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Move code for hOCR renderer to new file
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Signed-off-by: Stefan Weil <sw@weilnetz.de>
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@stweil
stweil committed Dec 15, 2018
1 parent e398601 commit 48713f7
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Showing 5 changed files with 442 additions and 409 deletions.
6 changes: 5 additions & 1 deletion src/api/Makefile.am
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Expand Up @@ -32,7 +32,11 @@ libtesseract_api_la_CPPFLAGS = $(AM_CPPFLAGS)
if VISIBILITY
libtesseract_api_la_CPPFLAGS += -DTESS_EXPORTS
endif
libtesseract_api_la_SOURCES = baseapi.cpp capi.cpp renderer.cpp pdfrenderer.cpp altorenderer.cpp
libtesseract_api_la_SOURCES = baseapi.cpp capi.cpp
libtesseract_api_la_SOURCES += altorenderer.cpp
libtesseract_api_la_SOURCES += hocrrenderer.cpp
libtesseract_api_la_SOURCES += pdfrenderer.cpp
libtesseract_api_la_SOURCES += renderer.cpp

lib_LTLIBRARIES += libtesseract.la
libtesseract_la_LDFLAGS = $(LEPTONICA_LIBS) $(OPENCL_LDFLAGS)
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359 changes: 5 additions & 354 deletions src/api/baseapi.cpp
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Expand Up @@ -1340,363 +1340,14 @@ char* TessBaseAPI::GetUTF8Text() {
return result;
}

/**
* Gets the block orientation at the current iterator position.
*/
static tesseract::Orientation GetBlockTextOrientation(const PageIterator *it) {
tesseract::Orientation orientation;
tesseract::WritingDirection writing_direction;
tesseract::TextlineOrder textline_order;
float deskew_angle;
it->Orientation(&orientation, &writing_direction, &textline_order,
&deskew_angle);
return orientation;
}

/**
* Fits a line to the baseline at the given level, and appends its coefficients
* to the hOCR string.
* NOTE: The hOCR spec is unclear on how to specify baseline coefficients for
* rotated textlines. For this reason, on textlines that are not upright, this
* method currently only inserts a 'textangle' property to indicate the rotation
* direction and does not add any baseline information to the hocr string.
*/
static void AddBaselineCoordsTohOCR(const PageIterator *it,
PageIteratorLevel level,
STRING* hocr_str) {
tesseract::Orientation orientation = GetBlockTextOrientation(it);
if (orientation != ORIENTATION_PAGE_UP) {
hocr_str->add_str_int("; textangle ", 360 - orientation * 90);
return;
}

int left, top, right, bottom;
it->BoundingBox(level, &left, &top, &right, &bottom);

// Try to get the baseline coordinates at this level.
int x1, y1, x2, y2;
if (!it->Baseline(level, &x1, &y1, &x2, &y2))
return;
// Following the description of this field of the hOCR spec, we convert the
// baseline coordinates so that "the bottom left of the bounding box is the
// origin".
x1 -= left;
x2 -= left;
y1 -= bottom;
y2 -= bottom;

// Now fit a line through the points so we can extract coefficients for the
// equation: y = p1 x + p0
double p1 = 0;
double p0 = 0;
if (x1 == x2) {
// Problem computing the polynomial coefficients.
return;
}
p1 = (y2 - y1) / static_cast<double>(x2 - x1);
p0 = y1 - static_cast<double>(p1 * x1);

hocr_str->add_str_double("; baseline ", round(p1 * 1000.0) / 1000.0);
hocr_str->add_str_double(" ", round(p0 * 1000.0) / 1000.0);
}

static void AddIdTohOCR(STRING* hocr_str, const std::string base, int num1,
int num2) {
const size_t BUFSIZE = 64;
char id_buffer[BUFSIZE];
if (num2 >= 0) {
snprintf(id_buffer, BUFSIZE - 1, "%s_%d_%d", base.c_str(), num1, num2);
} else {
snprintf(id_buffer, BUFSIZE - 1, "%s_%d", base.c_str(), num1);
}
id_buffer[BUFSIZE - 1] = '\0';
*hocr_str += " id='";
*hocr_str += id_buffer;
*hocr_str += "'";
}

static void AddIdTohOCR(STRING* hocr_str, const std::string base, int num1,
int num2, int num3) {
const size_t BUFSIZE = 64;
char id_buffer[BUFSIZE];
snprintf(id_buffer, BUFSIZE - 1, "%s_%d_%d_%d", base.c_str(), num1, num2,num3);
id_buffer[BUFSIZE - 1] = '\0';
*hocr_str += " id='";
*hocr_str += id_buffer;
*hocr_str += "'";
}

static void AddBoxTohOCR(const ResultIterator* it, PageIteratorLevel level,
STRING* hocr_str) {
int left, top, right, bottom;
it->BoundingBox(level, &left, &top, &right, &bottom);
// This is the only place we use double quotes instead of single quotes,
// but it may too late to change for consistency
hocr_str->add_str_int(" title=\"bbox ", left);
hocr_str->add_str_int(" ", top);
hocr_str->add_str_int(" ", right);
hocr_str->add_str_int(" ", bottom);
// Add baseline coordinates & heights for textlines only.
if (level == RIL_TEXTLINE) {
AddBaselineCoordsTohOCR(it, level, hocr_str);
// add custom height measures
float row_height, descenders, ascenders; // row attributes
it->RowAttributes(&row_height, &descenders, &ascenders);
// TODO(rays): Do we want to limit these to a single decimal place?
hocr_str->add_str_double("; x_size ", row_height);
hocr_str->add_str_double("; x_descenders ", descenders * -1);
hocr_str->add_str_double("; x_ascenders ", ascenders);
}
*hocr_str += "\">";
}

static void AddBoxToTSV(const PageIterator* it, PageIteratorLevel level,
STRING* hocr_str) {
STRING* text) {
int left, top, right, bottom;
it->BoundingBox(level, &left, &top, &right, &bottom);
hocr_str->add_str_int("\t", left);
hocr_str->add_str_int("\t", top);
hocr_str->add_str_int("\t", right - left);
hocr_str->add_str_int("\t", bottom - top);
}

/**
* Make a HTML-formatted string with hOCR markup from the internal
* data structures.
* page_number is 0-based but will appear in the output as 1-based.
* Image name/input_file_ can be set by SetInputName before calling
* GetHOCRText
* STL removed from original patch submission and refactored by rays.
* Returned string must be freed with the delete [] operator.
*/
char* TessBaseAPI::GetHOCRText(int page_number) {
return GetHOCRText(nullptr, page_number);
}

/**
* Make a HTML-formatted string with hOCR markup from the internal
* data structures.
* page_number is 0-based but will appear in the output as 1-based.
* Image name/input_file_ can be set by SetInputName before calling
* GetHOCRText
* STL removed from original patch submission and refactored by rays.
* Returned string must be freed with the delete [] operator.
*/
char* TessBaseAPI::GetHOCRText(ETEXT_DESC* monitor, int page_number) {
if (tesseract_ == nullptr || (page_res_ == nullptr && Recognize(monitor) < 0))
return nullptr;

int lcnt = 1, bcnt = 1, pcnt = 1, wcnt = 1, tcnt = 1, gcnt = 1;
int page_id = page_number + 1; // hOCR uses 1-based page numbers.
bool para_is_ltr = true; // Default direction is LTR
const char* paragraph_lang = nullptr;
bool font_info = false;
GetBoolVariable("hocr_font_info", &font_info);

STRING hocr_str("");

if (input_file_ == nullptr)
SetInputName(nullptr);

#ifdef _WIN32
// convert input name from ANSI encoding to utf-8
int str16_len =
MultiByteToWideChar(CP_ACP, 0, input_file_->string(), -1, nullptr, 0);
wchar_t *uni16_str = new WCHAR[str16_len];
str16_len = MultiByteToWideChar(CP_ACP, 0, input_file_->string(), -1,
uni16_str, str16_len);
int utf8_len = WideCharToMultiByte(CP_UTF8, 0, uni16_str, str16_len, nullptr, 0,
nullptr, nullptr);
char *utf8_str = new char[utf8_len];
WideCharToMultiByte(CP_UTF8, 0, uni16_str, str16_len, utf8_str,
utf8_len, nullptr, nullptr);
*input_file_ = utf8_str;
delete[] uni16_str;
delete[] utf8_str;
#endif

hocr_str += " <div class='ocr_page'";
AddIdTohOCR(&hocr_str, "page", page_id, -1);
hocr_str += " title='image \"";
if (input_file_) {
hocr_str += HOcrEscape(input_file_->string());
} else {
hocr_str += "unknown";
}
hocr_str.add_str_int("\"; bbox ", rect_left_);
hocr_str.add_str_int(" ", rect_top_);
hocr_str.add_str_int(" ", rect_width_);
hocr_str.add_str_int(" ", rect_height_);
hocr_str.add_str_int("; ppageno ", page_number);
hocr_str += "'>\n";

ResultIterator *res_it = GetIterator();
while (!res_it->Empty(RIL_BLOCK)) {
if (res_it->Empty(RIL_WORD)) {
res_it->Next(RIL_WORD);
continue;
}

// Open any new block/paragraph/textline.
if (res_it->IsAtBeginningOf(RIL_BLOCK)) {
para_is_ltr = true; // reset to default direction
hocr_str += " <div class='ocr_carea'";
AddIdTohOCR(&hocr_str, "block", page_id, bcnt);
AddBoxTohOCR(res_it, RIL_BLOCK, &hocr_str);
}
if (res_it->IsAtBeginningOf(RIL_PARA)) {
hocr_str += "\n <p class='ocr_par'";
para_is_ltr = res_it->ParagraphIsLtr();
if (!para_is_ltr) {
hocr_str += " dir='rtl'";
}
AddIdTohOCR(&hocr_str, "par", page_id, pcnt);
paragraph_lang = res_it->WordRecognitionLanguage();
if (paragraph_lang) {
hocr_str += " lang='";
hocr_str += paragraph_lang;
hocr_str += "'";
}
AddBoxTohOCR(res_it, RIL_PARA, &hocr_str);
}
if (res_it->IsAtBeginningOf(RIL_TEXTLINE)) {
hocr_str += "\n <span class='ocr_line'";
AddIdTohOCR(&hocr_str, "line", page_id, lcnt);
AddBoxTohOCR(res_it, RIL_TEXTLINE, &hocr_str);
}

// Now, process the word...
std::vector<std::vector<std::pair<const char*, float>>>* confidencemap = nullptr;
if (tesseract_->lstm_choice_mode) {
confidencemap = res_it->GetBestLSTMSymbolChoices();
}
hocr_str += "\n <span class='ocrx_word'";
AddIdTohOCR(&hocr_str, "word", page_id, wcnt);
int left, top, right, bottom;
bool bold, italic, underlined, monospace, serif, smallcaps;
int pointsize, font_id;
const char *font_name;
res_it->BoundingBox(RIL_WORD, &left, &top, &right, &bottom);
font_name = res_it->WordFontAttributes(&bold, &italic, &underlined,
&monospace, &serif, &smallcaps,
&pointsize, &font_id);
hocr_str.add_str_int(" title='bbox ", left);
hocr_str.add_str_int(" ", top);
hocr_str.add_str_int(" ", right);
hocr_str.add_str_int(" ", bottom);
hocr_str.add_str_int("; x_wconf ", res_it->Confidence(RIL_WORD));
if (font_info) {
if (font_name) {
hocr_str += "; x_font ";
hocr_str += HOcrEscape(font_name);
}
hocr_str.add_str_int("; x_fsize ", pointsize);
}
hocr_str += "'";
const char* lang = res_it->WordRecognitionLanguage();
if (lang && (!paragraph_lang || strcmp(lang, paragraph_lang))) {
hocr_str += " lang='";
hocr_str += lang;
hocr_str += "'";
}
switch (res_it->WordDirection()) {
// Only emit direction if different from current paragraph direction
case DIR_LEFT_TO_RIGHT:
if (!para_is_ltr) hocr_str += " dir='ltr'";
break;
case DIR_RIGHT_TO_LEFT:
if (para_is_ltr) hocr_str += " dir='rtl'";
break;
case DIR_MIX:
case DIR_NEUTRAL:
default: // Do nothing.
break;
}
hocr_str += ">";
bool last_word_in_line = res_it->IsAtFinalElement(RIL_TEXTLINE, RIL_WORD);
bool last_word_in_para = res_it->IsAtFinalElement(RIL_PARA, RIL_WORD);
bool last_word_in_block = res_it->IsAtFinalElement(RIL_BLOCK, RIL_WORD);
if (bold) hocr_str += "<strong>";
if (italic) hocr_str += "<em>";
do {
const std::unique_ptr<const char[]> grapheme(
res_it->GetUTF8Text(RIL_SYMBOL));
if (grapheme && grapheme[0] != 0) {
hocr_str += HOcrEscape(grapheme.get());
}
res_it->Next(RIL_SYMBOL);
} while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_WORD));
if (italic) hocr_str += "</em>";
if (bold) hocr_str += "</strong>";
// If the lstm choice mode is required it is added here
if (tesseract_->lstm_choice_mode == 1 && confidencemap != nullptr) {
for (size_t i = 0; i < confidencemap->size(); i++) {
hocr_str += "\n <span class='ocrx_cinfo'";
AddIdTohOCR(&hocr_str, "timestep", page_id, wcnt, tcnt);
hocr_str += ">";
std::vector<std::pair<const char*, float>> timestep = (*confidencemap)[i];
for (std::pair<const char*, float> conf : timestep) {
hocr_str += "<span class='ocr_glyph'";
AddIdTohOCR(&hocr_str, "choice", page_id, wcnt, gcnt);
hocr_str.add_str_int(" title='x_confs ", int(conf.second * 100));
hocr_str += "'";
hocr_str += ">";
hocr_str += conf.first;
hocr_str += "</span>";
gcnt++;
}
hocr_str += "</span>";
tcnt++;
}
} else if (tesseract_->lstm_choice_mode == 2 && confidencemap != nullptr) {
for (size_t i = 0; i < confidencemap->size(); i++) {
std::vector<std::pair<const char*, float>> timestep = (*confidencemap)[i];
if (timestep.size() > 0) {
hocr_str += "\n <span class='ocrx_cinfo'";
AddIdTohOCR(&hocr_str, "lstm_choices", page_id, wcnt, tcnt);
hocr_str += " chosen='";
hocr_str += timestep[0].first;
hocr_str += "'>";
for (size_t j = 1; j < timestep.size(); j++) {
hocr_str += "<span class='ocr_glyph'";
AddIdTohOCR(&hocr_str, "choice", page_id, wcnt, gcnt);
hocr_str.add_str_int(" title='x_confs ", int(timestep[j].second * 100));
hocr_str += "'";
hocr_str += ">";
hocr_str += timestep[j].first;
hocr_str += "</span>";
gcnt++;
}
hocr_str += "</span>";
tcnt++;
}
}
}
hocr_str += "</span>";
tcnt = 1;
gcnt = 1;
wcnt++;
// Close any ending block/paragraph/textline.
if (last_word_in_line) {
hocr_str += "\n </span>";
lcnt++;
}
if (last_word_in_para) {
hocr_str += "\n </p>\n";
pcnt++;
para_is_ltr = true; // back to default direction
}
if (last_word_in_block) {
hocr_str += " </div>\n";
bcnt++;
}
}
hocr_str += " </div>\n";

char *ret = new char[hocr_str.length() + 1];
strcpy(ret, hocr_str.string());
delete res_it;
return ret;
text->add_str_int("\t", left);
text->add_str_int("\t", top);
text->add_str_int("\t", right - left);
text->add_str_int("\t", bottom - top);
}

/**
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