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tesseract/textord/colpartition.cpp
zdenop@gmail.com 49c4ce3183 fix for GRAPHICS_DISABLED build 
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@686 d0cd1f9f-072b-0410-8dd7-cf729c803f20
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///////////////////////////////////////////////////////////////////////
// File: colpartition.cpp
// Description: Class to hold partitions of the page that correspond
// roughly to text lines.
// 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.
//
///////////////////////////////////////////////////////////////////////
#include "colpartition.h"
#include "colpartitiongrid.h"
#include "colpartitionset.h"
#include "detlinefit.h"
#include "dppoint.h"
#include "imagefind.h"
#include "workingpartset.h"
#ifdef _MSC_VER
#pragma warning(disable:4244) // Conversion warnings
#endif
namespace tesseract {
ELIST2IZE(ColPartition)
CLISTIZE(ColPartition)
//////////////// ColPartition Implementation ////////////////
// If multiple partners survive the partner depth test beyond this level,
// then arbitrarily pick one.
const int kMaxPartnerDepth = 4;
// Maximum change in spacing (in inches) to ignore.
const double kMaxSpacingDrift = 1.0 / 72; // 1/72 is one point.
// Maximum fraction of line height used as an additional allowance
// for top spacing.
const double kMaxTopSpacingFraction = 0.25;
// What multiple of the largest line height should be used as an upper bound
// for whether lines are in the same text block?
const double kMaxSameBlockLineSpacing = 3;
// Maximum ratio of sizes for lines to be considered the same size.
const double kMaxSizeRatio = 1.5;
// Fraction of max of leader width and gap for max IQR of gaps.
const double kMaxLeaderGapFractionOfMax = 0.25;
// Fraction of min of leader width and gap for max IQR of gaps.
const double kMaxLeaderGapFractionOfMin = 0.5;
// Minimum number of blobs to be considered a leader.
const int kMinLeaderCount = 5;
// Cost of a cut through a leader.
const int kLeaderCutCost = 8;
// Minimum score for a STRONG_CHAIN textline.
const int kMinStrongTextValue = 6;
// Minimum score for a CHAIN textline.
const int kMinChainTextValue = 3;
// Minimum number of blobs for strong horizontal text lines.
const int kHorzStrongTextlineCount = 8;
// Minimum height (in image pixels) for strong horizontal text lines.
const int kHorzStrongTextlineHeight = 10;
// Minimum aspect ratio for strong horizontal text lines.
const int kHorzStrongTextlineAspect = 5;
// Maximum upper quartile error allowed on a baseline fit as a fraction
// of height.
const double kMaxBaselineError = 0.4375;
// Min coverage for a good baseline between vectors
const double kMinBaselineCoverage = 0.5;
// Max RMS color noise to compare colors.
const int kMaxRMSColorNoise = 128;
// Maximum distance to allow a partition color to be to use that partition
// in smoothing neighbouring types. This is a squared distance.
const int kMaxColorDistance = 900;
// blob_type is the blob_region_type_ of the blobs in this partition.
// Vertical is the direction of logical vertical on the possibly skewed image.
ColPartition::ColPartition(BlobRegionType blob_type, const ICOORD& vertical)
: left_margin_(-MAX_INT32), right_margin_(MAX_INT32),
median_bottom_(MAX_INT32), median_top_(-MAX_INT32), median_size_(0),
median_left_(MAX_INT32), median_right_(-MAX_INT32), median_width_(0),
blob_type_(blob_type), flow_(BTFT_NONE), good_blob_score_(0),
good_width_(false), good_column_(false),
left_key_tab_(false), right_key_tab_(false),
left_key_(0), right_key_(0), type_(PT_UNKNOWN), vertical_(vertical),
working_set_(NULL), last_add_was_vertical_(false), block_owned_(false),
desperately_merged_(false),
first_column_(-1), last_column_(-1), column_set_(NULL),
side_step_(0), top_spacing_(0), bottom_spacing_(0),
type_before_table_(PT_UNKNOWN), inside_table_column_(false),
nearest_neighbor_above_(NULL), nearest_neighbor_below_(NULL),
space_above_(0), space_below_(0), space_to_left_(0), space_to_right_(0),
owns_blobs_(true) {
memset(special_blobs_densities_, 0, sizeof(special_blobs_densities_));
}
// Constructs a fake ColPartition with a single fake BLOBNBOX, all made
// from a single TBOX.
// WARNING: Despite being on C_LISTs, the BLOBNBOX owns the C_BLOB and
// the ColPartition owns the BLOBNBOX!!!
// Call DeleteBoxes before deleting the ColPartition.
ColPartition* ColPartition::FakePartition(const TBOX& box,
PolyBlockType block_type,
BlobRegionType blob_type,
BlobTextFlowType flow) {
ColPartition* part = new ColPartition(blob_type, ICOORD(0, 1));
part->set_type(block_type);
part->set_flow(flow);
part->AddBox(new BLOBNBOX(C_BLOB::FakeBlob(box)));
part->set_left_margin(box.left());
part->set_right_margin(box.right());
part->SetBlobTypes();
part->ComputeLimits();
part->ClaimBoxes();
return part;
}
// Constructs and returns a ColPartition with the given real BLOBNBOX,
// and sets it up to be a "big" partition (single-blob partition bigger
// than the surrounding text that may be a dropcap, two or more vertically
// touching characters, or some graphic element.
// If the given list is not NULL, the partition is also added to the list.
ColPartition* ColPartition::MakeBigPartition(BLOBNBOX* box,
ColPartition_LIST* big_part_list) {
box->set_owner(NULL);
ColPartition* single = new ColPartition(BRT_UNKNOWN, ICOORD(0, 1));
single->set_flow(BTFT_NONE);
single->AddBox(box);
single->ComputeLimits();
single->ClaimBoxes();
single->SetBlobTypes();
single->set_block_owned(true);
if (big_part_list != NULL) {
ColPartition_IT part_it(big_part_list);
part_it.add_to_end(single);
}
return single;
}
ColPartition::~ColPartition() {
// Remove this as a partner of all partners, as we don't want them
// referring to a deleted object.
ColPartition_C_IT it(&upper_partners_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
it.data()->RemovePartner(false, this);
}
it.set_to_list(&lower_partners_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
it.data()->RemovePartner(true, this);
}
}
// Constructs a fake ColPartition with no BLOBNBOXes to represent a
// horizontal or vertical line, given a type and a bounding box.
ColPartition* ColPartition::MakeLinePartition(BlobRegionType blob_type,
const ICOORD& vertical,
int left, int bottom,
int right, int top) {
ColPartition* part = new ColPartition(blob_type, vertical);
part->bounding_box_ = TBOX(left, bottom, right, top);
part->median_bottom_ = bottom;
part->median_top_ = top;
part->median_size_ = top - bottom;
part->median_width_ = right - left;
part->left_key_ = part->BoxLeftKey();
part->right_key_ = part->BoxRightKey();
return part;
}
// Adds the given box to the partition, updating the partition bounds.
// The list of boxes in the partition is updated, ensuring that no box is
// recorded twice, and the boxes are kept in increasing left position.
void ColPartition::AddBox(BLOBNBOX* bbox) {
TBOX box = bbox->bounding_box();
// Update the partition limits.
if (boxes_.length() == 0) {
bounding_box_ = box;
} else {
bounding_box_ += box;
}
if (IsVerticalType()) {
if (!last_add_was_vertical_) {
boxes_.sort(SortByBoxBottom<BLOBNBOX>);
last_add_was_vertical_ = true;
}
boxes_.add_sorted(SortByBoxBottom<BLOBNBOX>, true, bbox);
} else {
if (last_add_was_vertical_) {
boxes_.sort(SortByBoxLeft<BLOBNBOX>);
last_add_was_vertical_ = false;
}
boxes_.add_sorted(SortByBoxLeft<BLOBNBOX>, true, bbox);
}
if (!left_key_tab_)
left_key_ = BoxLeftKey();
if (!right_key_tab_)
right_key_ = BoxRightKey();
if (TabFind::WithinTestRegion(2, box.left(), box.bottom()))
tprintf("Added box (%d,%d)->(%d,%d) left_blob_x_=%d, right_blob_x_ = %d\n",
box.left(), box.bottom(), box.right(), box.top(),
bounding_box_.left(), bounding_box_.right());
}
// Removes the given box from the partition, updating the bounds.
void ColPartition::RemoveBox(BLOBNBOX* box) {
BLOBNBOX_C_IT bb_it(&boxes_);
for (bb_it.mark_cycle_pt(); !bb_it.cycled_list(); bb_it.forward()) {
if (box == bb_it.data()) {
bb_it.extract();
ComputeLimits();
return;
}
}
}
// Returns the tallest box in the partition, as measured perpendicular to the
// presumed flow of text.
BLOBNBOX* ColPartition::BiggestBox() {
BLOBNBOX* biggest = NULL;
BLOBNBOX_C_IT bb_it(&boxes_);
for (bb_it.mark_cycle_pt(); !bb_it.cycled_list(); bb_it.forward()) {
BLOBNBOX* bbox = bb_it.data();
if (IsVerticalType()) {
if (biggest == NULL ||
bbox->bounding_box().width() > biggest->bounding_box().width())
biggest = bbox;
} else {
if (biggest == NULL ||
bbox->bounding_box().height() > biggest->bounding_box().height())
biggest = bbox;
}
}
return biggest;
}
// Returns the bounding box excluding the given box.
TBOX ColPartition::BoundsWithoutBox(BLOBNBOX* box) {
TBOX result;
BLOBNBOX_C_IT bb_it(&boxes_);
for (bb_it.mark_cycle_pt(); !bb_it.cycled_list(); bb_it.forward()) {
if (box != bb_it.data()) {
result += bb_it.data()->bounding_box();
}
}
return result;
}
// Claims the boxes in the boxes_list by marking them with a this owner
// pointer. If a box is already owned, then it must be owned by this.
void ColPartition::ClaimBoxes() {
BLOBNBOX_C_IT bb_it(&boxes_);
for (bb_it.mark_cycle_pt(); !bb_it.cycled_list(); bb_it.forward()) {
BLOBNBOX* bblob = bb_it.data();
ColPartition* other = bblob->owner();
if (other == NULL) {
// Normal case: ownership is available.
bblob->set_owner(this);
} else {
ASSERT_HOST(other == this);
}
}
}
// NULL the owner of the blobs in this partition, so they can be deleted
// independently of the ColPartition.
void ColPartition::DisownBoxes() {
BLOBNBOX_C_IT bb_it(&boxes_);
for (bb_it.mark_cycle_pt(); !bb_it.cycled_list(); bb_it.forward()) {
BLOBNBOX* bblob = bb_it.data();
ASSERT_HOST(bblob->owner() == this || bblob->owner() == NULL);
bblob->set_owner(NULL);
}
}
// Delete the boxes that this partition owns.
void ColPartition::DeleteBoxes() {
// Although the boxes_ list is a C_LIST, in some cases it owns the
// BLOBNBOXes, as the ColPartition takes ownership from the grid,
// and the BLOBNBOXes own the underlying C_BLOBs.
for (BLOBNBOX_C_IT bb_it(&boxes_); !bb_it.empty(); bb_it.forward()) {
BLOBNBOX* bblob = bb_it.extract();
delete bblob->cblob();
delete bblob;
}
}
// Reflects the partition in the y-axis, assuming that its blobs have
// already been done. Corrects only a limited part of the members, since
// this function is assumed to be used shortly after initial creation, which
// is before a lot of the members are used.
void ColPartition::ReflectInYAxis() {
ColPartition_CLIST reversed_boxes;
ColPartition_C_IT reversed_it(&reversed_boxes);
// Reverse the order of the boxes_.
BLOBNBOX_C_IT bb_it(&boxes_);
for (bb_it.mark_cycle_pt(); !bb_it.cycled_list(); bb_it.forward()) {
reversed_it.add_before_then_move(bb_it.extract());
}
bb_it.add_list_after(&reversed_boxes);
ASSERT_HOST(!left_key_tab_ && !right_key_tab_);
int tmp = left_margin_;
left_margin_ = -right_margin_;
right_margin_ = -tmp;
ComputeLimits();
}
// Returns true if this is a legal partition - meaning that the conditions
// left_margin <= bounding_box left
// left_key <= bounding box left key
// bounding box left <= bounding box right
// and likewise for right margin and key
// are all met.
bool ColPartition::IsLegal() {
if (bounding_box_.left() > bounding_box_.right()) {
if (textord_debug_bugs) {
tprintf("Bounding box invalid\n");
Print();
}
return false; // Bounding box invalid.
}
if (left_margin_ > bounding_box_.left() ||
right_margin_ < bounding_box_.right()) {
if (textord_debug_bugs) {
tprintf("Margins invalid\n");
Print();
}
return false; // Margins invalid.
}
if (left_key_ > BoxLeftKey() || right_key_ < BoxRightKey()) {
if (textord_debug_bugs) {
tprintf("Key inside box: %d v %d or %d v %d\n",
left_key_, BoxLeftKey(), right_key_, BoxRightKey());
Print();
}
return false; // Keys inside the box.
}
return true;
}
// Returns true if the left and right edges are approximately equal.
bool ColPartition::MatchingColumns(const ColPartition& other) const {
int y = (MidY() + other.MidY()) / 2;
if (!NearlyEqual(other.LeftAtY(y) / kColumnWidthFactor,
LeftAtY(y) / kColumnWidthFactor, 1))
return false;
if (!NearlyEqual(other.RightAtY(y) / kColumnWidthFactor,
RightAtY(y) / kColumnWidthFactor, 1))
return false;
return true;
}
// Returns true if the colors match for two text partitions.
bool ColPartition::MatchingTextColor(const ColPartition& other) const {
if (color1_[L_ALPHA_CHANNEL] > kMaxRMSColorNoise &&
other.color1_[L_ALPHA_CHANNEL] > kMaxRMSColorNoise)
return false; // Too noisy.
// Colors must match for other to count.
double d_this1_o = ImageFind::ColorDistanceFromLine(other.color1_,
other.color2_,
color1_);
double d_this2_o = ImageFind::ColorDistanceFromLine(other.color1_,
other.color2_,
color2_);
double d_o1_this = ImageFind::ColorDistanceFromLine(color1_, color2_,
other.color1_);
double d_o2_this = ImageFind::ColorDistanceFromLine(color1_, color2_,
other.color2_);
// All 4 distances must be small enough.
return d_this1_o < kMaxColorDistance && d_this2_o < kMaxColorDistance &&
d_o1_this < kMaxColorDistance && d_o2_this < kMaxColorDistance;
}
// Returns true if the sizes match for two text partitions,
// taking orientation into account. See also SizesSimilar.
bool ColPartition::MatchingSizes(const ColPartition& other) const {
if (blob_type_ == BRT_VERT_TEXT || other.blob_type_ == BRT_VERT_TEXT)
return !TabFind::DifferentSizes(median_width_, other.median_width_);
else
return !TabFind::DifferentSizes(median_size_, other.median_size_);
}
// Returns true if there is no tabstop violation in merging this and other.
bool ColPartition::ConfirmNoTabViolation(const ColPartition& other) const {
if (bounding_box_.right() < other.bounding_box_.left() &&
bounding_box_.right() < other.LeftBlobRule())
return false;
if (other.bounding_box_.right() < bounding_box_.left() &&
other.bounding_box_.right() < LeftBlobRule())
return false;
if (bounding_box_.left() > other.bounding_box_.right() &&
bounding_box_.left() > other.RightBlobRule())
return false;
if (other.bounding_box_.left() > bounding_box_.right() &&
other.bounding_box_.left() > RightBlobRule())
return false;
return true;
}
// Returns true if other has a similar stroke width to this.
bool ColPartition::MatchingStrokeWidth(const ColPartition& other,
double fractional_tolerance,
double constant_tolerance) const {
int match_count = 0;
int nonmatch_count = 0;
BLOBNBOX_C_IT box_it(const_cast<BLOBNBOX_CLIST*>(&boxes_));
BLOBNBOX_C_IT other_it(const_cast<BLOBNBOX_CLIST*>(&other.boxes_));
box_it.mark_cycle_pt();
other_it.mark_cycle_pt();
while (!box_it.cycled_list() && !other_it.cycled_list()) {
if (box_it.data()->MatchingStrokeWidth(*other_it.data(),
fractional_tolerance,
constant_tolerance))
++match_count;
else
++nonmatch_count;
box_it.forward();
other_it.forward();
}
return match_count > nonmatch_count;
}
// Returns true if base is an acceptable diacritic base char merge
// with this as the diacritic.
// Returns true if:
// (1) this is a ColPartition containing only diacritics, and
// (2) the base characters indicated on the diacritics all believably lie
// within the text line of the candidate ColPartition.
bool ColPartition::OKDiacriticMerge(const ColPartition& candidate,
bool debug) const {
BLOBNBOX_C_IT it(const_cast<BLOBNBOX_CLIST*>(&boxes_));
int min_top = MAX_INT32;
int max_bottom = -MAX_INT32;
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
if (!blob->IsDiacritic()) {
if (debug) {
tprintf("Blob is not a diacritic:");
blob->bounding_box().print();
}
return false; // All blobs must have diacritic bases.
}
if (blob->base_char_top() < min_top)
min_top = blob->base_char_top();
if (blob->base_char_bottom() > max_bottom)
max_bottom = blob->base_char_bottom();
}
// If the intersection of all vertical ranges of all base characters
// overlaps the median range of this, then it is OK.
bool result = min_top > candidate.median_bottom_ &&
max_bottom < candidate.median_top_;
if (debug) {
if (result)
tprintf("OKDiacritic!\n");
else
tprintf("y ranges don\'t overlap: %d-%d / %d-%d\n",
max_bottom, min_top, median_bottom_, median_top_);
}
return result;
}
// Sets the sort key using either the tab vector, or the bounding box if
// the tab vector is NULL. If the tab_vector lies inside the bounding_box,
// use the edge of the box as a key any way.
void ColPartition::SetLeftTab(const TabVector* tab_vector) {
if (tab_vector != NULL) {
left_key_ = tab_vector->sort_key();
left_key_tab_ = left_key_ <= BoxLeftKey();
} else {
left_key_tab_ = false;
}
if (!left_key_tab_)
left_key_ = BoxLeftKey();
}
// As SetLeftTab, but with the right.
void ColPartition::SetRightTab(const TabVector* tab_vector) {
if (tab_vector != NULL) {
right_key_ = tab_vector->sort_key();
right_key_tab_ = right_key_ >= BoxRightKey();
} else {
right_key_tab_ = false;
}
if (!right_key_tab_)
right_key_ = BoxRightKey();
}
// Copies the left/right tab from the src partition, but if take_box is
// true, copies the box instead and uses that as a key.
void ColPartition::CopyLeftTab(const ColPartition& src, bool take_box) {
left_key_tab_ = take_box ? false : src.left_key_tab_;
if (left_key_tab_) {
left_key_ = src.left_key_;
} else {
bounding_box_.set_left(XAtY(src.BoxLeftKey(), MidY()));
left_key_ = BoxLeftKey();
}
if (left_margin_ > bounding_box_.left())
left_margin_ = src.left_margin_;
}
// As CopyLeftTab, but with the right.
void ColPartition::CopyRightTab(const ColPartition& src, bool take_box) {
right_key_tab_ = take_box ? false : src.right_key_tab_;
if (right_key_tab_) {
right_key_ = src.right_key_;
} else {
bounding_box_.set_right(XAtY(src.BoxRightKey(), MidY()));
right_key_ = BoxRightKey();
}
if (right_margin_ < bounding_box_.right())
right_margin_ = src.right_margin_;
}
// Returns the left rule line x coord of the leftmost blob.
int ColPartition::LeftBlobRule() const {
BLOBNBOX_C_IT it(const_cast<BLOBNBOX_CLIST*>(&boxes_));
return it.data()->left_rule();
}
// Returns the right rule line x coord of the rightmost blob.
int ColPartition::RightBlobRule() const {
BLOBNBOX_C_IT it(const_cast<BLOBNBOX_CLIST*>(&boxes_));
it.move_to_last();
return it.data()->right_rule();
}
float ColPartition::SpecialBlobsDensity(const BlobSpecialTextType type) const {
ASSERT_HOST(type < BSTT_COUNT);
return special_blobs_densities_[type];
}
int ColPartition::SpecialBlobsCount(const BlobSpecialTextType type) {
ASSERT_HOST(type < BSTT_COUNT);
BLOBNBOX_C_IT blob_it(&boxes_);
int count = 0;
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
BlobSpecialTextType blob_type = blob->special_text_type();
if (blob_type == type) {
count++;
}
}
return count;
}
void ColPartition::SetSpecialBlobsDensity(
const BlobSpecialTextType type, const float density) {
ASSERT_HOST(type < BSTT_COUNT);
special_blobs_densities_[type] = density;
}
void ColPartition::ComputeSpecialBlobsDensity() {
memset(special_blobs_densities_, 0, sizeof(special_blobs_densities_));
if (boxes_.empty()) {
return;
}
BLOBNBOX_C_IT blob_it(&boxes_);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
BlobSpecialTextType type = blob->special_text_type();
special_blobs_densities_[type]++;
}
for (int type = 0; type < BSTT_COUNT; ++type) {
special_blobs_densities_[type] /= boxes_.length();
}
}
// Add a partner above if upper, otherwise below.
// Add them uniquely and keep the list sorted by box left.
// Partnerships are added symmetrically to partner and this.
void ColPartition::AddPartner(bool upper, ColPartition* partner) {
if (upper) {
partner->lower_partners_.add_sorted(SortByBoxLeft<ColPartition>,
true, this);
upper_partners_.add_sorted(SortByBoxLeft<ColPartition>, true, partner);
} else {
partner->upper_partners_.add_sorted(SortByBoxLeft<ColPartition>,
true, this);
lower_partners_.add_sorted(SortByBoxLeft<ColPartition>, true, partner);
}
}
// Removes the partner from this, but does not remove this from partner.
// This asymmetric removal is so as not to mess up the iterator that is
// working on partner's partner list.
void ColPartition::RemovePartner(bool upper, ColPartition* partner) {
ColPartition_C_IT it(upper ? &upper_partners_ : &lower_partners_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
if (it.data() == partner) {
it.extract();
break;
}
}
}
// Returns the partner if the given partner is a singleton, otherwise NULL.
ColPartition* ColPartition::SingletonPartner(bool upper) {
ColPartition_CLIST* partners = upper ? &upper_partners_ : &lower_partners_;
if (!partners->singleton())
return NULL;
ColPartition_C_IT it(partners);
return it.data();
}
// Merge with the other partition and delete it.
void ColPartition::Absorb(ColPartition* other, WidthCallback* cb) {
// The result has to either own all of the blobs or none of them.
// Verify the flag is consisent.
ASSERT_HOST(owns_blobs() == other->owns_blobs());
// TODO(nbeato): check owns_blobs better. Right now owns_blobs
// should always be true when this is called. So there is no issues.
if (TabFind::WithinTestRegion(2, bounding_box_.left(),
bounding_box_.bottom()) ||
TabFind::WithinTestRegion(2, other->bounding_box_.left(),
other->bounding_box_.bottom())) {
tprintf("Merging:");
Print();
other->Print();
}
// Update the special_blobs_densities_.
memset(special_blobs_densities_, 0, sizeof(special_blobs_densities_));
for (int type = 0; type < BSTT_COUNT; ++type) {
int w1 = boxes_.length(), w2 = other->boxes_.length();
float new_val = special_blobs_densities_[type] * w1 +
other->special_blobs_densities_[type] * w2;
if (!w1 || !w2) {
special_blobs_densities_[type] = new_val / (w1 + w2);
}
}
// Merge the two sorted lists.
BLOBNBOX_C_IT it(&boxes_);
BLOBNBOX_C_IT it2(&other->boxes_);
for (; !it2.empty(); it2.forward()) {
BLOBNBOX* bbox2 = it2.extract();
ColPartition* prev_owner = bbox2->owner();
if (prev_owner != other && prev_owner != NULL) {
// A blob on other's list is owned by someone else; let them have it.
continue;
}
ASSERT_HOST(prev_owner == other || prev_owner == NULL);
if (prev_owner == other)
bbox2->set_owner(this);
it.add_to_end(bbox2);
}
left_margin_ = MIN(left_margin_, other->left_margin_);
right_margin_ = MAX(right_margin_, other->right_margin_);
if (other->left_key_ < left_key_) {
left_key_ = other->left_key_;
left_key_tab_ = other->left_key_tab_;
}
if (other->right_key_ > right_key_) {
right_key_ = other->right_key_;
right_key_tab_ = other->right_key_tab_;
}
// Combine the flow and blob_type in a sensible way.
// Dominant flows stay.
if (!DominatesInMerge(flow_, other->flow_)) {
flow_ = other->flow_;
blob_type_ = other->blob_type_;
}
SetBlobTypes();
if (IsVerticalType()) {
boxes_.sort(SortByBoxBottom<BLOBNBOX>);
last_add_was_vertical_ = true;
} else {
boxes_.sort(SortByBoxLeft<BLOBNBOX>);
last_add_was_vertical_ = false;
}
ComputeLimits();
// Fix partner lists. other is going away, so remove it as a
// partner of all its partners and add this in its place.
for (int upper = 0; upper < 2; ++upper) {
ColPartition_CLIST partners;
ColPartition_C_IT part_it(&partners);
part_it.add_list_after(upper ? &other->upper_partners_
: &other->lower_partners_);
for (part_it.move_to_first(); !part_it.empty(); part_it.forward()) {
ColPartition* partner = part_it.extract();
partner->RemovePartner(!upper, other);
partner->RemovePartner(!upper, this);
partner->AddPartner(!upper, this);
}
}
delete other;
if (cb != NULL) {
SetColumnGoodness(cb);
}
}
// Merge1 and merge2 are candidates to be merged, yet their combined box
// overlaps this. Is that allowed?
// Returns true if the overlap between this and the merged pair of
// merge candidates is sufficiently trivial to be allowed.
// The merged box can graze the edge of this by the ok_box_overlap
// if that exceeds the margin to the median top and bottom.
// ok_box_overlap should be set by the caller appropriate to the sizes of
// the text involved, and is usually a fraction of the median size of merge1
// and/or merge2, or this.
// TODO(rays) Determine whether vertical text needs to be considered.
bool ColPartition::OKMergeOverlap(const ColPartition& merge1,
const ColPartition& merge2,
int ok_box_overlap, bool debug) {
// Vertical partitions are not allowed to be involved.
if (IsVerticalType() || merge1.IsVerticalType() || merge2.IsVerticalType()) {
if (debug)
tprintf("Vertical partition\n");
return false;
}
// The merging partitions must strongly overlap each other.
if (!merge1.VSignificantCoreOverlap(merge2)) {
if (debug)
tprintf("Voverlap %d (%d)\n",
merge1.VCoreOverlap(merge2),
merge1.VSignificantCoreOverlap(merge2));
return false;
}
// The merged box must not overlap the median bounds of this.
TBOX merged_box(merge1.bounding_box());
merged_box += merge2.bounding_box();
if (merged_box.bottom() < median_top_ && merged_box.top() > median_bottom_ &&
merged_box.bottom() < bounding_box_.top() - ok_box_overlap &&
merged_box.top() > bounding_box_.bottom() + ok_box_overlap) {
if (debug)
tprintf("Excessive box overlap\n");
return false;
}
// Looks OK!
return true;
}
// Find the blob at which to split this to minimize the overlap with the
// given box. Returns the first blob to go in the second partition.
BLOBNBOX* ColPartition::OverlapSplitBlob(const TBOX& box) {
if (boxes_.empty() || boxes_.singleton())
return NULL;
BLOBNBOX_C_IT it(&boxes_);
TBOX left_box(it.data()->bounding_box());
for (it.forward(); !it.at_first(); it.forward()) {
BLOBNBOX* bbox = it.data();
left_box += bbox->bounding_box();
if (left_box.overlap(box))
return bbox;
}
return NULL;
}
// Split this partition keeping the first half in this and returning
// the second half.
// Splits by putting the split_blob and the blobs that follow
// in the second half, and the rest in the first half.
ColPartition* ColPartition::SplitAtBlob(BLOBNBOX* split_blob) {
ColPartition* split_part = ShallowCopy();
split_part->set_owns_blobs(owns_blobs());
BLOBNBOX_C_IT it(&boxes_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* bbox = it.data();
ColPartition* prev_owner = bbox->owner();
ASSERT_HOST(!owns_blobs() || prev_owner == this || prev_owner == NULL);
if (bbox == split_blob || !split_part->boxes_.empty()) {
split_part->AddBox(it.extract());
if (owns_blobs() && prev_owner != NULL)
bbox->set_owner(split_part);
}
}
ASSERT_HOST(!it.empty());
if (split_part->IsEmpty()) {
// Split part ended up with nothing. Possible if split_blob is not
// in the list of blobs.
delete split_part;
return NULL;
}
right_key_tab_ = false;
split_part->left_key_tab_ = false;
ComputeLimits();
// TODO(nbeato) Merge Ray's CL like this:
// if (owns_blobs())
// SetBlobTextlineGoodness();
split_part->ComputeLimits();
// TODO(nbeato) Merge Ray's CL like this:
// if (split_part->owns_blobs())
// split_part->SetBlobTextlineGoodness();
return split_part;
}
// Split this partition at the given x coordinate, returning the right
// half and keeping the left half in this.
ColPartition* ColPartition::SplitAt(int split_x) {
if (split_x <= bounding_box_.left() || split_x >= bounding_box_.right())
return NULL; // There will be no change.
ColPartition* split_part = ShallowCopy();
split_part->set_owns_blobs(owns_blobs());
BLOBNBOX_C_IT it(&boxes_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* bbox = it.data();
ColPartition* prev_owner = bbox->owner();
ASSERT_HOST(!owns_blobs() || prev_owner == this || prev_owner == NULL);
const TBOX& box = bbox->bounding_box();
if (box.left() >= split_x) {
split_part->AddBox(it.extract());
if (owns_blobs() && prev_owner != NULL)
bbox->set_owner(split_part);
}
}
ASSERT_HOST(!it.empty());
if (split_part->IsEmpty()) {
// Split part ended up with nothing. Possible if split_x passes
// through the last blob.
delete split_part;
return NULL;
}
right_key_tab_ = false;
split_part->left_key_tab_ = false;
right_margin_ = split_x;
split_part->left_margin_ = split_x;
ComputeLimits();
split_part->ComputeLimits();
return split_part;
}
// Recalculates all the coordinate limits of the partition.
void ColPartition::ComputeLimits() {
bounding_box_ = TBOX(); // Clear it
BLOBNBOX_C_IT it(&boxes_);
BLOBNBOX* bbox = NULL;
int non_leader_count = 0;
if (it.empty()) {
bounding_box_.set_left(left_margin_);
bounding_box_.set_right(right_margin_);
bounding_box_.set_bottom(0);
bounding_box_.set_top(0);
} else {
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
bbox = it.data();
bounding_box_ += bbox->bounding_box();
if (bbox->flow() != BTFT_LEADER)
++non_leader_count;
}
}
if (!left_key_tab_)
left_key_ = BoxLeftKey();
if (left_key_ > BoxLeftKey() && textord_debug_bugs) {
// TODO(rays) investigate the causes of these error messages, to find
// out if they are genuinely harmful, or just indicative of junk input.
tprintf("Computed left-illegal partition\n");
Print();
}
if (!right_key_tab_)
right_key_ = BoxRightKey();
if (right_key_ < BoxRightKey() && textord_debug_bugs) {
tprintf("Computed right-illegal partition\n");
Print();
}
if (it.empty())
return;
if (IsImageType() || blob_type() == BRT_RECTIMAGE ||
blob_type() == BRT_POLYIMAGE) {
median_top_ = bounding_box_.top();
median_bottom_ = bounding_box_.bottom();
median_size_ = bounding_box_.height();
median_left_ = bounding_box_.left();
median_right_ = bounding_box_.right();
median_width_ = bounding_box_.width();
} else {
STATS top_stats(bounding_box_.bottom(), bounding_box_.top() + 1);
STATS bottom_stats(bounding_box_.bottom(), bounding_box_.top() + 1);
STATS size_stats(0, bounding_box_.height() + 1);
STATS left_stats(bounding_box_.left(), bounding_box_.right() + 1);
STATS right_stats(bounding_box_.left(), bounding_box_.right() + 1);
STATS width_stats(0, bounding_box_.width() + 1);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
bbox = it.data();
if (non_leader_count == 0 || bbox->flow() != BTFT_LEADER) {
TBOX box = bbox->bounding_box();
int area = box.area();
top_stats.add(box.top(), area);
bottom_stats.add(box.bottom(), area);
size_stats.add(box.height(), area);
left_stats.add(box.left(), area);
right_stats.add(box.right(), area);
width_stats.add(box.width(), area);
}
}
median_top_ = static_cast<int>(top_stats.median() + 0.5);
median_bottom_ = static_cast<int>(bottom_stats.median() + 0.5);
median_size_ = static_cast<int>(size_stats.median() + 0.5);
median_left_ = static_cast<int>(left_stats.median() + 0.5);
median_right_ = static_cast<int>(right_stats.median() + 0.5);
median_width_ = static_cast<int>(width_stats.median() + 0.5);
}
if (right_margin_ < bounding_box_.right() && textord_debug_bugs) {
tprintf("Made partition with bad right coords");
Print();
}
if (left_margin_ > bounding_box_.left() && textord_debug_bugs) {
tprintf("Made partition with bad left coords");
Print();
}
// Fix partner lists. The bounding box has changed and partners are stored
// in bounding box order, so remove and reinsert this as a partner
// of all its partners.
for (int upper = 0; upper < 2; ++upper) {
ColPartition_CLIST partners;
ColPartition_C_IT part_it(&partners);
part_it.add_list_after(upper ? &upper_partners_ : &lower_partners_);
for (part_it.move_to_first(); !part_it.empty(); part_it.forward()) {
ColPartition* partner = part_it.extract();
partner->RemovePartner(!upper, this);
partner->AddPartner(!upper, this);
}
}
if (TabFind::WithinTestRegion(2, bounding_box_.left(),
bounding_box_.bottom())) {
tprintf("Recomputed box for partition %p\n", this);
Print();
}
}
// Returns the number of boxes that overlap the given box.
int ColPartition::CountOverlappingBoxes(const TBOX& box) {
BLOBNBOX_C_IT it(&boxes_);
int overlap_count = 0;
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* bbox = it.data();
if (box.overlap(bbox->bounding_box()))
++overlap_count;
}
return overlap_count;
}
// Computes and sets the type_ and first_colum_, last_column_ and column_set_.
// resolution refers to the ppi resolution of the image.
void ColPartition::SetPartitionType(int resolution, ColPartitionSet* columns) {
int first_spanned_col = -1;
ColumnSpanningType span_type =
columns->SpanningType(resolution,
bounding_box_.left(), bounding_box_.right(),
MidY(), left_margin_, right_margin_,
&first_column_, &last_column_,
&first_spanned_col);
column_set_ = columns;
if (first_column_ < last_column_ && span_type == CST_PULLOUT &&
!IsLineType()) {
// Unequal columns may indicate that the pullout spans one of the columns
// it lies in, so force it to be allocated to just that column.
if (first_spanned_col >= 0) {
first_column_ = first_spanned_col;
last_column_ = first_spanned_col;
} else {
if ((first_column_ & 1) == 0)
last_column_ = first_column_;
else if ((last_column_ & 1) == 0)
first_column_ = last_column_;
else
first_column_ = last_column_ = (first_column_ + last_column_) / 2;
}
}
type_ = PartitionType(span_type);
}
// Returns the PartitionType from the current BlobRegionType and a column
// flow spanning type ColumnSpanningType, generated by
// ColPartitionSet::SpanningType, that indicates how the partition sits
// in the columns.
PolyBlockType ColPartition::PartitionType(ColumnSpanningType flow) const {
if (flow == CST_NOISE) {
if (blob_type_ != BRT_HLINE && blob_type_ != BRT_VLINE &&
blob_type_ != BRT_RECTIMAGE && blob_type_ != BRT_VERT_TEXT)
return PT_NOISE;
flow = CST_FLOWING;
}
switch (blob_type_) {
case BRT_NOISE:
return PT_NOISE;
case BRT_HLINE:
return PT_HORZ_LINE;
case BRT_VLINE:
return PT_VERT_LINE;
case BRT_RECTIMAGE:
case BRT_POLYIMAGE:
switch (flow) {
case CST_FLOWING:
return PT_FLOWING_IMAGE;
case CST_HEADING:
return PT_HEADING_IMAGE;
case CST_PULLOUT:
return PT_PULLOUT_IMAGE;
default:
ASSERT_HOST(!"Undefined flow type for image!");
}
break;
case BRT_VERT_TEXT:
return PT_VERTICAL_TEXT;
case BRT_TEXT:
case BRT_UNKNOWN:
default:
switch (flow) {
case CST_FLOWING:
return PT_FLOWING_TEXT;
case CST_HEADING:
return PT_HEADING_TEXT;
case CST_PULLOUT:
return PT_PULLOUT_TEXT;
default:
ASSERT_HOST(!"Undefined flow type for text!");
}
}
ASSERT_HOST(!"Should never get here!");
return PT_NOISE;
}
// Returns the first and last column touched by this partition.
// resolution refers to the ppi resolution of the image.
void ColPartition::ColumnRange(int resolution, ColPartitionSet* columns,
int* first_col, int* last_col) {
int first_spanned_col = -1;
ColumnSpanningType span_type =
columns->SpanningType(resolution,
bounding_box_.left(), bounding_box_.right(),
MidY(), left_margin_, right_margin_,
first_col, last_col,
&first_spanned_col);
type_ = PartitionType(span_type);
}
// Sets the internal flags good_width_ and good_column_.
void ColPartition::SetColumnGoodness(WidthCallback* cb) {
int y = MidY();
int width = RightAtY(y) - LeftAtY(y);
good_width_ = cb->Run(width);
good_column_ = blob_type_ == BRT_TEXT && left_key_tab_ && right_key_tab_;
}
// Determines whether the blobs in this partition mostly represent
// a leader (fixed pitch sequence) and sets the member blobs accordingly.
// Note that height is assumed to have been tested elsewhere, and that this
// function will find most fixed-pitch text as leader without a height filter.
// Leader detection is limited to sequences of identical width objects,
// such as .... or ----, so patterns, such as .-.-.-.-. will not be found.
bool ColPartition::MarkAsLeaderIfMonospaced() {
bool result = false;
// Gather statistics on the gaps between blobs and the widths of the blobs.
int part_width = bounding_box_.width();
STATS gap_stats(0, part_width);
STATS width_stats(0, part_width);
BLOBNBOX_C_IT it(&boxes_);
BLOBNBOX* prev_blob = it.data();
prev_blob->set_flow(BTFT_NEIGHBOURS);
width_stats.add(prev_blob->bounding_box().width(), 1);
int blob_count = 1;
for (it.forward(); !it.at_first(); it.forward()) {
BLOBNBOX* blob = it.data();
int left = blob->bounding_box().left();
int right = blob->bounding_box().right();
gap_stats.add(left - prev_blob->bounding_box().right(), 1);
width_stats.add(right - left, 1);
blob->set_flow(BTFT_NEIGHBOURS);
prev_blob = blob;
++blob_count;
}
double median_gap = gap_stats.median();
double median_width = width_stats.median();
double max_width = MAX(median_gap, median_width);
double min_width = MIN(median_gap, median_width);
double gap_iqr = gap_stats.ile(0.75f) - gap_stats.ile(0.25f);
if (textord_debug_tabfind >= 4) {
tprintf("gap iqr = %g, blob_count=%d, limits=%g,%g\n",
gap_iqr, blob_count, max_width * kMaxLeaderGapFractionOfMax,
min_width * kMaxLeaderGapFractionOfMin);
}
if (gap_iqr < max_width * kMaxLeaderGapFractionOfMax &&
gap_iqr < min_width * kMaxLeaderGapFractionOfMin &&
blob_count >= kMinLeaderCount) {
// This is stable enough to be called a leader, so check the widths.
// Since leader dashes can join, run a dp cutting algorithm and go
// on the cost.
int offset = static_cast<int>(ceil(gap_iqr * 2));
int min_step = static_cast<int>(median_gap + median_width + 0.5);
int max_step = min_step + offset;
min_step -= offset;
// Pad the buffer with min_step/2 on each end.
int part_left = bounding_box_.left() - min_step / 2;
part_width += min_step;
DPPoint* projection = new DPPoint[part_width];
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
int left = blob->bounding_box().left();
int right = blob->bounding_box().right();
int height = blob->bounding_box().height();
for (int x = left; x < right; ++x) {
projection[left - part_left].AddLocalCost(height);
}
}
DPPoint* best_end = DPPoint::Solve(min_step, max_step, false,
&DPPoint::CostWithVariance,
part_width, projection);
if (best_end != NULL && best_end->total_cost() < blob_count) {
// Good enough. Call it a leader.
result = true;
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
TBOX box = blob->bounding_box();
// If the first or last blob is spaced too much, don't mark it.
if (it.at_first()) {
int gap = it.data_relative(1)->bounding_box().left() -
blob->bounding_box().right();
if (blob->bounding_box().width() + gap > max_step) {
it.extract();
continue;
}
}
if (it.at_last()) {
int gap = blob->bounding_box().left() -
it.data_relative(-1)->bounding_box().right();
if (blob->bounding_box().width() + gap > max_step) {
it.extract();
break;
}
}
blob->set_region_type(BRT_TEXT);
blob->set_flow(BTFT_LEADER);
}
blob_type_ = BRT_TEXT;
flow_ = BTFT_LEADER;
} else if (textord_debug_tabfind) {
if (best_end == NULL) {
tprintf("No path\n");
} else {
tprintf("Total cost = %d vs allowed %d\n",
best_end->total_cost() < blob_count);
}
}
delete [] projection;
}
return result;
}
// Given the result of TextlineProjection::EvaluateColPartition, (positive for
// horizontal text, negative for vertical text, and near zero for non-text),
// sets the blob_type_ and flow_ for this partition to indicate whether it
// is strongly or weakly vertical or horizontal text, or non-text.
// The function assumes that the blob neighbours are valid (from
// StrokeWidth::SetNeighbours) and that those neighbours have their
// region_type() set.
void ColPartition::SetRegionAndFlowTypesFromProjectionValue(int value) {
int blob_count = 0; // Total # blobs.
int good_blob_score_ = 0; // Total # good strokewidth neighbours.
int noisy_count = 0; // Total # neighbours marked as noise.
int hline_count = 0;
int vline_count = 0;
BLOBNBOX_C_IT it(&boxes_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
++blob_count;
noisy_count += blob->NoisyNeighbours();
good_blob_score_ += blob->GoodTextBlob();
if (blob->region_type() == BRT_HLINE) ++hline_count;
if (blob->region_type() == BRT_VLINE) ++vline_count;
}
flow_ = BTFT_NEIGHBOURS;
blob_type_ = BRT_UNKNOWN;
if (hline_count > vline_count) {
flow_ = BTFT_NONE;
blob_type_ = BRT_HLINE;
} else if (vline_count > hline_count) {
flow_ = BTFT_NONE;
blob_type_ = BRT_VLINE;
} else if (value < -1 || 1 < value) {
int long_side;
int short_side;
if (value > 0) {
long_side = bounding_box_.width();
short_side = bounding_box_.height();
blob_type_ = BRT_TEXT;
} else {
long_side = bounding_box_.height();
short_side = bounding_box_.width();
blob_type_ = BRT_VERT_TEXT;
}
// We will combine the old metrics using aspect ratio and blob counts
// with the input value by allowing a strong indication to flip the
// STRONG_CHAIN/CHAIN flow values.
int strong_score = blob_count >= kHorzStrongTextlineCount ? 1 : 0;
if (short_side > kHorzStrongTextlineHeight) ++strong_score;
if (short_side * kHorzStrongTextlineAspect < long_side) ++strong_score;
if (abs(value) >= kMinStrongTextValue)
flow_ = BTFT_STRONG_CHAIN;
else if (abs(value) >= kMinChainTextValue)
flow_ = BTFT_CHAIN;
else
flow_ = BTFT_NEIGHBOURS;
// Upgrade chain to strong chain if the other indicators are good
if (flow_ == BTFT_CHAIN && strong_score == 3)
flow_ = BTFT_STRONG_CHAIN;
// Downgrade strong vertical text to chain if the indicators are bad.
if (flow_ == BTFT_STRONG_CHAIN && value < 0 && strong_score < 2)
flow_ = BTFT_CHAIN;
}
if (flow_ == BTFT_NEIGHBOURS) {
// Check for noisy neighbours.
if (noisy_count >= blob_count) {
flow_ = BTFT_NONTEXT;
blob_type_= BRT_NOISE;
}
}
if (TabFind::WithinTestRegion(2, bounding_box_.left(),
bounding_box_.bottom())) {
tprintf("RegionFlowTypesFromProjectionValue count=%d, noisy=%d, score=%d,",
blob_count, noisy_count, good_blob_score_);
tprintf(" Projection value=%d, flow=%d, blob_type=%d\n",
value, flow_, blob_type_);
Print();
}
SetBlobTypes();
}
// Sets all blobs with the partition blob type and flow, but never overwrite
// leader blobs, as we need to be able to identify them later.
void ColPartition::SetBlobTypes() {
if (!owns_blobs())
return;
BLOBNBOX_C_IT it(&boxes_);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
if (blob->flow() != BTFT_LEADER)
blob->set_flow(flow_);
blob->set_region_type(blob_type_);
ASSERT_HOST(blob->owner() == NULL || blob->owner() == this);
}
}
// Returns true if a decent baseline can be fitted through the blobs.
// Works for both horizontal and vertical text.
bool ColPartition::HasGoodBaseline() {
// Approximation of the baseline.
DetLineFit linepoints;
// Calculation of the mean height on this line segment. Note that these
// variable names apply to the context of a horizontal line, and work
// analogously, rather than literally in the case of a vertical line.
int total_height = 0;
int coverage = 0;
int height_count = 0;
int width = 0;
BLOBNBOX_C_IT it(&boxes_);
TBOX box(it.data()->bounding_box());
// Accumulate points representing the baseline at the middle of each blob,
// but add an additional point for each end of the line. This makes it
// harder to fit a severe skew angle, as it is most likely not right.
if (IsVerticalType()) {
// For a vertical line, use the right side as the baseline.
ICOORD first_pt(box.right(), box.bottom());
// Use the bottom-right of the first (bottom) box, the top-right of the
// last, and the middle-right of all others.
linepoints.Add(first_pt);
for (it.forward(); !it.at_last(); it.forward()) {
BLOBNBOX* blob = it.data();
box = blob->bounding_box();
ICOORD box_pt(box.right(), (box.top() + box.bottom()) / 2);
linepoints.Add(box_pt);
total_height += box.width();
coverage += box.height();
++height_count;
}
box = it.data()->bounding_box();
ICOORD last_pt(box.right(), box.top());
linepoints.Add(last_pt);
width = last_pt.y() - first_pt.y();
} else {
// Horizontal lines use the bottom as the baseline.
TBOX box(it.data()->bounding_box());
// Use the bottom-left of the first box, the the bottom-right of the last,
// and the middle of all others.
ICOORD first_pt(box.left(), box.bottom());
linepoints.Add(first_pt);
for (it.forward(); !it.at_last(); it.forward()) {
BLOBNBOX* blob = it.data();
box = blob->bounding_box();
ICOORD box_pt((box.left() + box.right()) / 2, box.bottom());
linepoints.Add(box_pt);
total_height += box.height();
coverage += box.width();
++height_count;
}
box = it.data()->bounding_box();
ICOORD last_pt(box.right(), box.bottom());
linepoints.Add(last_pt);
width = last_pt.x() - first_pt.x();
}
// Maximum median error allowed to be a good text line.
double max_error = kMaxBaselineError * total_height / height_count;
ICOORD start_pt, end_pt;
double error = linepoints.Fit(&start_pt, &end_pt);
return error < max_error && coverage >= kMinBaselineCoverage * width;
}
// Adds this ColPartition to a matching WorkingPartSet if one can be found,
// otherwise starts a new one in the appropriate column, ending the previous.
void ColPartition::AddToWorkingSet(const ICOORD& bleft, const ICOORD& tright,
int resolution,
ColPartition_LIST* used_parts,
WorkingPartSet_LIST* working_sets) {
if (block_owned_)
return; // Done it already.
block_owned_ = true;
WorkingPartSet_IT it(working_sets);
// If there is an upper partner use its working_set_ directly.
ColPartition* partner = SingletonPartner(true);
if (partner != NULL && partner->working_set_ != NULL) {
working_set_ = partner->working_set_;
working_set_->AddPartition(this);
return;
}
if (partner != NULL && textord_debug_bugs) {
tprintf("Partition with partner has no working set!:");
Print();
partner->Print();
}
// Search for the column that the left edge fits in.
WorkingPartSet* work_set = NULL;
it.move_to_first();
int col_index = 0;
for (it.mark_cycle_pt(); !it.cycled_list() &&
col_index != first_column_;
it.forward(), ++col_index);
if (textord_debug_tabfind >= 2) {
tprintf("Match is %s for:", (col_index & 1) ? "Real" : "Between");
Print();
}
if (it.cycled_list() && textord_debug_bugs) {
tprintf("Target column=%d, only had %d\n", first_column_, col_index);
}
ASSERT_HOST(!it.cycled_list());
work_set = it.data();
// If last_column_ != first_column, then we need to scoop up all blocks
// between here and the last_column_ and put back in work_set.
if (!it.cycled_list() && last_column_ != first_column_) {
// Find the column that the right edge falls in.
BLOCK_LIST completed_blocks;
TO_BLOCK_LIST to_blocks;
for (; !it.cycled_list() && col_index <= last_column_;
it.forward(), ++col_index) {
WorkingPartSet* end_set = it.data();
end_set->ExtractCompletedBlocks(bleft, tright, resolution, used_parts,
&completed_blocks, &to_blocks);
}
work_set->InsertCompletedBlocks(&completed_blocks, &to_blocks);
}
working_set_ = work_set;
work_set->AddPartition(this);
}
// From the given block_parts list, builds one or more BLOCKs and
// corresponding TO_BLOCKs, such that the line spacing is uniform in each.
// Created blocks are appended to the end of completed_blocks and to_blocks.
// The used partitions are put onto used_parts, as they may still be referred
// to in the partition grid. bleft, tright and resolution are the bounds
// and resolution of the original image.
void ColPartition::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) {
int page_height = tright.y() - bleft.y();
// Compute the initial spacing stats.
ColPartition_IT it(block_parts);
int part_count = 0;
int max_line_height = 0;
// TODO(joeliu): We should add some special logic for PT_INLINE_EQUATION type
// because their line spacing with their neighbors maybe smaller and their
// height may be slightly larger.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColPartition* part = it.data();
ASSERT_HOST(!part->boxes()->empty());
STATS side_steps(0, part->bounding_box().height());
if (part->bounding_box().height() > max_line_height)
max_line_height = part->bounding_box().height();
BLOBNBOX_C_IT blob_it(part->boxes());
int prev_bottom = blob_it.data()->bounding_box().bottom();
for (blob_it.forward(); !blob_it.at_first(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
int bottom = blob->bounding_box().bottom();
int step = bottom - prev_bottom;
if (step < 0)
step = -step;
side_steps.add(step, 1);
prev_bottom = bottom;
}
part->set_side_step(static_cast<int>(side_steps.median() + 0.5));
if (!it.at_last()) {
ColPartition* next_part = it.data_relative(1);
part->set_bottom_spacing(part->median_bottom() -
next_part->median_bottom());
part->set_top_spacing(part->median_top() - next_part->median_top());
} else {
part->set_bottom_spacing(page_height);
part->set_top_spacing(page_height);
}
if (textord_debug_tabfind) {
part->Print();
tprintf("side step = %.2f, top spacing = %d, bottom spacing=%d\n",
side_steps.median(), part->top_spacing(), part->bottom_spacing());
}
++part_count;
}
if (part_count == 0)
return;
SmoothSpacings(resolution, page_height, block_parts);
// Move the partitions into individual block lists and make the blocks.
BLOCK_IT block_it(completed_blocks);
TO_BLOCK_IT to_block_it(to_blocks);
ColPartition_LIST spacing_parts;
ColPartition_IT sp_block_it(&spacing_parts);
int same_block_threshold = max_line_height * kMaxSameBlockLineSpacing;
for (it.mark_cycle_pt(); !it.empty();) {
ColPartition* part = it.extract();
sp_block_it.add_to_end(part);
it.forward();
if (it.empty() || part->bottom_spacing() > same_block_threshold ||
!part->SpacingsEqual(*it.data(), resolution)) {
// There is a spacing boundary. Check to see if it.data() belongs
// better in the current block or the next one.
if (!it.empty() && part->bottom_spacing() <= same_block_threshold) {
ColPartition* next_part = it.data();
// If there is a size match one-way, then the middle line goes with
// its matched size, otherwise it goes with the smallest spacing.
ColPartition* third_part = it.at_last() ? NULL : it.data_relative(1);
if (textord_debug_tabfind) {
tprintf("Spacings unequal: upper:%d/%d, lower:%d/%d,"
" sizes %d %d %d\n",
part->top_spacing(), part->bottom_spacing(),
next_part->top_spacing(), next_part->bottom_spacing(),
part->median_size(), next_part->median_size(),
third_part != NULL ? third_part->median_size() : 0);
}
// We can only consider adding the next line to the block if the sizes
// match and the lines are close enough for their size.
if (part->SizesSimilar(*next_part) &&
next_part->median_size() * kMaxSameBlockLineSpacing >
part->bottom_spacing() &&
part->median_size() * kMaxSameBlockLineSpacing >
part->top_spacing()) {
// Even now, we can only add it as long as the third line doesn't
// match in the same way and have a smaller bottom spacing.
if (third_part == NULL ||
!next_part->SizesSimilar(*third_part) ||
third_part->median_size() * kMaxSameBlockLineSpacing <=
next_part->bottom_spacing() ||
next_part->median_size() * kMaxSameBlockLineSpacing <=
next_part->top_spacing() ||
next_part->bottom_spacing() > part->bottom_spacing()) {
// Add to the current block.
sp_block_it.add_to_end(it.extract());
it.forward();
if (textord_debug_tabfind) {
tprintf("Added line to current block.\n");
}
}
}
}
TO_BLOCK* to_block = MakeBlock(bleft, tright, &spacing_parts, used_parts);
if (to_block != NULL) {
to_block_it.add_to_end(to_block);
block_it.add_to_end(to_block->block);
}
sp_block_it.set_to_list(&spacing_parts);
} else {
if (textord_debug_tabfind && !it.empty()) {
ColPartition* next_part = it.data();
tprintf("Spacings equal: upper:%d/%d, lower:%d/%d\n",
part->top_spacing(), part->bottom_spacing(),
next_part->top_spacing(), next_part->bottom_spacing(),
part->median_size(), next_part->median_size());
}
}
}
}
// Helper function to clip the input pos to the given bleft, tright bounds.
static void ClipCoord(const ICOORD& bleft, const ICOORD& tright, ICOORD* pos) {
if (pos->x() < bleft.x())
pos->set_x(bleft.x());
if (pos->x() > tright.x())
pos->set_x(tright.x());
if (pos->y() < bleft.y())
pos->set_y(bleft.y());
if (pos->y() > tright.y())
pos->set_y(tright.y());
}
// Helper moves the blobs from the given list of block_parts into the block
// itself. Sets up the block for (old) textline formation correctly for
// vertical and horizontal text. The partitions are moved to used_parts
// afterwards, as they cannot be deleted yet.
static TO_BLOCK* MoveBlobsToBlock(bool vertical_text, int line_spacing,
BLOCK* block,
ColPartition_LIST* block_parts,
ColPartition_LIST* used_parts) {
// Make a matching TO_BLOCK and put all the BLOBNBOXes from the parts in it.
// Move all the parts to a done list as they are no longer needed, except
// that have have to continue to exist until the part grid is deleted.
// Compute the median blob size as we go, as the block needs to know.
TBOX block_box(block->bounding_box());
STATS sizes(0, MAX(block_box.width(), block_box.height()));
bool text_type = block->poly_block()->IsText();
ColPartition_IT it(block_parts);
TO_BLOCK* to_block = new TO_BLOCK(block);
BLOBNBOX_IT blob_it(&to_block->blobs);
ColPartition_IT used_it(used_parts);
for (it.move_to_first(); !it.empty(); it.forward()) {
ColPartition* part = it.extract();
// Transfer blobs from all regions to the output blocks.
// Blobs for non-text regions will be used to define the polygonal
// bounds of the region.
for (BLOBNBOX_C_IT bb_it(part->boxes()); !bb_it.empty();
bb_it.forward()) {
BLOBNBOX* bblob = bb_it.extract();
if (bblob->owner() != part) {
tprintf("Ownership incorrect for blob:");
bblob->bounding_box().print();
tprintf("Part=");
part->Print();
if (bblob->owner() == NULL) {
tprintf("Not owned\n");
} else {
tprintf("Owner part:");
bblob->owner()->Print();
}
}
ASSERT_HOST(bblob->owner() == part);
// Assert failure here is caused by arbitrarily changing the partition
// type without also changing the blob type, such as in
// InsertSmallBlobsAsUnknowns.
ASSERT_HOST(!text_type || bblob->region_type() >= BRT_UNKNOWN);
C_OUTLINE_LIST* outlines = bblob->cblob()->out_list();
C_OUTLINE_IT ol_it(outlines);
if (outlines->singleton()) {
ASSERT_HOST(!text_type || ol_it.data()->pathlength() > 0);
if (vertical_text)
sizes.add(bblob->bounding_box().width(), 1);
else
sizes.add(bblob->bounding_box().height(), 1);
blob_it.add_after_then_move(bblob);
} else {
// This blob has multiple outlines from CJK repair.
// Explode the blob back into individual outlines.
for (;!ol_it.empty(); ol_it.forward()) {
C_OUTLINE* outline = ol_it.extract();
BLOBNBOX* blob = BLOBNBOX::RealBlob(outline);
if (vertical_text)
sizes.add(blob->bounding_box().width(), 1);
else
sizes.add(blob->bounding_box().height(), 1);
blob_it.add_after_then_move(blob);
}
delete bblob->cblob();
delete bblob;
}
}
used_it.add_to_end(part);
}
if (text_type && blob_it.empty()) {
delete block;
delete to_block;
return NULL;
}
to_block->line_size = sizes.median();
if (vertical_text) {
int block_width = block->bounding_box().width();
if (block_width < line_spacing)
line_spacing = block_width;
to_block->line_spacing = static_cast<float>(line_spacing);
to_block->max_blob_size = static_cast<float>(block_width + 1);
} else {
int block_height = block->bounding_box().height();
if (block_height < line_spacing)
line_spacing = block_height;
to_block->line_spacing = static_cast<float>(line_spacing);
to_block->max_blob_size = static_cast<float>(block_height + 1);
}
return to_block;
}
// Constructs a block from the given list of partitions.
// Arguments are as LineSpacingBlocks above.
TO_BLOCK* ColPartition::MakeBlock(const ICOORD& bleft, const ICOORD& tright,
ColPartition_LIST* block_parts,
ColPartition_LIST* used_parts) {
if (block_parts->empty())
return NULL; // Nothing to do.
ColPartition_IT it(block_parts);
ColPartition* part = it.data();
PolyBlockType type = part->type();
if (type == PT_VERTICAL_TEXT)
return MakeVerticalTextBlock(bleft, tright, block_parts, used_parts);
// LineSpacingBlocks has handed us a collection of evenly spaced lines and
// put the average spacing in each partition, so we can just take the
// linespacing from the first partition.
int line_spacing = part->bottom_spacing();
if (line_spacing < part->median_size())
line_spacing = part->bounding_box().height();
ICOORDELT_LIST vertices;
ICOORDELT_IT vert_it(&vertices);
ICOORD start, end;
int min_x = MAX_INT32;
int max_x = -MAX_INT32;
int min_y = MAX_INT32;
int max_y = -MAX_INT32;
int iteration = 0;
do {
if (iteration == 0)
ColPartition::LeftEdgeRun(&it, &start, &end);
else
ColPartition::RightEdgeRun(&it, &start, &end);
ClipCoord(bleft, tright, &start);
ClipCoord(bleft, tright, &end);
vert_it.add_after_then_move(new ICOORDELT(start));
vert_it.add_after_then_move(new ICOORDELT(end));
UpdateRange(start.x(), &min_x, &max_x);
UpdateRange(end.x(), &min_x, &max_x);
UpdateRange(start.y(), &min_y, &max_y);
UpdateRange(end.y(), &min_y, &max_y);
if ((iteration == 0 && it.at_first()) ||
(iteration == 1 && it.at_last())) {
++iteration;
it.move_to_last();
}
} while (iteration < 2);
if (textord_debug_tabfind)
tprintf("Making block at (%d,%d)->(%d,%d)\n",
min_x, min_y, max_x, max_y);
BLOCK* block = new BLOCK("", true, 0, 0, min_x, min_y, max_x, max_y);
block->set_poly_block(new POLY_BLOCK(&vertices, type));
return MoveBlobsToBlock(false, line_spacing, block, block_parts, used_parts);
}
// Constructs a block from the given list of vertical text partitions.
// Currently only creates rectangular blocks.
TO_BLOCK* ColPartition::MakeVerticalTextBlock(const ICOORD& bleft,
const ICOORD& tright,
ColPartition_LIST* block_parts,
ColPartition_LIST* used_parts) {
if (block_parts->empty())
return NULL; // Nothing to do.
ColPartition_IT it(block_parts);
ColPartition* part = it.data();
TBOX block_box = part->bounding_box();
int line_spacing = block_box.width();
PolyBlockType type = it.data()->type();
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
block_box += it.data()->bounding_box();
}
if (textord_debug_tabfind) {
tprintf("Making block at:");
block_box.print();
}
BLOCK* block = new BLOCK("", true, 0, 0, block_box.left(), block_box.bottom(),
block_box.right(), block_box.top());
block->set_poly_block(new POLY_BLOCK(block_box, type));
return MoveBlobsToBlock(true, line_spacing, block, block_parts, used_parts);
}
// Returns a copy of everything except the list of boxes. The resulting
// ColPartition is only suitable for keeping in a column candidate list.
ColPartition* ColPartition::ShallowCopy() const {
ColPartition* part = new ColPartition(blob_type_, vertical_);
part->left_margin_ = left_margin_;
part->right_margin_ = right_margin_;
part->bounding_box_ = bounding_box_;
memcpy(part->special_blobs_densities_, special_blobs_densities_,
sizeof(special_blobs_densities_));
part->median_bottom_ = median_bottom_;
part->median_top_ = median_top_;
part->median_size_ = median_size_;
part->median_left_ = median_left_;
part->median_right_ = median_right_;
part->median_width_ = median_width_;
part->good_width_ = good_width_;
part->good_column_ = good_column_;
part->left_key_tab_ = left_key_tab_;
part->right_key_tab_ = right_key_tab_;
part->type_ = type_;
part->flow_ = flow_;
part->left_key_ = left_key_;
part->right_key_ = right_key_;
part->first_column_ = first_column_;
part->last_column_ = last_column_;
part->owns_blobs_ = false;
return part;
}
ColPartition* ColPartition::CopyButDontOwnBlobs() {
ColPartition* copy = ShallowCopy();
copy->set_owns_blobs(false);
BLOBNBOX_C_IT inserter(copy->boxes());
BLOBNBOX_C_IT traverser(boxes());
for (traverser.mark_cycle_pt(); !traverser.cycled_list(); traverser.forward())
inserter.add_after_then_move(traverser.data());
return copy;
}
#ifndef GRAPHICS_DISABLED
// Provides a color for BBGrid to draw the rectangle.
// Must be kept in sync with PolyBlockType.
ScrollView::Color ColPartition::BoxColor() const {
if (type_ == PT_UNKNOWN)
return BLOBNBOX::TextlineColor(blob_type_, flow_);
return POLY_BLOCK::ColorForPolyBlockType(type_);
}
#endif // GRAPHICS_DISABLED
// Keep in sync with BlobRegionType.
static char kBlobTypes[BRT_COUNT + 1] = "NHSRIUVT";
// Prints debug information on this.
void ColPartition::Print() const {
int y = MidY();
tprintf("ColPart:%c(M%d-%c%d-B%d/%d,%d/%d)->(%dB-%d%c-%dM/%d,%d/%d)"
" w-ok=%d, v-ok=%d, type=%d%c%d, fc=%d, lc=%d, boxes=%d"
" ts=%d bs=%d ls=%d rs=%d\n",
boxes_.empty() ? 'E' : ' ',
left_margin_, left_key_tab_ ? 'T' : 'B', LeftAtY(y),
bounding_box_.left(), median_left_,
bounding_box_.bottom(), median_bottom_,
bounding_box_.right(), RightAtY(y), right_key_tab_ ? 'T' : 'B',
right_margin_, median_right_, bounding_box_.top(), median_top_,
good_width_, good_column_, type_,
kBlobTypes[blob_type_], flow_,
first_column_, last_column_, boxes_.length(),
space_above_, space_below_, space_to_left_, space_to_right_);
}
// Prints debug information on the colors.
void ColPartition::PrintColors() {
tprintf("Colors:(%d, %d, %d)%d -> (%d, %d, %d)\n",
color1_[COLOR_RED], color1_[COLOR_GREEN], color1_[COLOR_BLUE],
color1_[L_ALPHA_CHANNEL],
color2_[COLOR_RED], color2_[COLOR_GREEN], color2_[COLOR_BLUE]);
}
// Sets the types of all partitions in the run to be the max of the types.
void ColPartition::SmoothPartnerRun(int working_set_count) {
STATS left_stats(0, working_set_count);
STATS right_stats(0, working_set_count);
PolyBlockType max_type = type_;
ColPartition* partner;
for (partner = SingletonPartner(false); partner != NULL;
partner = partner->SingletonPartner(false)) {
if (partner->type_ > max_type)
max_type = partner->type_;
if (column_set_ == partner->column_set_) {
left_stats.add(partner->first_column_, 1);
right_stats.add(partner->last_column_, 1);
}
}
type_ = max_type;
// TODO(rays) Either establish that it isn't necessary to set the columns,
// or find a way to do it that does not cause an assert failure in
// AddToWorkingSet.
#if 0
first_column_ = left_stats.mode();
last_column_ = right_stats.mode();
if (last_column_ < first_column_)
last_column_ = first_column_;
#endif
for (partner = SingletonPartner(false); partner != NULL;
partner = partner->SingletonPartner(false)) {
partner->type_ = max_type;
#if 0 // See TODO above
if (column_set_ == partner->column_set_) {
partner->first_column_ = first_column_;
partner->last_column_ = last_column_;
}
#endif
}
}
// ======= Scenario common to all Refine*Partners* functions =======
// ColPartitions are aiming to represent textlines, or horizontal slices
// of images, and we are trying to form bi-directional (upper/lower) chains
// of UNIQUE partner ColPartitions that can be made into blocks.
// The ColPartitions have previously been typed (see SetPartitionType)
// according to a combination of the content type and
// how they lie on the columns. We want to chain text into
// groups of a single type, but image ColPartitions may have been typed
// differently in different parts of the image, due to being non-rectangular.
//
// We previously ran a search for upper and lower partners, but there may
// be more than one, and they may be of mixed types, so now we wish to
// refine the partners down to at most one.
// A heading may have multiple partners:
// ===============================
// ======== ========== =========
// ======== ========== =========
// but it should be a different type.
// A regular flowing text line may have multiple partners:
// ================== ===================
// ======= ================= ===========
// This could be the start of a pull-out, or it might all be in a single
// column and might be caused by tightly spaced text, bold words, bullets,
// funny punctuation etc, all of which can cause textlines to be split into
// multiple ColPartitions. Pullouts and figure captions should now be different
// types so we can more aggressively merge groups of partners that all sit
// in a single column.
//
// Cleans up the partners of the given type so that there is at most
// one partner. This makes block creation simpler.
// If get_desperate is true, goes to more desperate merge methods
// to merge flowing text before breaking partnerships.
void ColPartition::RefinePartners(PolyBlockType type, bool get_desperate,
ColPartitionGrid* grid) {
if (TypesSimilar(type_, type)) {
RefinePartnersInternal(true, get_desperate, grid);
RefinePartnersInternal(false, get_desperate, grid);
} else if (type == PT_COUNT) {
// This is the final pass. Make sure only the correctly typed
// partners surivive, however many there are.
RefinePartnersByType(true, &upper_partners_);
RefinePartnersByType(false, &lower_partners_);
// It is possible for a merge to have given a partition multiple
// partners again, so the last resort is to use overlap which is
// guaranteed to leave at most one partner left.
if (!upper_partners_.empty() && !upper_partners_.singleton())
RefinePartnersByOverlap(true, &upper_partners_);
if (!lower_partners_.empty() && !lower_partners_.singleton())
RefinePartnersByOverlap(false, &lower_partners_);
}
}
////////////////// PRIVATE CODE /////////////////////////////
// Cleans up the partners above if upper is true, else below.
// If get_desperate is true, goes to more desperate merge methods
// to merge flowing text before breaking partnerships.
void ColPartition::RefinePartnersInternal(bool upper, bool get_desperate,
ColPartitionGrid* grid) {
ColPartition_CLIST* partners = upper ? &upper_partners_ : &lower_partners_;
if (!partners->empty() && !partners->singleton()) {
RefinePartnersByType(upper, partners);
if (!partners->empty() && !partners->singleton()) {
// Check for transitive partnerships and break the cycle.
RefinePartnerShortcuts(upper, partners);
if (!partners->empty() && !partners->singleton()) {
// Types didn't fix it. Flowing text keeps the one with the longest
// sequence of singleton matching partners. All others max overlap.
if (TypesSimilar(type_, PT_FLOWING_TEXT) && get_desperate) {
RefineTextPartnersByMerge(upper, false, partners, grid);
if (!partners->empty() && !partners->singleton())
RefineTextPartnersByMerge(upper, true, partners, grid);
}
// The last resort is to use overlap.
if (!partners->empty() && !partners->singleton())
RefinePartnersByOverlap(upper, partners);
}
}
}
}
// Cleans up the partners above if upper is true, else below.
// Restricts the partners to only desirable types. For text and BRT_HLINE this
// means the same type_ , and for image types it means any image type.
void ColPartition::RefinePartnersByType(bool upper,
ColPartition_CLIST* partners) {
bool debug = TabFind::WithinTestRegion(2, bounding_box_.left(),
bounding_box_.bottom());
if (debug) {
tprintf("Refining %d %s partners by type for:\n",
partners->length(), upper ? "Upper" : "Lower");
Print();
}
ColPartition_C_IT it(partners);
// Purify text by type.
if (!IsImageType()) {
// Keep only partners matching type_.
// Exception: PT_VERTICAL_TEXT is allowed to stay with the other
// text types if it is the only partner.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColPartition* partner = it.data();
if (!TypesSimilar(type_, partner->type_)) {
if (debug) {
tprintf("Removing partner:");
partner->Print();
}
partner->RemovePartner(!upper, this);
it.extract();
} else if (debug) {
tprintf("Keeping partner:");
partner->Print();
}
}
} else {
// Only polyimages are allowed to have partners of any kind!
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColPartition* partner = it.data();
if (partner->blob_type() != BRT_POLYIMAGE ||
blob_type() != BRT_POLYIMAGE) {
if (debug) {
tprintf("Removing partner:");
partner->Print();
}
partner->RemovePartner(!upper, this);
it.extract();
} else if (debug) {
tprintf("Keeping partner:");
partner->Print();
}
}
}
}
// Cleans up the partners above if upper is true, else below.
// Remove transitive partnerships: this<->a, and a<->b and this<->b.
// Gets rid of this<->b, leaving a clean chain.
// Also if we have this<->a and a<->this, then gets rid of this<->a, as
// this has multiple partners.
void ColPartition::RefinePartnerShortcuts(bool upper,
ColPartition_CLIST* partners) {
bool done_any = false;
do {
done_any = false;
ColPartition_C_IT it(partners);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColPartition* a = it.data();
// Check for a match between all of a's partners (it1/b1) and all
// of this's partners (it2/b2).
ColPartition_C_IT it1(upper ? &a->upper_partners_ : &a->lower_partners_);
for (it1.mark_cycle_pt(); !it1.cycled_list(); it1.forward()) {
ColPartition* b1 = it1.data();
if (b1 == this) {
done_any = true;
it.extract();
a->RemovePartner(!upper, this);
break;
}
ColPartition_C_IT it2(partners);
for (it2.mark_cycle_pt(); !it2.cycled_list(); it2.forward()) {
ColPartition* b2 = it2.data();
if (b1 == b2) {
// Jackpot! b2 should not be a partner of this.
it2.extract();
b2->RemovePartner(!upper, this);
done_any = true;
// That potentially invalidated all the iterators, so break out
// and start again.
break;
}
}
if (done_any)
break;
}
if (done_any)
break;
}
} while (done_any && !partners->empty() && !partners->singleton());
}
// Cleans up the partners above if upper is true, else below.
// If multiple text partners can be merged, (with each other, NOT with this),
// then do so.
// If desperate is true, then an increase in overlap with the merge is
// allowed. If the overlap increases, then the desperately_merged_ flag
// is set, indicating that the textlines probably need to be regenerated
// by aggressive line fitting/splitting, as there are probably vertically
// joined blobs that cross textlines.
void ColPartition::RefineTextPartnersByMerge(bool upper, bool desperate,
ColPartition_CLIST* partners,
ColPartitionGrid* grid) {
bool debug = TabFind::WithinTestRegion(2, bounding_box_.left(),
bounding_box_.bottom());
if (debug) {
tprintf("Refining %d %s partners by merge for:\n",
partners->length(), upper ? "Upper" : "Lower");
Print();
}
while (!partners->empty() && !partners->singleton()) {
// Absorb will mess up the iterators, so we have to merge one partition
// at a time and rebuild the iterators each time.
ColPartition_C_IT it(partners);
ColPartition* part = it.data();
// Gather a list of merge candidates, from the list of partners, that
// are all in the same single column. See general scenario comment above.
ColPartition_CLIST candidates;
ColPartition_C_IT cand_it(&candidates);
for (it.forward(); !it.at_first(); it.forward()) {
ColPartition* candidate = it.data();
if (part->first_column_ == candidate->last_column_ &&
part->last_column_ == candidate->first_column_)
cand_it.add_after_then_move(it.data());
}
int overlap_increase;
ColPartition* candidate = grid->BestMergeCandidate(part, &candidates, debug,
NULL, &overlap_increase);
if (candidate != NULL && (overlap_increase <= 0 || desperate)) {
if (debug) {
tprintf("Merging:hoverlap=%d, voverlap=%d, OLI=%d\n",
part->HCoreOverlap(*candidate), part->VCoreOverlap(*candidate),
overlap_increase);
}
// Remove before merge and re-insert to keep the integrity of the grid.
grid->RemoveBBox(candidate);
grid->RemoveBBox(part);
part->Absorb(candidate, NULL);
// We modified the box of part, so re-insert it into the grid.
grid->InsertBBox(true, true, part);
if (overlap_increase > 0)
part->desperately_merged_ = true;
} else {
break; // Can't merge.
}
}
}
// Cleans up the partners above if upper is true, else below.
// Keep the partner with the biggest overlap.
void ColPartition::RefinePartnersByOverlap(bool upper,
ColPartition_CLIST* partners) {
bool debug = TabFind::WithinTestRegion(2, bounding_box_.left(),
bounding_box_.bottom());
if (debug) {
tprintf("Refining %d %s partners by overlap for:\n",
partners->length(), upper ? "Upper" : "Lower");
Print();
}
ColPartition_C_IT it(partners);
ColPartition* best_partner = it.data();
// Find the partner with the best overlap.
int best_overlap = 0;
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColPartition* partner = it.data();
int overlap = MIN(bounding_box_.right(), partner->bounding_box_.right())
- MAX(bounding_box_.left(), partner->bounding_box_.left());
if (overlap > best_overlap) {
best_overlap = overlap;
best_partner = partner;
}
}
// Keep only the best partner.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
ColPartition* partner = it.data();
if (partner != best_partner) {
if (debug) {
tprintf("Removing partner:");
partner->Print();
}
partner->RemovePartner(!upper, this);
it.extract();
}
}
}
// Return true if bbox belongs better in this than other.
bool ColPartition::ThisPartitionBetter(BLOBNBOX* bbox,
const ColPartition& other) {
TBOX box = bbox->bounding_box();
// Margins take priority.
int left = box.left();
int right = box.right();
if (left < left_margin_ || right > right_margin_)
return false;
if (left < other.left_margin_ || right > other.right_margin_)
return true;
int top = box.top();
int bottom = box.bottom();
int this_overlap = MIN(top, median_top_) - MAX(bottom, median_bottom_);
int other_overlap = MIN(top, other.median_top_) -
MAX(bottom, other.median_bottom_);
int this_miss = median_top_ - median_bottom_ - this_overlap;
int other_miss = other.median_top_ - other.median_bottom_ - other_overlap;
if (TabFind::WithinTestRegion(3, box.left(), box.bottom())) {
tprintf("Unique on (%d,%d)->(%d,%d) overlap %d/%d, miss %d/%d, mt=%d/%d\n",
box.left(), box.bottom(), box.right(), box.top(),
this_overlap, other_overlap, this_miss, other_miss,
median_top_, other.median_top_);
}
if (this_miss < other_miss)
return true;
if (this_miss > other_miss)
return false;
if (this_overlap > other_overlap)
return true;
if (this_overlap < other_overlap)
return false;
return median_top_ >= other.median_top_;
}
// Returns the median line-spacing between the current position and the end
// of the list.
// The iterator is passed by value so the iteration does not modify the
// caller's iterator.
static int MedianSpacing(int page_height, ColPartition_IT it) {
STATS stats(0, page_height);
while (!it.cycled_list()) {
ColPartition* part = it.data();
it.forward();
stats.add(part->bottom_spacing(), 1);
stats.add(part->top_spacing(), 1);
}
return static_cast<int>(stats.median() + 0.5);
}
// Returns true if this column partition is in the same column as
// part. This function will only work after the SetPartitionType function
// has been called on both column partitions. This is useful for
// doing a SideSearch when you want things in the same page column.
//
// Currently called by the table detection code to identify if potential table
// partitions exist in the same column.
bool ColPartition::IsInSameColumnAs(const ColPartition& part) const {
// Overlap does not occur when last < part.first or first > part.last.
// In other words, one is completely to the side of the other.
// This is just DeMorgan's law applied to that so the function returns true.
return (last_column_ >= part.first_column_) &&
(first_column_ <= part.last_column_);
}
// Smoothes the spacings in the list into groups of equal linespacing.
// resolution is the resolution of the original image, used as a basis
// for thresholds in change of spacing. page_height is in pixels.
void ColPartition::SmoothSpacings(int resolution, int page_height,
ColPartition_LIST* parts) {
// The task would be trivial if we didn't have to allow for blips -
// occasional offsets in spacing caused by anomolous text, such as all
// caps, groups of descenders, joined words, Arabic etc.
// The neighbourhood stores a consecutive group of partitions so that
// blips can be detected correctly, yet conservatively enough to not
// mistake genuine spacing changes for blips. See example below.
ColPartition* neighbourhood[PN_COUNT];
ColPartition_IT it(parts);
it.mark_cycle_pt();
// Although we know nothing about the spacings is this list, the median is
// used as an approximation to allow blips.
// If parts of this block aren't spaced to the median, then we can't
// accept blips in those parts, but we'll recalculate it each time we
// split the block, so the median becomes more likely to match all the text.
int median_space = MedianSpacing(page_height, it);
ColPartition_IT start_it(it);
ColPartition_IT end_it(it);
for (int i = 0; i < PN_COUNT; ++i) {
if (i < PN_UPPER || it.cycled_list()) {
neighbourhood[i] = NULL;
} else {
if (i == PN_LOWER)
end_it = it;
neighbourhood[i] = it.data();
it.forward();
}
}
while (neighbourhood[PN_UPPER] != NULL) {
// Test for end of a group. Normally SpacingsEqual is true within a group,
// but in the case of a blip, it will be false. Here is an example:
// Line enum Spacing below (spacing between tops of lines)
// 1 ABOVE2 20
// 2 ABOVE1 20
// 3 UPPER 15
// 4 LOWER 25
// 5 BELOW1 20
// 6 BELOW2 20
// Line 4 is all in caps (regular caps), so the spacing between line 3
// and line 4 (looking at the tops) is smaller than normal, and the
// spacing between line 4 and line 5 is larger than normal, but the
// two of them add to twice the normal spacing.
// The following if has to accept unequal spacings 3 times to pass the
// blip (20/15, 15/25 and 25/20)
// When the blip is in the middle, OKSpacingBlip tests that one of
// ABOVE1 and BELOW1 matches the median.
// The first time, everything is shifted down 1, so we present
// OKSpacingBlip with neighbourhood+1 and check that PN_UPPER is median.
// The last time, everything is shifted up 1, so we present OKSpacingBlip
// with neighbourhood-1 and check that PN_LOWER matches the median.
if (neighbourhood[PN_LOWER] == NULL ||
(!neighbourhood[PN_UPPER]->SpacingsEqual(*neighbourhood[PN_LOWER],
resolution) &&
!OKSpacingBlip(resolution, median_space, neighbourhood) &&
(!OKSpacingBlip(resolution, median_space, neighbourhood - 1) ||
!neighbourhood[PN_LOWER]->SpacingEqual(median_space, resolution)) &&
(!OKSpacingBlip(resolution, median_space, neighbourhood + 1) ||
!neighbourhood[PN_UPPER]->SpacingEqual(median_space, resolution)))) {
// The group has ended. PN_UPPER is the last member.
// Compute the mean spacing over the group.
ColPartition_IT sum_it(start_it);
ColPartition* last_part = neighbourhood[PN_UPPER];
double total_bottom = 0.0;
double total_top = 0.0;
int total_count = 0;
ColPartition* upper = sum_it.data();
// We do not process last_part, as its spacing is different.
while (upper != last_part) {
total_bottom += upper->bottom_spacing();
total_top += upper->top_spacing();
++total_count;
sum_it.forward();
upper = sum_it.data();
}
if (total_count > 0) {
// There were at least 2 lines, so set them all to the mean.
int top_spacing = static_cast<int>(total_top / total_count + 0.5);
int bottom_spacing = static_cast<int>(total_bottom / total_count + 0.5);
if (textord_debug_tabfind) {
tprintf("Spacing run ended. Cause:");
if (neighbourhood[PN_LOWER] == NULL) {
tprintf("No more lines\n");
} else {
tprintf("Spacing change. Spacings:\n");
for (int i = 0; i < PN_COUNT; ++i) {
if (neighbourhood[i] == NULL) {
tprintf("NULL");
if (i > 0 && neighbourhood[i - 1] != NULL) {
if (neighbourhood[i - 1]->SingletonPartner(false) != NULL) {
tprintf(" Lower partner:");
neighbourhood[i - 1]->SingletonPartner(false)->Print();
} else {
tprintf(" NULL lower partner:\n");
}
} else {
tprintf("\n");
}
} else {
tprintf("Top = %d, bottom = %d\n",
neighbourhood[i]->top_spacing(),
neighbourhood[i]->bottom_spacing());
}
}
}
tprintf("Mean spacing = %d/%d\n", top_spacing, bottom_spacing);
}
sum_it = start_it;
upper = sum_it.data();
while (upper != last_part) {
upper->set_top_spacing(top_spacing);
upper->set_bottom_spacing(bottom_spacing);
if (textord_debug_tabfind) {
tprintf("Setting mean on:");
upper->Print();
}
sum_it.forward();
upper = sum_it.data();
}
}
// PN_LOWER starts the next group and end_it is the next start_it.
start_it = end_it;
// Recalculate the median spacing to maximize the chances of detecting
// spacing blips.
median_space = MedianSpacing(page_height, end_it);
}
// Shuffle pointers.
for (int j = 1; j < PN_COUNT; ++j) {
neighbourhood[j - 1] = neighbourhood[j];
}
if (it.cycled_list()) {
neighbourhood[PN_COUNT - 1] = NULL;
} else {
neighbourhood[PN_COUNT - 1] = it.data();
it.forward();
}
end_it.forward();
}
}
// Returns true if the parts array of pointers to partitions matches the
// condition for a spacing blip. See SmoothSpacings for what this means
// and how it is used.
bool ColPartition::OKSpacingBlip(int resolution, int median_spacing,
ColPartition** parts) {
if (parts[PN_UPPER] == NULL || parts[PN_LOWER] == NULL)
return false;
// The blip is OK if upper and lower sum to an OK value and at least
// one of above1 and below1 is equal to the median.
return parts[PN_UPPER]->SummedSpacingOK(*parts[PN_LOWER],
median_spacing, resolution) &&
((parts[PN_ABOVE1] != NULL &&
parts[PN_ABOVE1]->SpacingEqual(median_spacing, resolution)) ||
(parts[PN_BELOW1] != NULL &&
parts[PN_BELOW1]->SpacingEqual(median_spacing, resolution)));
}
// Returns true if both the top and bottom spacings of this match the given
// spacing to within suitable margins dictated by the image resolution.
bool ColPartition::SpacingEqual(int spacing, int resolution) const {
int bottom_error = BottomSpacingMargin(resolution);
int top_error = TopSpacingMargin(resolution);
return NearlyEqual(bottom_spacing_, spacing, bottom_error) &&
NearlyEqual(top_spacing_, spacing, top_error);
}
// Returns true if both the top and bottom spacings of this and other
// match to within suitable margins dictated by the image resolution.
bool ColPartition::SpacingsEqual(const ColPartition& other,
int resolution) const {
int bottom_error = MAX(BottomSpacingMargin(resolution),
other.BottomSpacingMargin(resolution));
int top_error = MAX(TopSpacingMargin(resolution),
other.TopSpacingMargin(resolution));
return NearlyEqual(bottom_spacing_, other.bottom_spacing_, bottom_error) &&
(NearlyEqual(top_spacing_, other.top_spacing_, top_error) ||
NearlyEqual(top_spacing_ + other.top_spacing_, bottom_spacing_ * 2,
bottom_error));
}
// Returns true if the sum spacing of this and other match the given
// spacing (or twice the given spacing) to within a suitable margin dictated
// by the image resolution.
bool ColPartition::SummedSpacingOK(const ColPartition& other,
int spacing, int resolution) const {
int bottom_error = MAX(BottomSpacingMargin(resolution),
other.BottomSpacingMargin(resolution));
int top_error = MAX(TopSpacingMargin(resolution),
other.TopSpacingMargin(resolution));
int bottom_total = bottom_spacing_ + other.bottom_spacing_;
int top_total = top_spacing_ + other.top_spacing_;
return (NearlyEqual(spacing, bottom_total, bottom_error) &&
NearlyEqual(spacing, top_total, top_error)) ||
(NearlyEqual(spacing * 2, bottom_total, bottom_error) &&
NearlyEqual(spacing * 2, top_total, top_error));
}
// Returns a suitable spacing margin that can be applied to bottoms of
// text lines, based on the resolution and the stored side_step_.
int ColPartition::BottomSpacingMargin(int resolution) const {
return static_cast<int>(kMaxSpacingDrift * resolution + 0.5) + side_step_;
}
// Returns a suitable spacing margin that can be applied to tops of
// text lines, based on the resolution and the stored side_step_.
int ColPartition::TopSpacingMargin(int resolution) const {
return static_cast<int>(kMaxTopSpacingFraction * median_size_ + 0.5) +
BottomSpacingMargin(resolution);
}
// Returns true if the median text sizes of this and other agree to within
// a reasonable multiplicative factor.
bool ColPartition::SizesSimilar(const ColPartition& other) const {
return median_size_ <= other.median_size_ * kMaxSizeRatio &&
other.median_size_ <= median_size_ * kMaxSizeRatio;
}
// Helper updates margin_left and margin_right, being the bounds of the left
// margin of part of a block. Returns false and does not update the bounds if
// this partition has a disjoint margin with the established margin.
static bool UpdateLeftMargin(const ColPartition& part,
int* margin_left, int* margin_right) {
const TBOX& part_box = part.bounding_box();
int top = part_box.top();
int bottom = part_box.bottom();
int tl_key = part.SortKey(part.left_margin(), top);
int tr_key = part.SortKey(part_box.left(), top);
int bl_key = part.SortKey(part.left_margin(), bottom);
int br_key = part.SortKey(part_box.left(), bottom);
int left_key = MAX(tl_key, bl_key);
int right_key = MIN(tr_key, br_key);
if (left_key <= *margin_right && right_key >= *margin_left) {
// This part is good - let's keep it.
*margin_right = MIN(*margin_right, right_key);
*margin_left = MAX(*margin_left, left_key);
return true;
}
return false;
}
// Computes and returns in start, end a line segment formed from a
// forwards-iterated group of left edges of partitions that satisfy the
// condition that the intersection of the left margins is non-empty, ie the
// rightmost left margin is to the left of the leftmost left bounding box edge.
// On return the iterator is set to the start of the next run.
void ColPartition::LeftEdgeRun(ColPartition_IT* part_it,
ICOORD* start, ICOORD* end) {
ColPartition* part = part_it->data();
ColPartition* start_part = part;
int start_y = part->bounding_box_.top();
if (!part_it->at_first()) {
int prev_bottom = part_it->data_relative(-1)->bounding_box_.bottom();
if (prev_bottom < start_y)
start_y = prev_bottom;
else if (prev_bottom > start_y)
start_y = (start_y + prev_bottom) / 2;
}
int end_y = part->bounding_box_.bottom();
int margin_right = MAX_INT32;
int margin_left = -MAX_INT32;
UpdateLeftMargin(*part, &margin_left, &margin_right);
do {
part_it->forward();
part = part_it->data();
} while (!part_it->at_first() &&
UpdateLeftMargin(*part, &margin_left, &margin_right));
// The run ended. If we were pushed inwards, compute the next run and
// extend it backwards into the run we just calculated to find the end of
// this run that provides a tight box.
int next_margin_right = MAX_INT32;
int next_margin_left = -MAX_INT32;
UpdateLeftMargin(*part, &next_margin_left, &next_margin_right);
if (next_margin_left > margin_right) {
ColPartition_IT next_it(*part_it);
do {
next_it.forward();
part = next_it.data();
} while (!next_it.at_first() &&
UpdateLeftMargin(*part, &next_margin_left, &next_margin_right));
// Now extend the next run backwards into the original run to get the
// tightest fit.
do {
part_it->backward();
part = part_it->data();
} while (part != start_part &&
UpdateLeftMargin(*part, &next_margin_left, &next_margin_right));
part_it->forward();
}
// Now calculate the end_y.
part = part_it->data_relative(-1);
end_y = part->bounding_box_.bottom();
if (!part_it->at_first() && part_it->data()->bounding_box_.top() < end_y)
end_y = (end_y + part_it->data()->bounding_box_.top()) / 2;
start->set_y(start_y);
start->set_x(part->XAtY(margin_right, start_y));
end->set_y(end_y);
end->set_x(part->XAtY(margin_right, end_y));
if (textord_debug_tabfind && !part_it->at_first())
tprintf("Left run from y=%d to %d terminated with sum %d-%d, new %d-%d\n",
start_y, end_y, part->XAtY(margin_left, end_y),
end->x(), part->left_margin_, part->bounding_box_.left());
}
// Helper updates margin_left and margin_right, being the bounds of the right
// margin of part of a block. Returns false and does not update the bounds if
// this partition has a disjoint margin with the established margin.
static bool UpdateRightMargin(const ColPartition& part,
int* margin_left, int* margin_right) {
const TBOX& part_box = part.bounding_box();
int top = part_box.top();
int bottom = part_box.bottom();
int tl_key = part.SortKey(part_box.right(), top);
int tr_key = part.SortKey(part.right_margin(), top);
int bl_key = part.SortKey(part_box.right(), bottom);
int br_key = part.SortKey(part.right_margin(), bottom);
int left_key = MAX(tl_key, bl_key);
int right_key = MIN(tr_key, br_key);
if (left_key <= *margin_right && right_key >= *margin_left) {
// This part is good - let's keep it.
*margin_right = MIN(*margin_right, right_key);
*margin_left = MAX(*margin_left, left_key);
return true;
}
return false;
}
// Computes and returns in start, end a line segment formed from a
// backwards-iterated group of right edges of partitions that satisfy the
// condition that the intersection of the right margins is non-empty, ie the
// leftmost right margin is to the right of the rightmost right bounding box
// edge.
// On return the iterator is set to the start of the next run.
void ColPartition::RightEdgeRun(ColPartition_IT* part_it,
ICOORD* start, ICOORD* end) {
ColPartition* part = part_it->data();
ColPartition* start_part = part;
int start_y = part->bounding_box_.bottom();
if (!part_it->at_last()) {
int next_y = part_it->data_relative(1)->bounding_box_.top();
if (next_y > start_y)
start_y = next_y;
else if (next_y < start_y)
start_y = (start_y + next_y) / 2;
}
int end_y = part->bounding_box_.top();
int margin_right = MAX_INT32;
int margin_left = -MAX_INT32;
UpdateRightMargin(*part, &margin_left, &margin_right);
do {
part_it->backward();
part = part_it->data();
} while (!part_it->at_last() &&
UpdateRightMargin(*part, &margin_left, &margin_right));
// The run ended. If we were pushed inwards, compute the next run and
// extend it backwards to find the end of this run for a tight box.
int next_margin_right = MAX_INT32;
int next_margin_left = -MAX_INT32;
UpdateRightMargin(*part, &next_margin_left, &next_margin_right);
if (next_margin_right < margin_left) {
ColPartition_IT next_it(*part_it);
do {
next_it.backward();
part = next_it.data();
} while (!next_it.at_last() &&
UpdateRightMargin(*part, &next_margin_left,
&next_margin_right));
// Now extend the next run forwards into the original run to get the
// tightest fit.
do {
part_it->forward();
part = part_it->data();
} while (part != start_part &&
UpdateRightMargin(*part, &next_margin_left,
&next_margin_right));
part_it->backward();
}
// Now calculate the end_y.
part = part_it->data_relative(1);
end_y = part->bounding_box().top();
if (!part_it->at_last() &&
part_it->data()->bounding_box_.bottom() > end_y)
end_y = (end_y + part_it->data()->bounding_box_.bottom()) / 2;
start->set_y(start_y);
start->set_x(part->XAtY(margin_left, start_y));
end->set_y(end_y);
end->set_x(part->XAtY(margin_left, end_y));
if (textord_debug_tabfind && !part_it->at_last())
tprintf("Right run from y=%d to %d terminated with sum %d-%d, new %d-%d\n",
start_y, end_y, end->x(), part->XAtY(margin_right, end_y),
part->bounding_box_.right(), part->right_margin_);
}
} // namespace tesseract.
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