					postMessage({
						index: index,
						'progress': {
							'loaded_lang_model': e.loaded/filesizes[lang], //this is kinda wrong on safari
							cached: false
						}
					})
				}
				xhr.onload = function(){
					if (xhr.status == 200 || (xhr.status == 0 && xhr.response)) {
						postMessage({
							index: index,
							'progress': 'unzipping_lang_model'
						})

						var response = new Uint8Array(xhr.response)

						while(response[0] == 0x1f && response[1] == 0x8b){
							response = pako.ungzip(response)
						}
						console.log('asdf')

						postMessage({
							index: index,
							'progress': {
								'unzipped_lang_model': true,
								'lang_model_size': response.length
							}
						})

						Module.FS_createDataFile('tessdata', lang +".traineddata", response, true, false);

						if(shouldcache){
							db.put(lang, response, function(err){
								console.log('cached lang')
							})
						}

						postMessage({
							index: index,
							'progress': {
								'created_virtual_datafile': true,
								'cached_file': shouldcache
							}
						})

						loaded_langs.push(lang)

						cb(null, lang)
					} else cb(xhr, null);
				}
				xhr.send(null)
			}

			db.open({compression: false},function(err){
				// err = true
				if (err) {
					downloadlang(false)
				}
				else {
					db.get(lang, function (err, value) {

						// err = true

						if (err) {
							downloadlang(true)
						}
						else {

							while(value[0] == 0x1f && value[1] == 0x8b){
								value = pako.ungzip(value)
							}

							postMessage({
								index: index,
								'progress': {
									loaded_lang_model:1,
									cached: true
								}
							})

							Module.FS_createDataFile('tessdata', lang +".traineddata", value, true, false);
							loaded_langs.push(lang)
							cb(null, lang)
						}
					})
				}
			})
		}
	}

	function circularize(page){
	    page.paragraphs = []
	    page.lines = []
	    page.words = []
	    page.symbols = []

	    page.blocks.forEach(function(block){
	        block.page = page;

	        block.lines = []
	        block.words = []
	        block.symbols = []

	        block.paragraphs.forEach(function(para){
	            para.block = block;
	            para.page = page;

	            para.words = []
	            para.symbols = []
	            
	            para.lines.forEach(function(line){
	                line.paragraph = para;
	                line.block = block;
	                line.page = page;

	                line.symbols = []

	                line.words.forEach(function(word){
	                    word.line = line;
	                    word.paragraph = para;
	                    word.block = block;
	                    word.page = page;
	                    word.symbols.forEach(function(sym){
	                        sym.word = word;
	                        sym.line = line;
	                        sym.paragraph = para;
	                        sym.block = block;
	                        sym.page = page;
	                        
	                        sym.line.symbols.push(sym)
	                        sym.paragraph.symbols.push(sym)
	                        sym.block.symbols.push(sym)
	                        sym.page.symbols.push(sym)
	                    })
	                    word.paragraph.words.push(word)
	                    word.block.words.push(word)
	                    word.page.words.push(word)
	                })
	                line.block.lines.push(line)
	                line.page.lines.push(line)
	            })
	            para.page.paragraphs.push(para)
	        })
	    })
	    return page
	}

	function DumpLiterallyEverything(){
			var ri = base.GetIterator();
			var blocks = [];
			var block, para, textline, word, symbol;

			function enumToString(value, prefix){
			   return (Object.keys(Module)
			       .filter(function(e){ return e.substr(0, prefix.length + 1) == prefix + '_' })
			       .filter(function(e){ return Module[e] === value })
			       .map(function(e){ return e.slice(prefix.length + 1) })[0])
			}

			ri.Begin()
			do {
				if(ri.IsAtBeginningOf(Module.RIL_BLOCK)){
					var poly = ri.BlockPolygon();
					var polygon = null;
					// BlockPolygon() returns null when automatic page segmentation is off
					if(Module.getPointer(poly) > 0){
						var n = poly.get_n(),
							px = poly.get_x(),
							py = poly.get_y(),
							polygon = [];
						for(var i = 0; i < n; i++){
							polygon.push([px.getValue(i), py.getValue(i)]);
						}
						Module._ptaDestroy(Module.getPointer(poly));	
					}
					
					block = {
						paragraphs: [],

						text: ri.GetUTF8Text(Module.RIL_BLOCK),
						confidence: ri.Confidence(Module.RIL_BLOCK),
						baseline: ri.getBaseline(Module.RIL_BLOCK),
						bbox: ri.getBoundingBox(Module.RIL_BLOCK),

						blocktype: enumToString(ri.BlockType(), 'PT'),
						polygon: polygon
					}
					blocks.push(block)
				}
				if(ri.IsAtBeginningOf(Module.RIL_PARA)){
					para = {
						lines: [],

						text: ri.GetUTF8Text(Module.RIL_PARA),
						confidence: ri.Confidence(Module.RIL_PARA),
						baseline: ri.getBaseline(Module.RIL_PARA),
						bbox: ri.getBoundingBox(Module.RIL_PARA),

						is_ltr: !!ri.ParagraphIsLtr()
					}
					block.paragraphs.push(para)
				}
				if(ri.IsAtBeginningOf(Module.RIL_TEXTLINE)){
					textline = {
						words: [],

						text: ri.GetUTF8Text(Module.RIL_TEXTLINE),
						confidence: ri.Confidence(Module.RIL_TEXTLINE),
						baseline: ri.getBaseline(Module.RIL_TEXTLINE),
						bbox: ri.getBoundingBox(Module.RIL_TEXTLINE)
					}
					para.lines.push(textline)
				}
				if(ri.IsAtBeginningOf(Module.RIL_WORD)){
					var fontInfo = ri.getWordFontAttributes(),
						wordDir = ri.WordDirection();
					word = {
						symbols: [],
						choices: [],

						text: ri.GetUTF8Text(Module.RIL_WORD),
						confidence: ri.Confidence(Module.RIL_WORD),
						baseline: ri.getBaseline(Module.RIL_WORD),
						bbox: ri.getBoundingBox(Module.RIL_WORD),

						is_numeric: !!ri.WordIsNumeric(),
						in_dictionary: !!ri.WordIsFromDictionary(),
						direction: enumToString(wordDir, 'DIR'),
						language: ri.WordRecognitionLanguage(),

						is_bold: fontInfo.is_bold,
						is_italic: fontInfo.is_italic,
						is_underlined: fontInfo.is_underlined,
						is_monospace: fontInfo.is_monospace,
						is_serif: fontInfo.is_serif,
						is_smallcaps: fontInfo.is_smallcaps,
						font_size: fontInfo.pointsize,
						font_id: fontInfo.font_id,
						font_name: fontInfo.font_name,
					}
					var wc = new Module.WordChoiceIterator(ri);
					do {
						word.choices.push({
							text: wc.GetUTF8Text(),
							confidence: wc.Confidence()
						})
					} while (wc.Next());
					Module.destroy(wc)
					textline.words.push(word)
				}
				
				var image = null;
				// var pix = ri.GetBinaryImage(Module.RIL_SYMBOL)
				// var image = pix2array(pix);
				// // for some reason it seems that things stop working if you destroy pics
				// Module._pixDestroy(Module.getPointer(pix));
				if(ri.IsAtBeginningOf(Module.RIL_SYMBOL)){
					symbol = {
						choices: [],
						image: image,

						text: ri.GetUTF8Text(Module.RIL_SYMBOL),
						confidence: ri.Confidence(Module.RIL_SYMBOL),
						baseline: ri.getBaseline(Module.RIL_SYMBOL),
						bbox: ri.getBoundingBox(Module.RIL_SYMBOL),

						is_superscript: !!ri.SymbolIsSuperscript(),
						is_subscript: !!ri.SymbolIsSubscript(),
						is_dropcap: !!ri.SymbolIsDropcap(),
					}
					word.symbols.push(symbol)
					var ci = new Module.ChoiceIterator(ri);
					do {
						symbol.choices.push({
							text: ci.GetUTF8Text(),
							confidence: ci.Confidence()
						})
					} while (ci.Next());
					Module.destroy(ci)
				}
			} while (ri.Next(Module.RIL_SYMBOL));
			Module.destroy(ri)

			return {
				text: base.GetUTF8Text(),
				html: deindent(base.GetHOCRText()),

				confidence: base.MeanTextConf(),

				blocks: blocks,

				psm: enumToString(base.GetPageSegMode(), 'PSM'),
				oem: enumToString(base.oem(), 'OEM'),
				version: base.Version(),
			}
	}

	function deindent(html){
		var lines = html.split('\n')
		if(lines[0].substring(0,2) === "  "){
			for (var i = 0; i < lines.length; i++) {
				if (lines[i].substring(0,2) === "  ") {
					lines[i] = lines[i].slice(2)
				}
			};
		}
		return lines.join('\n')
	}

	function desaturate(image){
		var width, height;
		if(image.data){
			var src       = image.data;
			width     	  = image.width, height = image.height;
			var dst       = new Uint8Array(width * height);
			var srcLength = src.length | 0, srcLength_16 = (srcLength - 16) | 0;
			
			for (var i = 0, j = 0; i <= srcLength_16; i += 16, j += 4) {
				// convert to grayscale 4 pixels at a time; eveything with alpha get put in front of 50% gray
				dst[j]     = (((src[i] * 77 + src[i+1] * 151 + src[i+2] * 28) * src[i+3]) + ((255-src[i+3]) << 15) + 32768) >> 16
				dst[j+1]   = (((src[i+4] * 77 + src[i+5] * 151 + src[i+6] * 28) * src[i+7]) + ((255-src[i+7]) << 15) + 32768) >> 16
				dst[j+2]   = (((src[i+8] * 77 + src[i+9] * 151 + src[i+10] * 28) * src[i+11]) + ((255-src[i+11]) << 15) + 32768) >> 16
				dst[j+3]   = (((src[i+12] * 77 + src[i+13] * 151 + src[i+14] * 28) * src[i+15]) + ((255-src[i+15]) << 15) + 32768) >> 16
				
			}
			for (; i < srcLength; i += 4, ++j) //finish up
				dst[j]     = (((src[i] * 77 + src[i+1] * 151 + src[i+2] * 28) * src[i+3]) + ((255-src[i+3]) << 15) + 32768) >> 16
			
			image = dst;
		}
		else {
			throw 'Expected ImageData'
		}
		return image
	}

	function recognize(index, image, lang, options, cb){


		var width = image.width, height = image.height;

		image = desaturate(image)

		var ptr = Module.allocate(image, 'i8', Module.ALLOC_NORMAL);
		
		loadLanguage(lang, index, function(err, result){

			if(err){
				console.error("error loading", lang);
				Module._free(ptr); 
				cb(err, null)
			}
			else {
				curindex = index

				base.Init(null, lang)

				postMessage({
					index: index,			
					'progress': {
						'initialized_with_lang': true,
						'lang': lang
					}
				})

				for (var option in options) {
				    if (options.hasOwnProperty(option)) {
				        base.SetVariable(option, options[option]);
				        postMessage({
							index: index,			
							'progress': {
								'set_variable': {
									variable: option,
									value: options[option]
								}
							}
						})
				    }
				}


				base.SetImage(Module.wrapPointer(ptr), width, height, 1, width)
				base.SetRectangle(0, 0, width, height)
				// base.GetUTF8Text()
				base.Recognize(null)
				var everything = circularize(DumpLiterallyEverything())
				base.End();
				Module._free(ptr); 
				cb(null, everything)

			}
		})
	}

	function detect(index, image, cb){
		var width = image.width, height = image.height;
		image = desaturate(image)

		var ptr = Module.allocate(image, 'i8', Module.ALLOC_NORMAL);
		console.log('allocated image')
		// base = new Module.TessBaseAPI()

		loadLanguage('osd', index, function(err, result){
			if(err){
				Module._free(ptr);
				cb(err)
			}
			else {
				curindex = index
				base.Init(null, 'osd')
				base.SetPageSegMode(Module.PSM_OSD_ONLY)
				console.log('loaded language')
				
				base.SetImage(Module.wrapPointer(ptr), width, height, 1, width)
				base.SetRectangle(0, 0, width, height)

				var results = new Module.OSResults();
				var success = base.DetectOS(results);
				if(!success){
					base.End();
					Module._free(ptr);
					cb("failed to detect os")
				}
				else {
					var charset = results.get_unicharset()
					console.log(charset)
					// results.print_scores()

					var best = results.get_best_result()
					var oid = best.get_orientation_id(),
						sid = best.get_script_id();
					// console.log('orientation id', oid, [0, 270, 180, 90][oid], best.get_oconfidence())
					// console.log('script id', sid, charset.get_script_from_script_id(sid), best.get_sconfidence())
					// console.log(best)

					cb(null, {
						tesseract_script_id: sid,
						script: charset.get_script_from_script_id(sid),
						script_confidence: best.get_sconfidence(),
						orientation_degrees: [0, 270, 180, 90][oid],
						orientation_confidence: best.get_oconfidence()
					})

					base.End();
					Module._free(ptr);
				}
			}
		})
	}

	return {
		recognize: recognize,
		detect: detect
	}
})

onmessage = function(e) {

	if(e.data.init){
		T = tesseractinit(e.data.init.mem)
	}
	else if(e.data.fun === 'recognize'){
		T.recognize(e.data.index, e.data.image, e.data.lang, e.data.options, function(err, result){
			postMessage({index: e.data.index, err:err, result: result})
		})		
	}
	else if(e.data.fun === 'detect'){
		T.detect(e.data.index, e.data.image, function(err, result){
			postMessage({index: e.data.index, err:err, result: result})
		})
	}
}