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tesseract/textord/strokewidth.cpp

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///////////////////////////////////////////////////////////////////////
// File: strokewidth.cpp
// Description: Subclass of BBGrid to find uniformity of strokewidth.
// Author: Ray Smith
// Created: Mon Mar 31 16:17:01 PST 2008
//
// (C) Copyright 2008, Google Inc.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
///////////////////////////////////////////////////////////////////////
#ifdef _MSC_VER
#pragma warning(disable:4244) // Conversion warnings
#endif
#include "strokewidth.h"
#include "blobbox.h"
#include "colpartition.h"
#include "colpartitiongrid.h"
#include "statistc.h"
#include "tabfind.h"
#include "tordmain.h" // For SetBlobStrokeWidth.
// Include automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#include "config_auto.h"
#endif
namespace tesseract {
INT_VAR(textord_tabfind_show_strokewidths, 0, "Show stroke widths");
BOOL_VAR(textord_tabfind_only_strokewidths, false, "Only run stroke widths");
double_VAR(textord_strokewidth_minsize, 0.25,
"Min multiple of linesize for medium-sized blobs");
double_VAR(textord_strokewidth_maxsize, 4.0,
"Max multiple of linesize for medium-sized blobs");
BOOL_VAR(textord_tabfind_vertical_text, true, "Enable vertical detection");
BOOL_VAR(textord_tabfind_force_vertical_text, false,
"Force using vertical text page mode");
BOOL_VAR(textord_tabfind_vertical_horizontal_mix, true,
"find horizontal lines such as headers in vertical page mode");
double_VAR(textord_tabfind_vertical_text_ratio, 0.5,
"Fraction of textlines deemed vertical to use vertical page mode");
/** Allowed proportional change in stroke width to be the same font. */
const double kStrokeWidthFractionTolerance = 0.125;
/**
* Allowed constant change in stroke width to be the same font.
* Really 1.5 pixels.
*/
const double kStrokeWidthTolerance = 1.5;
// Same but for CJK we are a bit more generous.
const double kStrokeWidthFractionCJK = 0.25;
const double kStrokeWidthCJK = 2.0;
// Radius in grid cells of search for broken CJK. Doesn't need to be very
// large as the grid size should be about the size of a character anyway.
const int kCJKRadius = 2;
// Max distance fraction of size to join close but broken CJK characters.
const double kCJKBrokenDistanceFraction = 0.25;
// Max number of components in a broken CJK character.
const int kCJKMaxComponents = 8;
// Max aspect ratio of CJK broken characters when put back together.
const double kCJKAspectRatio = 1.25;
// Max increase in aspect ratio of CJK broken characters when merged.
const double kCJKAspectRatioIncrease = 1.0625;
// Max multiple of the grid size that will be used in computing median CJKsize.
const int kMaxCJKSizeRatio = 5;
// Min multiple of diacritic height that a neighbour must be to be a
// convincing base character.
const int kMinDiacriticSizeRatio = 2;
// Radius of a search for diacritics in grid units.
const int kSearchRadius = 2;
// Ratio between longest side of a line and longest side of a character.
// (neighbor_min > blob_min * kLineTrapShortest &&
// neighbor_max < blob_max / kLineTrapLongest)
// => neighbor is a grapheme and blob is a line.
const int kLineTrapLongest = 4;
// Ratio between shortest side of a line and shortest side of a character.
const int kLineTrapShortest = 2;
// Max aspect ratio of the total box before CountNeighbourGaps
// decides immediately based on the aspect ratio.
const int kMostlyOneDirRatio = 3;
// Max number of neighbour small objects per squared gridsize before a grid
// cell becomes image.
const double kMaxSmallNeighboursPerPix = 3.0 / 128;
// Aspect ratio filter for OSD.
const float kSizeRatioToReject = 2.0;
/** Maximum height in inches of the largest possible text. */
const double kMaxTextSize = 2.0;
StrokeWidth::StrokeWidth(int gridsize,
const ICOORD& bleft, const ICOORD& tright)
: BBGrid<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT>(gridsize, bleft, tright),
noise_density_(NULL) {
leaders_win_ = NULL;
widths_win_ = NULL;
initial_widths_win_ = NULL;
}
StrokeWidth::~StrokeWidth() {
delete noise_density_;
if (widths_win_ != NULL) {
delete widths_win_->AwaitEvent(SVET_DESTROY);
if (textord_tabfind_only_strokewidths)
exit(0);
delete widths_win_;
}
delete leaders_win_;
delete initial_widths_win_;
}
// Types all the blobs as vertical or horizontal text or unknown and
// returns true if the majority are vertical.
// If the blobs are rotated, it is necessary to call CorrectForRotation
// after rotating everything, otherwise the work done here will be enough.
// If cjk_merge is true, it will attempt to merge broken cjk characters.
// If osd_blobs is not null, a list of blobs from the dominant textline
// direction are returned for use in orientation and script detection.
bool StrokeWidth::TestVerticalTextDirection(bool cjk_merge, TO_BLOCK* block,
TabFind* line_grid,
BLOBNBOX_CLIST* osd_blobs) {
// Reset all blobs to initial state and filter by size.
ReFilterBlobs(block);
// Compute the noise density in the grid.
ComputeNoiseDensity(block, line_grid);
// Setup the grid with the remaining blobs
InsertBlobs(block, line_grid);
// Repair broken CJK characters if needed.
if (cjk_merge)
FixBrokenCJK(&block->blobs, line_grid);
if (textord_tabfind_force_vertical_text) return true;
// Grade blobs by inspection of neighbours.
FindTextlineFlowDirection(false);
if (!textord_tabfind_vertical_text) return false;
int vertical_boxes = 0;
int horizontal_boxes = 0;
// Count vertical bboxes in the grid.
BlobGridSearch gsearch(this);
gsearch.StartFullSearch();
BLOBNBOX* blob;
BLOBNBOX_CLIST vertical_blobs;
BLOBNBOX_CLIST horizontal_blobs;
BLOBNBOX_CLIST nondescript_blobs;
BLOBNBOX_C_IT v_it(&vertical_blobs);
BLOBNBOX_C_IT h_it(&horizontal_blobs);
BLOBNBOX_C_IT n_it(&nondescript_blobs);
while ((blob = gsearch.NextFullSearch()) != NULL) {
const TBOX& box = blob->bounding_box();
float y_x = static_cast<float>(box.height()) / box.width();
float x_y = 1.0f / y_x;
// Select a >= 1.0 ratio
float ratio = x_y > y_x ? x_y : y_x;
// If the aspect ratio is small and we want them for osd, save the blob.
bool ok_blob = ratio <= kSizeRatioToReject && osd_blobs != NULL;
if (blob->UniquelyVertical()) {
++vertical_boxes;
if (ok_blob) v_it.add_after_then_move(blob);
} else if (blob->UniquelyHorizontal()) {
++horizontal_boxes;
if (ok_blob) h_it.add_after_then_move(blob);
} else if (ok_blob) {
n_it.add_after_then_move(blob);
}
}
if (textord_debug_tabfind)
tprintf("TextDir hbox=%d vs vbox=%d, %dH, %dV, %dN osd blobs\n",
horizontal_boxes, vertical_boxes,
horizontal_blobs.length(), vertical_blobs.length(),
nondescript_blobs.length());
if (osd_blobs != NULL && vertical_boxes == 0 && horizontal_boxes == 0) {
// Only nondescript blobs available, so return those.
BLOBNBOX_C_IT osd_it(osd_blobs);
osd_it.add_list_after(&nondescript_blobs);
return false;
}
int min_vert_boxes = static_cast<int>((vertical_boxes + horizontal_boxes) *
textord_tabfind_vertical_text_ratio);
if (vertical_boxes >= min_vert_boxes) {
if (osd_blobs != NULL) {
BLOBNBOX_C_IT osd_it(osd_blobs);
osd_it.add_list_after(&vertical_blobs);
}
return true;
} else {
if (osd_blobs != NULL) {
BLOBNBOX_C_IT osd_it(osd_blobs);
osd_it.add_list_after(&horizontal_blobs);
}
return false;
}
}
// Corrects the data structures for the given rotation.
void StrokeWidth::CorrectForRotation(const FCOORD& rotation, TO_BLOCK* block) {
noise_density_->Rotate(rotation);
Init(noise_density_->gridsize(), noise_density_->bleft(),
noise_density_->tright());
// Reset all blobs to initial state and filter by size.
// Since they have rotated, the list they belong on could have changed.
ReFilterBlobs(block);
}
// Finds leader partitions and inserts them into the give grid.
void StrokeWidth::FindLeaderPartitions(TO_BLOCK* block, TabFind* line_grid) {
Clear();
// Find and isolate leaders in the noise list.
ColPartition_LIST leader_parts;
FindLeadersAndMarkNoise(true, block, line_grid, &leader_parts);
// Setup the grid with the remaining blobs
InsertBlobs(block, line_grid);
// Mark blobs that have leader neighbours.
for (ColPartition_IT it(&leader_parts); !it.empty(); it.forward()) {
ColPartition* part = it.extract();
MarkLeaderNeighbours(part, true);
MarkLeaderNeighbours(part, false);
delete part;
}
}
static void PrintBoxWidths(BLOBNBOX* neighbour) {
TBOX nbox = neighbour->bounding_box();
tprintf("Box (%d,%d)->(%d,%d): h-width=%.1f, v-width=%.1f p-width=%1.f\n",
nbox.left(), nbox.bottom(), nbox.right(), nbox.top(),
neighbour->horz_stroke_width(), neighbour->vert_stroke_width(),
2.0 * neighbour->cblob()->area()/neighbour->cblob()->perimeter());
}
/** Handles a click event in a display window. */
void StrokeWidth::HandleClick(int x, int y) {
BBGrid<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT>::HandleClick(x, y);
// Run a radial search for blobs that overlap.
BlobGridSearch radsearch(this);
radsearch.StartRadSearch(x, y, 1);
BLOBNBOX* neighbour;
FCOORD click(static_cast<float>(x), static_cast<float>(y));
while ((neighbour = radsearch.NextRadSearch()) != NULL) {
TBOX nbox = neighbour->bounding_box();
if (nbox.contains(click) && neighbour->cblob() != NULL) {
PrintBoxWidths(neighbour);
if (neighbour->neighbour(BND_LEFT) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_LEFT));
if (neighbour->neighbour(BND_RIGHT) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_RIGHT));
if (neighbour->neighbour(BND_ABOVE) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_ABOVE));
if (neighbour->neighbour(BND_BELOW) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_BELOW));
int gaps[BND_COUNT];
neighbour->NeighbourGaps(gaps);
tprintf("Left gap=%d, right=%d, above=%d, below=%d, horz=%d, vert=%d\n"
"Good= %d %d %d %d\n",
gaps[BND_LEFT], gaps[BND_RIGHT],
gaps[BND_ABOVE], gaps[BND_BELOW],
neighbour->horz_possible(),
neighbour->vert_possible(),
neighbour->good_stroke_neighbour(BND_LEFT),
neighbour->good_stroke_neighbour(BND_RIGHT),
neighbour->good_stroke_neighbour(BND_ABOVE),
neighbour->good_stroke_neighbour(BND_BELOW));
break;
}
}
}
// Helper function to divide the input blobs over noise, small, medium
// and large lists. Blobs small in height and (small in width or large in width)
// go in the noise list. Dash (-) candidates go in the small list, and
// medium and large are by height.
// SIDE-EFFECT: reset all blobs to initial state by calling Init().
static void SizeFilterBlobs(int min_height, int max_height,
BLOBNBOX_LIST* src_list,
BLOBNBOX_LIST* noise_list,
BLOBNBOX_LIST* small_list,
BLOBNBOX_LIST* medium_list,
BLOBNBOX_LIST* large_list) {
BLOBNBOX_IT noise_it(noise_list);
BLOBNBOX_IT small_it(small_list);
BLOBNBOX_IT medium_it(medium_list);
BLOBNBOX_IT large_it(large_list);
for (BLOBNBOX_IT src_it(src_list); !src_it.empty(); src_it.forward()) {
BLOBNBOX* blob = src_it.extract();
blob->ReInit();
int width = blob->bounding_box().width();
int height = blob->bounding_box().height();
if (height < min_height &&
(width < min_height || width > max_height))
noise_it.add_after_then_move(blob);
else if (height > max_height)
large_it.add_after_then_move(blob);
else if (height < min_height)
small_it.add_after_then_move(blob);
else
medium_it.add_after_then_move(blob);
}
}
// Reorganize the blob lists with a different definition of small, medium
// and large, compared to the original definition.
// Height is still the primary filter key, but medium width blobs of small
// height become small, and very wide blobs of small height stay noise, along
// with small dot-shaped blobs.
void StrokeWidth::ReFilterBlobs(TO_BLOCK* block) {
int min_height =
static_cast<int>(textord_strokewidth_minsize * block->line_size + 0.5);
int max_height =
static_cast<int>(textord_strokewidth_maxsize * block->line_size + 0.5);
BLOBNBOX_LIST noise_list;
BLOBNBOX_LIST small_list;
BLOBNBOX_LIST medium_list;
BLOBNBOX_LIST large_list;
SizeFilterBlobs(min_height, max_height, &block->blobs,
&noise_list, &small_list, &medium_list, &large_list);
SizeFilterBlobs(min_height, max_height, &block->large_blobs,
&noise_list, &small_list, &medium_list, &large_list);
SizeFilterBlobs(min_height, max_height, &block->small_blobs,
&noise_list, &small_list, &medium_list, &large_list);
SizeFilterBlobs(min_height, max_height, &block->noise_blobs,
&noise_list, &small_list, &medium_list, &large_list);
BLOBNBOX_IT blob_it(&block->blobs);
blob_it.add_list_after(&medium_list);
blob_it.set_to_list(&block->large_blobs);
blob_it.add_list_after(&large_list);
blob_it.set_to_list(&block->small_blobs);
blob_it.add_list_after(&small_list);
blob_it.set_to_list(&block->noise_blobs);
blob_it.add_list_after(&noise_list);
}
// Computes the noise_density_ by summing the number of elements in a
// neighbourhood of each grid cell.
void StrokeWidth::ComputeNoiseDensity(TO_BLOCK* block, TabFind* line_grid) {
// Run a preliminary strokewidth neighbour detection on the medium blobs.
line_grid->InsertBlobList(true, true, false, &block->blobs, false, this);
BLOBNBOX_IT blob_it(&block->blobs);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
SetNeighbours(false, blob_it.data());
}
// Remove blobs with a good strokewidth neighbour from the grid.
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
if (blob->GoodTextBlob() > 0)
RemoveBBox(blob);
blob->ClearNeighbours();
}
// Insert the smaller blobs into the grid.
line_grid->InsertBlobList(true, true, false, &block->small_blobs,
false, this);
line_grid->InsertBlobList(true, true, false, &block->noise_blobs,
false, this);
if (noise_density_ != NULL)
delete noise_density_;
IntGrid* cell_counts = CountCellElements();
noise_density_ = cell_counts->NeighbourhoodSum();
delete cell_counts;
// Clear the grid as we don't want the small stuff hanging around in it.
Clear();
}
// Detects and marks leader dots/dashes.
// Leaders are horizontal chains of small or noise blobs that look
// monospace according to ColPartition::MarkAsLeaderIfMonospaced().
// Detected leaders become the only occupants of small_blobs list.
// Non-leader small blobs get moved to the blobs list.
// Non-leader noise blobs remain singletons in the noise list.
// All small and noise blobs in high density regions are marked BTFT_NONTEXT.
void StrokeWidth::FindLeadersAndMarkNoise(bool final, TO_BLOCK* block,
TabFind* line_grid,
ColPartition_LIST* leader_parts) {
line_grid->InsertBlobList(true, true, false, &block->small_blobs,
false, this);
line_grid->InsertBlobList(true, true, false, &block->noise_blobs,
false, this);
int max_noise_count =
static_cast<int>(kMaxSmallNeighboursPerPix * gridsize() * gridsize());
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
// For every bbox in the grid, set its neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
int noise_count = noise_density_->GridCellValue(gsearch.GridX(),
gsearch.GridY());
if (noise_count <= max_noise_count) {
SetNeighbours(true, bbox);
} else {
bbox->set_flow(BTFT_NONTEXT);
}
}
ColPartition_IT part_it(leader_parts);
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
if (bbox->flow() == BTFT_NONE) {
if (bbox->neighbour(BND_RIGHT) == NULL &&
bbox->neighbour(BND_LEFT) == NULL)
continue;
// Put all the linked blobs into a ColPartition.
ColPartition* part = new ColPartition(BRT_UNKNOWN, ICOORD(0, 1));
BLOBNBOX* blob;
for (blob = bbox; blob != NULL && blob->flow() == BTFT_NONE;
blob = blob->neighbour(BND_RIGHT))
part->AddBox(blob);
for (blob = bbox->neighbour(BND_LEFT); blob != NULL &&
blob->flow() == BTFT_NONE;
blob = blob->neighbour(BND_LEFT))
part->AddBox(blob);
if (part->MarkAsLeaderIfMonospaced())
part_it.add_after_then_move(part);
else
delete part;
}
}
if (textord_tabfind_show_strokewidths && final) {
leaders_win_ = DisplayGoodBlobs("LeaderNeighbours", 0, 0);
}
// Move any non-leaders from the small to the blobs list, as they are
// most likely dashes or broken characters.
BLOBNBOX_IT blob_it(&block->blobs);
BLOBNBOX_IT small_it(&block->small_blobs);
for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
BLOBNBOX* blob = small_it.data();
if (blob->flow() != BTFT_LEADER) {
if (blob->flow() == BTFT_NEIGHBOURS)
blob->set_flow(BTFT_NONE);
blob->ClearNeighbours();
blob_it.add_to_end(small_it.extract());
}
}
// Move leaders from the noise list to the small list, leaving the small
// list exclusively leaders, so they don't get processed further,
// and the remaining small blobs all in the noise list.
BLOBNBOX_IT noise_it(&block->noise_blobs);
for (noise_it.mark_cycle_pt(); !noise_it.cycled_list(); noise_it.forward()) {
BLOBNBOX* blob = noise_it.data();
if (blob->flow() == BTFT_LEADER || blob->joined_to_prev()) {
small_it.add_to_end(noise_it.extract());
} else if (blob->flow() == BTFT_NEIGHBOURS) {
blob->set_flow(BTFT_NONE);
blob->ClearNeighbours();
}
}
// Clear the grid as we don't want the small stuff hanging around in it.
Clear();
}
/** Puts the block blobs (normal and large) into the grid. */
void StrokeWidth::InsertBlobs(TO_BLOCK* block, TabFind* line_grid) {
// Insert the blobs into this grid using the separator lines in line_grid.
line_grid->InsertBlobList(true, true, false, &block->blobs, false, this);
line_grid->InsertBlobList(true, true, true, &block->large_blobs,
false, this);
}
// Sets the leader_on_left or leader_on_right flags for blobs
// that are next to one end of the given leader partition.
// If left_of_part is true, then look at the left side of the partition for
// blobs on which to set the leader_on_right flag.
void StrokeWidth::MarkLeaderNeighbours(const ColPartition* part,
bool left_of_part) {
const TBOX& part_box = part->bounding_box();
BlobGridSearch blobsearch(this);
// Search to the side of the leader for the nearest neighbour.
BLOBNBOX* best_blob = NULL;
int best_gap = 0;
blobsearch.StartSideSearch(left_of_part ? part_box.left() : part_box.right(),
part_box.bottom(), part_box.top());
BLOBNBOX* blob;
while ((blob = blobsearch.NextSideSearch(left_of_part)) != NULL) {
const TBOX& blob_box = blob->bounding_box();
if (!blob_box.y_overlap(part_box))
continue;
int x_gap = blob_box.x_gap(part_box);
if (x_gap > 2 * gridsize()) {
break;
} else if (best_blob == NULL || x_gap < best_gap) {
best_blob = blob;
best_gap = x_gap;
}
}
if (best_blob != NULL) {
if (left_of_part)
best_blob->set_leader_on_right(true);
else
best_blob->set_leader_on_left(true);
if (leaders_win_ != NULL) {
leaders_win_->Pen(left_of_part ? ScrollView::RED : ScrollView::GREEN);
const TBOX& blob_box = best_blob->bounding_box();
leaders_win_->Rectangle(blob_box.left(), blob_box.bottom(),
blob_box.right(), blob_box.top());
}
}
}
// Helper to compute the UQ of the square-ish CJK charcters.
static int UpperQuartileCJKSize(int gridsize, BLOBNBOX_LIST* blobs) {
STATS sizes(0, gridsize * kMaxCJKSizeRatio);
BLOBNBOX_IT it(blobs);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
int width = blob->bounding_box().width();
int height = blob->bounding_box().height();
if (width <= height * kCJKAspectRatio && height < width * kCJKAspectRatio)
sizes.add(height, 1);
}
return static_cast<int>(sizes.ile(0.75f) + 0.5);
}
// Fix broken CJK characters, using the fake joined blobs mechanism.
// Blobs are really merged, ie the master takes all the outlines and the
// others are deleted.
void StrokeWidth::FixBrokenCJK(BLOBNBOX_LIST* blobs, TabFind* line_grid) {
int median_height = UpperQuartileCJKSize(gridsize(), blobs);
int max_dist = static_cast<int>(median_height * kCJKBrokenDistanceFraction);
int max_size = static_cast<int>(median_height * kCJKAspectRatio);
BLOBNBOX_IT blob_it(blobs);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
if (blob->cblob() == NULL || blob->cblob()->out_list()->empty())
continue;
TBOX bbox = blob->bounding_box();
bool debug = AlignedBlob::WithinTestRegion(3, bbox.left(),
bbox.bottom());
if (debug) {
tprintf("Checking for Broken CJK (max size=%d):", max_size);
bbox.print();
}
// Generate a list of blobs that overlap or are near enough to merge.
BLOBNBOX_CLIST overlapped_blobs;
AccumulateOverlaps(blob, debug, max_size, max_dist,
&bbox, &overlapped_blobs);
if (!overlapped_blobs.empty()) {
// There are overlapping blobs, so qualify them as being satisfactory
// before removing them from the grid and replacing them with the union.
// The final box must be roughly square.
if (bbox.width() > bbox.height() * kCJKAspectRatio ||
bbox.height() > bbox.width() * kCJKAspectRatio) {
if (debug) {
tprintf("Bad final aspectratio:");
bbox.print();
}
continue;
}
// There can't be too many blobs to merge.
if (overlapped_blobs.length() >= kCJKMaxComponents) {
if (debug)
tprintf("Too many neighbours: %d\n", overlapped_blobs.length());
continue;
}
// The strokewidths must match amongst the join candidates.
BLOBNBOX_C_IT n_it(&overlapped_blobs);
for (n_it.mark_cycle_pt(); !n_it.cycled_list(); n_it.forward()) {
BLOBNBOX* neighbour = NULL;
neighbour = n_it.data();
if (!blob->MatchingStrokeWidth(*neighbour, kStrokeWidthFractionCJK,
kStrokeWidthCJK))
break;
}
if (!n_it.cycled_list()) {
if (debug) {
tprintf("Bad stroke widths:");
PrintBoxWidths(blob);
}
continue; // Not good enough.
}
// Merge all the candidates into blob.
// We must remove blob from the grid and reinsert it after merging
// to maintain the integrity of the grid.
RemoveBBox(blob);
// Everything else will be calculated later.
for (n_it.mark_cycle_pt(); !n_it.cycled_list(); n_it.forward()) {
BLOBNBOX* neighbour = n_it.data();
RemoveBBox(neighbour);
blob->really_merge(neighbour);
}
line_grid->InsertBlob(true, true, false, blob, this);
if (debug) {
tprintf("Done! Final box:");
bbox.print();
}
}
}
// Permanently delete all the empty shell blobs that contain no outlines.
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
if (blob->cblob() == NULL || blob->cblob()->out_list()->empty()) {
if (blob->cblob() != NULL)
delete blob->cblob();
delete blob_it.extract();
}
}
}
// Helper function to determine whether it is reasonable to merge the
// bbox and the nbox for repairing broken CJK.
// The distance apart must not exceed max_dist, the combined size must
// not exceed max_size, and the aspect ratio must either improve or at
// least not get worse by much.
static bool AcceptableCJKMerge(const TBOX& bbox, const TBOX& nbox,
bool debug, int max_size, int max_dist,
int* x_gap, int* y_gap) {
*x_gap = bbox.x_gap(nbox);
*y_gap = bbox.y_gap(nbox);
TBOX merged(nbox);
merged += bbox;
if (debug) {
tprintf("gaps = %d, %d, merged_box:", *x_gap, *y_gap);
merged.print();
}
if (*x_gap <= max_dist && *y_gap <= max_dist &&
merged.width() <= max_size && merged.height() <= max_size) {
// Close enough to call overlapping. Check aspect ratios.
double old_ratio = static_cast<double>(bbox.width()) / bbox.height();
if (old_ratio < 1.0) old_ratio = 1.0 / old_ratio;
double new_ratio = static_cast<double>(merged.width()) / merged.height();
if (new_ratio < 1.0) new_ratio = 1.0 / new_ratio;
if (new_ratio <= old_ratio * kCJKAspectRatioIncrease)
return true;
}
return false;
}
// Collect blobs that overlap or are within max_dist of the input bbox.
// Return them in the list of blobs and expand the bbox to be the union
// of all the boxes. not_this is excluded from the search, as are blobs
// that cause the merged box to exceed max_size in either dimension.
void StrokeWidth::AccumulateOverlaps(const BLOBNBOX* not_this, bool debug,
int max_size, int max_dist,
TBOX* bbox, BLOBNBOX_CLIST* blobs) {
// While searching, nearests holds the nearest failed blob in each
// direction. When we have a nearest in each of the 4 directions, then
// the search is over, and at this point the final bbox must not overlap
// any of the nearests.
BLOBNBOX* nearests[BND_COUNT];
for (int i = 0; i < BND_COUNT; ++i) {
nearests[i] = NULL;
}
int x = (bbox->left() + bbox->right()) / 2;
int y = (bbox->bottom() + bbox->top()) / 2;
// Run a radial search for blobs that overlap or are sufficiently close.
BlobGridSearch radsearch(this);
radsearch.StartRadSearch(x, y, kCJKRadius);
BLOBNBOX* neighbour;
while ((neighbour = radsearch.NextRadSearch()) != NULL) {
if (neighbour == not_this) continue;
TBOX nbox = neighbour->bounding_box();
int x_gap, y_gap;
if (AcceptableCJKMerge(*bbox, nbox, debug, max_size, max_dist,
&x_gap, &y_gap)) {
// Close enough to call overlapping. Merge boxes.
*bbox += nbox;
blobs->add_sorted(SortByBoxLeft<BLOBNBOX>, true, neighbour);
if (debug) {
tprintf("Added:");
nbox.print();
}
// Since we merged, search the nearests, as some might now me mergeable.
for (int dir = 0; dir < BND_COUNT; ++dir) {
if (nearests[dir] == NULL) continue;
nbox = nearests[dir]->bounding_box();
if (AcceptableCJKMerge(*bbox, nbox, debug, max_size,
max_dist, &x_gap, &y_gap)) {
// Close enough to call overlapping. Merge boxes.
*bbox += nbox;
blobs->add_sorted(SortByBoxLeft<BLOBNBOX>, true, nearests[dir]);
if (debug) {
tprintf("Added:");
nbox.print();
}
nearests[dir] = NULL;
dir = -1; // Restart the search.
}
}
} else if (x_gap < 0 && x_gap <= y_gap) {
// A vertical neighbour. Record the nearest.
BlobNeighbourDir dir = nbox.top() > bbox->top() ? BND_ABOVE : BND_BELOW;
if (nearests[dir] == NULL ||
y_gap < bbox->y_gap(nearests[dir]->bounding_box())) {
nearests[dir] = neighbour;
}
} else if (y_gap < 0 && y_gap <= x_gap) {
// A horizontal neighbour. Record the nearest.
BlobNeighbourDir dir = nbox.left() > bbox->left() ? BND_RIGHT : BND_LEFT;
if (nearests[dir] == NULL ||
x_gap < bbox->x_gap(nearests[dir]->bounding_box())) {
nearests[dir] = neighbour;
}
}
// If all nearests are non-null, then we have finished.
if (nearests[BND_LEFT] && nearests[BND_RIGHT] &&
nearests[BND_ABOVE] && nearests[BND_BELOW])
break;
}
// Final overlap with a nearest is not allowed.
for (int dir = 0; dir < BND_COUNT; ++dir) {
if (nearests[dir] == NULL) continue;
const TBOX& nbox = nearests[dir]->bounding_box();
if (debug) {
tprintf("Testing for overlap with:");
nbox.print();
}
if (bbox->overlap(nbox)) {
blobs->shallow_clear();
if (debug)
tprintf("Final box overlaps nearest\n");
return;
}
}
}
// Finds the textline direction to be horizontal or vertical according
// to distance to neighbours and 1st and 2nd order neighbours.
// Non-text tends to end up without a definite direction.
void StrokeWidth::FindTextlineFlowDirection(bool final) {
int max_noise_count =
static_cast<int>(kMaxSmallNeighboursPerPix * gridsize() * gridsize());
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
// For every bbox in the grid, set its neighbours, unless in a noisy area.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
int noise_count = noise_density_->GridCellValue(gsearch.GridX(),
gsearch.GridY());
if (noise_count <= max_noise_count) {
SetNeighbours(false, bbox);
} else {
// The noise density is so high, that it must be non-text.
bbox->set_flow(BTFT_NONTEXT);
}
}
// Where vertical or horizontal wins by a big margin, clarify it.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SimplifyObviousNeighbours(bbox);
}
// Now try to make the blobs only vertical or horizontal using neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SetNeighbourFlows(bbox);
}
if ((textord_tabfind_show_strokewidths && final) ||
textord_tabfind_show_strokewidths > 1) {
initial_widths_win_ = DisplayGoodBlobs("InitialStrokewidths", 400, 0);
}
// Improve flow direction with neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SmoothNeighbourTypes(bbox, false);
}
// Now allow reset of firm values to fix renegades.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SmoothNeighbourTypes(bbox, true);
}
// Repeat.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SmoothNeighbourTypes(bbox, true);
}
if ((textord_tabfind_show_strokewidths && final) ||
textord_tabfind_show_strokewidths > 1) {
widths_win_ = DisplayGoodBlobs("ImprovedStrokewidths", 800, 0);
}
}
// Sets the neighbours and good_stroke_neighbours members of the blob by
// searching close on all 4 sides.
// When finding leader dots/dashes, there is a slightly different rule for
// what makes a good neighbour.
void StrokeWidth::SetNeighbours(bool leaders, BLOBNBOX* blob) {
int line_trap_count = 0;
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
line_trap_count += FindGoodNeighbour(bnd, leaders, blob);
}
if (line_trap_count > 0) {
// It looks like a line so isolate it by clearing its neighbours.
blob->ClearNeighbours();
const TBOX& box = blob->bounding_box();
blob->set_region_type(box.width() > box.height() ? BRT_HLINE : BRT_VLINE);
}
}
// Sets the good_stroke_neighbours member of the blob if it has a
// GoodNeighbour on the given side.
// Also sets the neighbour in the blob, whether or not a good one is found.
// Returns the number of blobs in the nearby search area that would lead us to
// believe that this blob is a line separator.
// Leaders get extra special lenient treatment.
int StrokeWidth::FindGoodNeighbour(BlobNeighbourDir dir, bool leaders,
BLOBNBOX* blob) {
// Search for neighbours that overlap vertically.
TBOX blob_box = blob->bounding_box();
int top = blob_box.top();
int bottom = blob_box.bottom();
int left = blob_box.left();
int right = blob_box.right();
int width = right - left;
int height = top - bottom;
// A trap to detect lines tests for the min dimension of neighbours
// being larger than a multiple of the min dimension of the line
// and the larger dimension being smaller than a fraction of the max
// dimension of the line.
int line_trap_max = MAX(width, height) / kLineTrapLongest;
int line_trap_min = MIN(width, height) * kLineTrapShortest;
int line_trap_count = 0;
int min_good_overlap = (dir == BND_LEFT || dir == BND_RIGHT)
? height / 2 : width / 2;
int min_decent_overlap = (dir == BND_LEFT || dir == BND_RIGHT)
? height / 3 : width / 3;
if (leaders)
min_good_overlap = min_decent_overlap = 1;
int search_pad = static_cast<int>(sqrt(static_cast<double>(width * height)));
if (gridsize() > search_pad)
search_pad = gridsize();
TBOX search_box = blob_box;
// Pad the search in the appropriate direction.
switch (dir) {
case BND_LEFT:
search_box.set_left(search_box.left() - search_pad);
break;
case BND_RIGHT:
search_box.set_right(search_box.right() + search_pad);
break;
case BND_BELOW:
search_box.set_bottom(search_box.bottom() - search_pad);
break;
case BND_ABOVE:
search_box.set_top(search_box.top() + search_pad);
break;
case BND_COUNT:
return 0;
}
BlobGridSearch rectsearch(this);
rectsearch.StartRectSearch(search_box);
BLOBNBOX* best_neighbour = NULL;
double best_goodness = 0.0;
bool best_is_good = false;
BLOBNBOX* neighbour;
while ((neighbour = rectsearch.NextRectSearch()) != NULL) {
TBOX nbox = neighbour->bounding_box();
if (neighbour == blob)
continue;
int mid_x = (nbox.left() + nbox.right()) / 2;
if (mid_x < blob->left_rule() || mid_x > blob->right_rule())
continue; // In a different column.
// Last-minute line detector. There is a small upper limit to the line
// width accepted by the morphological line detector.
int n_width = nbox.width();
int n_height = nbox.height();
if (MIN(n_width, n_height) > line_trap_min &&
MAX(n_width, n_height) < line_trap_max)
++line_trap_count;
if (TabFind::VeryDifferentSizes(MAX(n_width, n_height),
MAX(width, height)))
continue; // Could be a different font size or non-text.
// Amount of vertical overlap between the blobs.
int overlap;
// If the overlap is along the short side of the neighbour, and it
// is fully overlapped, then perp_overlap holds the length of the long
// side of the neighbour. A measure to include hyphens and dashes as
// legitimate neighbours.
int perp_overlap;
int gap;
if (dir == BND_LEFT || dir == BND_RIGHT) {
overlap = MIN(nbox.top(), top) - MAX(nbox.bottom(), bottom);
if (overlap == nbox.height() && nbox.width() > nbox.height())
perp_overlap = nbox.width();
else
perp_overlap = overlap;
gap = dir == BND_LEFT ? left - nbox.left() : nbox.right() - right;
if (gap <= 0)
continue; // On the wrong side.
gap -= n_width;
} else {
overlap = MIN(nbox.right(), right) - MAX(nbox.left(), left);
if (overlap == nbox.width() && nbox.height() > nbox.width())
perp_overlap = nbox.height();
else
perp_overlap = overlap;
gap = dir == BND_BELOW ? bottom - nbox.bottom() : nbox.top() - top;
if (gap <= 0)
continue; // On the wrong side.
gap -= n_height;
}
if (-gap > overlap)
continue; // Overlaps the wrong way.
if (perp_overlap < min_decent_overlap)
continue; // Doesn't overlap enough.
bool bad_sizes = TabFind::DifferentSizes(height, n_height) &&
TabFind::DifferentSizes(width, n_width);
bool is_good = overlap >= min_good_overlap && !bad_sizes &&
blob->MatchingStrokeWidth(*neighbour,
kStrokeWidthFractionTolerance,
kStrokeWidthTolerance);
// Best is a fuzzy combination of gap, overlap and is good.
// Basically if you make one thing twice as good without making
// anything else twice as bad, then it is better.
if (gap < 1) gap = 1;
double goodness = (1.0 + is_good) * overlap / gap;
if (goodness > best_goodness) {
best_neighbour = neighbour;
best_goodness = goodness;
best_is_good = is_good;
}
}
blob->set_neighbour(dir, best_neighbour, best_is_good);
return line_trap_count;
}
// Helper to get a list of 1st-order neighbours.
static void ListNeighbours(const BLOBNBOX* blob,
BLOBNBOX_CLIST* neighbours) {
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
BLOBNBOX* neighbour = blob->neighbour(bnd);
if (neighbour != NULL) {
neighbours->add_sorted(SortByBoxLeft<BLOBNBOX>, true, neighbour);
}
}
}
// Helper to get a list of 1st and 2nd order neighbours.
static void List2ndNeighbours(const BLOBNBOX* blob,
BLOBNBOX_CLIST* neighbours) {
ListNeighbours(blob, neighbours);
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
BLOBNBOX* neighbour = blob->neighbour(bnd);
if (neighbour != NULL) {
ListNeighbours(neighbour, neighbours);
}
}
}
// Helper to get a list of 1st, 2nd and 3rd order neighbours.
static void List3rdNeighbours(const BLOBNBOX* blob,
BLOBNBOX_CLIST* neighbours) {
List2ndNeighbours(blob, neighbours);
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
BLOBNBOX* neighbour = blob->neighbour(bnd);
if (neighbour != NULL) {
List2ndNeighbours(neighbour, neighbours);
}
}
}
// Helper to count the evidence for verticalness or horizontalness
// in a list of neighbours.
static void CountNeighbourGaps(bool debug, BLOBNBOX_CLIST* neighbours,
int* pure_h_count, int* pure_v_count) {
if (neighbours->length() <= kMostlyOneDirRatio)
return;
BLOBNBOX_C_IT it(neighbours);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
int h_min, h_max, v_min, v_max;
blob->MinMaxGapsClipped(&h_min, &h_max, &v_min, &v_max);
if (debug)
tprintf("Hgaps [%d,%d], vgaps [%d,%d]:", h_min, h_max, v_min, v_max);
if (h_max < v_min ||
blob->leader_on_left() || blob->leader_on_right()) {
// Horizontal gaps are clear winners. Count a pure horizontal.
++*pure_h_count;
if (debug) tprintf("Horz at:");
} else if (v_max < h_min) {
// Vertical gaps are clear winners. Clear a pure vertical.
++*pure_v_count;
if (debug) tprintf("Vert at:");
} else {
if (debug) tprintf("Neither at:");
}
if (debug)
blob->bounding_box().print();
}
}
// Makes the blob to be only horizontal or vertical where evidence
// is clear based on gaps of 2nd order neighbours, or definite individual
// blobs.
void StrokeWidth::SetNeighbourFlows(BLOBNBOX* blob) {
if (blob->DefiniteIndividualFlow())
return;
bool debug = AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom());
if (debug) {
tprintf("SetNeighbourFLows on:");
blob->bounding_box().print();
}
BLOBNBOX_CLIST neighbours;
List3rdNeighbours(blob, &neighbours);
// The number of pure horizontal and vertical neighbours.
int pure_h_count = 0;
int pure_v_count = 0;
CountNeighbourGaps(debug, &neighbours, &pure_h_count, &pure_v_count);
if (debug) {
HandleClick(blob->bounding_box().left() + 1,
blob->bounding_box().bottom() + 1);
tprintf("SetFlows: h_count=%d, v_count=%d\n",
pure_h_count, pure_v_count);
}
if (!neighbours.empty()) {
blob->set_vert_possible(true);
blob->set_horz_possible(true);
if (pure_h_count > 2 * pure_v_count) {
// Horizontal gaps are clear winners. Clear vertical neighbours.
blob->set_vert_possible(false);
} else if (pure_v_count > 2 * pure_h_count) {
// Vertical gaps are clear winners. Clear horizontal neighbours.
blob->set_horz_possible(false);
}
} else {
// Lonely blob. Can't tell its flow direction.
blob->set_vert_possible(false);
blob->set_horz_possible(false);
}
}
// Helper to count the number of horizontal and vertical blobs in a list.
static void CountNeighbourTypes(BLOBNBOX_CLIST* neighbours,
int* pure_h_count, int* pure_v_count) {
BLOBNBOX_C_IT it(neighbours);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
if (blob->UniquelyHorizontal())
++*pure_h_count;
if (blob->UniquelyVertical())
++*pure_v_count;
}
}
// Nullify the neighbours in the wrong directions where the direction
// is clear-cut based on a distance margin. Good for isolating vertical
// text from neighbouring horizontal text.
void StrokeWidth::SimplifyObviousNeighbours(BLOBNBOX* blob) {
// Case 1: We have text that is likely several characters, blurry and joined
// together.
if ((blob->bounding_box().width() > 3 * blob->area_stroke_width() &&
blob->bounding_box().height() > 3 * blob->area_stroke_width())) {
// The blob is complex (not stick-like).
if (blob->bounding_box().width() > 4 * blob->bounding_box().height()) {
// Horizontal conjoined text.
blob->set_neighbour(BND_ABOVE, NULL, false);
blob->set_neighbour(BND_BELOW, NULL, false);
return;
}
if (blob->bounding_box().height() > 4 * blob->bounding_box().width()) {
// Vertical conjoined text.
blob->set_neighbour(BND_LEFT, NULL, false);
blob->set_neighbour(BND_RIGHT, NULL, false);
return;
}
}
// Case 2: This blob is likely a single character.
int margin = gridsize() / 2;
int h_min, h_max, v_min, v_max;
blob->MinMaxGapsClipped(&h_min, &h_max, &v_min, &v_max);
if ((h_max + margin < v_min && h_max < margin / 2) ||
blob->leader_on_left() || blob->leader_on_right()) {
// Horizontal gaps are clear winners. Clear vertical neighbours.
blob->set_neighbour(BND_ABOVE, NULL, false);
blob->set_neighbour(BND_BELOW, NULL, false);
} else if (v_max + margin < h_min && v_max < margin / 2) {
// Vertical gaps are clear winners. Clear horizontal neighbours.
blob->set_neighbour(BND_LEFT, NULL, false);
blob->set_neighbour(BND_RIGHT, NULL, false);
}
}
// Smoothes the vertical/horizontal type of the blob based on the
// 2nd-order neighbours. If reset_all is true, then all blobs are
// changed. Otherwise, only ambiguous blobs are processed.
void StrokeWidth::SmoothNeighbourTypes(BLOBNBOX* blob, bool reset_all) {
if ((blob->vert_possible() && blob->horz_possible()) || reset_all) {
// There are both horizontal and vertical so try to fix it.
BLOBNBOX_CLIST neighbours;
List2ndNeighbours(blob, &neighbours);
// The number of pure horizontal and vertical neighbours.
int pure_h_count = 0;
int pure_v_count = 0;
CountNeighbourTypes(&neighbours, &pure_h_count, &pure_v_count);
if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom())) {
HandleClick(blob->bounding_box().left() + 1,
blob->bounding_box().bottom() + 1);
tprintf("pure_h=%d, pure_v=%d\n",
pure_h_count, pure_v_count);
}
if (pure_h_count > pure_v_count) {
// Horizontal gaps are clear winners. Clear vertical neighbours.
blob->set_vert_possible(false);
blob->set_horz_possible(true);
} else if (pure_v_count > pure_h_count) {
// Vertical gaps are clear winners. Clear horizontal neighbours.
blob->set_horz_possible(false);
blob->set_vert_possible(true);
}
} else if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom())) {
HandleClick(blob->bounding_box().left() + 1,
blob->bounding_box().bottom() + 1);
tprintf("Clean on pass 3!\n");
}
}
// Puts the block blobs (normal and large) into the grid.
void StrokeWidth::InsertBlobsOld(TO_BLOCK* block, TabFind* line_grid) {
// Insert the blobs into this grid using the separator lines in line_grid.
line_grid->InsertBlobList(true, false, false, &block->blobs, false, this);
line_grid->InsertBlobList(true, false, true, &block->large_blobs,
false, this);
}
/**
* Moves the large blobs that have good stroke-width neighbours to the normal
* blobs list.
*/
void StrokeWidth::MoveGoodLargeBlobs(int resolution, TO_BLOCK* block) {
BLOBNBOX_IT large_it = &block->large_blobs;
BLOBNBOX_IT blob_it = &block->blobs;
int max_height = static_cast<int>(resolution * kMaxTextSize);
int b_count = 0;
for (large_it.mark_cycle_pt(); !large_it.cycled_list(); large_it.forward()) {
BLOBNBOX* large_blob = large_it.data();
if (large_blob->bounding_box().height() <= max_height &&
GoodTextBlob(large_blob)) {
blob_it.add_to_end(large_it.extract());
++b_count;
}
}
if (textord_debug_tabfind) {
tprintf("Moved %d large blobs to normal list\n",
b_count);
}
}
/** Displays the blobs colored according to the number of good neighbours
* and the vertical/horizontal flow.
*/
ScrollView* StrokeWidth::DisplayGoodBlobs(const char* window_name,
int x, int y) {
ScrollView* window = NULL;
#ifndef GRAPHICS_DISABLED
window = MakeWindow(x, y, window_name);
// For every blob in the grid, display it.
window->Brush(ScrollView::NONE);
// For every bbox in the grid, display it.
BlobGridSearch gsearch(this);
gsearch.StartFullSearch();
BLOBNBOX* bbox;
while ((bbox = gsearch.NextFullSearch()) != NULL) {
TBOX box = bbox->bounding_box();
int left_x = box.left();
int right_x = box.right();
int top_y = box.top();
int bottom_y = box.bottom();
int goodness = bbox->GoodTextBlob();
BlobRegionType blob_type = bbox->region_type();
if (bbox->UniquelyVertical())
blob_type = BRT_VERT_TEXT;
if (bbox->UniquelyHorizontal())
blob_type = BRT_TEXT;
BlobTextFlowType flow = bbox->flow();
if (flow == BTFT_NONE) {
if (goodness == 0)
flow = BTFT_NEIGHBOURS;
else if (goodness == 1)
flow = BTFT_CHAIN;
else
flow = BTFT_STRONG_CHAIN;
}
window->Pen(BLOBNBOX::TextlineColor(blob_type, flow));
window->Rectangle(left_x, bottom_y, right_x, top_y);
}
window->Update();
#endif
return window;
}
/**
* Returns true if there is at least one side neighbour that has a similar
* stroke width and is not on the other side of a rule line.
*/
bool StrokeWidth::GoodTextBlob(BLOBNBOX* blob) {
double h_width = blob->horz_stroke_width();
double v_width = blob->vert_stroke_width();
// The perimeter-based width is used as a backup in case there is
// no information in the blob.
double p_width = 2.0f * blob->cblob()->area();
p_width /= blob->cblob()->perimeter();
double h_tolerance = h_width * kStrokeWidthFractionTolerance
+ kStrokeWidthTolerance;
double v_tolerance = v_width * kStrokeWidthFractionTolerance
+ kStrokeWidthTolerance;
double p_tolerance = p_width * kStrokeWidthFractionTolerance
+ kStrokeWidthTolerance;
// Run a radial search for neighbours that overlap.
TBOX box = blob->bounding_box();
int radius = box.height() / gridsize_ + 2;
GridSearch<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT> radsearch(this);
radsearch.StartRadSearch((box.left() + box.right()) / 2, box.bottom(),
radius);
int top = box.top();
int bottom = box.bottom();
int min_overlap = (top - bottom) / 2;
BLOBNBOX* neighbour;
while ((neighbour = radsearch.NextRadSearch()) != NULL) {
TBOX nbox = neighbour->bounding_box();
if (neighbour == blob) {
continue;
}
// In finding a suitable neighbour, do not cross rule lines.
if (nbox.right() > blob->right_rule() || nbox.left() < blob->left_rule()) {
continue; // Can't use it.
}
int overlap = MIN(nbox.top(), top) - MAX(nbox.bottom(), bottom);
if (overlap >= min_overlap &&
!TabFind::DifferentSizes(box.height(), nbox.height())) {
double n_h_width = neighbour->horz_stroke_width();
double n_v_width = neighbour->vert_stroke_width();
double n_p_width = 2.0f * neighbour->cblob()->area();
n_p_width /= neighbour->cblob()->perimeter();
bool h_zero = h_width == 0.0f || n_h_width == 0.0f;
bool v_zero = v_width == 0.0f || n_v_width == 0.0f;
bool h_ok = !h_zero && NearlyEqual(h_width, n_h_width, h_tolerance);
bool v_ok = !v_zero && NearlyEqual(v_width, n_v_width, v_tolerance);
bool p_ok = h_zero && v_zero &&
NearlyEqual(p_width, n_p_width, p_tolerance);
// For a match, at least one of the horizontal and vertical widths
// must match, and the other one must either match or be zero.
// Only if both are zero will we look at the perimeter metric.
if (p_ok || ((v_ok || h_ok) && (h_ok || h_zero) && (v_ok || v_zero))) {
return true;
}
}
}
return false;
}
} // namespace tesseract.
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