tesseract 4.1.1
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workingpartset.cpp
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1
2// File: workingpartset.cpp
3// Description: Class to hold a working set of partitions of the page
4// during construction of text/image regions.
5// Author: Ray Smith
6// Created: Tue Ocr 28 17:21:01 PDT 2008
7//
8// (C) Copyright 2008, Google Inc.
9// Licensed under the Apache License, Version 2.0 (the "License");
10// you may not use this file except in compliance with the License.
11// You may obtain a copy of the License at
12// http://www.apache.org/licenses/LICENSE-2.0
13// Unless required by applicable law or agreed to in writing, software
14// distributed under the License is distributed on an "AS IS" BASIS,
15// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16// See the License for the specific language governing permissions and
17// limitations under the License.
18//
20
21#include "workingpartset.h"
22#include "colpartition.h"
23
24namespace tesseract {
25
26ELISTIZE(WorkingPartSet)
27
28// Add the partition to this WorkingPartSet. Unrelated partitions are
29// stored in the order in which they are received, but if the partition
30// has a SingletonPartner, make sure that it stays with its partner.
31void WorkingPartSet::AddPartition(ColPartition* part) {
32 ColPartition* partner = part->SingletonPartner(true);
33 if (partner != nullptr) {
34 ASSERT_HOST(partner->SingletonPartner(false) == part);
35 }
36 if (latest_part_ == nullptr || partner == nullptr) {
37 // This partition goes at the end of the list
38 part_it_.move_to_last();
39 } else if (latest_part_->SingletonPartner(false) != part) {
40 // Reposition the iterator to the correct partner, or at the end.
41 for (part_it_.move_to_first(); !part_it_.at_last() &&
42 part_it_.data() != partner;
43 part_it_.forward());
44 }
45 part_it_.add_after_then_move(part);
46 latest_part_ = part;
47}
48
49// Make blocks out of any partitions in this WorkingPartSet, and append
50// them to the end of the blocks list. bleft, tright and resolution give
51// the bounds and resolution of the source image, so that blocks can be
52// made to fit in the bounds.
53// All ColPartitions go in the used_parts list, as they need to be kept
54// around, but are no longer needed.
56 const ICOORD& tright,
57 int resolution,
58 ColPartition_LIST* used_parts,
59 BLOCK_LIST* blocks,
60 TO_BLOCK_LIST* to_blocks) {
61 MakeBlocks(bleft, tright, resolution, used_parts);
62 BLOCK_IT block_it(blocks);
63 block_it.move_to_last();
64 block_it.add_list_after(&completed_blocks_);
65 TO_BLOCK_IT to_block_it(to_blocks);
66 to_block_it.move_to_last();
67 to_block_it.add_list_after(&to_blocks_);
68}
69
70// Insert the given blocks at the front of the completed_blocks_ list so
71// they can be kept in the correct reading order.
73 TO_BLOCK_LIST* to_blocks) {
74 BLOCK_IT block_it(&completed_blocks_);
75 block_it.add_list_before(blocks);
76 TO_BLOCK_IT to_block_it(&to_blocks_);
77 to_block_it.add_list_before(to_blocks);
78}
79
80// Make a block using lines parallel to the given vector that fit between
81// the min and max coordinates specified by the ColPartitions.
82// Construct a block from the given list of partitions.
83void WorkingPartSet::MakeBlocks(const ICOORD& bleft, const ICOORD& tright,
84 int resolution, ColPartition_LIST* used_parts) {
85 part_it_.move_to_first();
86 while (!part_it_.empty()) {
87 // Gather a list of ColPartitions in block_parts that will be split
88 // by linespacing into smaller blocks.
89 ColPartition_LIST block_parts;
90 ColPartition_IT block_it(&block_parts);
91 ColPartition* next_part = nullptr;
92 bool text_block = false;
93 do {
94 ColPartition* part = part_it_.extract();
95 if (part->blob_type() == BRT_UNKNOWN ||
96 (part->IsTextType() && part->type() != PT_TABLE))
97 text_block = true;
98 part->set_working_set(nullptr);
99 part_it_.forward();
100 block_it.add_after_then_move(part);
101 next_part = part->SingletonPartner(false);
102 if (part_it_.empty() || next_part != part_it_.data()) {
103 // Sequences of partitions can get split by titles.
104 next_part = nullptr;
105 }
106 // Merge adjacent blocks that are of the same type and let the
107 // linespacing determine the real boundaries.
108 if (next_part == nullptr && !part_it_.empty()) {
109 ColPartition* next_block_part = part_it_.data();
110 const TBOX& part_box = part->bounding_box();
111 const TBOX& next_box = next_block_part->bounding_box();
112
113 // In addition to the same type, the next box must not be above the
114 // current box, nor (if image) too far below.
115 PolyBlockType type = part->type(), next_type = next_block_part->type();
116 if (ColPartition::TypesSimilar(type, next_type) &&
117 !part->IsLineType() && !next_block_part->IsLineType() &&
118 next_box.bottom() <= part_box.top() &&
119 (text_block || part_box.bottom() <= next_box.top()))
120 next_part = next_block_part;
121 }
122 } while (!part_it_.empty() && next_part != nullptr);
123 if (!text_block) {
124 TO_BLOCK* to_block = ColPartition::MakeBlock(bleft, tright,
125 &block_parts, used_parts);
126 if (to_block != nullptr) {
127 TO_BLOCK_IT to_block_it(&to_blocks_);
128 to_block_it.add_to_end(to_block);
129 BLOCK_IT block_it(&completed_blocks_);
130 block_it.add_to_end(to_block->block);
131 }
132 } else {
133 // Further sub-divide text blocks where linespacing changes.
134 ColPartition::LineSpacingBlocks(bleft, tright, resolution, &block_parts,
135 used_parts,
136 &completed_blocks_, &to_blocks_);
137 }
138 }
139 part_it_.set_to_list(&part_set_);
140 latest_part_ = nullptr;
141 ASSERT_HOST(completed_blocks_.length() == to_blocks_.length());
142}
143
144} // namespace tesseract.
@ PT_TABLE
Definition: capi.h:135
@ BRT_UNKNOWN
Definition: blobbox.h:78
PolyBlockType
Definition: publictypes.h:53
#define ELISTIZE(CLASSNAME)
Definition: elst.h:931
#define ASSERT_HOST(x)
Definition: errcode.h:88
BLOCK * block
Definition: blobbox.h:777
integer coordinate
Definition: points.h:32
Definition: rect.h:34
int16_t top() const
Definition: rect.h:58
int16_t bottom() const
Definition: rect.h:65
static void LineSpacingBlocks(const ICOORD &bleft, const ICOORD &tright, int resolution, ColPartition_LIST *block_parts, ColPartition_LIST *used_parts, BLOCK_LIST *completed_blocks, TO_BLOCK_LIST *to_blocks)
static TO_BLOCK * MakeBlock(const ICOORD &bleft, const ICOORD &tright, ColPartition_LIST *block_parts, ColPartition_LIST *used_parts)
PolyBlockType type() const
Definition: colpartition.h:182
void set_working_set(WorkingPartSet *working_set)
Definition: colpartition.h:203
BlobRegionType blob_type() const
Definition: colpartition.h:149
const TBOX & bounding_box() const
Definition: colpartition.h:110
static bool TypesSimilar(PolyBlockType type1, PolyBlockType type2)
Definition: colpartition.h:419
ColPartition * SingletonPartner(bool upper)
void ExtractCompletedBlocks(const ICOORD &bleft, const ICOORD &tright, int resolution, ColPartition_LIST *used_parts, BLOCK_LIST *blocks, TO_BLOCK_LIST *to_blocks)
void InsertCompletedBlocks(BLOCK_LIST *blocks, TO_BLOCK_LIST *to_blocks)