/********************************************************************** * File: text2image.cpp * Description: Program to generate OCR training pages. Given a text file it * outputs an image with a given font and degradation. * * Note that since the results depend on the fonts available on * your system, running the code on a different machine, or * different OS, or even at a different time on the same machine, * may produce different fonts even if --font is given explicitly. * To see names of available fonts, use --list_available_fonts with * the appropriate --fonts_dir path. * Specifying --use_only_legacy_fonts will restrict the available * fonts to those listed in legacy_fonts.h * * Authors: Ranjith Unnikrishnan, Ray Smith * Created: Tue Nov 19 2013 * * (C) Copyright 2013, Google Inc. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * http://www.apache.org/licenses/LICENSE-2.0 * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * **********************************************************************/ #include #include #include #include #include #include #include #include #include "allheaders.h" // from leptonica #include "boxchar.h" #include "commandlineflags.h" #include "degradeimage.h" #include "errcode.h" #include "fileio.h" #include "helpers.h" #include "normstrngs.h" #include "stringrenderer.h" #include "tlog.h" #include "unicharset.h" #include "util.h" #ifdef USE_STD_NAMESPACE using std::make_pair; using std::map; using std::pair; #endif // A number with which to initialize the random number generator. const int kRandomSeed = 0x18273645; // The text input file. STRING_PARAM_FLAG(text, "", "File name of text input to process"); // The text output file. STRING_PARAM_FLAG(outputbase, "", "Basename for output image/box file"); // Degrade the rendered image to mimic scanner quality. BOOL_PARAM_FLAG(degrade_image, true, "Degrade rendered image with speckle noise, dilation/erosion " "and rotation"); // Degradation to apply to the image. INT_PARAM_FLAG(exposure, 0, "Exposure level in photocopier"); // Output image resolution. INT_PARAM_FLAG(resolution, 300, "Pixels per inch"); // Width of output image (in pixels). INT_PARAM_FLAG(xsize, 3600, "Width of output image"); // Max height of output image (in pixels). INT_PARAM_FLAG(ysize, 4800, "Height of output image"); // Margin around text (in pixels). INT_PARAM_FLAG(margin, 100, "Margin round edges of image"); // Size of text (in points). INT_PARAM_FLAG(ptsize, 12, "Size of printed text"); // Inter-character space (in ems). DOUBLE_PARAM_FLAG(char_spacing, 0, "Inter-character space in ems"); // Sets the probability (value in [0, 1]) of starting to render a word with an // underline. Words are assumed to be space-delimited. DOUBLE_PARAM_FLAG(underline_start_prob, 0, "Fraction of words to underline (value in [0,1])"); // Set the probability (value in [0, 1]) of continuing a started underline to // the next word. DOUBLE_PARAM_FLAG(underline_continuation_prob, 0, "Fraction of words to underline (value in [0,1])"); // Inter-line space (in pixels). INT_PARAM_FLAG(leading, 12, "Inter-line space (in pixels)"); // Layout and glyph orientation on rendering. STRING_PARAM_FLAG(writing_mode, "horizontal", "Specify one of the following writing" " modes.\n" "'horizontal' : Render regular horizontal text. (default)\n" "'vertical' : Render vertical text. Glyph orientation is" " selected by Pango.\n" "'vertical-upright' : Render vertical text. Glyph " " orientation is set to be upright."); INT_PARAM_FLAG(box_padding, 0, "Padding around produced bounding boxes"); BOOL_PARAM_FLAG(strip_unrenderable_words, true, "Remove unrenderable words from source text"); // Font name. STRING_PARAM_FLAG(font, "Arial", "Font description name to use"); BOOL_PARAM_FLAG(ligatures, false, "Rebuild and render ligatures"); BOOL_PARAM_FLAG(find_fonts, false, "Search for all fonts that can render the text"); BOOL_PARAM_FLAG(render_per_font, true, "If find_fonts==true, render each font to its own image. " "Image filenames are of the form output_name.font_name.tif"); DOUBLE_PARAM_FLAG(min_coverage, 1.0, "If find_fonts==true, the minimum coverage the font has of " "the characters in the text file to include it, between " "0 and 1."); BOOL_PARAM_FLAG(list_available_fonts, false, "List available fonts and quit."); BOOL_PARAM_FLAG(render_ngrams, false, "Put each space-separated entity from the" " input file into one bounding box. The ngrams in the input" " file will be randomly permuted before rendering (so that" " there is sufficient variety of characters on each line)."); BOOL_PARAM_FLAG(output_word_boxes, false, "Output word bounding boxes instead of character boxes. " "This is used for Cube training, and implied by " "--render_ngrams."); STRING_PARAM_FLAG(unicharset_file, "", "File with characters in the unicharset. If --render_ngrams" " is true and --unicharset_file is specified, ngrams with" " characters that are not in unicharset will be omitted"); BOOL_PARAM_FLAG(bidirectional_rotation, false, "Rotate the generated characters both ways."); BOOL_PARAM_FLAG(only_extract_font_properties, false, "Assumes that the input file contains a list of ngrams. Renders" " each ngram, extracts spacing properties and records them in" " output_base/[font_name].fontinfo file."); // Use these flags to output zero-padded, square individual character images BOOL_PARAM_FLAG(output_individual_glyph_images, false, "If true also outputs individual character images"); INT_PARAM_FLAG(glyph_resized_size, 0, "Each glyph is square with this side length in pixels"); INT_PARAM_FLAG(glyph_num_border_pixels_to_pad, 0, "Final_size=glyph_resized_size+2*glyph_num_border_pixels_to_pad"); namespace tesseract { struct SpacingProperties { SpacingProperties() : x_gap_before(0), x_gap_after(0) {} SpacingProperties(int b, int a) : x_gap_before(b), x_gap_after(a) {} // These values are obtained from FT_Glyph_Metrics struct // used by the FreeType font engine. int x_gap_before; // horizontal x bearing int x_gap_after; // horizontal advance - x_gap_before - width map kerned_x_gaps; }; static bool IsWhitespaceBox(const BoxChar* boxchar) { return (boxchar->box() == NULL || SpanUTF8Whitespace(boxchar->ch().c_str())); } static string StringReplace(const string& in, const string& oldsub, const string& newsub) { string out; int start_pos = 0; do { int pos = in.find(oldsub, start_pos); if (pos == string::npos) break; out.append(in.data() + start_pos, pos - start_pos); out.append(newsub.data(), newsub.length()); start_pos = pos + oldsub.length(); } while (true); out.append(in.data() + start_pos, in.length() - start_pos); return out; } // Assumes that each word (whitespace-separated entity) in text is a bigram. // Renders the bigrams and calls FontInfo::GetSpacingProperties() to // obtain spacing information. Produces the output .fontinfo file with a line // per unichar of the form: // unichar space_before space_after kerned1 kerned_space1 kerned2 ... // Fox example, if unichar "A" has spacing of 0 pixels before and -1 pixels // after, is kerned with "V" resulting in spacing of "AV" to be -7 and kerned // with "T", such that "AT" has spacing of -5, the entry/line for unichar "A" // in .fontinfo file will be: // A 0 -1 T -5 V -7 void ExtractFontProperties(const string &utf8_text, StringRenderer *render, const string &output_base) { map spacing_map; map::iterator spacing_map_it0; map::iterator spacing_map_it1; int x_bearing, x_advance; int len = utf8_text.length(); int offset = 0; const char* text = utf8_text.c_str(); while (offset < len) { offset += render->RenderToImage(text + offset, strlen(text + offset), NULL); const vector &boxes = render->GetBoxes(); // If the page break split a bigram, correct the offset so we try the bigram // on the next iteration. if (boxes.size() > 2 && !IsWhitespaceBox(boxes[boxes.size() - 1]) && IsWhitespaceBox(boxes[boxes.size() - 2])) { if (boxes.size() > 3) { tprintf("WARNING: Adjusting to bad page break after '%s%s'\n", boxes[boxes.size() - 4]->ch().c_str(), boxes[boxes.size() - 3]->ch().c_str()); } offset -= boxes[boxes.size() - 1]->ch().size(); } for (int b = 0; b < boxes.size(); b += 2) { while (b < boxes.size() && IsWhitespaceBox(boxes[b])) ++b; if (b + 1 >= boxes.size()) break; const string &ch0 = boxes[b]->ch(); // We encountered a ligature. This happens in at least two scenarios: // One is when the rendered bigram forms a grapheme cluster (eg. the // second character in the bigram is a combining vowel), in which case we // correctly output only one bounding box. // A second far less frequent case is when caused some fonts like 'DejaVu // Sans Ultra-Light' force Pango to render a ligatured character even if // the input consists of the separated characters. NOTE(ranjith): As per // behdad@ this is not currently controllable at the level of the Pango // API. // Safeguard against these cases here by just skipping the bigram. if (IsWhitespaceBox(boxes[b+1])) { tprintf("WARNING: Found unexpected ligature: %s\n", ch0.c_str()); continue; } int xgap = (boxes[b+1]->box()->x - (boxes[b]->box()->x + boxes[b]->box()->w)); spacing_map_it0 = spacing_map.find(ch0); int ok_count = 0; if (spacing_map_it0 == spacing_map.end() && render->font().GetSpacingProperties(ch0, &x_bearing, &x_advance)) { spacing_map[ch0] = SpacingProperties( x_bearing, x_advance - x_bearing - boxes[b]->box()->w); spacing_map_it0 = spacing_map.find(ch0); ++ok_count; } const string &ch1 = boxes[b+1]->ch(); tlog(3, "%s%s\n", ch0.c_str(), ch1.c_str()); spacing_map_it1 = spacing_map.find(ch1); if (spacing_map_it1 == spacing_map.end() && render->font().GetSpacingProperties(ch1, &x_bearing, &x_advance)) { spacing_map[ch1] = SpacingProperties( x_bearing, x_advance - x_bearing - boxes[b+1]->box()->w); spacing_map_it1 = spacing_map.find(ch1); ++ok_count; } if (ok_count == 2 && xgap != (spacing_map_it0->second.x_gap_after + spacing_map_it1->second.x_gap_before)) { spacing_map_it0->second.kerned_x_gaps[ch1] = xgap; } } render->ClearBoxes(); } string output_string; const int kBufSize = 1024; char buf[kBufSize]; snprintf(buf, kBufSize, "%d\n", static_cast(spacing_map.size())); output_string.append(buf); map::const_iterator spacing_map_it; for (spacing_map_it = spacing_map.begin(); spacing_map_it != spacing_map.end(); ++spacing_map_it) { snprintf(buf, kBufSize, "%s %d %d %d", spacing_map_it->first.c_str(), spacing_map_it->second.x_gap_before, spacing_map_it->second.x_gap_after, static_cast(spacing_map_it->second.kerned_x_gaps.size())); output_string.append(buf); map::const_iterator kern_it; for (kern_it = spacing_map_it->second.kerned_x_gaps.begin(); kern_it != spacing_map_it->second.kerned_x_gaps.end(); ++kern_it) { snprintf(buf, kBufSize, " %s %d", kern_it->first.c_str(), kern_it->second); output_string.append(buf); } output_string.append("\n"); } File::WriteStringToFileOrDie(output_string, output_base + ".fontinfo"); } bool MakeIndividualGlyphs(Pix* pix, const vector& vbox, const int input_tiff_page) { // If checks fail, return false without exiting text2image if (!pix) { tprintf("ERROR: MakeIndividualGlyphs(): Input Pix* is NULL\n"); return false; } else if (FLAGS_glyph_resized_size <= 0) { tprintf("ERROR: --glyph_resized_size must be positive\n"); return false; } else if (FLAGS_glyph_num_border_pixels_to_pad < 0) { tprintf("ERROR: --glyph_num_border_pixels_to_pad must be 0 or positive\n"); return false; } const int n_boxes = vbox.size(); int n_boxes_saved = 0; int current_tiff_page = 0; int y_previous = 0; static int glyph_count = 0; for (int i = 0; i < n_boxes; i++) { // Get one bounding box Box* b = vbox[i]->mutable_box(); if (!b) continue; const int x = b->x; const int y = b->y; const int w = b->w; const int h = b->h; // Check present tiff page (for multipage tiff) if (y < y_previous-pixGetHeight(pix)/10) { tprintf("ERROR: Wrap-around encountered, at i=%d\n", i); current_tiff_page++; } if (current_tiff_page < input_tiff_page) continue; else if (current_tiff_page > input_tiff_page) break; // Check box validity if (x < 0 || y < 0 || (x+w-1) >= pixGetWidth(pix) || (y+h-1) >= pixGetHeight(pix)) { tprintf("ERROR: MakeIndividualGlyphs(): Index out of range, at i=%d" " (x=%d, y=%d, w=%d, h=%d\n)", i, x, y, w, h); continue; } else if (w < FLAGS_glyph_num_border_pixels_to_pad && h < FLAGS_glyph_num_border_pixels_to_pad) { tprintf("ERROR: Input image too small to be a character, at i=%d\n", i); continue; } // Crop the boxed character Pix* pix_glyph = pixClipRectangle(pix, b, NULL); if (!pix_glyph) { tprintf("ERROR: MakeIndividualGlyphs(): Failed to clip, at i=%d\n", i); continue; } // Resize to square Pix* pix_glyph_sq = pixScaleToSize(pix_glyph, FLAGS_glyph_resized_size, FLAGS_glyph_resized_size); if (!pix_glyph_sq) { tprintf("ERROR: MakeIndividualGlyphs(): Failed to resize, at i=%d\n", i); continue; } // Zero-pad Pix* pix_glyph_sq_pad = pixAddBorder(pix_glyph_sq, FLAGS_glyph_num_border_pixels_to_pad, 0); if (!pix_glyph_sq_pad) { tprintf("ERROR: MakeIndividualGlyphs(): Failed to zero-pad, at i=%d\n", i); continue; } // Write out Pix* pix_glyph_sq_pad_8 = pixConvertTo8(pix_glyph_sq_pad, false); char filename[1024]; snprintf(filename, 1024, "%s_%d.jpg", FLAGS_outputbase.c_str(), glyph_count++); if (pixWriteJpeg(filename, pix_glyph_sq_pad_8, 100, 0)) { tprintf("ERROR: MakeIndividualGlyphs(): Failed to write JPEG to %s," " at i=%d\n", filename, i); continue; } pixDestroy(&pix_glyph); pixDestroy(&pix_glyph_sq); pixDestroy(&pix_glyph_sq_pad); pixDestroy(&pix_glyph_sq_pad_8); n_boxes_saved++; y_previous = y; } if (n_boxes_saved == 0) { return false; } else { tprintf("Total number of characters saved = %d\n", n_boxes_saved); return true; } } } // namespace tesseract using tesseract::DegradeImage; using tesseract::ExtractFontProperties; using tesseract::File; using tesseract::FontUtils; using tesseract::SpanUTF8NotWhitespace; using tesseract::SpanUTF8Whitespace; using tesseract::StringRenderer; int main(int argc, char** argv) { tesseract::ParseCommandLineFlags(argv[0], &argc, &argv, true); if (FLAGS_list_available_fonts) { const vector& all_fonts = FontUtils::ListAvailableFonts(); for (int i = 0; i < all_fonts.size(); ++i) { tprintf("%3d: %s\n", i, all_fonts[i].c_str()); ASSERT_HOST_MSG(FontUtils::IsAvailableFont(all_fonts[i].c_str()), "Font %s is unrecognized.\n", all_fonts[i].c_str()); } return EXIT_SUCCESS; } // Check validity of input flags. ASSERT_HOST_MSG(!FLAGS_text.empty(), "Text file missing!\n"); ASSERT_HOST_MSG(!FLAGS_outputbase.empty(), "Output file missing!\n"); ASSERT_HOST_MSG(FLAGS_render_ngrams || FLAGS_unicharset_file.empty(), "Use --unicharset_file only if --render_ngrams is set.\n"); ASSERT_HOST_MSG(FLAGS_find_fonts || FontUtils::IsAvailableFont(FLAGS_font.c_str()), "Could not find font named %s\n", FLAGS_font.c_str()); if (FLAGS_render_ngrams) FLAGS_output_word_boxes = true; char font_desc_name[1024]; snprintf(font_desc_name, 1024, "%s %d", FLAGS_font.c_str(), static_cast(FLAGS_ptsize)); StringRenderer render(font_desc_name, FLAGS_xsize, FLAGS_ysize); render.set_add_ligatures(FLAGS_ligatures); render.set_leading(FLAGS_leading); render.set_resolution(FLAGS_resolution); render.set_char_spacing(FLAGS_char_spacing * FLAGS_ptsize); render.set_h_margin(FLAGS_margin); render.set_v_margin(FLAGS_margin); render.set_output_word_boxes(FLAGS_output_word_boxes); render.set_box_padding(FLAGS_box_padding); render.set_strip_unrenderable_words(FLAGS_strip_unrenderable_words); render.set_underline_start_prob(FLAGS_underline_start_prob); render.set_underline_continuation_prob(FLAGS_underline_continuation_prob); // Set text rendering orientation and their forms. if (FLAGS_writing_mode == "horizontal") { // Render regular horizontal text (default). render.set_vertical_text(false); render.set_gravity_hint_strong(false); render.set_render_fullwidth_latin(false); } else if (FLAGS_writing_mode == "vertical") { // Render vertical text. Glyph orientation is selected by Pango. render.set_vertical_text(true); render.set_gravity_hint_strong(false); render.set_render_fullwidth_latin(false); } else if (FLAGS_writing_mode == "vertical-upright") { // Render vertical text. Glyph orientation is set to be upright. // Also Basic Latin characters are converted to their fullwidth forms // on rendering, since fullwidth Latin characters are well designed to fit // vertical text lines, while .box files store halfwidth Basic Latin // unichars. render.set_vertical_text(true); render.set_gravity_hint_strong(true); render.set_render_fullwidth_latin(true); } else { TLOG_FATAL("Invalid writing mode : %s\n", FLAGS_writing_mode.c_str()); } string src_utf8; // This c_str is NOT redundant! File::ReadFileToStringOrDie(FLAGS_text.c_str(), &src_utf8); // Remove the unicode mark if present. if (strncmp(src_utf8.c_str(), "\xef\xbb\xbf", 3) == 0) { src_utf8.erase(0, 3); } tlog(1, "Render string of size %d\n", src_utf8.length()); if (FLAGS_render_ngrams || FLAGS_only_extract_font_properties) { // Try to preserve behavior of old text2image by expanding inter-word // spaces by a factor of 4. const string kSeparator = FLAGS_render_ngrams ? " " : " "; // Also restrict the number of charactes per line to try and avoid // line-breaking in the middle of words like "-A", "R$" etc. which are // otherwise allowed by the standard unicode line-breaking rules. const int kCharsPerLine = (FLAGS_ptsize > 20) ? 50 : 100; string rand_utf8; UNICHARSET unicharset; if (FLAGS_render_ngrams && !FLAGS_unicharset_file.empty() && !unicharset.load_from_file(FLAGS_unicharset_file.c_str())) { TLOG_FATAL("Failed to load unicharset from file %s\n", FLAGS_unicharset_file.c_str()); } // If we are rendering ngrams that will be OCRed later, shuffle them so that // tesseract does not have difficulties finding correct baseline, word // spaces, etc. const char *str8 = src_utf8.c_str(); int len = src_utf8.length(); int step; vector > offsets; int offset = SpanUTF8Whitespace(str8); while (offset < len) { step = SpanUTF8NotWhitespace(str8 + offset); offsets.push_back(make_pair(offset, step)); offset += step; offset += SpanUTF8Whitespace(str8 + offset); } if (FLAGS_render_ngrams) std::random_shuffle(offsets.begin(), offsets.end()); for (int i = 0, line = 1; i < offsets.size(); ++i) { const char *curr_pos = str8 + offsets[i].first; int ngram_len = offsets[i].second; // Skip words that contain characters not in found in unicharset. if (!FLAGS_unicharset_file.empty() && !unicharset.encodable_string(curr_pos, NULL)) { continue; } rand_utf8.append(curr_pos, ngram_len); if (rand_utf8.length() > line * kCharsPerLine) { rand_utf8.append(" \n"); ++line; if (line & 0x1) rand_utf8.append(kSeparator); } else { rand_utf8.append(kSeparator); } } tlog(1, "Rendered ngram string of size %d\n", rand_utf8.length()); src_utf8.swap(rand_utf8); } if (FLAGS_only_extract_font_properties) { tprintf("Extracting font properties only\n"); ExtractFontProperties(src_utf8, &render, FLAGS_outputbase.c_str()); tprintf("Done!\n"); return 0; } int im = 0; vector page_rotation; const char* to_render_utf8 = src_utf8.c_str(); tesseract::TRand randomizer; randomizer.set_seed(kRandomSeed); vector font_names; // We use a two pass mechanism to rotate images in both direction. // The first pass(0) will rotate the images in random directions and // the second pass(1) will mirror those rotations. int num_pass = FLAGS_bidirectional_rotation ? 2 : 1; for (int pass = 0; pass < num_pass; ++pass) { int page_num = 0; string font_used; for (int offset = 0; offset < strlen(to_render_utf8); ++im, ++page_num) { tlog(1, "Starting page %d\n", im); Pix* pix = NULL; if (FLAGS_find_fonts) { offset += render.RenderAllFontsToImage(FLAGS_min_coverage, to_render_utf8 + offset, strlen(to_render_utf8 + offset), &font_used, &pix); } else { offset += render.RenderToImage(to_render_utf8 + offset, strlen(to_render_utf8 + offset), &pix); } if (pix != NULL) { float rotation = 0; if (pass == 1) { // Pass 2, do mirror rotation. rotation = -1 * page_rotation[page_num]; } if (FLAGS_degrade_image) { pix = DegradeImage(pix, FLAGS_exposure, &randomizer, &rotation); } render.RotatePageBoxes(rotation); if (pass == 0) { // Pass 1, rotate randomly and store the rotation.. page_rotation.push_back(rotation); } Pix* gray_pix = pixConvertTo8(pix, false); pixDestroy(&pix); Pix* binary = pixThresholdToBinary(gray_pix, 128); pixDestroy(&gray_pix); char tiff_name[1024]; if (FLAGS_find_fonts) { if (FLAGS_render_per_font) { string fontname_for_file = tesseract::StringReplace( font_used, " ", "_"); snprintf(tiff_name, 1024, "%s.%s.tif", FLAGS_outputbase.c_str(), fontname_for_file.c_str()); pixWriteTiff(tiff_name, binary, IFF_TIFF_G4, "w"); tprintf("Rendered page %d to file %s\n", im, tiff_name); } else { font_names.push_back(font_used); } } else { snprintf(tiff_name, 1024, "%s.tif", FLAGS_outputbase.c_str()); pixWriteTiff(tiff_name, binary, IFF_TIFF_G4, im == 0 ? "w" : "a"); tprintf("Rendered page %d to file %s\n", im, tiff_name); } // Make individual glyphs if (FLAGS_output_individual_glyph_images) { if (!MakeIndividualGlyphs(binary, render.GetBoxes(), im)) { tprintf("ERROR: Individual glyphs not saved\n"); } } pixDestroy(&binary); } if (FLAGS_find_fonts && offset != 0) { // We just want a list of names, or some sample images so we don't need // to render more than the first page of the text. break; } } } if (!FLAGS_find_fonts) { string box_name = FLAGS_outputbase.c_str(); box_name += ".box"; render.WriteAllBoxes(box_name); } else if (!FLAGS_render_per_font && !font_names.empty()) { string filename = FLAGS_outputbase + ".fontlist.txt"; FILE* fp = fopen(filename.c_str(), "wb"); if (fp == NULL) { tprintf("Failed to create output font list %s\n", filename.c_str()); } else { for (int i = 0; i < font_names.size(); ++i) { fprintf(fp, "%s\n", font_names[i].c_str()); } fclose(fp); } } return 0; }