/////////////////////////////////////////////////////////////////////// // File: colpartitionset.cpp // Description: Class to hold a list of ColPartitions of the page that // correspond roughly to columns. // Author: Ray Smith // Created: Thu Aug 14 10:54:01 PDT 2008 // // (C) Copyright 2008, 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. // /////////////////////////////////////////////////////////////////////// #ifdef HAVE_CONFIG_H #include "config_auto.h" #endif #include "colpartitionset.h" #include "ndminx.h" #include "workingpartset.h" #include "tablefind.h" namespace tesseract { // Minimum width of a column to be interesting as a multiple of resolution. const double kMinColumnWidth = 2.0 / 3; ELISTIZE(ColPartitionSet) ColPartitionSet::ColPartitionSet(ColPartition_LIST* partitions) { ColPartition_IT it(&parts_); it.add_list_after(partitions); ComputeCoverage(); } ColPartitionSet::ColPartitionSet(ColPartition* part) { ColPartition_IT it(&parts_); it.add_after_then_move(part); ComputeCoverage(); } ColPartitionSet::~ColPartitionSet() { } // Returns the number of columns of good width. int ColPartitionSet::GoodColumnCount() const { int num_good_cols = 0; // This is a read-only iteration of the list. ColPartition_IT it(const_cast(&parts_)); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { if (it.data()->good_width()) ++num_good_cols; } return num_good_cols; } // Return an element of the parts_ list from its index. ColPartition* ColPartitionSet::GetColumnByIndex(int index) { ColPartition_IT it(&parts_); it.mark_cycle_pt(); for (int i = 0; i < index && !it.cycled_list(); ++i, it.forward()); if (it.cycled_list()) return NULL; return it.data(); } // Return the ColPartition that contains the given coords, if any, else NULL. ColPartition* ColPartitionSet::ColumnContaining(int x, int y) { ColPartition_IT it(&parts_); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); if (part->ColumnContains(x, y)) return part; } return NULL; } // Extract all the parts from the list, relinquishing ownership. void ColPartitionSet::RelinquishParts() { ColPartition_IT it(&parts_); while (!it.empty()) { it.extract(); it.forward(); } } // Attempt to improve this by adding partitions or expanding partitions. void ColPartitionSet::ImproveColumnCandidate(WidthCallback* cb, PartSetVector* src_sets) { int set_size = src_sets->size(); // Iterate over the provided column sets, as each one may have something // to improve this. for (int i = 0; i < set_size; ++i) { ColPartitionSet* column_set = src_sets->get(i); if (column_set == NULL) continue; // Iterate over the parts in this and column_set, adding bigger or // new parts in column_set to this. ColPartition_IT part_it(&parts_); ASSERT_HOST(!part_it.empty()); int prev_right = MIN_INT32; part_it.mark_cycle_pt(); ColPartition_IT col_it(&column_set->parts_); for (col_it.mark_cycle_pt(); !col_it.cycled_list(); col_it.forward()) { ColPartition* col_part = col_it.data(); if (col_part->blob_type() < BRT_UNKNOWN) continue; // Ignore image partitions. int col_left = col_part->left_key(); int col_right = col_part->right_key(); // Sync-up part_it (in this) so it matches the col_part in column_set. ColPartition* part = part_it.data(); while (!part_it.at_last() && part->right_key() < col_left) { prev_right = part->right_key(); part_it.forward(); part = part_it.data(); } int part_left = part->left_key(); int part_right = part->right_key(); if (part_right < col_left || col_right < part_left) { // There is no overlap so this is a new partition. AddPartition(col_part->ShallowCopy(), &part_it); continue; } // Check the edges of col_part to see if they can improve part. bool part_width_ok = cb->Run(part->KeyWidth(part_left, part_right)); if (col_left < part_left && col_left > prev_right) { // The left edge of the column is better and it doesn't overlap, // so we can potentially expand it. int col_box_left = col_part->BoxLeftKey(); bool tab_width_ok = cb->Run(part->KeyWidth(col_left, part_right)); bool box_width_ok = cb->Run(part->KeyWidth(col_box_left, part_right)); if (tab_width_ok || (!part_width_ok )) { // The tab is leaving the good column metric at least as good as // it was before, so use the tab. part->CopyLeftTab(*col_part, false); part->SetColumnGoodness(cb); } else if (col_box_left < part_left && (box_width_ok || !part_width_ok)) { // The box is leaving the good column metric at least as good as // it was before, so use the box. part->CopyLeftTab(*col_part, true); part->SetColumnGoodness(cb); } part_left = part->left_key(); } if (col_right > part_right && (part_it.at_last() || part_it.data_relative(1)->left_key() > col_right)) { // The right edge is better, so we can possibly expand it. int col_box_right = col_part->BoxRightKey(); bool tab_width_ok = cb->Run(part->KeyWidth(part_left, col_right)); bool box_width_ok = cb->Run(part->KeyWidth(part_left, col_box_right)); if (tab_width_ok || (!part_width_ok )) { // The tab is leaving the good column metric at least as good as // it was before, so use the tab. part->CopyRightTab(*col_part, false); part->SetColumnGoodness(cb); } else if (col_box_right > part_right && (box_width_ok || !part_width_ok)) { // The box is leaving the good column metric at least as good as // it was before, so use the box. part->CopyRightTab(*col_part, true); part->SetColumnGoodness(cb); } } } } ComputeCoverage(); } // If this set is good enough to represent a new partitioning into columns, // add it to the vector of sets, otherwise delete it. void ColPartitionSet::AddToColumnSetsIfUnique(PartSetVector* column_sets, WidthCallback* cb) { bool debug = TabFind::WithinTestRegion(2, bounding_box_.left(), bounding_box_.bottom()); if (debug) { tprintf("Considering new column candidate:\n"); Print(); } if (!LegalColumnCandidate()) { if (debug) { tprintf("Not a legal column candidate:\n"); Print(); } delete this; return; } for (int i = 0; i < column_sets->size(); ++i) { ColPartitionSet* columns = column_sets->get(i); // In ordering the column set candidates, good_coverage_ is king, // followed by good_column_count_ and then bad_coverage_. bool better = good_coverage_ > columns->good_coverage_; if (good_coverage_ == columns->good_coverage_) { better = good_column_count_ > columns->good_column_count_; if (good_column_count_ == columns->good_column_count_) { better = bad_coverage_ > columns->bad_coverage_; } } if (better) { // The new one is better so add it. if (debug) tprintf("Good one\n"); column_sets->insert(this, i); return; } if (columns->CompatibleColumns(false, this, cb)) { if (debug) tprintf("Duplicate\n"); delete this; return; // It is not unique. } } if (debug) tprintf("Added to end\n"); column_sets->push_back(this); } // Return true if the partitions in other are all compatible with the columns // in this. bool ColPartitionSet::CompatibleColumns(bool debug, ColPartitionSet* other, WidthCallback* cb) { if (debug) { tprintf("CompatibleColumns testing compatibility\n"); Print(); other->Print(); } if (other->parts_.empty()) { if (debug) tprintf("CompatibleColumns true due to empty other\n"); return true; } ColPartition_IT it(&other->parts_); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); if (part->blob_type() < BRT_UNKNOWN) { if (debug) { tprintf("CompatibleColumns ignoring image partition\n"); part->Print(); } continue; // Image partitions are irrelevant to column compatibility. } int y = part->MidY(); int left = part->bounding_box().left(); int right = part->bounding_box().right(); ColPartition* left_col = ColumnContaining(left, y); ColPartition* right_col = ColumnContaining(right, y); if (right_col == NULL || left_col == NULL) { if (debug) { tprintf("CompatibleColumns false due to partition edge outside\n"); part->Print(); } return false; // A partition edge lies outside of all columns } if (right_col != left_col && cb->Run(right - left)) { if (debug) { tprintf("CompatibleColumns false due to good width in multiple cols\n"); part->Print(); } return false; // Partition with a good width must be in a single column. } ColPartition_IT it2= it; while (!it2.at_last()) { it2.forward(); ColPartition* next_part = it2.data(); if (!BLOBNBOX::IsTextType(next_part->blob_type())) continue; // Non-text partitions are irrelevant. int next_left = next_part->bounding_box().left(); if (next_left == right) { break; // They share the same edge, so one must be a pull-out. } // Search to see if right and next_left fall within a single column. ColPartition* next_left_col = ColumnContaining(next_left, y); if (right_col == next_left_col) { // There is a column break in this column. // This can be due to a figure caption within a column, a pull-out // block, or a simple broken textline that remains to be merged: // all allowed, or a change in column layout: not allowed. // If both partitions are of good width, then it is likely // a change in column layout, otherwise probably an allowed situation. if (part->good_width() && next_part->good_width()) { if (debug) { int next_right = next_part->bounding_box().right(); tprintf("CompatibleColumns false due to 2 parts of good width\n"); tprintf("part1 %d-%d, part2 %d-%d\n", left, right, next_left, next_right); right_col->Print(); } return false; } } break; } } if (debug) tprintf("CompatibleColumns true!\n"); return true; } // Returns the total width of all blobs in the part_set that do not lie // within an approved column. Used as a cost measure for using this // column set over another that might be compatible. int ColPartitionSet::UnmatchedWidth(ColPartitionSet* part_set) { int total_width = 0; ColPartition_IT it(&part_set->parts_); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); if (!BLOBNBOX::IsTextType(part->blob_type())) { continue; // Non-text partitions are irrelevant to column compatibility. } int y = part->MidY(); BLOBNBOX_C_IT box_it(part->boxes()); for (box_it.mark_cycle_pt(); !box_it.cycled_list(); box_it.forward()) { const TBOX& box = it.data()->bounding_box(); // Assume that the whole blob is outside any column iff its x-middle // is outside. int x = (box.left() + box.right()) / 2; ColPartition* col = ColumnContaining(x, y); if (col == NULL) total_width += box.width(); } } return total_width; } // Return true if this ColPartitionSet makes a legal column candidate by // having legal individual partitions and non-overlapping adjacent pairs. bool ColPartitionSet::LegalColumnCandidate() { ColPartition_IT it(&parts_); if (it.empty()) return false; bool any_text_parts = false; for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); if (BLOBNBOX::IsTextType(part->blob_type())) { if (!part->IsLegal()) return false; // Individual partition is illegal. any_text_parts = true; } if (!it.at_last()) { ColPartition* next_part = it.data_relative(1); if (next_part->left_key() < part->right_key()) { return false; } } } return any_text_parts; } // Return a copy of this. If good_only will only copy the Good ColPartitions. ColPartitionSet* ColPartitionSet::Copy(bool good_only) { ColPartition_LIST copy_parts; ColPartition_IT src_it(&parts_); ColPartition_IT dest_it(©_parts); for (src_it.mark_cycle_pt(); !src_it.cycled_list(); src_it.forward()) { ColPartition* part = src_it.data(); if (BLOBNBOX::IsTextType(part->blob_type()) && (!good_only || part->good_width() || part->good_column())) dest_it.add_after_then_move(part->ShallowCopy()); } if (dest_it.empty()) return NULL; return new ColPartitionSet(©_parts); } // Return the bounding boxes of columns at the given y-range void ColPartitionSet::GetColumnBoxes(int y_bottom, int y_top, ColSegment_LIST *segments) { ColPartition_IT it(&parts_); ColSegment_IT col_it(segments); col_it.move_to_last(); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); ICOORD bot_left(part->LeftAtY(y_top), y_bottom); ICOORD top_right(part->RightAtY(y_bottom), y_top); ColSegment *col_seg = new ColSegment(); col_seg->InsertBox(TBOX(bot_left, top_right)); col_it.add_after_then_move(col_seg); } } // Display the edges of the columns at the given y coords. void ColPartitionSet::DisplayColumnEdges(int y_bottom, int y_top, ScrollView* win) { #ifndef GRAPHICS_DISABLED ColPartition_IT it(&parts_); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); win->Line(part->LeftAtY(y_top), y_top, part->LeftAtY(y_bottom), y_bottom); win->Line(part->RightAtY(y_top), y_top, part->RightAtY(y_bottom), y_bottom); } #endif // GRAPHICS_DISABLED } // Return the ColumnSpanningType that best explains the columns overlapped // by the given coords(left,right,y), with the given margins. // Also return the first and last column index touched by the coords and // the leftmost spanned column. // Column indices are 2n + 1 for real columns (0 based) and even values // represent the gaps in between columns, with 0 being left of the leftmost. // resolution refers to the ppi resolution of the image. ColumnSpanningType ColPartitionSet::SpanningType(int resolution, int left, int right, int height, int y, int left_margin, int right_margin, int* first_col, int* last_col, int* first_spanned_col) { *first_col = -1; *last_col = -1; *first_spanned_col = -1; int margin_columns = 0; ColPartition_IT it(&parts_); int col_index = 1; for (it.mark_cycle_pt(); !it.cycled_list(); it.forward(), col_index += 2) { ColPartition* part = it.data(); if (part->ColumnContains(left, y) || (it.at_first() && part->ColumnContains(left + height, y))) { // In the default case, first_col is set, but columns_spanned remains // zero, so first_col will get reset in the first column genuinely // spanned, but we can tell the difference from a noise partition // that touches no column. *first_col = col_index; if (part->ColumnContains(right, y) || (it.at_last() && part->ColumnContains(right - height, y))) { // Both within a single column. *last_col = col_index; return CST_FLOWING; } if (left_margin <= part->LeftAtY(y)) { // It completely spans this column. *first_spanned_col = col_index; margin_columns = 1; } } else if (part->ColumnContains(right, y) || (it.at_last() && part->ColumnContains(right - height, y))) { if (*first_col < 0) { // It started in-between. *first_col = col_index - 1; } if (right_margin >= part->RightAtY(y)) { // It completely spans this column. if (margin_columns == 0) *first_spanned_col = col_index; ++margin_columns; } *last_col = col_index; break; } else if (left < part->LeftAtY(y) && right > part->RightAtY(y)) { // Neither left nor right are contained within, so it spans this // column. if (*first_col < 0) { // It started in between the previous column and the current column. *first_col = col_index - 1; } if (margin_columns == 0) *first_spanned_col = col_index; *last_col = col_index; } else if (right < part->LeftAtY(y)) { // We have gone past the end. *last_col = col_index - 1; if (*first_col < 0) { // It must lie completely between columns =>noise. *first_col = col_index - 1; } break; } } if (*first_col < 0) *first_col = col_index - 1; // The last in-between. if (*last_col < 0) *last_col = col_index - 1; // The last in-between. ASSERT_HOST(*first_col >= 0 && *last_col >= 0); ASSERT_HOST(*first_col <= *last_col); if (*first_col == *last_col && right - left < kMinColumnWidth * resolution) { // Neither end was in a column, and it didn't span any, so it lies // entirely between columns, therefore noise. return CST_NOISE; } else if (margin_columns <= 1) { // An exception for headings that stick outside of single-column text. if (margin_columns == 1 && parts_.singleton()) { return CST_HEADING; } // It is a pullout, as left and right were not in the same column, but // it doesn't go to the edge of its start and end. return CST_PULLOUT; } // Its margins went to the edges of first and last columns => heading. return CST_HEADING; } // The column_set has changed. Close down all in-progress WorkingPartSets in // columns that do not match and start new ones for the new columns in this. // As ColPartitions are turned into BLOCKs, the used ones are put in // used_parts, as they still need to be referenced in the grid. void ColPartitionSet::ChangeWorkColumns(const ICOORD& bleft, const ICOORD& tright, int resolution, ColPartition_LIST* used_parts, WorkingPartSet_LIST* working_set_list) { // Move the input list to a temporary location so we can delete its elements // as we add them to the output working_set. WorkingPartSet_LIST work_src; WorkingPartSet_IT src_it(&work_src); src_it.add_list_after(working_set_list); src_it.move_to_first(); WorkingPartSet_IT dest_it(working_set_list); // Completed blocks and to_blocks are accumulated and given to the first new // one whenever we keep a column, or at the end. BLOCK_LIST completed_blocks; TO_BLOCK_LIST to_blocks; WorkingPartSet* first_new_set = NULL; WorkingPartSet* working_set = NULL; ColPartition_IT col_it(&parts_); for (col_it.mark_cycle_pt(); !col_it.cycled_list(); col_it.forward()) { ColPartition* column = col_it.data(); // Any existing column to the left of column is completed. while (!src_it.empty() && ((working_set = src_it.data())->column() == NULL || working_set->column()->right_key() <= column->left_key())) { src_it.extract(); working_set->ExtractCompletedBlocks(bleft, tright, resolution, used_parts, &completed_blocks, &to_blocks); delete working_set; src_it.forward(); } // Make a new between-column WorkingSet for before the current column. working_set = new WorkingPartSet(NULL); dest_it.add_after_then_move(working_set); if (first_new_set == NULL) first_new_set = working_set; // A matching column gets to stay, and first_new_set gets all the // completed_sets. working_set = src_it.empty() ? NULL : src_it.data(); if (working_set != NULL && working_set->column()->MatchingColumns(*column)) { working_set->set_column(column); dest_it.add_after_then_move(src_it.extract()); src_it.forward(); first_new_set->InsertCompletedBlocks(&completed_blocks, &to_blocks); first_new_set = NULL; } else { // Just make a new working set for the current column. working_set = new WorkingPartSet(column); dest_it.add_after_then_move(working_set); } } // Complete any remaining src working sets. while (!src_it.empty()) { working_set = src_it.extract(); working_set->ExtractCompletedBlocks(bleft, tright, resolution, used_parts, &completed_blocks, &to_blocks); delete working_set; src_it.forward(); } // Make a new between-column WorkingSet for after the last column. working_set = new WorkingPartSet(NULL); dest_it.add_after_then_move(working_set); if (first_new_set == NULL) first_new_set = working_set; // The first_new_set now gets any accumulated completed_parts/blocks. first_new_set->InsertCompletedBlocks(&completed_blocks, &to_blocks); } // Accumulate the widths and gaps into the given variables. void ColPartitionSet::AccumulateColumnWidthsAndGaps(int* total_width, int* width_samples, int* total_gap, int* gap_samples) { ColPartition_IT it(&parts_); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); *total_width += part->ColumnWidth(); ++*width_samples; if (!it.at_last()) { ColPartition* next_part = it.data_relative(1); int gap = part->KeyWidth(part->right_key(), next_part->left_key()); *total_gap += gap; ++*gap_samples; } } } // Provide debug output for this ColPartitionSet and all the ColPartitions. void ColPartitionSet::Print() { ColPartition_IT it(&parts_); tprintf("Partition set of %d parts, %d good, coverage=%d+%d" " (%d,%d)->(%d,%d)\n", it.length(), good_column_count_, good_coverage_, bad_coverage_, bounding_box_.left(), bounding_box_.bottom(), bounding_box_.right(), bounding_box_.top()); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); part->Print(); } } // PRIVATE CODE. // Add the given partition to the list in the appropriate place. void ColPartitionSet::AddPartition(ColPartition* new_part, ColPartition_IT* it) { AddPartitionCoverageAndBox(*new_part); int new_right = new_part->right_key(); if (it->data()->left_key() >= new_right) it->add_before_stay_put(new_part); else it->add_after_stay_put(new_part); } // Compute the coverage and good column count. Coverage is the amount of the // width of the page (in pixels) that is covered by ColPartitions, which are // used to provide candidate column layouts. // Coverage is split into good and bad. Good coverage is provided by // ColPartitions of a frequent width (according to the callback function // provided by TabFinder::WidthCB, which accesses stored statistics on the // widths of ColParititions) and bad coverage is provided by all other // ColPartitions, even if they have tab vectors at both sides. Thus: // |-----------------------------------------------------------------| // | Double width heading | // |-----------------------------------------------------------------| // |-------------------------------| |-------------------------------| // | Common width ColParition | | Common width ColPartition | // |-------------------------------| |-------------------------------| // the layout with two common-width columns has better coverage than the // double width heading, because the coverage is "good," even though less in // total coverage than the heading, because the heading coverage is "bad." void ColPartitionSet::ComputeCoverage() { // Count the number of good columns and sum their width. ColPartition_IT it(&parts_); good_column_count_ = 0; good_coverage_ = 0; bad_coverage_ = 0; bounding_box_ = TBOX(); for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) { ColPartition* part = it.data(); AddPartitionCoverageAndBox(*part); } } // Adds the coverage, column count and box for a single partition, // without adding it to the list. (Helper factored from ComputeCoverage.) void ColPartitionSet::AddPartitionCoverageAndBox(const ColPartition& part) { bounding_box_ += part.bounding_box(); int coverage = part.ColumnWidth(); if (part.good_width()) { good_coverage_ += coverage; good_column_count_ += 2; } else { if (part.blob_type() < BRT_UNKNOWN) coverage /= 2; if (part.good_column()) ++good_column_count_; bad_coverage_ += coverage; } } } // namespace tesseract.