Wrap TessBaseAPIRecognize() and some ResultIterator functions

Wrapped enums:
TessPageIteratorLevel

Wrapped functions:
TessBaseAPIRecognize()
TessBaseAPIGetIterator()
TessResultIteratorDelete()
TessResultIteratorNext()
TessResultIteratorGetUTF8Text()

Wrapped structs:
TessResultIterator

Author: tsudoko

helpers.go

@@ -7,6 +7,14 @@ import (
 	"unsafe"
 )
 
+func gobool(b C.int) bool {
+	if b != 0 {
+		return true
+	}
+
+	return false
+}
+
 func cStringVectorToStringslice(cStringVector **C.char) []string {
 	// get pointer size to do iteration
 	cPtrSize := unsafe.Sizeof(cStringVector)

tesseract.go

@@ -358,8 +358,71 @@ func (t *Tess) SetRectangle(left, top, width, height int) {
 	C.TessBaseAPISetRectangle(t.tba, C.int(left), C.int(top), C.int(width), C.int(height))
 }
 
-// typedef struct TessPageIterator TessPageIterator;
+// int TessBaseAPIRecognize(TessBaseAPI* handle, ETEXT_DESC* monitor);
+func (t *Tess) Recognize() error {
+	ret := C.TessBaseAPIRecognize(t.tba, nil)
+	if ret != 0 {
+		return errors.New("recognition failed")
+	}
+	return nil
+}
+
+// typedef enum TessPageIteratorLevel { RIL_BLOCK, RIL_PARA, RIL_TEXTLINE, RIL_WORD, RIL_SYMBOL} TessPageIteratorLevel;
+type PageIteratorLevel int
+
+const (
+	RIL_BLOCK PageIteratorLevel = iota
+	RIL_PARA
+	RIL_TEXTLINE
+	RIL_WORD
+	RIL_SYMBOL
+)
+
+// TessResultIterator* TessBaseAPIGetIterator(TessBaseAPI* handle);
+func (t *Tess) Iterator() (*ResultIterator, error) {
+	ri := C.TessBaseAPIGetIterator(t.tba)
+
+	if ri == nil {
+		return nil, errors.New("no results")
+	}
+
+	resultIterator := &ResultIterator{
+		ri: ri,
+	}
+
+	runtime.SetFinalizer(resultIterator, (*ResultIterator).delete)
+	return resultIterator, nil
+}
+
 // typedef struct TessResultIterator TessResultIterator;
+type ResultIterator struct {
+	ri *C.TessResultIterator
+}
+
+// void TessResultIteratorDelete(TessResultIterator* handle);
+func (r *ResultIterator) delete() {
+	if r.ri != nil {
+		C.TessResultIteratorDelete(r.ri)
+	}
+}
+
+// TESS_API BOOL  TESS_CALL TessResultIteratorNext(TessResultIterator* handle, TessPageIteratorLevel level);
+func (r *ResultIterator) Next(level PageIteratorLevel) bool {
+	return gobool(C.TessResultIteratorNext(r.ri, C.TessPageIteratorLevel(level)))
+}
+
+// char* TessResultIteratorGetUTF8Text(const TessResultIterator* handle, TessPageIteratorLevel level);
+func (r *ResultIterator) Text(level PageIteratorLevel) (string, error) {
+	cText := C.TessResultIteratorGetUTF8Text(r.ri, C.TessPageIteratorLevel(level))
+	if cText == nil {
+		return "", errors.New("already at the end")
+	}
+	defer C.free(unsafe.Pointer(cText))
+	text := C.GoString(cText)
+	return text, nil
+}
+
+// typedef struct TessPageIterator TessPageIterator;
 // typedef struct TessMutableIterator TessMutableIterator;
 // typedef enum TessOcrEngineMode { OEM_TESSERACT_ONLY, OEM_CUBE_ONLY, OEM_TESSERACT_CUBE_COMBINED, OEM_DEFAULT } TessOcrEngineMode;
 // typedef enum TessPageSegMode { PSM_OSD_ONLY, PSM_AUTO_OSD, PSM_AUTO_ONLY, PSM_AUTO, PSM_SINGLE_COLUMN, PSM_SINGLE_BLOCK_VERT_TEXT, PSM_SINGLE_BLOCK, PSM_SINGLE_LINE, PSM_SINGLE_WORD, PSM_CIRCLE_WORD, PSM_SINGLE_CHAR, PSM_COUNT } TessPageSegMode;
@@ -425,12 +488,10 @@ func (t *Tess) SetRectangle(left, top, width, height int) {
 
 // TessPageIterator* TessBaseAPIAnalyseLayout(TessBaseAPI* handle);
 
-// int TessBaseAPIRecognize(TessBaseAPI* handle, ETEXT_DESC* monitor);
 // int TessBaseAPIRecognizeForChopTest(TessBaseAPI* handle, ETEXT_DESC* monitor);
 // char* TessBaseAPIProcessPages(TessBaseAPI* handle, const char* filename, const char* retry_config, int timeout_millisec);
 // char* TessBaseAPIProcessPage(TessBaseAPI* handle, PIX* pix, int page_index, const char* filename, const char* retry_config, int timeout_millisec);
 
-// TessResultIterator* TessBaseAPIGetIterator(TessBaseAPI* handle);
 // TessMutableIterator* TessBaseAPIGetMutableIterator(TessBaseAPI* handle);
 
 // int TessBaseAPIMeanTextConf(TessBaseAPI* handle);
@@ -460,7 +521,6 @@ func (t *Tess) SetRectangle(left, top, width, height int) {
 // void TessPageIteratorOrientation(TessPageIterator* handle, TessOrientation *orientation, TessWritingDirection *writing_direction, TessTextlineOrder *textline_order, float *deskew_angle);
 
 // /* Result iterator */
-// void TessResultIteratorDelete(TessResultIterator* handle);
 // TessResultIterator* TessResultIteratorCopy(const TessResultIterator* handle);
 // TessPageIterator* TessResultIteratorGetPageIterator(TessResultIterator* handle);
 // const TessPageIterator* TessResultIteratorGetPageIteratorConst(const TessResultIterator* handle);