change loadlanguage api

README.md

@@ -44,12 +44,115 @@ worker.recognize('#my-image')
 
 
 ## npm
-###TODO
+### TODO
 
 <!-- ```shell
 > npm install tesseract-js ?
 ```-->
 
+# Docs
+## Tesseract.recognize(image) -> [TesseractJob](#tesseractjob)
+Returns a TesseractJob whose `then` method can be used to act on the result of the OCR.
+
+For example:
+
+`image` can be 
+ - an `img` element or querySelector that matches an `img` element
+ - a `video` element or querySelector that matches a `video` element
+ - a `canvas` element or querySelector that matches a `canvas` element
+ - a CanvasRenderingContext2D (returned by `canvas.getContext('2d')`)
+ - the absolute `url` of an image from the same website that is running your script. Browser security policies don't allow access to the content of images from other websites :(
+ - 
+
+## Tesseract.detect(image) -> [TesseractJob](#tesseractjob)
+Returns a TesseractJob whose `then` method can be used to act on the result of the OCR.
+
+For example:
+
+`image` can be 
+ - an `img` element or querySelector that matches an `img` element
+ - a `video` element or querySelector that matches a `video` element
+ - a `canvas` element or querySelector that matches a `canvas` element
+ - a CanvasRenderingContext2D (returned by `canvas.getContext('2d')`)
+ - the absolute `url` of an image from the same website that is running your script. Browser security policies don't allow access to the content of images from other websites :(
+
+## TesseractJob
+A TesseractJob is an an object returned by a call to recognize or detect.
+All methods of a TesseractJob return itself to enable chaining. 
+
+Typical use is: 
+```javascript
+var job1 = Tesseract.recognize('#my-image')
+
+job1.progress(function(message){console.log(message)})
+    .error(function(err){console.error(err)})
+    .then(function(result){console.log(result)})
+```
+
+or more concisely:
+```javascript
+Tesseract.recognize('#my-image')
+    .progress(function(message){console.log(message)})
+    .error(function(err){console.error(err)})
+    .then(function(result){console.log(result)})
+```
+
+
+### TesseractJob.progress(callback: function) -> TesseractJob
+Sets `callback` as the function that will be called every time the job progresses. 
+
+`callback` is a function with the signature `callback(progress)` where progress is json object.
+
+For example: 
+```javascript
+Tesseract.recognize('#my-image')
+    .progress(function(message){console.log('progress is: 'message)})
+```
+
+The console will show something like: 
+```javascript
+progress is: {loaded_lang_model: "eng", from_cache: true}
+progress is: {initialized_with_lang: "eng"}
+progress is: {set_variable: Object}
+progress is: {set_variable: Object}
+progress is: {recognized: 0}
+progress is: {recognized: 0.3}
+progress is: {recognized: 0.6}
+progress is: {recognized: 0.9}
+progress is: {recognized: 1}
+```
+
+
+### TesseractJob.then(callback: function) -> TesseractJob
+Sets `callback` as the function that will be called if and when the job successfully completes. 
+
+For example: 
+```javascript
+Tesseract.recognize('#my-image')
+    .then(function(result){console.log('result is: 'result)})
+```
+
+The console will show something like: 
+```javascript
+progress is: {
+    blocks: Array[1]
+    confidence: 87
+    html: "<div class='ocr_page' id='page_1' ..."
+    lines: Array[3]
+    oem: "DEFAULT"
+    paragraphs: Array[1]
+    psm: "SINGLE_BLOCK"
+    symbols: Array[33]
+    text: "Hello World↵from beyond↵the Cosmic Void↵↵"
+    version: "3.04.00"
+    words: Array[7]
+}
+```
+
+### TesseractJob.error(callback: function) -> TesseractJob
+Sets `callback` as the function that will be called if and when the job successfully completes. 
+
+
 # Contributing
 ## Development
 To run a development copy of tesseract.js, first clone this repo.

index.html

@@ -16,15 +16,15 @@
 
 	var tesseract = createTesseractWorker();
 
+	tesseract.detect(canvas)
 	// tesseract.recognize('http://localhost:7355/westmorland.jpg')
-	tesseract.recognize(canvas, {
-		tessedit_char_blacklist: 'e'
-	})
+	// tesseract.recognize(canvas, {
+	// 	tessedit_char_blacklist: 'e'
+	// })
 	.progress(function(e){
 		console.log('progress', e)
 	})
 	.then(function(e){
 		console.log('result', e)
 	})
-
 </script>

src/worker/detect.js

@@ -1,20 +1,20 @@
+import desaturate from './desaturate'
+import loadLanguage from './loadLanguage'
+
 export default function detect(jobId, module, base, 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()
+	// console.log('allocated image')
 
-	loadLanguage('osd', jobId, function(err, result){
-		if(err){
+	loadLanguage(jobId, module, 'osd', err => {
 		module._free(ptr);
 		cb(err)
-		}
-		else {
+	}, success => {
 		base.Init(null, 'osd')
 		base.SetPageSegMode(module.PSM_OSD_ONLY)
-			console.log('loaded language')
+		// console.log('loaded language')
 		
 		base.SetImage(module.wrapPointer(ptr), width, height, 1, width)
 		base.SetRectangle(0, 0, width, height)
@@ -28,7 +28,7 @@ export default function detect(jobId, module, base, image, cb){
 		}
 		else {
 			var charset = results.get_unicharset()
-				console.log(charset)
+			// console.log(charset)
 			// results.print_scores()
 
 			var best = results.get_best_result()
@@ -49,6 +49,5 @@ export default function detect(jobId, module, base, image, cb){
 			base.End();
 			module._free(ptr);
 		}
-		}
 	})
 }

src/worker/loadLanguage.js

@@ -39,14 +39,11 @@ function getLanguageData(lang, progress, cb, url='https://cdn.rawgit.com/naptha/
 	xhr.send()
 }
 
-// var loaded_langs = []
 
-export default function loadLanguage(lang, jobId, cb, url){
+function load(lang, jobId, cb, url){
 
 	console.log('loadLanguage jobId', jobId)
 
-	// if(loaded_langs.indexOf(lang) != -1) return cb(null, lang);
-
 	function progressMessage(progress){
 		postMessage({ jobId, progress })
 	}	
@@ -86,3 +83,17 @@ export default function loadLanguage(lang, jobId, cb, url){
 		})
 	})	
 }
+
+var loaded_langs = []
+
+export default function loadLanguage(jobId, module, lang, error, success){
+	if(loaded_langs.indexOf(lang) == -1) load(lang, jobId, function(err, result){
+		if(err) return error(err)
+
+		loaded_langs.push(lang)
+		module.FS_createDataFile('tessdata', lang +".traineddata", result, true, false);
+
+		success()
+	})
+	else run();
+}

src/worker/recognize.js

@@ -15,8 +15,10 @@ export default function recognize(jobId, module, base, image, options, cb){
 
 	var ptr = module.allocate(image, 'i8', module.ALLOC_NORMAL);
 
-
-	function run() {
+	loadLanguage(jobId, module, lang, err => {
+		module._free(ptr)
+		cb(err)
+	}, success => {
 		base.Init(null, lang)
 
 		postMessage({
@@ -50,22 +52,5 @@ export default function recognize(jobId, module, base, image, options, cb){
 		base.End();
 		module._free(ptr); 
 		cb(null, everything)
-	}
-
-
-
-	if(loaded_langs.indexOf(lang) == -1) loadLanguage(lang, jobId, function(err, result){
-
-		if(err){
-			console.error("error loading", lang);
-			module._free(ptr);
-			return cb(err, null);
-		}
-
-		loaded_langs.push(lang)
-		module.FS_createDataFile('tessdata', lang +".traineddata", result, true, false);
-		run()
-
 	})	
-	else run();
 }