Allow for text angle/gradient to be retrieved

include/tesseract/baseapi.h

@@ -346,6 +346,11 @@ class TESS_API TessBaseAPI {
  */
  Pix *GetThresholdedImage();
 
+ /**
+ * Return average gradient of lines on page.
+ */
+ float GetGradient();
+
  /**
  * Get the result of page layout analysis as a leptonica-style
  * Boxa, Pixa pair, in reading order.

src/api/baseapi.cpp

@@ -2201,6 +2201,13 @@ int TessBaseAPI::FindLines() {
  return 0;
 }
 
+/**
+ * Return average gradient of lines on page.
+ */
+float TessBaseAPI::GetGradient() {
+ return tesseract_->gradient();
+}
+
 /** Delete the pageres and clear the block list ready for a new page. */
 void TessBaseAPI::ClearResults() {
  if (tesseract_ != nullptr) {

src/ccmain/pagesegmain.cpp

@@ -168,7 +168,7 @@ int Tesseract::SegmentPage(const char *input_file, BLOCK_LIST *blocks, Tesseract
  bool cjk_mode = textord_use_cjk_fp_model;
 
  textord_.TextordPage(pageseg_mode, reskew_, width, height, pix_binary_, pix_thresholds_,
- pix_grey_, splitting || cjk_mode, &diacritic_blobs, blocks, &to_blocks);
+ pix_grey_, splitting || cjk_mode, &diacritic_blobs, blocks, &to_blocks, &gradient_);
  return auto_page_seg_ret_val;
 }
 

src/ccmain/tesseractclass.cpp

@@ -495,6 +495,7 @@ void Tesseract::Clear() {
  scaled_color_.destroy();
  deskew_ = FCOORD(1.0f, 0.0f);
  reskew_ = FCOORD(1.0f, 0.0f);
+ gradient_ = 0.0f;
  splitter_.Clear();
  scaled_factor_ = -1;
  for (auto &sub_lang : sub_langs_) {

src/ccmain/tesseractclass.h

@@ -200,6 +200,9 @@ class TESS_API Tesseract : public Wordrec {
  const FCOORD &reskew() const {
  return reskew_;
  }
+ float gradient() const {
+ return gradient_;
+ }
  // Destroy any existing pix and return a pointer to the pointer.
  Image *mutable_pix_binary() {
  pix_binary_.destroy();
@@ -1001,6 +1004,7 @@ class TESS_API Tesseract : public Wordrec {
  int scaled_factor_;
  FCOORD deskew_;
  FCOORD reskew_;
+ float gradient_;
  TesseractStats stats_;
  // Sub-languages to be tried in addition to this.
  std::vector<Tesseract *> sub_langs_;

src/textord/textord.cpp

@@ -177,7 +177,7 @@ Textord::Textord(CCStruct *ccstruct)
 void Textord::TextordPage(PageSegMode pageseg_mode, const FCOORD &reskew, int width, int height,
  Image binary_pix, Image thresholds_pix, Image grey_pix, bool use_box_bottoms,
  BLOBNBOX_LIST *diacritic_blobs, BLOCK_LIST *blocks,
- TO_BLOCK_LIST *to_blocks) {
+ TO_BLOCK_LIST *to_blocks, float *gradient) {
  page_tr_.set_x(width);
  page_tr_.set_y(height);
  if (to_blocks->empty()) {
@@ -219,15 +219,14 @@ void Textord::TextordPage(PageSegMode pageseg_mode, const FCOORD &reskew, int wi
  TO_BLOCK_IT to_block_it(to_blocks);
  TO_BLOCK *to_block = to_block_it.data();
  // Make the rows in the block.
- float gradient;
  // Do it the old fashioned way.
  if (PSM_LINE_FIND_ENABLED(pageseg_mode)) {
- gradient = make_rows(page_tr_, to_blocks);
+ *gradient = make_rows(page_tr_, to_blocks);
  } else if (!PSM_SPARSE(pageseg_mode)) {
  // RAW_LINE, SINGLE_LINE, SINGLE_WORD and SINGLE_CHAR all need a single row.
- gradient = make_single_row(page_tr_, pageseg_mode != PSM_RAW_LINE, to_block, to_blocks);
+ *gradient = make_single_row(page_tr_, pageseg_mode != PSM_RAW_LINE, to_block, to_blocks);
  } else {
- gradient = 0.0f;
+ *gradient = 0.0f;
  }
  BaselineDetect baseline_detector(textord_baseline_debug, reskew, to_blocks);
  baseline_detector.ComputeStraightBaselines(use_box_bottoms);
@@ -236,7 +235,7 @@ void Textord::TextordPage(PageSegMode pageseg_mode, const FCOORD &reskew, int wi
  // Now make the words in the lines.
  if (PSM_WORD_FIND_ENABLED(pageseg_mode)) {
  // SINGLE_LINE uses the old word maker on the single line.
- make_words(this, page_tr_, gradient, blocks, to_blocks);
+ make_words(this, page_tr_, *gradient, blocks, to_blocks);
  } else {
  // SINGLE_WORD and SINGLE_CHAR cram all the blobs into a
  // single word, and in SINGLE_CHAR mode, all the outlines

src/textord/textord.h

@@ -89,7 +89,8 @@ class Textord {
  // to the appropriate word(s) in case they are really diacritics.
  void TextordPage(PageSegMode pageseg_mode, const FCOORD &reskew, int width, int height,
  Image binary_pix, Image thresholds_pix, Image grey_pix, bool use_box_bottoms,
- BLOBNBOX_LIST *diacritic_blobs, BLOCK_LIST *blocks, TO_BLOCK_LIST *to_blocks);
+ BLOBNBOX_LIST *diacritic_blobs, BLOCK_LIST *blocks, TO_BLOCK_LIST *to_blocks,
+ float *gradient);
 
  // If we were supposed to return only a single textline, and there is more
  // than one, clean up and leave only the best.