tesseract  3.03
/usr/local/google/home/jbreiden/tesseract-ocr-read-only/textord/strokewidth.cpp
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00001 
00002 // File:        strokewidth.cpp
00003 // Description: Subclass of BBGrid to find uniformity of strokewidth.
00004 // Author:      Ray Smith
00005 // Created:     Mon Mar 31 16:17:01 PST 2008
00006 //
00007 // (C) Copyright 2008, Google Inc.
00008 // Licensed under the Apache License, Version 2.0 (the "License");
00009 // you may not use this file except in compliance with the License.
00010 // You may obtain a copy of the License at
00011 // http://www.apache.org/licenses/LICENSE-2.0
00012 // Unless required by applicable law or agreed to in writing, software
00013 // distributed under the License is distributed on an "AS IS" BASIS,
00014 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00015 // See the License for the specific language governing permissions and
00016 // limitations under the License.
00017 //
00019 
00020 #ifdef _MSC_VER
00021 #pragma warning(disable:4244)  // Conversion warnings
00022 #endif
00023 
00024 #ifdef HAVE_CONFIG_H
00025 #include "config_auto.h"
00026 #endif
00027 
00028 #include "strokewidth.h"
00029 
00030 #include <math.h>
00031 
00032 #include "blobbox.h"
00033 #include "colpartition.h"
00034 #include "colpartitiongrid.h"
00035 #include "imagefind.h"
00036 #include "linlsq.h"
00037 #include "statistc.h"
00038 #include "tabfind.h"
00039 #include "textlineprojection.h"
00040 #include "tordmain.h"  // For SetBlobStrokeWidth.
00041 
00042 namespace tesseract {
00043 
00044 INT_VAR(textord_tabfind_show_strokewidths, 0, "Show stroke widths");
00045 BOOL_VAR(textord_tabfind_only_strokewidths, false, "Only run stroke widths");
00046 BOOL_VAR(textord_tabfind_vertical_text, true, "Enable vertical detection");
00047 BOOL_VAR(textord_tabfind_force_vertical_text, false,
00048          "Force using vertical text page mode");
00049 BOOL_VAR(textord_tabfind_vertical_horizontal_mix, true,
00050          "find horizontal lines such as headers in vertical page mode");
00051 double_VAR(textord_tabfind_vertical_text_ratio, 0.5,
00052            "Fraction of textlines deemed vertical to use vertical page mode");
00053 
00055 const double kStrokeWidthFractionTolerance = 0.125;
00060 const double kStrokeWidthTolerance = 1.5;
00061 // Same but for CJK we are a bit more generous.
00062 const double kStrokeWidthFractionCJK = 0.25;
00063 const double kStrokeWidthCJK = 2.0;
00064 // Radius in grid cells of search for broken CJK. Doesn't need to be very
00065 // large as the grid size should be about the size of a character anyway.
00066 const int kCJKRadius = 2;
00067 // Max distance fraction of size to join close but broken CJK characters.
00068 const double kCJKBrokenDistanceFraction = 0.25;
00069 // Max number of components in a broken CJK character.
00070 const int kCJKMaxComponents = 8;
00071 // Max aspect ratio of CJK broken characters when put back together.
00072 const double kCJKAspectRatio = 1.25;
00073 // Max increase in aspect ratio of CJK broken characters when merged.
00074 const double kCJKAspectRatioIncrease = 1.0625;
00075 // Max multiple of the grid size that will be used in computing median CJKsize.
00076 const int kMaxCJKSizeRatio = 5;
00077 // Min fraction of blobs broken CJK to iterate and run it again.
00078 const double kBrokenCJKIterationFraction = 0.125;
00079 // Multiple of gridsize as x-padding for a search box for diacritic base
00080 // characters.
00081 const double kDiacriticXPadRatio = 7.0;
00082 // Multiple of gridsize as y-padding for a search box for diacritic base
00083 // characters.
00084 const double kDiacriticYPadRatio = 1.75;
00085 // Min multiple of diacritic height that a neighbour must be to be a
00086 // convincing base character.
00087 const double kMinDiacriticSizeRatio = 1.0625;
00088 // Max multiple of a textline's median height as a threshold for the sum of
00089 // a diacritic's farthest x and y distances (gap + size).
00090 const double kMaxDiacriticDistanceRatio = 1.25;
00091 // Max x-gap between a diacritic and its base char as a fraction of the height
00092 // of the base char (allowing other blobs to fill the gap.)
00093 const double kMaxDiacriticGapToBaseCharHeight = 1.0;
00094 // Radius of a search for diacritics in grid units.
00095 const int kSearchRadius = 2;
00096 // Ratio between longest side of a line and longest side of a character.
00097 // (neighbor_min > blob_min * kLineTrapShortest &&
00098 //  neighbor_max < blob_max / kLineTrapLongest)
00099 // => neighbor is a grapheme and blob is a line.
00100 const int kLineTrapLongest = 4;
00101 // Ratio between shortest side of a line and shortest side of a character.
00102 const int kLineTrapShortest = 2;
00103 // Max aspect ratio of the total box before CountNeighbourGaps
00104 // decides immediately based on the aspect ratio.
00105 const int kMostlyOneDirRatio = 3;
00106 // Aspect ratio for a blob to be considered as line residue.
00107 const double kLineResidueAspectRatio = 8.0;
00108 // Padding ratio for line residue search box.
00109 const int kLineResiduePadRatio = 3;
00110 // Min multiple of neighbour size for a line residue to be genuine.
00111 const double kLineResidueSizeRatio = 1.75;
00112 // Aspect ratio filter for OSD.
00113 const float kSizeRatioToReject = 2.0;
00114 // Max number of normal blobs a large blob may overlap before it is rejected
00115 // and determined to be image
00116 const int kMaxLargeOverlaps = 3;
00117 // Expansion factor for search box for good neighbours.
00118 const double kNeighbourSearchFactor = 2.5;
00119 
00120 StrokeWidth::StrokeWidth(int gridsize,
00121                          const ICOORD& bleft, const ICOORD& tright)
00122   : BlobGrid(gridsize, bleft, tright), nontext_map_(NULL), projection_(NULL),
00123     denorm_(NULL), grid_box_(bleft, tright), rerotation_(1.0f, 0.0f) {
00124   leaders_win_ = NULL;
00125   widths_win_ = NULL;
00126   initial_widths_win_ = NULL;
00127   chains_win_ = NULL;
00128   diacritics_win_ = NULL;
00129   textlines_win_ = NULL;
00130   smoothed_win_ = NULL;
00131 }
00132 
00133 StrokeWidth::~StrokeWidth() {
00134   if (widths_win_ != NULL) {
00135     #ifndef GRAPHICS_DISABLED
00136     delete widths_win_->AwaitEvent(SVET_DESTROY);
00137     #endif  // GRAPHICS_DISABLED
00138     if (textord_tabfind_only_strokewidths)
00139       exit(0);
00140     delete widths_win_;
00141   }
00142   delete leaders_win_;
00143   delete initial_widths_win_;
00144   delete chains_win_;
00145   delete textlines_win_;
00146   delete smoothed_win_;
00147   delete diacritics_win_;
00148 }
00149 
00150 // Sets the neighbours member of the medium-sized blobs in the block.
00151 // Searches on 4 sides of each blob for similar-sized, similar-strokewidth
00152 // blobs and sets pointers to the good neighbours.
00153 void StrokeWidth::SetNeighboursOnMediumBlobs(TO_BLOCK* block) {
00154   // Run a preliminary strokewidth neighbour detection on the medium blobs.
00155   InsertBlobList(&block->blobs);
00156   BLOBNBOX_IT blob_it(&block->blobs);
00157   for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
00158     SetNeighbours(false, false, blob_it.data());
00159   }
00160   Clear();
00161 }
00162 
00163 // Sets the neighbour/textline writing direction members of the medium
00164 // and large blobs with optional repair of broken CJK characters first.
00165 // Repair of broken CJK is needed here because broken CJK characters
00166 // can fool the textline direction detection algorithm.
00167 void StrokeWidth::FindTextlineDirectionAndFixBrokenCJK(bool cjk_merge,
00168                                                        TO_BLOCK* input_block) {
00169   // Setup the grid with the remaining (non-noise) blobs.
00170   InsertBlobs(input_block);
00171   // Repair broken CJK characters if needed.
00172   while (cjk_merge && FixBrokenCJK(input_block));
00173   // Grade blobs by inspection of neighbours.
00174   FindTextlineFlowDirection(false);
00175   // Clear the grid ready for rotation or leader finding.
00176   Clear();
00177 }
00178 
00179 // Helper to collect and count horizontal and vertical blobs from a list.
00180 static void CollectHorizVertBlobs(BLOBNBOX_LIST* input_blobs,
00181                                   int* num_vertical_blobs,
00182                                   int* num_horizontal_blobs,
00183                                   BLOBNBOX_CLIST* vertical_blobs,
00184                                   BLOBNBOX_CLIST* horizontal_blobs,
00185                                   BLOBNBOX_CLIST* nondescript_blobs) {
00186   BLOBNBOX_C_IT v_it(vertical_blobs);
00187   BLOBNBOX_C_IT h_it(horizontal_blobs);
00188   BLOBNBOX_C_IT n_it(nondescript_blobs);
00189   BLOBNBOX_IT blob_it(input_blobs);
00190   for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
00191     BLOBNBOX* blob = blob_it.data();
00192     const TBOX& box = blob->bounding_box();
00193     float y_x = static_cast<float>(box.height()) / box.width();
00194     float x_y = 1.0f / y_x;
00195     // Select a >= 1.0 ratio
00196     float ratio = x_y > y_x ? x_y : y_x;
00197     // If the aspect ratio is small and we want them for osd, save the blob.
00198     bool ok_blob = ratio <= kSizeRatioToReject;
00199     if (blob->UniquelyVertical()) {
00200       ++*num_vertical_blobs;
00201       if (ok_blob) v_it.add_after_then_move(blob);
00202     } else if (blob->UniquelyHorizontal()) {
00203       ++*num_horizontal_blobs;
00204       if (ok_blob) h_it.add_after_then_move(blob);
00205     } else if (ok_blob) {
00206       n_it.add_after_then_move(blob);
00207     }
00208   }
00209 }
00210 
00211 
00212 // Types all the blobs as vertical or horizontal text or unknown and
00213 // returns true if the majority are vertical.
00214 // If the blobs are rotated, it is necessary to call CorrectForRotation
00215 // after rotating everything, otherwise the work done here will be enough.
00216 // If osd_blobs is not null, a list of blobs from the dominant textline
00217 // direction are returned for use in orientation and script detection.
00218 bool StrokeWidth::TestVerticalTextDirection(TO_BLOCK* block,
00219                                             BLOBNBOX_CLIST* osd_blobs) {
00220   if (textord_tabfind_force_vertical_text) return true;
00221   if (!textord_tabfind_vertical_text) return false;
00222 
00223   int vertical_boxes = 0;
00224   int horizontal_boxes = 0;
00225   // Count vertical normal and large blobs.
00226   BLOBNBOX_CLIST vertical_blobs;
00227   BLOBNBOX_CLIST horizontal_blobs;
00228   BLOBNBOX_CLIST nondescript_blobs;
00229   CollectHorizVertBlobs(&block->blobs, &vertical_boxes, &horizontal_boxes,
00230                         &vertical_blobs, &horizontal_blobs, &nondescript_blobs);
00231   CollectHorizVertBlobs(&block->large_blobs, &vertical_boxes, &horizontal_boxes,
00232                         &vertical_blobs, &horizontal_blobs, &nondescript_blobs);
00233   if (textord_debug_tabfind)
00234     tprintf("TextDir hbox=%d vs vbox=%d, %dH, %dV, %dN osd blobs\n",
00235             horizontal_boxes, vertical_boxes,
00236             horizontal_blobs.length(), vertical_blobs.length(),
00237             nondescript_blobs.length());
00238   if (osd_blobs != NULL && vertical_boxes == 0 && horizontal_boxes == 0) {
00239     // Only nondescript blobs available, so return those.
00240     BLOBNBOX_C_IT osd_it(osd_blobs);
00241     osd_it.add_list_after(&nondescript_blobs);
00242     return false;
00243   }
00244   int min_vert_boxes = static_cast<int>((vertical_boxes + horizontal_boxes) *
00245                                         textord_tabfind_vertical_text_ratio);
00246   if (vertical_boxes >= min_vert_boxes) {
00247     if (osd_blobs != NULL) {
00248       BLOBNBOX_C_IT osd_it(osd_blobs);
00249       osd_it.add_list_after(&vertical_blobs);
00250     }
00251     return true;
00252   } else {
00253     if (osd_blobs != NULL) {
00254       BLOBNBOX_C_IT osd_it(osd_blobs);
00255       osd_it.add_list_after(&horizontal_blobs);
00256     }
00257     return false;
00258   }
00259 }
00260 
00261 // Corrects the data structures for the given rotation.
00262 void StrokeWidth::CorrectForRotation(const FCOORD& rotation,
00263                                      ColPartitionGrid* part_grid) {
00264   Init(part_grid->gridsize(), part_grid->bleft(), part_grid->tright());
00265   grid_box_ = TBOX(bleft(), tright());
00266   rerotation_.set_x(rotation.x());
00267   rerotation_.set_y(-rotation.y());
00268 }
00269 
00270 // Finds leader partitions and inserts them into the given part_grid.
00271 void StrokeWidth::FindLeaderPartitions(TO_BLOCK* block,
00272                                        ColPartitionGrid* part_grid) {
00273   Clear();
00274   // Find and isolate leaders in the noise list.
00275   ColPartition_LIST leader_parts;
00276   FindLeadersAndMarkNoise(block, &leader_parts);
00277   // Setup the strokewidth grid with the block's remaining (non-noise) blobs.
00278   InsertBlobList(&block->blobs);
00279   // Mark blobs that have leader neighbours.
00280   for (ColPartition_IT it(&leader_parts); !it.empty(); it.forward()) {
00281     ColPartition* part = it.extract();
00282     part->ClaimBoxes();
00283     MarkLeaderNeighbours(part, LR_LEFT);
00284     MarkLeaderNeighbours(part, LR_RIGHT);
00285     part_grid->InsertBBox(true, true, part);
00286   }
00287 }
00288 
00289 // Finds and marks noise those blobs that look like bits of vertical lines
00290 // that would otherwise screw up layout analysis.
00291 void StrokeWidth::RemoveLineResidue(ColPartition_LIST* big_part_list) {
00292   BlobGridSearch gsearch(this);
00293   BLOBNBOX* bbox;
00294   // For every vertical line-like bbox in the grid, search its neighbours
00295   // to find the tallest, and if the original box is taller by sufficient
00296   // margin, then call it line residue and delete it.
00297   gsearch.StartFullSearch();
00298   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00299     TBOX box = bbox->bounding_box();
00300     if (box.height() < box.width() * kLineResidueAspectRatio)
00301       continue;
00302     // Set up a rectangle search around the blob to find the size of its
00303     // neighbours.
00304     int padding = box.height() * kLineResiduePadRatio;
00305     TBOX search_box = box;
00306     search_box.pad(padding, padding);
00307     bool debug = AlignedBlob::WithinTestRegion(2, box.left(),
00308                                                box.bottom());
00309     // Find the largest object in the search box not equal to bbox.
00310     BlobGridSearch rsearch(this);
00311     int max_size = 0;
00312     BLOBNBOX* n;
00313     rsearch.StartRectSearch(search_box);
00314     while ((n = rsearch.NextRectSearch()) != NULL) {
00315       if (n == bbox) continue;
00316       TBOX nbox = n->bounding_box();
00317       if (nbox.height() > max_size) {
00318         max_size = nbox.height();
00319       }
00320     }
00321     if (debug) {
00322       tprintf("Max neighbour size=%d for candidate line box at:", max_size);
00323       box.print();
00324     }
00325     if (max_size * kLineResidueSizeRatio < box.height()) {
00326       #ifndef GRAPHICS_DISABLED
00327       if (leaders_win_ != NULL) {
00328         // We are debugging, so display deleted in pink blobs in the same
00329         // window that we use to display leader detection.
00330         leaders_win_->Pen(ScrollView::PINK);
00331         leaders_win_->Rectangle(box.left(), box.bottom(),
00332                                 box.right(), box.top());
00333       }
00334       #endif  // GRAPHICS_DISABLED
00335       ColPartition::MakeBigPartition(bbox, big_part_list);
00336     }
00337   }
00338 }
00339 
00340 // Types all the blobs as vertical text or horizontal text or unknown and
00341 // puts them into initial ColPartitions in the supplied part_grid.
00342 // rerotation determines how to get back to the image coordinates from the
00343 // blob coordinates (since they may have been rotated for vertical text).
00344 // block is the single block for the whole page or rectangle to be OCRed.
00345 // nontext_pix (full-size), is a binary mask used to prevent merges across
00346 // photo/text boundaries. It is not kept beyond this function.
00347 // denorm provides a mapping back to the image from the current blob
00348 // coordinate space.
00349 // projection provides a measure of textline density over the image and
00350 // provides functions to assist with diacritic detection. It should be a
00351 // pointer to a new TextlineProjection, and will be setup here.
00352 // part_grid is the output grid of textline partitions.
00353 // Large blobs that cause overlap are put in separate partitions and added
00354 // to the big_parts list.
00355 void StrokeWidth::GradeBlobsIntoPartitions(const FCOORD& rerotation,
00356                                            TO_BLOCK* block,
00357                                            Pix* nontext_pix,
00358                                            const DENORM* denorm,
00359                                            bool cjk_script,
00360                                            TextlineProjection* projection,
00361                                            ColPartitionGrid* part_grid,
00362                                            ColPartition_LIST* big_parts) {
00363   nontext_map_ = nontext_pix;
00364   projection_ = projection;
00365   denorm_ = denorm;
00366   // Clear and re Insert to take advantage of the tab stops in the blobs.
00367   Clear();
00368   // Setup the strokewidth grid with the remaining non-noise, non-leader blobs.
00369   InsertBlobs(block);
00370 
00371   // Run FixBrokenCJK() again if the page is CJK.
00372   if (cjk_script) {
00373     FixBrokenCJK(block);
00374   }
00375   FindTextlineFlowDirection(true);
00376   projection_->ConstructProjection(block, rerotation, nontext_map_);
00377   if (textord_tabfind_show_strokewidths) {
00378     ScrollView* line_blobs_win = MakeWindow(0, 0, "Initial textline Blobs");
00379     projection_->PlotGradedBlobs(&block->blobs, line_blobs_win);
00380     projection_->PlotGradedBlobs(&block->small_blobs, line_blobs_win);
00381   }
00382   projection_->MoveNonTextlineBlobs(&block->blobs, &block->noise_blobs);
00383   projection_->MoveNonTextlineBlobs(&block->small_blobs, &block->noise_blobs);
00384   // Clear and re Insert to take advantage of the removed diacritics.
00385   Clear();
00386   InsertBlobs(block);
00387   FindInitialPartitions(rerotation, block, part_grid, big_parts);
00388   nontext_map_ = NULL;
00389   projection_ = NULL;
00390   denorm_ = NULL;
00391 }
00392 
00393 static void PrintBoxWidths(BLOBNBOX* neighbour) {
00394   TBOX nbox = neighbour->bounding_box();
00395   tprintf("Box (%d,%d)->(%d,%d): h-width=%.1f, v-width=%.1f p-width=%1.f\n",
00396           nbox.left(), nbox.bottom(), nbox.right(), nbox.top(),
00397           neighbour->horz_stroke_width(), neighbour->vert_stroke_width(),
00398           2.0 * neighbour->cblob()->area()/neighbour->cblob()->perimeter());
00399 }
00400 
00402 void StrokeWidth::HandleClick(int x, int y) {
00403   BBGrid<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT>::HandleClick(x, y);
00404   // Run a radial search for blobs that overlap.
00405   BlobGridSearch radsearch(this);
00406   radsearch.StartRadSearch(x, y, 1);
00407   BLOBNBOX* neighbour;
00408   FCOORD click(static_cast<float>(x), static_cast<float>(y));
00409   while ((neighbour = radsearch.NextRadSearch()) != NULL) {
00410     TBOX nbox = neighbour->bounding_box();
00411     if (nbox.contains(click) && neighbour->cblob() != NULL) {
00412       PrintBoxWidths(neighbour);
00413       if (neighbour->neighbour(BND_LEFT) != NULL)
00414         PrintBoxWidths(neighbour->neighbour(BND_LEFT));
00415       if (neighbour->neighbour(BND_RIGHT) != NULL)
00416         PrintBoxWidths(neighbour->neighbour(BND_RIGHT));
00417       if (neighbour->neighbour(BND_ABOVE) != NULL)
00418         PrintBoxWidths(neighbour->neighbour(BND_ABOVE));
00419       if (neighbour->neighbour(BND_BELOW) != NULL)
00420         PrintBoxWidths(neighbour->neighbour(BND_BELOW));
00421       int gaps[BND_COUNT];
00422       neighbour->NeighbourGaps(gaps);
00423       tprintf("Left gap=%d, right=%d, above=%d, below=%d, horz=%d, vert=%d\n"
00424               "Good=    %d        %d        %d        %d\n",
00425               gaps[BND_LEFT], gaps[BND_RIGHT],
00426               gaps[BND_ABOVE], gaps[BND_BELOW],
00427               neighbour->horz_possible(),
00428               neighbour->vert_possible(),
00429               neighbour->good_stroke_neighbour(BND_LEFT),
00430               neighbour->good_stroke_neighbour(BND_RIGHT),
00431               neighbour->good_stroke_neighbour(BND_ABOVE),
00432               neighbour->good_stroke_neighbour(BND_BELOW));
00433       break;
00434     }
00435   }
00436 }
00437 
00438 // Detects and marks leader dots/dashes.
00439 //    Leaders are horizontal chains of small or noise blobs that look
00440 //    monospace according to ColPartition::MarkAsLeaderIfMonospaced().
00441 // Detected leaders become the only occupants of the block->small_blobs list.
00442 // Non-leader small blobs get moved to the blobs list.
00443 // Non-leader noise blobs remain singletons in the noise list.
00444 // All small and noise blobs in high density regions are marked BTFT_NONTEXT.
00445 // block is the single block for the whole page or rectangle to be OCRed.
00446 // leader_parts is the output.
00447 void StrokeWidth::FindLeadersAndMarkNoise(TO_BLOCK* block,
00448                                           ColPartition_LIST* leader_parts) {
00449   InsertBlobList(&block->small_blobs);
00450   InsertBlobList(&block->noise_blobs);
00451   BlobGridSearch gsearch(this);
00452   BLOBNBOX* bbox;
00453   // For every bbox in the grid, set its neighbours.
00454   gsearch.StartFullSearch();
00455   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00456     SetNeighbours(true, false, bbox);
00457   }
00458   ColPartition_IT part_it(leader_parts);
00459   gsearch.StartFullSearch();
00460   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00461     if (bbox->flow() == BTFT_NONE) {
00462       if (bbox->neighbour(BND_RIGHT) == NULL &&
00463           bbox->neighbour(BND_LEFT) == NULL)
00464         continue;
00465       // Put all the linked blobs into a ColPartition.
00466       ColPartition* part = new ColPartition(BRT_UNKNOWN, ICOORD(0, 1));
00467       BLOBNBOX* blob;
00468       for (blob = bbox; blob != NULL && blob->flow() == BTFT_NONE;
00469            blob = blob->neighbour(BND_RIGHT))
00470         part->AddBox(blob);
00471       for (blob = bbox->neighbour(BND_LEFT); blob != NULL &&
00472            blob->flow() == BTFT_NONE;
00473            blob = blob->neighbour(BND_LEFT))
00474         part->AddBox(blob);
00475       if (part->MarkAsLeaderIfMonospaced())
00476         part_it.add_after_then_move(part);
00477       else
00478         delete part;
00479     }
00480   }
00481   if (textord_tabfind_show_strokewidths) {
00482     leaders_win_ = DisplayGoodBlobs("LeaderNeighbours", 0, 0);
00483   }
00484   // Move any non-leaders from the small to the blobs list, as they are
00485   // most likely dashes or broken characters.
00486   BLOBNBOX_IT blob_it(&block->blobs);
00487   BLOBNBOX_IT small_it(&block->small_blobs);
00488   for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
00489     BLOBNBOX* blob = small_it.data();
00490     if (blob->flow() != BTFT_LEADER) {
00491       if (blob->flow() == BTFT_NEIGHBOURS)
00492         blob->set_flow(BTFT_NONE);
00493       blob->ClearNeighbours();
00494       blob_it.add_to_end(small_it.extract());
00495     }
00496   }
00497   // Move leaders from the noise list to the small list, leaving the small
00498   // list exclusively leaders, so they don't get processed further,
00499   // and the remaining small blobs all in the noise list.
00500   BLOBNBOX_IT noise_it(&block->noise_blobs);
00501   for (noise_it.mark_cycle_pt(); !noise_it.cycled_list(); noise_it.forward()) {
00502     BLOBNBOX* blob = noise_it.data();
00503     if (blob->flow() == BTFT_LEADER || blob->joined_to_prev()) {
00504       small_it.add_to_end(noise_it.extract());
00505     } else if (blob->flow() == BTFT_NEIGHBOURS) {
00506       blob->set_flow(BTFT_NONE);
00507       blob->ClearNeighbours();
00508     }
00509   }
00510   // Clear the grid as we don't want the small stuff hanging around in it.
00511   Clear();
00512 }
00513 
00516 void StrokeWidth::InsertBlobs(TO_BLOCK* block) {
00517   InsertBlobList(&block->blobs);
00518   InsertBlobList(&block->large_blobs);
00519 }
00520 
00521 // Checks the left or right side of the given leader partition and sets the
00522 // (opposite) leader_on_right or leader_on_left flags for blobs
00523 // that are next to the given side of the given leader partition.
00524 void StrokeWidth::MarkLeaderNeighbours(const ColPartition* part,
00525                                        LeftOrRight side) {
00526   const TBOX& part_box = part->bounding_box();
00527   BlobGridSearch blobsearch(this);
00528   // Search to the side of the leader for the nearest neighbour.
00529   BLOBNBOX* best_blob = NULL;
00530   int best_gap = 0;
00531   blobsearch.StartSideSearch(side == LR_LEFT ? part_box.left()
00532                                              : part_box.right(),
00533                              part_box.bottom(), part_box.top());
00534   BLOBNBOX* blob;
00535   while ((blob = blobsearch.NextSideSearch(side == LR_LEFT)) != NULL) {
00536     const TBOX& blob_box = blob->bounding_box();
00537     if (!blob_box.y_overlap(part_box))
00538       continue;
00539     int x_gap = blob_box.x_gap(part_box);
00540     if (x_gap > 2 * gridsize()) {
00541       break;
00542     } else if (best_blob == NULL || x_gap < best_gap) {
00543       best_blob = blob;
00544       best_gap = x_gap;
00545     }
00546   }
00547   if (best_blob != NULL) {
00548     if (side == LR_LEFT)
00549       best_blob->set_leader_on_right(true);
00550     else
00551       best_blob->set_leader_on_left(true);
00552     #ifndef GRAPHICS_DISABLED
00553     if (leaders_win_ != NULL) {
00554       leaders_win_->Pen(side == LR_LEFT ? ScrollView::RED : ScrollView::GREEN);
00555       const TBOX& blob_box = best_blob->bounding_box();
00556       leaders_win_->Rectangle(blob_box.left(), blob_box.bottom(),
00557                               blob_box.right(), blob_box.top());
00558     }
00559     #endif  // GRAPHICS_DISABLED
00560   }
00561 }
00562 
00563 // Helper to compute the UQ of the square-ish CJK charcters.
00564 static int UpperQuartileCJKSize(int gridsize, BLOBNBOX_LIST* blobs) {
00565   STATS sizes(0, gridsize * kMaxCJKSizeRatio);
00566   BLOBNBOX_IT it(blobs);
00567   for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
00568     BLOBNBOX* blob = it.data();
00569     int width = blob->bounding_box().width();
00570     int height = blob->bounding_box().height();
00571     if (width <= height * kCJKAspectRatio && height < width * kCJKAspectRatio)
00572       sizes.add(height, 1);
00573   }
00574   return static_cast<int>(sizes.ile(0.75f) + 0.5);
00575 }
00576 
00577 // Fix broken CJK characters, using the fake joined blobs mechanism.
00578 // Blobs are really merged, ie the master takes all the outlines and the
00579 // others are deleted.
00580 // Returns true if sufficient blobs are merged that it may be worth running
00581 // again, due to a better estimate of character size.
00582 bool StrokeWidth::FixBrokenCJK(TO_BLOCK* block) {
00583   BLOBNBOX_LIST* blobs = &block->blobs;
00584   int median_height = UpperQuartileCJKSize(gridsize(), blobs);
00585   int max_dist = static_cast<int>(median_height * kCJKBrokenDistanceFraction);
00586   int max_size = static_cast<int>(median_height * kCJKAspectRatio);
00587   int num_fixed = 0;
00588   BLOBNBOX_IT blob_it(blobs);
00589 
00590   for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
00591     BLOBNBOX* blob = blob_it.data();
00592     if (blob->cblob() == NULL || blob->cblob()->out_list()->empty())
00593       continue;
00594     TBOX bbox = blob->bounding_box();
00595     bool debug = AlignedBlob::WithinTestRegion(3, bbox.left(),
00596                                                bbox.bottom());
00597     if (debug) {
00598       tprintf("Checking for Broken CJK (max size=%d):", max_size);
00599       bbox.print();
00600     }
00601     // Generate a list of blobs that overlap or are near enough to merge.
00602     BLOBNBOX_CLIST overlapped_blobs;
00603     AccumulateOverlaps(blob, debug, max_size, max_dist,
00604                        &bbox, &overlapped_blobs);
00605     if (!overlapped_blobs.empty()) {
00606       // There are overlapping blobs, so qualify them as being satisfactory
00607       // before removing them from the grid and replacing them with the union.
00608       // The final box must be roughly square.
00609       if (bbox.width() > bbox.height() * kCJKAspectRatio ||
00610           bbox.height() > bbox.width() * kCJKAspectRatio) {
00611         if (debug) {
00612           tprintf("Bad final aspectratio:");
00613           bbox.print();
00614         }
00615         continue;
00616       }
00617       // There can't be too many blobs to merge.
00618       if (overlapped_blobs.length() >= kCJKMaxComponents) {
00619         if (debug)
00620           tprintf("Too many neighbours: %d\n", overlapped_blobs.length());
00621         continue;
00622       }
00623       // The strokewidths must match amongst the join candidates.
00624       BLOBNBOX_C_IT n_it(&overlapped_blobs);
00625       for (n_it.mark_cycle_pt(); !n_it.cycled_list(); n_it.forward()) {
00626         BLOBNBOX* neighbour = NULL;
00627         neighbour = n_it.data();
00628         if (!blob->MatchingStrokeWidth(*neighbour, kStrokeWidthFractionCJK,
00629                                        kStrokeWidthCJK))
00630           break;
00631       }
00632       if (!n_it.cycled_list()) {
00633         if (debug) {
00634           tprintf("Bad stroke widths:");
00635           PrintBoxWidths(blob);
00636         }
00637         continue;  // Not good enough.
00638       }
00639 
00640       // Merge all the candidates into blob.
00641       // We must remove blob from the grid and reinsert it after merging
00642       // to maintain the integrity of the grid.
00643       RemoveBBox(blob);
00644       // Everything else will be calculated later.
00645       for (n_it.mark_cycle_pt(); !n_it.cycled_list(); n_it.forward()) {
00646         BLOBNBOX* neighbour = n_it.data();
00647         RemoveBBox(neighbour);
00648         // Mark empty blob for deletion.
00649         neighbour->set_region_type(BRT_NOISE);
00650         blob->really_merge(neighbour);
00651         if (rerotation_.x() != 1.0f || rerotation_.y() != 0.0f) {
00652           blob->rotate_box(rerotation_);
00653         }
00654       }
00655       InsertBBox(true, true, blob);
00656       ++num_fixed;
00657       if (debug) {
00658         tprintf("Done! Final box:");
00659         bbox.print();
00660       }
00661     }
00662   }
00663   // Count remaining blobs.
00664   int num_remaining = 0;
00665   for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
00666     BLOBNBOX* blob = blob_it.data();
00667     if (blob->cblob() != NULL && !blob->cblob()->out_list()->empty()) {
00668       ++num_remaining;
00669     }
00670   }
00671   // Permanently delete all the marked blobs after first removing all
00672   // references in the neighbour members.
00673   block->DeleteUnownedNoise();
00674   return num_fixed > num_remaining * kBrokenCJKIterationFraction;
00675 }
00676 
00677 // Helper function to determine whether it is reasonable to merge the
00678 // bbox and the nbox for repairing broken CJK.
00679 // The distance apart must not exceed max_dist, the combined size must
00680 // not exceed max_size, and the aspect ratio must either improve or at
00681 // least not get worse by much.
00682 static bool AcceptableCJKMerge(const TBOX& bbox, const TBOX& nbox,
00683                                bool debug, int max_size, int max_dist,
00684                                int* x_gap, int* y_gap) {
00685   *x_gap = bbox.x_gap(nbox);
00686   *y_gap = bbox.y_gap(nbox);
00687   TBOX merged(nbox);
00688   merged += bbox;
00689   if (debug) {
00690     tprintf("gaps = %d, %d, merged_box:", *x_gap, *y_gap);
00691     merged.print();
00692   }
00693   if (*x_gap <= max_dist && *y_gap <= max_dist &&
00694       merged.width() <= max_size && merged.height() <= max_size) {
00695     // Close enough to call overlapping. Check aspect ratios.
00696     double old_ratio = static_cast<double>(bbox.width()) / bbox.height();
00697     if (old_ratio < 1.0) old_ratio = 1.0 / old_ratio;
00698     double new_ratio = static_cast<double>(merged.width()) / merged.height();
00699     if (new_ratio < 1.0) new_ratio = 1.0 / new_ratio;
00700     if (new_ratio <= old_ratio * kCJKAspectRatioIncrease)
00701       return true;
00702   }
00703   return false;
00704 }
00705 
00706 // Collect blobs that overlap or are within max_dist of the input bbox.
00707 // Return them in the list of blobs and expand the bbox to be the union
00708 // of all the boxes. not_this is excluded from the search, as are blobs
00709 // that cause the merged box to exceed max_size in either dimension.
00710 void StrokeWidth::AccumulateOverlaps(const BLOBNBOX* not_this, bool debug,
00711                                      int max_size, int max_dist,
00712                                      TBOX* bbox, BLOBNBOX_CLIST* blobs) {
00713   // While searching, nearests holds the nearest failed blob in each
00714   // direction. When we have a nearest in each of the 4 directions, then
00715   // the search is over, and at this point the final bbox must not overlap
00716   // any of the nearests.
00717   BLOBNBOX* nearests[BND_COUNT];
00718   for (int i = 0; i < BND_COUNT; ++i) {
00719     nearests[i] = NULL;
00720   }
00721   int x = (bbox->left() + bbox->right()) / 2;
00722   int y = (bbox->bottom() + bbox->top()) / 2;
00723   // Run a radial search for blobs that overlap or are sufficiently close.
00724   BlobGridSearch radsearch(this);
00725   radsearch.StartRadSearch(x, y, kCJKRadius);
00726   BLOBNBOX* neighbour;
00727   while ((neighbour = radsearch.NextRadSearch()) != NULL) {
00728     if (neighbour == not_this) continue;
00729     TBOX nbox = neighbour->bounding_box();
00730     int x_gap, y_gap;
00731     if (AcceptableCJKMerge(*bbox, nbox, debug, max_size, max_dist,
00732                            &x_gap, &y_gap)) {
00733       // Close enough to call overlapping. Merge boxes.
00734       *bbox += nbox;
00735       blobs->add_sorted(SortByBoxLeft<BLOBNBOX>, true, neighbour);
00736       if (debug) {
00737         tprintf("Added:");
00738         nbox.print();
00739       }
00740       // Since we merged, search the nearests, as some might now me mergeable.
00741       for (int dir = 0; dir < BND_COUNT; ++dir) {
00742         if (nearests[dir] == NULL) continue;
00743         nbox = nearests[dir]->bounding_box();
00744         if (AcceptableCJKMerge(*bbox, nbox, debug, max_size,
00745                                max_dist, &x_gap, &y_gap)) {
00746           // Close enough to call overlapping. Merge boxes.
00747           *bbox += nbox;
00748           blobs->add_sorted(SortByBoxLeft<BLOBNBOX>, true, nearests[dir]);
00749           if (debug) {
00750             tprintf("Added:");
00751             nbox.print();
00752           }
00753           nearests[dir] = NULL;
00754           dir = -1;  // Restart the search.
00755         }
00756       }
00757     } else if (x_gap < 0 && x_gap <= y_gap) {
00758       // A vertical neighbour. Record the nearest.
00759       BlobNeighbourDir dir = nbox.top() > bbox->top() ? BND_ABOVE : BND_BELOW;
00760       if (nearests[dir] == NULL ||
00761           y_gap < bbox->y_gap(nearests[dir]->bounding_box())) {
00762         nearests[dir] = neighbour;
00763       }
00764     } else if (y_gap < 0 && y_gap <= x_gap) {
00765       // A horizontal neighbour. Record the nearest.
00766       BlobNeighbourDir dir = nbox.left() > bbox->left() ? BND_RIGHT : BND_LEFT;
00767       if (nearests[dir] == NULL ||
00768           x_gap < bbox->x_gap(nearests[dir]->bounding_box())) {
00769         nearests[dir] = neighbour;
00770       }
00771     }
00772     // If all nearests are non-null, then we have finished.
00773     if (nearests[BND_LEFT] && nearests[BND_RIGHT] &&
00774         nearests[BND_ABOVE] && nearests[BND_BELOW])
00775       break;
00776   }
00777   // Final overlap with a nearest is not allowed.
00778   for (int dir = 0; dir < BND_COUNT; ++dir) {
00779     if (nearests[dir] == NULL) continue;
00780     const TBOX& nbox = nearests[dir]->bounding_box();
00781     if (debug) {
00782       tprintf("Testing for overlap with:");
00783       nbox.print();
00784     }
00785     if (bbox->overlap(nbox)) {
00786       blobs->shallow_clear();
00787       if (debug)
00788         tprintf("Final box overlaps nearest\n");
00789       return;
00790     }
00791   }
00792 }
00793 
00794 // For each blob in this grid, Finds the textline direction to be horizontal
00795 // or vertical according to distance to neighbours and 1st and 2nd order
00796 // neighbours. Non-text tends to end up without a definite direction.
00797 // Result is setting of the neighbours and vert_possible/horz_possible
00798 // flags in the BLOBNBOXes currently in this grid.
00799 // This function is called more than once if page orientation is uncertain,
00800 // so display_if_debugging is true on the final call to display the results.
00801 void StrokeWidth::FindTextlineFlowDirection(bool display_if_debugging) {
00802   BlobGridSearch gsearch(this);
00803   BLOBNBOX* bbox;
00804   // For every bbox in the grid, set its neighbours.
00805   gsearch.StartFullSearch();
00806   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00807     SetNeighbours(false, display_if_debugging, bbox);
00808   }
00809   // Where vertical or horizontal wins by a big margin, clarify it.
00810   gsearch.StartFullSearch();
00811   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00812     SimplifyObviousNeighbours(bbox);
00813   }
00814   // Now try to make the blobs only vertical or horizontal using neighbours.
00815   gsearch.StartFullSearch();
00816   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00817     SetNeighbourFlows(bbox);
00818   }
00819   if ((textord_tabfind_show_strokewidths  && display_if_debugging) ||
00820       textord_tabfind_show_strokewidths > 1) {
00821     initial_widths_win_ = DisplayGoodBlobs("InitialStrokewidths", 400, 0);
00822   }
00823   // Improve flow direction with neighbours.
00824   gsearch.StartFullSearch();
00825   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00826     SmoothNeighbourTypes(bbox, false);
00827   }
00828   // Now allow reset of firm values to fix renegades.
00829   gsearch.StartFullSearch();
00830   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00831     SmoothNeighbourTypes(bbox, true);
00832   }
00833   // Repeat.
00834   gsearch.StartFullSearch();
00835   while ((bbox = gsearch.NextFullSearch()) != NULL) {
00836     SmoothNeighbourTypes(bbox, true);
00837   }
00838   if ((textord_tabfind_show_strokewidths  && display_if_debugging) ||
00839       textord_tabfind_show_strokewidths > 1) {
00840     widths_win_ = DisplayGoodBlobs("ImprovedStrokewidths", 800, 0);
00841   }
00842 }
00843 
00844 // Sets the neighbours and good_stroke_neighbours members of the blob by
00845 // searching close on all 4 sides.
00846 // When finding leader dots/dashes, there is a slightly different rule for
00847 // what makes a good neighbour.
00848 void StrokeWidth::SetNeighbours(bool leaders, bool activate_line_trap,
00849                                 BLOBNBOX* blob) {
00850   int line_trap_count = 0;
00851   for (int dir = 0; dir < BND_COUNT; ++dir) {
00852     BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
00853     line_trap_count += FindGoodNeighbour(bnd, leaders, blob);
00854   }
00855   if (line_trap_count > 0 && activate_line_trap) {
00856     // It looks like a line so isolate it by clearing its neighbours.
00857     blob->ClearNeighbours();
00858     const TBOX& box = blob->bounding_box();
00859     blob->set_region_type(box.width() > box.height() ? BRT_HLINE : BRT_VLINE);
00860   }
00861 }
00862 
00863 
00864 // Sets the good_stroke_neighbours member of the blob if it has a
00865 // GoodNeighbour on the given side.
00866 // Also sets the neighbour in the blob, whether or not a good one is found.
00867 // Returns the number of blobs in the nearby search area that would lead us to
00868 // believe that this blob is a line separator.
00869 // Leaders get extra special lenient treatment.
00870 int StrokeWidth::FindGoodNeighbour(BlobNeighbourDir dir, bool leaders,
00871                                    BLOBNBOX* blob) {
00872   // Search for neighbours that overlap vertically.
00873   TBOX blob_box = blob->bounding_box();
00874   bool debug = AlignedBlob::WithinTestRegion(2, blob_box.left(),
00875                                              blob_box.bottom());
00876   if (debug) {
00877     tprintf("FGN in dir %d for blob:", dir);
00878     blob_box.print();
00879   }
00880   int top = blob_box.top();
00881   int bottom = blob_box.bottom();
00882   int left = blob_box.left();
00883   int right = blob_box.right();
00884   int width = right - left;
00885   int height = top - bottom;
00886 
00887   // A trap to detect lines tests for the min dimension of neighbours
00888   // being larger than a multiple of the min dimension of the line
00889   // and the larger dimension being smaller than a fraction of the max
00890   // dimension of the line.
00891   int line_trap_max = MAX(width, height) / kLineTrapLongest;
00892   int line_trap_min = MIN(width, height) * kLineTrapShortest;
00893   int line_trap_count = 0;
00894 
00895   int min_good_overlap = (dir == BND_LEFT || dir == BND_RIGHT)
00896                        ? height / 2 : width / 2;
00897   int min_decent_overlap = (dir == BND_LEFT || dir == BND_RIGHT)
00898                        ? height / 3 : width / 3;
00899   if (leaders)
00900     min_good_overlap = min_decent_overlap = 1;
00901 
00902   int search_pad = static_cast<int>(
00903       sqrt(static_cast<double>(width * height)) * kNeighbourSearchFactor);
00904   if (gridsize() > search_pad)
00905     search_pad = gridsize();
00906   TBOX search_box = blob_box;
00907   // Pad the search in the appropriate direction.
00908   switch (dir) {
00909   case BND_LEFT:
00910     search_box.set_left(search_box.left() - search_pad);
00911     break;
00912   case BND_RIGHT:
00913     search_box.set_right(search_box.right() + search_pad);
00914     break;
00915   case BND_BELOW:
00916     search_box.set_bottom(search_box.bottom() - search_pad);
00917     break;
00918   case BND_ABOVE:
00919     search_box.set_top(search_box.top() + search_pad);
00920     break;
00921   case BND_COUNT:
00922     return 0;
00923   }
00924 
00925   BlobGridSearch rectsearch(this);
00926   rectsearch.StartRectSearch(search_box);
00927   BLOBNBOX* best_neighbour = NULL;
00928   double best_goodness = 0.0;
00929   bool best_is_good = false;
00930   BLOBNBOX* neighbour;
00931   while ((neighbour = rectsearch.NextRectSearch()) != NULL) {
00932     TBOX nbox = neighbour->bounding_box();
00933     if (neighbour == blob)
00934       continue;
00935     int mid_x = (nbox.left() + nbox.right()) / 2;
00936     if (mid_x < blob->left_rule() || mid_x > blob->right_rule())
00937       continue;  // In a different column.
00938     if (debug) {
00939       tprintf("Neighbour at:");
00940       nbox.print();
00941     }
00942 
00943     // Last-minute line detector. There is a small upper limit to the line
00944     // width accepted by the morphological line detector.
00945     int n_width = nbox.width();
00946     int n_height = nbox.height();
00947     if (MIN(n_width, n_height) > line_trap_min &&
00948         MAX(n_width, n_height) < line_trap_max)
00949       ++line_trap_count;
00950     // Heavily joined text, such as Arabic may have very different sizes when
00951     // looking at the maxes, but the heights may be almost identical, so check
00952     // for a difference in height if looking sideways or width vertically.
00953     if (TabFind::VeryDifferentSizes(MAX(n_width, n_height),
00954                                     MAX(width, height)) &&
00955         (((dir == BND_LEFT || dir ==BND_RIGHT) &&
00956             TabFind::DifferentSizes(n_height, height)) ||
00957          ((dir == BND_BELOW || dir ==BND_ABOVE) &&
00958              TabFind::DifferentSizes(n_width, width)))) {
00959       if (debug) tprintf("Bad size\n");
00960       continue;  // Could be a different font size or non-text.
00961     }
00962     // Amount of vertical overlap between the blobs.
00963     int overlap;
00964     // If the overlap is along the short side of the neighbour, and it
00965     // is fully overlapped, then perp_overlap holds the length of the long
00966     // side of the neighbour. A measure to include hyphens and dashes as
00967     // legitimate neighbours.
00968     int perp_overlap;
00969     int gap;
00970     if (dir == BND_LEFT || dir == BND_RIGHT) {
00971       overlap = MIN(nbox.top(), top) - MAX(nbox.bottom(), bottom);
00972       if (overlap == nbox.height() && nbox.width() > nbox.height())
00973         perp_overlap = nbox.width();
00974       else
00975         perp_overlap = overlap;
00976       gap = dir == BND_LEFT ? left - nbox.left() : nbox.right() - right;
00977       if (gap <= 0) {
00978         if (debug) tprintf("On wrong side\n");
00979         continue;  // On the wrong side.
00980       }
00981       gap -= n_width;
00982     } else {
00983       overlap = MIN(nbox.right(), right) - MAX(nbox.left(), left);
00984       if (overlap == nbox.width() && nbox.height() > nbox.width())
00985         perp_overlap = nbox.height();
00986       else
00987         perp_overlap = overlap;
00988       gap = dir == BND_BELOW ? bottom - nbox.bottom() : nbox.top() - top;
00989       if (gap <= 0) {
00990         if (debug) tprintf("On wrong side\n");
00991         continue;  // On the wrong side.
00992       }
00993       gap -= n_height;
00994     }
00995     if (-gap > overlap) {
00996       if (debug) tprintf("Overlaps wrong way\n");
00997       continue;  // Overlaps the wrong way.
00998     }
00999     if (perp_overlap < min_decent_overlap) {
01000       if (debug) tprintf("Doesn't overlap enough\n");
01001       continue;  // Doesn't overlap enough.
01002     }
01003     bool bad_sizes = TabFind::DifferentSizes(height, n_height) &&
01004                      TabFind::DifferentSizes(width, n_width);
01005     bool is_good = overlap >= min_good_overlap && !bad_sizes &&
01006                    blob->MatchingStrokeWidth(*neighbour,
01007                                              kStrokeWidthFractionTolerance,
01008                                              kStrokeWidthTolerance);
01009     // Best is a fuzzy combination of gap, overlap and is good.
01010     // Basically if you make one thing twice as good without making
01011     // anything else twice as bad, then it is better.
01012     if (gap < 1) gap = 1;
01013     double goodness = (1.0 + is_good) * overlap / gap;
01014     if (debug) {
01015       tprintf("goodness = %g vs best of %g, good=%d, overlap=%d, gap=%d\n",
01016               goodness, best_goodness, is_good, overlap, gap);
01017     }
01018     if (goodness > best_goodness) {
01019       best_neighbour = neighbour;
01020       best_goodness = goodness;
01021       best_is_good = is_good;
01022     }
01023   }
01024   blob->set_neighbour(dir, best_neighbour, best_is_good);
01025   return line_trap_count;
01026 }
01027 
01028 // Helper to get a list of 1st-order neighbours.
01029 static void ListNeighbours(const BLOBNBOX* blob,
01030                            BLOBNBOX_CLIST* neighbours) {
01031   for (int dir = 0; dir < BND_COUNT; ++dir) {
01032     BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
01033     BLOBNBOX* neighbour = blob->neighbour(bnd);
01034     if (neighbour != NULL) {
01035       neighbours->add_sorted(SortByBoxLeft<BLOBNBOX>, true, neighbour);
01036     }
01037   }
01038 }
01039 
01040 // Helper to get a list of 1st and 2nd order neighbours.
01041 static void List2ndNeighbours(const BLOBNBOX* blob,
01042                               BLOBNBOX_CLIST* neighbours) {
01043   ListNeighbours(blob, neighbours);
01044   for (int dir = 0; dir < BND_COUNT; ++dir) {
01045     BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
01046     BLOBNBOX* neighbour = blob->neighbour(bnd);
01047     if (neighbour != NULL) {
01048       ListNeighbours(neighbour, neighbours);
01049     }
01050   }
01051 }
01052 
01053 // Helper to get a list of 1st, 2nd and 3rd order neighbours.
01054 static void List3rdNeighbours(const BLOBNBOX* blob,
01055                               BLOBNBOX_CLIST* neighbours) {
01056   List2ndNeighbours(blob, neighbours);
01057   for (int dir = 0; dir < BND_COUNT; ++dir) {
01058     BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
01059     BLOBNBOX* neighbour = blob->neighbour(bnd);
01060     if (neighbour != NULL) {
01061       List2ndNeighbours(neighbour, neighbours);
01062     }
01063   }
01064 }
01065 
01066 // Helper to count the evidence for verticalness or horizontalness
01067 // in a list of neighbours.
01068 static void CountNeighbourGaps(bool debug, BLOBNBOX_CLIST* neighbours,
01069                                int* pure_h_count, int* pure_v_count) {
01070   if (neighbours->length() <= kMostlyOneDirRatio)
01071     return;
01072   BLOBNBOX_C_IT it(neighbours);
01073   for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
01074     BLOBNBOX* blob = it.data();
01075     int h_min, h_max, v_min, v_max;
01076     blob->MinMaxGapsClipped(&h_min, &h_max, &v_min, &v_max);
01077     if (debug)
01078       tprintf("Hgaps [%d,%d], vgaps [%d,%d]:", h_min, h_max, v_min, v_max);
01079     if (h_max < v_min ||
01080         blob->leader_on_left() || blob->leader_on_right()) {
01081       // Horizontal gaps are clear winners. Count a pure horizontal.
01082       ++*pure_h_count;
01083       if (debug) tprintf("Horz at:");
01084     } else if (v_max < h_min) {
01085       // Vertical gaps are clear winners. Clear a pure vertical.
01086       ++*pure_v_count;
01087       if (debug) tprintf("Vert at:");
01088     } else {
01089       if (debug) tprintf("Neither at:");
01090     }
01091     if (debug)
01092       blob->bounding_box().print();
01093   }
01094 }
01095 
01096 // Makes the blob to be only horizontal or vertical where evidence
01097 // is clear based on gaps of 2nd order neighbours, or definite individual
01098 // blobs.
01099 void StrokeWidth::SetNeighbourFlows(BLOBNBOX* blob) {
01100   if (blob->DefiniteIndividualFlow())
01101     return;
01102   bool debug = AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
01103                                              blob->bounding_box().bottom());
01104   if (debug) {
01105     tprintf("SetNeighbourFlows (current flow=%d, type=%d) on:",
01106             blob->flow(), blob->region_type());
01107     blob->bounding_box().print();
01108   }
01109   BLOBNBOX_CLIST neighbours;
01110   List3rdNeighbours(blob, &neighbours);
01111   // The number of pure horizontal and vertical neighbours.
01112   int pure_h_count = 0;
01113   int pure_v_count = 0;
01114   CountNeighbourGaps(debug, &neighbours, &pure_h_count, &pure_v_count);
01115   if (debug) {
01116     HandleClick(blob->bounding_box().left() + 1,
01117                 blob->bounding_box().bottom() + 1);
01118     tprintf("SetFlows: h_count=%d, v_count=%d\n",
01119             pure_h_count, pure_v_count);
01120   }
01121   if (!neighbours.empty()) {
01122     blob->set_vert_possible(true);
01123     blob->set_horz_possible(true);
01124     if (pure_h_count > 2 * pure_v_count) {
01125       // Horizontal gaps are clear winners. Clear vertical neighbours.
01126       blob->set_vert_possible(false);
01127     } else if (pure_v_count > 2 * pure_h_count) {
01128       // Vertical gaps are clear winners. Clear horizontal neighbours.
01129       blob->set_horz_possible(false);
01130     }
01131   } else {
01132     // Lonely blob. Can't tell its flow direction.
01133     blob->set_vert_possible(false);
01134     blob->set_horz_possible(false);
01135   }
01136 }
01137 
01138 
01139 // Helper to count the number of horizontal and vertical blobs in a list.
01140 static void CountNeighbourTypes(BLOBNBOX_CLIST* neighbours,
01141                                 int* pure_h_count, int* pure_v_count) {
01142   BLOBNBOX_C_IT it(neighbours);
01143   for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
01144     BLOBNBOX* blob = it.data();
01145     if (blob->UniquelyHorizontal())
01146       ++*pure_h_count;
01147     if (blob->UniquelyVertical())
01148       ++*pure_v_count;
01149   }
01150 }
01151 
01152 // Nullify the neighbours in the wrong directions where the direction
01153 // is clear-cut based on a distance margin. Good for isolating vertical
01154 // text from neighbouring horizontal text.
01155 void StrokeWidth::SimplifyObviousNeighbours(BLOBNBOX* blob) {
01156   // Case 1: We have text that is likely several characters, blurry and joined
01157   //         together.
01158   if ((blob->bounding_box().width() > 3 * blob->area_stroke_width() &&
01159        blob->bounding_box().height() > 3 * blob->area_stroke_width())) {
01160     // The blob is complex (not stick-like).
01161     if (blob->bounding_box().width() > 4 * blob->bounding_box().height()) {
01162       // Horizontal conjoined text.
01163       blob->set_neighbour(BND_ABOVE, NULL, false);
01164       blob->set_neighbour(BND_BELOW, NULL, false);
01165       return;
01166     }
01167     if (blob->bounding_box().height() > 4 * blob->bounding_box().width()) {
01168       // Vertical conjoined text.
01169       blob->set_neighbour(BND_LEFT, NULL, false);
01170       blob->set_neighbour(BND_RIGHT, NULL, false);
01171       return;
01172     }
01173   }
01174 
01175   // Case 2: This blob is likely a single character.
01176   int margin = gridsize() / 2;
01177   int h_min, h_max, v_min, v_max;
01178   blob->MinMaxGapsClipped(&h_min, &h_max, &v_min, &v_max);
01179   if ((h_max + margin < v_min && h_max < margin / 2) ||
01180       blob->leader_on_left() || blob->leader_on_right()) {
01181     // Horizontal gaps are clear winners. Clear vertical neighbours.
01182     blob->set_neighbour(BND_ABOVE, NULL, false);
01183     blob->set_neighbour(BND_BELOW, NULL, false);
01184   } else if (v_max + margin < h_min && v_max < margin / 2) {
01185     // Vertical gaps are clear winners. Clear horizontal neighbours.
01186     blob->set_neighbour(BND_LEFT, NULL, false);
01187     blob->set_neighbour(BND_RIGHT, NULL, false);
01188   }
01189 }
01190 
01191 // Smoothes the vertical/horizontal type of the blob based on the
01192 // 2nd-order neighbours. If reset_all is true, then all blobs are
01193 // changed. Otherwise, only ambiguous blobs are processed.
01194 void StrokeWidth::SmoothNeighbourTypes(BLOBNBOX* blob, bool reset_all) {
01195   if ((blob->vert_possible() && blob->horz_possible()) || reset_all) {
01196     // There are both horizontal and vertical so try to fix it.
01197     BLOBNBOX_CLIST neighbours;
01198     List2ndNeighbours(blob, &neighbours);
01199     // The number of pure horizontal and vertical neighbours.
01200     int pure_h_count = 0;
01201     int pure_v_count = 0;
01202     CountNeighbourTypes(&neighbours, &pure_h_count, &pure_v_count);
01203     if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
01204                                       blob->bounding_box().bottom())) {
01205       HandleClick(blob->bounding_box().left() + 1,
01206                   blob->bounding_box().bottom() + 1);
01207       tprintf("pure_h=%d, pure_v=%d\n",
01208               pure_h_count, pure_v_count);
01209     }
01210     if (pure_h_count > pure_v_count) {
01211       // Horizontal gaps are clear winners. Clear vertical neighbours.
01212       blob->set_vert_possible(false);
01213       blob->set_horz_possible(true);
01214     } else if (pure_v_count > pure_h_count) {
01215       // Vertical gaps are clear winners. Clear horizontal neighbours.
01216       blob->set_horz_possible(false);
01217       blob->set_vert_possible(true);
01218     }
01219   } else if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
01220                                     blob->bounding_box().bottom())) {
01221     HandleClick(blob->bounding_box().left() + 1,
01222                 blob->bounding_box().bottom() + 1);
01223     tprintf("Clean on pass 3!\n");
01224   }
01225 }
01226 
01227 // Partition creation. Accumulates vertical and horizontal text chains,
01228 // puts the remaining blobs in as unknowns, and then merges/splits to
01229 // minimize overlap and smoothes the types with neighbours and the color
01230 // image if provided. rerotation is used to rotate the coordinate space
01231 // back to the nontext_map_ image.
01232 void StrokeWidth::FindInitialPartitions(const FCOORD& rerotation,
01233                                         TO_BLOCK* block,
01234                                         ColPartitionGrid* part_grid,
01235                                         ColPartition_LIST* big_parts) {
01236   FindVerticalTextChains(part_grid);
01237   FindHorizontalTextChains(part_grid);
01238   if (textord_tabfind_show_strokewidths) {
01239     chains_win_ = MakeWindow(0, 400, "Initial text chains");
01240     part_grid->DisplayBoxes(chains_win_);
01241     projection_->DisplayProjection();
01242   }
01243   part_grid->SplitOverlappingPartitions(big_parts);
01244   EasyMerges(part_grid);
01245   RemoveLargeUnusedBlobs(block, part_grid, big_parts);
01246   TBOX grid_box(bleft(), tright());
01247   while (part_grid->GridSmoothNeighbours(BTFT_CHAIN, nontext_map_, grid_box,
01248                                          rerotation));
01249   while (part_grid->GridSmoothNeighbours(BTFT_NEIGHBOURS, nontext_map_,
01250                                          grid_box, rerotation));
01251   TestDiacritics(part_grid, block);
01252   MergeDiacritics(block, part_grid);
01253   if (textord_tabfind_show_strokewidths) {
01254     textlines_win_ = MakeWindow(400, 400, "GoodTextline blobs");
01255     part_grid->DisplayBoxes(textlines_win_);
01256     diacritics_win_ = DisplayDiacritics("Diacritics", 0, 0, block);
01257   }
01258   PartitionRemainingBlobs(part_grid);
01259   part_grid->SplitOverlappingPartitions(big_parts);
01260   EasyMerges(part_grid);
01261   while (part_grid->GridSmoothNeighbours(BTFT_CHAIN, nontext_map_, grid_box,
01262                                          rerotation));
01263   while (part_grid->GridSmoothNeighbours(BTFT_NEIGHBOURS, nontext_map_,
01264                                          grid_box, rerotation));
01265   // Now eliminate strong stuff in a sea of the opposite.
01266   while (part_grid->GridSmoothNeighbours(BTFT_STRONG_CHAIN, nontext_map_,
01267                                          grid_box, rerotation));
01268   if (textord_tabfind_show_strokewidths) {
01269     smoothed_win_ = MakeWindow(800, 400, "Smoothed blobs");
01270     part_grid->DisplayBoxes(smoothed_win_);
01271   }
01272 }
01273 
01274 // Helper verifies that blob's neighbour in direction dir is good to add to a
01275 // vertical text chain by returning the neighbour if it is not null, not owned,
01276 // and not uniquely horizontal, as well as its neighbour in the opposite
01277 // direction is blob.
01278 static BLOBNBOX* MutualUnusedVNeighbour(const BLOBNBOX* blob,
01279                                         BlobNeighbourDir dir) {
01280   BLOBNBOX* next_blob = blob->neighbour(dir);
01281   if (next_blob == NULL || next_blob->owner() != NULL ||
01282       next_blob->UniquelyHorizontal())
01283     return NULL;
01284   if (next_blob->neighbour(DirOtherWay(dir)) == blob)
01285     return next_blob;
01286   return NULL;
01287 }
01288 
01289 // Finds vertical chains of text-like blobs and puts them in ColPartitions.
01290 void StrokeWidth::FindVerticalTextChains(ColPartitionGrid* part_grid) {
01291   BlobGridSearch gsearch(this);
01292   BLOBNBOX* bbox;
01293   gsearch.StartFullSearch();
01294   while ((bbox = gsearch.NextFullSearch()) != NULL) {
01295     // Only process boxes that have no horizontal hope and have not yet
01296     // been included in a chain.
01297     BLOBNBOX* blob;
01298     if (bbox->owner() == NULL && bbox->UniquelyVertical() &&
01299         (blob = MutualUnusedVNeighbour(bbox, BND_ABOVE)) != NULL) {
01300       // Put all the linked blobs into a ColPartition.
01301       ColPartition* part = new ColPartition(BRT_VERT_TEXT, ICOORD(0, 1));
01302       part->AddBox(bbox);
01303       while (blob != NULL) {
01304         part->AddBox(blob);
01305         blob = MutualUnusedVNeighbour(blob, BND_ABOVE);
01306       }
01307       blob = MutualUnusedVNeighbour(bbox, BND_BELOW);
01308       while (blob != NULL) {
01309         part->AddBox(blob);
01310         blob = MutualUnusedVNeighbour(blob, BND_BELOW);
01311       }
01312       CompletePartition(part, part_grid);
01313     }
01314   }
01315 }
01316 
01317 // Helper verifies that blob's neighbour in direction dir is good to add to a
01318 // horizontal text chain by returning the neighbour if it is not null, not
01319 // owned, and not uniquely vertical, as well as its neighbour in the opposite
01320 // direction is blob.
01321 static BLOBNBOX* MutualUnusedHNeighbour(const BLOBNBOX* blob,
01322                                         BlobNeighbourDir dir) {
01323   BLOBNBOX* next_blob = blob->neighbour(dir);
01324   if (next_blob == NULL || next_blob->owner() != NULL ||
01325       next_blob->UniquelyVertical())
01326     return NULL;
01327   if (next_blob->neighbour(DirOtherWay(dir)) == blob)
01328     return next_blob;
01329   return NULL;
01330 }
01331 
01332 // Finds horizontal chains of text-like blobs and puts them in ColPartitions.
01333 void StrokeWidth::FindHorizontalTextChains(ColPartitionGrid* part_grid) {
01334   BlobGridSearch gsearch(this);
01335   BLOBNBOX* bbox;
01336   gsearch.StartFullSearch();
01337   while ((bbox = gsearch.NextFullSearch()) != NULL) {
01338     BLOBNBOX* blob;
01339     if (bbox->owner() == NULL && bbox->UniquelyHorizontal() &&
01340         (blob = MutualUnusedHNeighbour(bbox, BND_RIGHT)) != NULL) {
01341       // Put all the linked blobs into a ColPartition.
01342       ColPartition* part = new ColPartition(BRT_TEXT, ICOORD(0, 1));
01343       part->AddBox(bbox);
01344       while (blob != NULL) {
01345         part->AddBox(blob);
01346         blob = MutualUnusedHNeighbour(blob, BND_RIGHT);
01347       }
01348       blob = MutualUnusedHNeighbour(bbox, BND_LEFT);
01349       while (blob != NULL) {
01350         part->AddBox(blob);
01351         blob = MutualUnusedVNeighbour(blob, BND_LEFT);
01352       }
01353       CompletePartition(part, part_grid);
01354     }
01355   }
01356 }
01357 
01358 // Finds diacritics and saves their base character in the blob.
01359 // The objective is to move all diacritics to the noise_blobs list, so
01360 // they don't mess up early textline finding/merging, or force splits
01361 // on textlines that overlap a bit. Blobs that become diacritics must be
01362 // either part of no ColPartition (NULL owner) or in a small partition in
01363 // which ALL the blobs are diacritics, in which case the partition is
01364 // exploded (deleted) back to its blobs.
01365 void StrokeWidth::TestDiacritics(ColPartitionGrid* part_grid, TO_BLOCK* block) {
01366   BlobGrid small_grid(gridsize(), bleft(), tright());
01367   small_grid.InsertBlobList(&block->noise_blobs);
01368   small_grid.InsertBlobList(&block->blobs);
01369   int medium_diacritics = 0;
01370   int small_diacritics = 0;
01371   BLOBNBOX_IT small_it(&block->noise_blobs);
01372   for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
01373     BLOBNBOX* blob = small_it.data();
01374     if (blob->owner() == NULL && !blob->IsDiacritic() &&
01375         DiacriticBlob(&small_grid, blob)) {
01376       ++small_diacritics;
01377     }
01378   }
01379   BLOBNBOX_IT blob_it(&block->blobs);
01380   for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
01381     BLOBNBOX* blob = blob_it.data();
01382     if (blob->IsDiacritic()) {
01383       small_it.add_to_end(blob_it.extract());
01384       continue;  // Already a diacritic.
01385     }
01386     ColPartition* part = blob->owner();
01387     if (part == NULL && DiacriticBlob(&small_grid, blob)) {
01388       ++medium_diacritics;
01389       RemoveBBox(blob);
01390       small_it.add_to_end(blob_it.extract());
01391     } else if (part != NULL && !part->block_owned() &&
01392         part->boxes_count() < 3) {
01393       // We allow blobs in small partitions to become diacritics if ALL the
01394       // blobs in the partition qualify as we can then cleanly delete the
01395       // partition, turn all the blobs in it to diacritics and they can be
01396       // merged into the base character partition more easily than merging
01397       // the partitions.
01398       BLOBNBOX_C_IT box_it(part->boxes());
01399       for (box_it.mark_cycle_pt(); !box_it.cycled_list() &&
01400            DiacriticBlob(&small_grid, box_it.data());
01401            box_it.forward());
01402       if (box_it.cycled_list()) {
01403         // They are all good.
01404         while (!box_it.empty()) {
01405           // Liberate the blob from its partition so it can be treated
01406           // as a diacritic and merged explicitly with the base part.
01407           // The blob is really owned by the block. The partition "owner"
01408           // is NULLed to allow the blob to get merged with its base character
01409           // partition.
01410           BLOBNBOX* box = box_it.extract();
01411           box->set_owner(NULL);
01412           box_it.forward();
01413           ++medium_diacritics;
01414           // We remove the blob from the grid so it isn't found by subsequent
01415           // searches where we might not want to include diacritics.
01416           RemoveBBox(box);
01417         }
01418         // We only move the one blob to the small list here, but the others
01419         // all get moved by the test at the top of the loop.
01420         small_it.add_to_end(blob_it.extract());
01421         part_grid->RemoveBBox(part);
01422         delete part;
01423       }
01424     } else if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
01425                                              blob->bounding_box().bottom())) {
01426       tprintf("Blob not available to be a diacritic at:");
01427       blob->bounding_box().print();
01428     }
01429   }
01430   if (textord_tabfind_show_strokewidths) {
01431     tprintf("Found %d small diacritics, %d medium\n",
01432             small_diacritics, medium_diacritics);
01433   }
01434 }
01435 
01436 // Searches this grid for an appropriately close and sized neighbour of the
01437 // given [small] blob. If such a blob is found, the diacritic base is saved
01438 // in the blob and true is returned.
01439 // The small_grid is a secondary grid that contains the small/noise objects
01440 // that are not in this grid, but may be useful for determining a connection
01441 // between blob and its potential base character. (See DiacriticXGapFilled.)
01442 bool StrokeWidth::DiacriticBlob(BlobGrid* small_grid, BLOBNBOX* blob) {
01443   if (BLOBNBOX::UnMergeableType(blob->region_type()) ||
01444       blob->region_type() == BRT_VERT_TEXT)
01445     return false;
01446   TBOX small_box(blob->bounding_box());
01447   bool debug = AlignedBlob::WithinTestRegion(2, small_box.left(),
01448                                              small_box.bottom());
01449   if (debug) {
01450     tprintf("Testing blob for diacriticness at:");
01451     small_box.print();
01452   }
01453   int x = (small_box.left() + small_box.right()) / 2;
01454   int y = (small_box.bottom() + small_box.top()) / 2;
01455   int grid_x, grid_y;
01456   GridCoords(x, y, &grid_x, &grid_y);
01457   int height = small_box.height();
01458   // Setup a rectangle search to find its nearest base-character neighbour.
01459   // We keep 2 different best candidates:
01460   // best_x_overlap is a category of base characters that have an overlap in x
01461   // (like a acute) in which we look for the least y-gap, computed using the
01462   // projection to favor base characters in the same textline.
01463   // best_y_overlap is a category of base characters that have no x overlap,
01464   // (nominally a y-overlap is preferrecd but not essential) in which we
01465   // look for the least weighted sum of x-gap and y-gap, with x-gap getting
01466   // a lower weight to catch quotes at the end of a textline.
01467   // NOTE that x-gap and y-gap are measured from the nearest side of the base
01468   // character to the FARTHEST side of the diacritic to allow small diacritics
01469   // to be a reasonable distance away, but not big diacritics.
01470   BLOBNBOX* best_x_overlap = NULL;
01471   BLOBNBOX* best_y_overlap = NULL;
01472   int best_total_dist = 0;
01473   int best_y_gap = 0;
01474   TBOX best_xbox;
01475   // TODO(rays) the search box could be setup using the projection as a guide.
01476   TBOX search_box(small_box);
01477   int x_pad = IntCastRounded(gridsize() * kDiacriticXPadRatio);
01478   int y_pad = IntCastRounded(gridsize() * kDiacriticYPadRatio);
01479   search_box.pad(x_pad, y_pad);
01480   BlobGridSearch rsearch(this);
01481   rsearch.SetUniqueMode(true);
01482   int min_height = height * kMinDiacriticSizeRatio;
01483   rsearch.StartRectSearch(search_box);
01484   BLOBNBOX* neighbour;
01485   while ((neighbour = rsearch.NextRectSearch()) != NULL) {
01486     if (BLOBNBOX::UnMergeableType(neighbour->region_type()) ||
01487         neighbour == blob || neighbour->owner() == blob->owner())
01488       continue;
01489     TBOX nbox = neighbour->bounding_box();
01490     if (neighbour->owner() == NULL || neighbour->owner()->IsVerticalType() ||
01491         (neighbour->flow() != BTFT_CHAIN &&
01492             neighbour->flow() != BTFT_STRONG_CHAIN)) {
01493       if (debug) {
01494         tprintf("Neighbour not strong enough:");
01495         nbox.print();
01496       }
01497       continue;  // Diacritics must be attached to strong text.
01498     }
01499     if (nbox.height() < min_height) {
01500       if (debug) {
01501         tprintf("Neighbour not big enough:");
01502         nbox.print();
01503       }
01504       continue;  // Too small to be the base character.
01505     }
01506     int x_gap = small_box.x_gap(nbox);
01507     int y_gap = small_box.y_gap(nbox);
01508     int total_distance = projection_->DistanceOfBoxFromBox(small_box, nbox,
01509                                                            true, denorm_,
01510                                                            debug);
01511     if (debug) tprintf("xgap=%d, y=%d, total dist=%d\n",
01512                        x_gap, y_gap, total_distance);
01513     if (total_distance >
01514         neighbour->owner()->median_size() * kMaxDiacriticDistanceRatio) {
01515       if (debug) {
01516         tprintf("Neighbour with median size %d too far away:",
01517                 neighbour->owner()->median_size());
01518         neighbour->bounding_box().print();
01519       }
01520       continue;  // Diacritics must not be too distant.
01521     }
01522     if (x_gap <= 0) {
01523       if (debug) {
01524         tprintf("Computing reduced box for :");
01525         nbox.print();
01526       }
01527       int left = small_box.left() - small_box.width();
01528       int right = small_box.right() + small_box.width();
01529       nbox = neighbour->BoundsWithinLimits(left, right);
01530       y_gap = small_box.y_gap(nbox);
01531       if (best_x_overlap == NULL || y_gap < best_y_gap) {
01532         best_x_overlap = neighbour;
01533         best_xbox = nbox;
01534         best_y_gap = y_gap;
01535         if (debug) {
01536           tprintf("New best:");
01537           nbox.print();
01538         }
01539       } else if (debug) {
01540         tprintf("Shrunken box doesn't win:");
01541         nbox.print();
01542       }
01543     } else if (blob->ConfirmNoTabViolation(*neighbour)) {
01544       if (best_y_overlap == NULL || total_distance < best_total_dist) {
01545         if (debug) {
01546           tprintf("New best y overlap:");
01547           nbox.print();
01548         }
01549         best_y_overlap = neighbour;
01550         best_total_dist = total_distance;
01551       } else if (debug) {
01552         tprintf("New y overlap box doesn't win:");
01553         nbox.print();
01554       }
01555     } else if (debug) {
01556       tprintf("Neighbour wrong side of a tab:");
01557       nbox.print();
01558     }
01559   }
01560   if (best_x_overlap != NULL &&
01561       (best_y_overlap == NULL ||
01562        best_xbox.major_y_overlap(best_y_overlap->bounding_box()))) {
01563     blob->set_diacritic_box(best_xbox);
01564     blob->set_base_char_blob(best_x_overlap);
01565     if (debug) {
01566       tprintf("DiacriticBlob OK! (x-overlap:");
01567       small_box.print();
01568       best_xbox.print();
01569     }
01570     return true;
01571   }
01572   if (best_y_overlap != NULL &&
01573       DiacriticXGapFilled(small_grid, small_box,
01574                           best_y_overlap->bounding_box()) &&
01575       NoNoiseInBetween(small_box, best_y_overlap->bounding_box())) {
01576     blob->set_diacritic_box(best_y_overlap->bounding_box());
01577     blob->set_base_char_blob(best_y_overlap);
01578     if (debug) {
01579       tprintf("DiacriticBlob OK! (y-overlap:");
01580       small_box.print();
01581       best_y_overlap->bounding_box().print();
01582     }
01583     return true;
01584   }
01585   if (debug) {
01586     tprintf("DiacriticBlob fails:");
01587     small_box.print();
01588     tprintf("Best x+y gap = %d, y = %d\n", best_total_dist, best_y_gap);
01589     if (best_y_overlap != NULL) {
01590       tprintf("XGapFilled=%d, NoiseBetween=%d\n",
01591               DiacriticXGapFilled(small_grid, small_box,
01592                                   best_y_overlap->bounding_box()),
01593               NoNoiseInBetween(small_box, best_y_overlap->bounding_box()));
01594     }
01595   }
01596   return false;
01597 }
01598 
01599 // Returns true if there is no gap between the base char and the diacritic
01600 // bigger than a fraction of the height of the base char:
01601 // Eg: line end.....'
01602 // The quote is a long way from the end of the line, yet it needs to be a
01603 // diacritic. To determine that the quote is not part of an image, or
01604 // a different text block, we check for other marks in the gap between
01605 // the base char and the diacritic.
01606 //                          '<--Diacritic
01607 // |---------|
01608 // |         |<-toobig-gap->
01609 // | Base    |<ok gap>
01610 // |---------|        x<-----Dot occupying gap
01611 // The grid is const really.
01612 bool StrokeWidth::DiacriticXGapFilled(BlobGrid* grid,
01613                                       const TBOX& diacritic_box,
01614                                       const TBOX& base_box) {
01615   // Since most gaps are small, use an iterative algorithm to search the gap.
01616   int max_gap = IntCastRounded(base_box.height() *
01617                                kMaxDiacriticGapToBaseCharHeight);
01618   TBOX occupied_box(base_box);
01619   int diacritic_gap;
01620   while ((diacritic_gap = diacritic_box.x_gap(occupied_box)) > max_gap) {
01621     TBOX search_box(occupied_box);
01622     if (diacritic_box.left() > search_box.right()) {
01623       // We are looking right.
01624       search_box.set_left(search_box.right());
01625       search_box.set_right(search_box.left() + max_gap);
01626     } else {
01627       // We are looking left.
01628       search_box.set_right(search_box.left());
01629       search_box.set_left(search_box.left() - max_gap);
01630     }
01631     BlobGridSearch rsearch(grid);
01632     rsearch.StartRectSearch(search_box);
01633     BLOBNBOX* neighbour;
01634     while ((neighbour = rsearch.NextRectSearch()) != NULL) {
01635       const TBOX& nbox = neighbour->bounding_box();
01636       if (nbox.x_gap(diacritic_box) < diacritic_gap) {
01637         if (nbox.left() < occupied_box.left())
01638           occupied_box.set_left(nbox.left());
01639         if (nbox.right() > occupied_box.right())
01640           occupied_box.set_right(nbox.right());
01641         break;
01642       }
01643     }
01644     if (neighbour == NULL)
01645       return false;  // Found a big gap.
01646   }
01647   return true;  // The gap was filled.
01648 }
01649 
01650 // Merges diacritics with the ColPartition of the base character blob.
01651 void StrokeWidth::MergeDiacritics(TO_BLOCK* block,
01652                                   ColPartitionGrid* part_grid) {
01653   BLOBNBOX_IT small_it(&block->noise_blobs);
01654   for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
01655     BLOBNBOX* blob = small_it.data();
01656     if (blob->base_char_blob() != NULL) {
01657       ColPartition* part = blob->base_char_blob()->owner();
01658       // The base character must be owned by a partition and that partition
01659       // must not be on the big_parts list (not block owned).
01660       if (part != NULL && !part->block_owned() && blob->owner() == NULL &&
01661           blob->IsDiacritic()) {
01662         // The partition has to be removed from the grid and reinserted
01663         // because its bounding box may change.
01664         part_grid->RemoveBBox(part);
01665         part->AddBox(blob);
01666         blob->set_region_type(part->blob_type());
01667         blob->set_flow(part->flow());
01668         blob->set_owner(part);
01669         part_grid->InsertBBox(true, true, part);
01670       }
01671       // Set all base chars to NULL before any blobs get deleted.
01672       blob->set_base_char_blob(NULL);
01673     }
01674   }
01675 }
01676 
01677 // Any blobs on the large_blobs list of block that are still unowned by a
01678 // ColPartition, are probably drop-cap or vertically touching so the blobs
01679 // are removed to the big_parts list and treated separately.
01680 void StrokeWidth::RemoveLargeUnusedBlobs(TO_BLOCK* block,
01681                                          ColPartitionGrid* part_grid,
01682                                          ColPartition_LIST* big_parts) {
01683   BLOBNBOX_IT large_it(&block->large_blobs);
01684   for (large_it.mark_cycle_pt(); !large_it.cycled_list(); large_it.forward()) {
01685     BLOBNBOX* blob = large_it.data();
01686     ColPartition* big_part = blob->owner();
01687     if (big_part == NULL) {
01688       // Large blobs should have gone into partitions by now if they are
01689       // genuine characters, so move any unowned ones out to the big parts
01690       // list. This will include drop caps and vertically touching characters.
01691       ColPartition::MakeBigPartition(blob, big_parts);
01692     }
01693   }
01694 }
01695 
01696 // All remaining unused blobs are put in individual ColPartitions.
01697 void StrokeWidth::PartitionRemainingBlobs(ColPartitionGrid* part_grid) {
01698   BlobGridSearch gsearch(this);
01699   BLOBNBOX* bbox;
01700   int prev_grid_x = -1;
01701   int prev_grid_y = -1;
01702   BLOBNBOX_CLIST cell_list;
01703   BLOBNBOX_C_IT cell_it(&cell_list);
01704   bool cell_all_noise = true;
01705   gsearch.StartFullSearch();
01706   while ((bbox = gsearch.NextFullSearch()) != NULL) {
01707     int grid_x = gsearch.GridX();
01708     int grid_y = gsearch.GridY();
01709     if (grid_x != prev_grid_x || grid_y != prev_grid_y) {
01710       // New cell. Process old cell.
01711       MakePartitionsFromCellList(cell_all_noise, part_grid, &cell_list);
01712       cell_it.set_to_list(&cell_list);
01713       prev_grid_x = grid_x;
01714       prev_grid_y = grid_y;
01715       cell_all_noise = true;
01716     }
01717     if (bbox->owner() == NULL) {
01718       cell_it.add_to_end(bbox);
01719       if (bbox->flow() != BTFT_NONTEXT)
01720         cell_all_noise = false;
01721     } else {
01722       cell_all_noise = false;
01723     }
01724   }
01725   MakePartitionsFromCellList(cell_all_noise, part_grid, &cell_list);
01726 }
01727 
01728 // If combine, put all blobs in the cell_list into a single partition, otherwise
01729 // put each one into its own partition.
01730 void StrokeWidth::MakePartitionsFromCellList(bool combine,
01731                                              ColPartitionGrid* part_grid,
01732                                              BLOBNBOX_CLIST* cell_list) {
01733   if (cell_list->empty())
01734     return;
01735   BLOBNBOX_C_IT cell_it(cell_list);
01736   if (combine) {
01737     BLOBNBOX* bbox = cell_it.extract();
01738     ColPartition* part = new ColPartition(bbox->region_type(), ICOORD(0, 1));
01739     part->AddBox(bbox);
01740     part->set_flow(bbox->flow());
01741     for (cell_it.forward(); !cell_it.empty(); cell_it.forward()) {
01742       part->AddBox(cell_it.extract());
01743     }
01744     CompletePartition(part, part_grid);
01745   } else {
01746     for (; !cell_it.empty(); cell_it.forward()) {
01747       BLOBNBOX* bbox = cell_it.extract();
01748       ColPartition* part = new ColPartition(bbox->region_type(), ICOORD(0, 1));
01749       part->set_flow(bbox->flow());
01750       part->AddBox(bbox);
01751       CompletePartition(part, part_grid);
01752     }
01753   }
01754 }
01755 
01756 // Helper function to finish setting up a ColPartition and insert into
01757 // part_grid.
01758 void StrokeWidth::CompletePartition(ColPartition* part,
01759                                     ColPartitionGrid* part_grid) {
01760   part->ComputeLimits();
01761   TBOX box = part->bounding_box();
01762   bool debug = AlignedBlob::WithinTestRegion(2, box.left(),
01763                                              box.bottom());
01764   int value = projection_->EvaluateColPartition(*part, denorm_, debug);
01765   part->SetRegionAndFlowTypesFromProjectionValue(value);
01766   part->ClaimBoxes();
01767   part_grid->InsertBBox(true, true, part);
01768 }
01769 
01770 // Merge partitions where the merge appears harmless.
01771 // As this
01772 void StrokeWidth::EasyMerges(ColPartitionGrid* part_grid) {
01773   part_grid->Merges(
01774       NewPermanentTessCallback(this, &StrokeWidth::OrientationSearchBox),
01775       NewPermanentTessCallback(this, &StrokeWidth::ConfirmEasyMerge));
01776 }
01777 
01778 // Compute a search box based on the orientation of the partition.
01779 // Returns true if a suitable box can be calculated.
01780 // Callback for EasyMerges.
01781 bool StrokeWidth::OrientationSearchBox(ColPartition* part, TBOX* box) {
01782   if (part->IsVerticalType()) {
01783     box->set_top(box->top() + box->width());
01784     box->set_bottom(box->bottom() - box->width());
01785   } else {
01786     box->set_left(box->left() - box->height());
01787     box->set_right(box->right() + box->height());
01788   }
01789   return true;
01790 }
01791 
01792 // Merge confirmation callback for EasyMerges.
01793 bool StrokeWidth::ConfirmEasyMerge(const ColPartition* p1,
01794                                    const ColPartition* p2) {
01795   ASSERT_HOST(p1 != NULL && p2 != NULL);
01796   ASSERT_HOST(!p1->IsEmpty() && !p2->IsEmpty());
01797   if ((p1->flow() == BTFT_NONTEXT && p2->flow() >= BTFT_CHAIN) ||
01798       (p1->flow() >= BTFT_CHAIN && p2->flow() == BTFT_NONTEXT))
01799     return false;  // Don't merge confirmed image with text.
01800   if ((p1->IsVerticalType() || p2->IsVerticalType()) &&
01801        p1->HCoreOverlap(*p2) <= 0 &&
01802        ((!p1->IsSingleton() &&
01803          !p2->IsSingleton()) ||
01804         !p1->bounding_box().major_overlap(p2->bounding_box())))
01805     return false;  // Overlap must be in the text line.
01806   if ((p1->IsHorizontalType() || p2->IsHorizontalType()) &&
01807       p1->VCoreOverlap(*p2) <= 0 &&
01808       ((!p1->IsSingleton() &&
01809         !p2->IsSingleton()) ||
01810        (!p1->bounding_box().major_overlap(p2->bounding_box()) &&
01811         !p1->OKDiacriticMerge(*p2, false) &&
01812         !p2->OKDiacriticMerge(*p1, false))))
01813     return false;  // Overlap must be in the text line.
01814   if (!p1->ConfirmNoTabViolation(*p2))
01815     return false;
01816   if (p1->flow() <= BTFT_NONTEXT && p2->flow() <= BTFT_NONTEXT)
01817     return true;
01818   return NoNoiseInBetween(p1->bounding_box(), p2->bounding_box());
01819 }
01820 
01821 // Returns true if there is no significant noise in between the boxes.
01822 bool StrokeWidth::NoNoiseInBetween(const TBOX& box1, const TBOX& box2) const {
01823   return ImageFind::BlankImageInBetween(box1, box2, grid_box_, rerotation_,
01824                                         nontext_map_);
01825 }
01826 
01830 ScrollView* StrokeWidth::DisplayGoodBlobs(const char* window_name,
01831                                           int x, int y) {
01832   ScrollView* window = NULL;
01833 #ifndef GRAPHICS_DISABLED
01834   window = MakeWindow(x, y, window_name);
01835   // For every blob in the grid, display it.
01836   window->Brush(ScrollView::NONE);
01837 
01838   // For every bbox in the grid, display it.
01839   BlobGridSearch gsearch(this);
01840   gsearch.StartFullSearch();
01841   BLOBNBOX* bbox;
01842   while ((bbox = gsearch.NextFullSearch()) != NULL) {
01843     TBOX box = bbox->bounding_box();
01844     int left_x = box.left();
01845     int right_x = box.right();
01846     int top_y = box.top();
01847     int bottom_y = box.bottom();
01848     int goodness = bbox->GoodTextBlob();
01849     BlobRegionType blob_type = bbox->region_type();
01850     if (bbox->UniquelyVertical())
01851       blob_type = BRT_VERT_TEXT;
01852     if (bbox->UniquelyHorizontal())
01853       blob_type = BRT_TEXT;
01854     BlobTextFlowType flow = bbox->flow();
01855     if (flow == BTFT_NONE) {
01856       if (goodness == 0)
01857         flow = BTFT_NEIGHBOURS;
01858       else if (goodness == 1)
01859         flow = BTFT_CHAIN;
01860       else
01861         flow = BTFT_STRONG_CHAIN;
01862     }
01863     window->Pen(BLOBNBOX::TextlineColor(blob_type, flow));
01864     window->Rectangle(left_x, bottom_y, right_x, top_y);
01865   }
01866   window->Update();
01867 #endif
01868   return window;
01869 }
01870 
01871 static void DrawDiacriticJoiner(const BLOBNBOX* blob, ScrollView* window) {
01872 #ifndef GRAPHICS_DISABLED
01873   const TBOX& blob_box(blob->bounding_box());
01874   int top = MAX(blob_box.top(), blob->base_char_top());
01875   int bottom = MIN(blob_box.bottom(), blob->base_char_bottom());
01876   int x = (blob_box.left() + blob_box.right()) / 2;
01877   window->Line(x, top, x, bottom);
01878 #endif  // GRAPHICS_DISABLED
01879 }
01880 
01881 // Displays blobs colored according to whether or not they are diacritics.
01882 ScrollView* StrokeWidth::DisplayDiacritics(const char* window_name,
01883                                            int x, int y, TO_BLOCK* block) {
01884   ScrollView* window = NULL;
01885 #ifndef GRAPHICS_DISABLED
01886   window = MakeWindow(x, y, window_name);
01887   // For every blob in the grid, display it.
01888   window->Brush(ScrollView::NONE);
01889 
01890   BLOBNBOX_IT it(&block->blobs);
01891   for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
01892     BLOBNBOX* blob = it.data();
01893     if (blob->IsDiacritic()) {
01894       window->Pen(ScrollView::GREEN);
01895       DrawDiacriticJoiner(blob, window);
01896     } else {
01897       window->Pen(blob->BoxColor());
01898     }
01899     const TBOX& box = blob->bounding_box();
01900     window->Rectangle(box.left(), box. bottom(), box.right(), box.top());
01901   }
01902   it.set_to_list(&block->noise_blobs);
01903   for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
01904     BLOBNBOX* blob = it.data();
01905     if (blob->IsDiacritic()) {
01906       window->Pen(ScrollView::GREEN);
01907       DrawDiacriticJoiner(blob, window);
01908     } else {
01909       window->Pen(ScrollView::WHITE);
01910     }
01911     const TBOX& box = blob->bounding_box();
01912     window->Rectangle(box.left(), box. bottom(), box.right(), box.top());
01913   }
01914   window->Update();
01915 #endif
01916   return window;
01917 }
01918 
01919 }  // namespace tesseract.
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