///////////////////////////////////////////////////////////////////////
// File: bbgrid.h
// Description: Class to hold BLOBNBOXs in a grid for fast access
// to neighbours.
// Author: Ray Smith
// Created: Wed Jun 06 17:22:01 PDT 2007
//
// (C) Copyright 2007, 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.
//
///////////////////////////////////////////////////////////////////////
#ifndef TESSERACT_TEXTORD_BBGRID_H__
#define TESSERACT_TEXTORD_BBGRID_H__
#include "clst.h"
#include "coutln.h"
#include "rect.h"
#include "scrollview.h"
// Some code is dependent upon leptonica. If you don't have it,
// you don't get this functionality.
#ifdef HAVE_CONFIG_H
#include "config_auto.h"
#endif
#ifdef HAVE_LIBLEPT
#include "allheaders.h"
#endif
class BLOCK;
namespace tesseract {
#ifdef HAVE_LIBLEPT
// Helper function to return a scaled Pix with one pixel per grid cell,
// set (black) where the given outline enters the corresponding grid cell,
// and clear where the outline does not touch the grid cell.
// Also returns the grid coords of the bottom-left of the Pix, in *left
// and *bottom, which corresponds to (0, 0) on the Pix.
// Note that the Pix is used upside-down, with (0, 0) being the bottom-left.
Pix* TraceOutlineOnReducedPix(C_OUTLINE* outline, int gridsize,
ICOORD bleft, int* left, int* bottom);
// As TraceOutlineOnReducedPix above, but on a BLOCK instead of a C_OUTLINE.
Pix* TraceBlockOnReducedPix(BLOCK* block, int gridsize,
ICOORD bleft, int* left, int* bottom);
#endif
template<class BBC, class BBC_CLIST, class BBC_C_IT> class GridSearch;
// The BBGrid class holds C_LISTs of template classes BBC (bounding box class)
// in a grid for fast neighbour access.
// The BBC class must have a member const TBOX& bounding_box() const.
// The BBC class must have been CLISTIZEH'ed elsewhere to make the
// list class BBC_CLIST and the iterator BBC_C_IT.
// Use of C_LISTs enables BBCs to exist in multiple cells simultaneously.
// As a consequence, ownership of BBCs is assumed to be elsewhere and
// persistent for at least the life of the BBGrid, or at least until Clear is
// called which removes all references to inserted objects without actually
// deleting them.
// Most uses derive a class from a specific instantiation of BBGrid,
// thereby making most of the ugly template notation go away.
// The friend class GridSearch, with the same template arguments, is
// used to search a grid efficiently in one of several search patterns.
template<class BBC, class BBC_CLIST, class BBC_C_IT> class BBGrid {
friend class GridSearch<BBC, BBC_CLIST, BBC_C_IT>;
public:
BBGrid();
BBGrid(int gridsize, const ICOORD& bleft, const ICOORD& tright);
virtual ~BBGrid();
// (Re)Initialize the grid. The gridsize is the size in pixels of each cell,
// and bleft, tright are the bounding box of everything to go in it.
void Init(int gridsize, const ICOORD& bleft, const ICOORD& tright);
// Empty all the lists but leave the grid itself intact.
void Clear();
// Deallocate the data in the lists but otherwise leave the lists and the grid
// intact.
void ClearGridData(void (*free_method)(BBC*));
// Simple accessors.
int gridsize() const {
return gridsize_;
}
int gridwidth() const {
return gridwidth_;
}
int gridheight() const {
return gridheight_;
}
ICOORD bleft() const {
return bleft_;
}
ICOORD tright() const {
return tright_;
}
// Insert a bbox into the appropriate place in the grid.
// If h_spread, then all cells covered horizontally by the box are
// used, otherwise, just the bottom-left. Similarly for v_spread.
// WARNING: InsertBBox may invalidate an active GridSearch. Call
// RepositionIterator() on any GridSearches that are active on this grid.
void InsertBBox(bool h_spread, bool v_spread, BBC* bbox);
#ifdef HAVE_LIBLEPT
// Using a pix from TraceOutlineOnReducedPix or TraceBlockOnReducedPix, in
// which each pixel corresponds to a grid cell, insert a bbox into every
// place in the grid where the corresponding pixel is 1. The Pix is handled
// upside-down to match the Tesseract coordinate system. (As created by
// TraceOutlineOnReducedPix or TraceBlockOnReducedPix.)
// (0, 0) in the pix corresponds to (left, bottom) in the
// grid (in grid coords), and the pix works up the grid from there.
// WARNING: InsertPixPtBBox may invalidate an active GridSearch. Call
// RepositionIterator() on any GridSearches that are active on this grid.
void InsertPixPtBBox(int left, int bottom, Pix* pix, BBC* bbox);
#endif
// Remove the bbox from the grid.
// WARNING: Any GridSearch operating on this grid could be invalidated!
// If a GridSearch is operating, call GridSearch::RemoveBBox() instead.
void RemoveBBox(BBC* bbox);
// Compute the given grid coordinates from image coords.
void GridCoords(int x, int y, int* grid_x, int* grid_y);
// Clip the given grid coordinates to fit within the grid.
void ClipGridCoords(int* x, int* y);
// Make a window of an appropriate size to display things in the grid.
ScrollView* MakeWindow(int x, int y, const char* window_name);
// Display the bounding boxes of the BLOBNBOXes in this grid.
// Use of this function requires an additional member of the BBC class:
// ScrollView::Color BBC::BoxColor() const.
void DisplayBoxes(ScrollView* window);
// ASSERT_HOST that every cell contains no more than one copy of each entry.
void AssertNoDuplicates();
// Handle a click event in a display window.
virtual void HandleClick(int x, int y);
protected:
int gridsize_; // Pixel size of each grid cell.
int gridwidth_; // Size of the grid in cells.
int gridheight_;
int gridbuckets_; // Total cells in grid.
ICOORD bleft_; // Pixel coords of bottom-left of grid.
ICOORD tright_; // Pixel coords of top-right of grid.
BBC_CLIST* grid_; // 2-d array of CLISTS of BBC elements.
private:
};
// The GridSearch class enables neighbourhood searching on a BBGrid.
template<class BBC, class BBC_CLIST, class BBC_C_IT> class GridSearch {
public:
GridSearch(BBGrid<BBC, BBC_CLIST, BBC_C_IT>* grid)
: grid_(grid), previous_return_(NULL), next_return_(NULL) {
}
// Get the grid x, y coords of the most recently returned BBC.
int GridX() const {
return x_;
}
int GridY() const {
return y_;
}
// Apart from full search, all other searches return a box several
// times if the box is inserted with h_spread or v_spread.
// This method will return true for only one occurrance of each box
// that was inserted with both h_spread and v_spread as true.
// It will usually return false for boxes that were not inserted with
// both h_spread=true and v_spread=true
bool ReturnedSeedElement() const {
TBOX box = previous_return_->bounding_box();
int x_center = (box.left()+box.right())/2;
int y_center = (box.top()+box.bottom())/2;
int grid_x, grid_y;
grid_->GridCoords(x_center, y_center, &grid_x, &grid_y);
return (x_ == grid_x) && (y_ == grid_y);
}
// Various searching iterations... Note that these iterations
// all share data members, so you can't run more than one iteration
// in parallel in a single GridSearch instance, but multiple instances
// can search the same BBGrid in parallel.
// Note that all the searches can return blobs that may not exactly
// match the search conditions, since they return everything in the
// covered grid cells. It is up to the caller to check for
// appropriateness.
// Start a new full search. Will iterate all stored blobs, from the top.
// If the blobs have been inserted using InsertBBox, (not InsertPixPtBBox)
// then the full search guarantees to return each blob in the grid once.
// Other searches may return a blob more than once if they have been
// inserted using h_spread or v_spread.
void StartFullSearch();
// Return the next bbox in the search or NULL if done.
BBC* NextFullSearch();
// Start a new radius search. Will search in a spiral upto a
// given maximum radius in grid cells from the given center in pixels.
void StartRadSearch(int x, int y, int max_radius);
// Return the next bbox in the radius search or NULL if the
// maximum radius has been reached.
BBC* NextRadSearch();
// Start a new left or right-looking search. Will search to the side
// for a box that vertically overlaps the given vertical line segment.
// CAVEAT: This search returns all blobs from the cells to the side
// of the start, and somewhat below, since there is no guarantee
// that there may not be a taller object in a lower cell. The
// blobs returned will include all those that vertically overlap and
// are no more than twice as high, but may also include some that do
// not overlap and some that are more than twice as high.
void StartSideSearch(int x, int ymin, int ymax);
// Return the next bbox in the side search or NULL if the
// edge has been reached. Searches left to right or right to left
// according to the flag.
BBC* NextSideSearch(bool right_to_left);
// Start a vertical-looking search. Will search up or down
// for a box that horizontally overlaps the given line segment.
void StartVerticalSearch(int xmin, int xmax, int y);
// Return the next bbox in the vertical search or NULL if the
// edge has been reached. Searches top to bottom or bottom to top
// according to the flag.
BBC* NextVerticalSearch(bool top_to_bottom);
// Start a rectangular search. Will search for a box that overlaps the
// given rectangle.
void StartRectSearch(const TBOX& rect);
// Return the next bbox in the rectangular search or NULL if complete.
BBC* NextRectSearch();
// Remove the last returned BBC. Will not invalidate this. May invalidate
// any other concurrent GridSearch on the same grid. If any others are
// in use, call RepositionIterator on those, to continue without harm.
void RemoveBBox();
void RepositionIterator();
private:
// Factored out helper to start a search.
void CommonStart(int x, int y);
// Factored out helper to complete a next search.
BBC* CommonNext();
// Factored out final return when search is exhausted.
BBC* CommonEnd();
// Factored out function to set the iterator to the current x_, y_
// grid coords and mark the cycle pt.
void SetIterator();
private:
// The grid we are searching.
BBGrid<BBC, BBC_CLIST, BBC_C_IT>* grid_;
// For executing a search. The different search algorithms use these in
// different ways, but most use x_origin_ and y_origin_ as the start position.
int x_origin_;
int y_origin_;
int max_radius_;
int radius_;
int rad_index_;
int rad_dir_;
TBOX rect_;
int x_; // The current location in grid coords, of the current search.
int y_;
BBC* previous_return_; // Previous return from Next*.
BBC* next_return_; // Current value of it_.data() used for repositioning.
// An iterator over the list at (x_, y_) in the grid_.
BBC_C_IT it_;
};
// Sort function to sort a BBC by bounding_box().left().
template<class BBC>
int SortByBoxLeft(const void* void1, const void* void2) {
// The void*s are actually doubly indirected, so get rid of one level.
const BBC* p1 = *reinterpret_cast<const BBC* const *>(void1);
const BBC* p2 = *reinterpret_cast<const BBC* const *>(void2);
return p1->bounding_box().left() - p2->bounding_box().left();
}
///////////////////////////////////////////////////////////////////////
// BBGrid IMPLEMENTATION.
///////////////////////////////////////////////////////////////////////
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBGrid<BBC, BBC_CLIST, BBC_C_IT>::BBGrid() : grid_(NULL) {
}
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBGrid<BBC, BBC_CLIST, BBC_C_IT>::BBGrid(
int gridsize, const ICOORD& bleft, const ICOORD& tright)
: grid_(NULL) {
Init(gridsize, bleft, tright);
}
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBGrid<BBC, BBC_CLIST, BBC_C_IT>::~BBGrid() {
if (grid_ != NULL)
delete [] grid_;
}
// (Re)Initialize the grid. The gridsize is the size in pixels of each cell,
// and bleft, tright are the bounding box of everything to go in it.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::Init(int gridsize,
const ICOORD& bleft,
const ICOORD& tright) {
gridsize_ = gridsize;
bleft_ = bleft;
tright_ = tright;
if (grid_ != NULL)
delete [] grid_;
if (gridsize_ == 0)
gridsize_ = 1;
gridwidth_ = (tright.x() - bleft.x() + gridsize_ - 1) / gridsize_;
gridheight_ = (tright.y() - bleft.y() + gridsize_ - 1) / gridsize_;
gridbuckets_ = gridwidth_ * gridheight_;
grid_ = new BBC_CLIST[gridbuckets_];
}
// Clear all lists, but leave the array of lists present.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::Clear() {
for (int i = 0; i < gridbuckets_; ++i) {
grid_[i].shallow_clear();
}
}
// Deallocate the data in the lists but otherwise leave the lists and the grid
// intact.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::ClearGridData(
void (*free_method)(BBC*)) {
if (grid_ == NULL) return;
GridSearch<BBC, BBC_CLIST, BBC_C_IT> search(this);
search.StartFullSearch();
BBC* bb;
BBC_CLIST bb_list;
BBC_C_IT it(&bb_list);
while ((bb = search.NextFullSearch()) != NULL) {
it.add_after_then_move(bb);
}
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
free_method(it.data());
}
}
// Insert a bbox into the appropriate place in the grid.
// If h_spread, then all cells covered horizontally by the box are
// used, otherwise, just the bottom-left. Similarly for v_spread.
// WARNING: InsertBBox may invalidate an active GridSearch. Call
// RepositionIterator() on any GridSearches that are active on this grid.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::InsertBBox(bool h_spread, bool v_spread,
BBC* bbox) {
TBOX box = bbox->bounding_box();
int start_x, start_y, end_x, end_y;
GridCoords(box.left(), box.bottom(), &start_x, &start_y);
GridCoords(box.right(), box.top(), &end_x, &end_y);
if (!h_spread)
end_x = start_x;
if (!v_spread)
end_y = start_y;
int grid_index = start_y * gridwidth_;
for (int y = start_y; y <= end_y; ++y, grid_index += gridwidth_) {
for (int x = start_x; x <= end_x; ++x) {
grid_[grid_index + x].add_sorted(SortByBoxLeft<BBC>, true, bbox);
}
}
}
#ifdef HAVE_LIBLEPT
// Using a pix from TraceOutlineOnReducedPix or TraceBlockOnReducedPix, in
// which each pixel corresponds to a grid cell, insert a bbox into every
// place in the grid where the corresponding pixel is 1. The Pix is handled
// upside-down to match the Tesseract coordinate system. (As created by
// TraceOutlineOnReducedPix or TraceBlockOnReducedPix.)
// (0, 0) in the pix corresponds to (left, bottom) in the
// grid (in grid coords), and the pix works up the grid from there.
// WARNING: InsertPixPtBBox may invalidate an active GridSearch. Call
// RepositionIterator() on any GridSearches that are active on this grid.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::InsertPixPtBBox(int left, int bottom,
Pix* pix, BBC* bbox) {
int width = pixGetWidth(pix);
int height = pixGetHeight(pix);
for (int y = 0; y < height; ++y) {
l_uint32* data = pixGetData(pix) + y * pixGetWpl(pix);
for (int x = 0; x < width; ++x) {
if (GET_DATA_BIT(data, x)) {
grid_[(bottom + y) * gridwidth_ + x + left].
add_sorted(SortByBoxLeft<BBC>, true, bbox);
}
}
}
}
#endif
// Remove the bbox from the grid.
// WARNING: Any GridSearch operating on this grid could be invalidated!
// If a GridSearch is operating, call GridSearch::RemoveBBox() instead.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::RemoveBBox(BBC* bbox) {
TBOX box = bbox->bounding_box();
int start_x, start_y, end_x, end_y;
GridCoords(box.left(), box.bottom(), &start_x, &start_y);
GridCoords(box.right(), box.top(), &end_x, &end_y);
int grid_index = start_y * gridwidth_;
for (int y = start_y; y <= end_y; ++y, grid_index += gridwidth_) {
for (int x = start_x; x <= end_x; ++x) {
BBC_C_IT it(&grid_[grid_index + x]);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
if (it.data() == bbox)
it.extract();
}
}
}
}
// Compute the given grid coordinates from image coords.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::GridCoords(int x, int y,
int* grid_x, int* grid_y) {
*grid_x = (x - bleft_.x()) / gridsize_;
*grid_y = (y - bleft_.y()) / gridsize_;
ClipGridCoords(grid_x, grid_y);
}
// Clip the given grid coordinates to fit within the grid.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::ClipGridCoords(int* x, int* y) {
if (*x < 0) *x = 0;
if (*x >= gridwidth_) *x = gridwidth_ - 1;
if (*y < 0) *y = 0;
if (*y >= gridheight_) *y = gridheight_ - 1;
}
template<class G> class TabEventHandler : public SVEventHandler {
public:
explicit TabEventHandler(G* grid) : grid_(grid) {
}
void Notify(const SVEvent* sv_event) {
if (sv_event->type == SVET_CLICK) {
grid_->HandleClick(sv_event->x, sv_event->y);
}
}
private:
G* grid_;
};
// Make a window of an appropriate size to display things in the grid.
// Position the window at the given x,y.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
ScrollView* BBGrid<BBC, BBC_CLIST, BBC_C_IT>::MakeWindow(
int x, int y, const char* window_name) {
ScrollView* tab_win = NULL;
#ifndef GRAPHICS_DISABLED
tab_win = new ScrollView(window_name, x, y,
tright_.x() - bleft_.x(),
tright_.y() - bleft_.y(),
tright_.x() - bleft_.x(),
tright_.y() - bleft_.y(),
true);
TabEventHandler<BBGrid<BBC, BBC_CLIST, BBC_C_IT> >* handler =
new TabEventHandler<BBGrid<BBC, BBC_CLIST, BBC_C_IT> >(this);
tab_win->AddEventHandler(handler);
tab_win->Pen(ScrollView::GREY);
tab_win->Rectangle(0, 0, tright_.x(), tright_.y());
#endif
return tab_win;
}
// Create a window at (x,y) and display the bounding boxes of the
// BLOBNBOXes in this grid.
// Use of this function requires an additional member of the BBC class:
// ScrollView::Color BBC::BoxColor() const.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::DisplayBoxes(ScrollView* tab_win) {
#ifndef GRAPHICS_DISABLED
tab_win->Pen(ScrollView::BLUE);
tab_win->Brush(ScrollView::NONE);
// For every bbox in the grid, display it.
GridSearch<BBC, BBC_CLIST, BBC_C_IT> gsearch(this);
gsearch.StartFullSearch();
BBC* 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();
ScrollView::Color box_color = bbox->BoxColor();
tab_win->Pen(box_color);
tab_win->Rectangle(left_x, bottom_y, right_x, top_y);
}
tab_win->Update();
#endif
}
// ASSERT_HOST that every cell contains no more than one copy of each entry.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::AssertNoDuplicates() {
// Process all grid cells.
for (int i = gridwidth_ * gridheight_ - 1; i >= 0; --i) {
// Iterate over all elements excent the last.
for (BBC_C_IT it(&grid_[i]); !it.at_last(); it.forward()) {
BBC* ptr = it.data();
BBC_C_IT it2(it);
// None of the rest of the elements in the list should equal ptr.
for (it2.forward(); !it2.at_first(); it2.forward()) {
ASSERT_HOST(it2.data() != ptr);
}
}
}
}
// Handle a click event in a display window.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void BBGrid<BBC, BBC_CLIST, BBC_C_IT>::HandleClick(int x, int y) {
tprintf("Click at (%d, %d)\n", x, y);
}
///////////////////////////////////////////////////////////////////////
// GridSearch IMPLEMENTATION.
///////////////////////////////////////////////////////////////////////
// Start a new full search. Will iterate all stored blobs.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::StartFullSearch() {
// Full search uses x_ and y_ as the current grid
// cell being searched.
CommonStart(grid_->bleft_.x(), grid_->tright_.y());
}
// Return the next bbox in the search or NULL if done.
// The other searches will return a box that overlaps the grid cell
// thereby duplicating boxes, but NextFullSearch only returns each box once.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::NextFullSearch() {
int x;
int y;
do {
while (it_.cycled_list()) {
++x_;
if (x_ >= grid_->gridwidth_) {
--y_;
if (y_ < 0)
return CommonEnd();
x_ = 0;
}
SetIterator();
}
CommonNext();
TBOX box = previous_return_->bounding_box();
grid_->GridCoords(box.left(), box.bottom(), &x, &y);
} while (x != x_ || y != y_);
return previous_return_;
}
// Start a new radius search.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::StartRadSearch(int x, int y,
int max_radius) {
// Rad search uses x_origin_ and y_origin_ as the center of the circle.
// The radius_ is the radius of the (diamond-shaped) circle and
// rad_index/rad_dir_ combine to determine the position around it.
max_radius_ = max_radius;
radius_ = 0;
rad_index_ = 0;
rad_dir_ = 3;
CommonStart(x, y);
}
// Return the next bbox in the radius search or NULL if the
// maximum radius has been reached.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::NextRadSearch() {
while (it_.cycled_list()) {
++rad_index_;
if (rad_index_ >= radius_) {
++rad_dir_;
rad_index_ = 0;
if (rad_dir_ >= 4) {
++radius_;
if (radius_ > max_radius_)
return CommonEnd();
rad_dir_ = 0;
}
}
ICOORD offset = C_OUTLINE::chain_step(rad_dir_);
offset *= radius_ - rad_index_;
offset += C_OUTLINE::chain_step(rad_dir_ + 1) * rad_index_;
x_ = x_origin_ + offset.x();
y_ = y_origin_ + offset.y();
if (x_ >= 0 && x_ < grid_->gridwidth_ &&
y_ >= 0 && y_ < grid_->gridheight_)
SetIterator();
}
return CommonNext();
}
// Start a new left or right-looking search. Will search to the side
// for a box that vertically overlaps the given vertical line segment.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::StartSideSearch(int x,
int ymin, int ymax) {
// Right search records the x in x_origin_, the ymax in y_origin_
// and the size of the vertical strip to search in radius_.
// To guarantee finding overlapping objects of upto twice the
// given size, double the height.
radius_ = ((ymax - ymin) * 2 + grid_->gridsize_ - 1) / grid_->gridsize_;
rad_index_ = 0;
CommonStart(x, ymax);
}
// Return the next bbox in the side search or NULL if the
// edge has been reached. Searches left to right or right to left
// according to the flag.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::NextSideSearch(bool right_to_left) {
while (it_.cycled_list()) {
++rad_index_;
if (rad_index_ > radius_) {
if (right_to_left)
--x_;
else
++x_;
rad_index_ = 0;
if (x_ < 0 || x_ >= grid_->gridwidth_)
return CommonEnd();
}
y_ = y_origin_ - rad_index_;
if (y_ >= 0 && y_ < grid_->gridheight_)
SetIterator();
}
return CommonNext();
}
// Start a vertical-looking search. Will search up or down
// for a box that horizontally overlaps the given line segment.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::StartVerticalSearch(int xmin,
int xmax,
int y) {
// Right search records the xmin in x_origin_, the y in y_origin_
// and the size of the horizontal strip to search in radius_.
radius_ = (xmax - xmin + grid_->gridsize_ - 1) / grid_->gridsize_;
rad_index_ = 0;
CommonStart(xmin, y);
}
// Return the next bbox in the vertical search or NULL if the
// edge has been reached. Searches top to bottom or bottom to top
// according to the flag.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::NextVerticalSearch(
bool top_to_bottom) {
while (it_.cycled_list()) {
++rad_index_;
if (rad_index_ > radius_) {
if (top_to_bottom)
--y_;
else
++y_;
rad_index_ = 0;
if (y_ < 0 || y_ >= grid_->gridheight_)
return CommonEnd();
}
x_ = x_origin_ + rad_index_;
if (x_ >= 0 && x_ < grid_->gridwidth_)
SetIterator();
}
return CommonNext();
}
// Start a rectangular search. Will search for a box that overlaps the
// given rectangle.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::StartRectSearch(const TBOX& rect) {
// Rect search records the xmin in x_origin_, the ymin in y_origin_
// and the xmax in max_radius_.
// The search proceeds left to right, top to bottom.
rect_ = rect;
CommonStart(rect.left(), rect.top());
grid_->GridCoords(rect.right(), rect.bottom(), // - rect.height(),
&max_radius_, &y_origin_);
}
// Return the next bbox in the rectangular search or NULL if complete.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::NextRectSearch() {
while (it_.cycled_list()) {
++x_;
if (x_ > max_radius_) {
--y_;
x_ = x_origin_;
if (y_ < y_origin_)
return CommonEnd();
}
SetIterator();
}
return CommonNext();
}
// Remove the last returned BBC. Will not invalidate this. May invalidate
// any other concurrent GridSearch on the same grid. If any others are
// in use, call RepositionIterator on those, to continue without harm.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::RemoveBBox() {
if (previous_return_ != NULL) {
// Remove all instances of previous_return_ from the list, so the iterator
// remains valid after removal from the rest of the grid cells.
// if previous_return_ is not on the list, then it has been removed already.
BBC* prev_data = NULL;
BBC* new_previous_return = NULL;
it_.move_to_first();
for (it_.mark_cycle_pt(); !it_.cycled_list();) {
if (it_.data() == previous_return_) {
new_previous_return = prev_data;
it_.extract();
it_.forward();
next_return_ = it_.cycled_list() ? NULL : it_.data();
} else {
prev_data = it_.data();
it_.forward();
}
}
grid_->RemoveBBox(previous_return_);
previous_return_ = new_previous_return;
RepositionIterator();
}
}
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::RepositionIterator() {
// Reset the iterator back to one past the previous return.
// If the previous_return_ is no longer in the list, then
// next_return_ serves as a backup.
it_.move_to_first();
for (it_.mark_cycle_pt(); !it_.cycled_list(); it_.forward()) {
if (it_.data() == previous_return_ ||
it_.data_relative(1) == next_return_) {
CommonNext();
return;
}
}
// We ran off the end of the list. Move to a new cell next time.
previous_return_ = NULL;
next_return_ = NULL;
}
// Factored out helper to start a search.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::CommonStart(int x, int y) {
grid_->GridCoords(x, y, &x_origin_, &y_origin_);
x_ = x_origin_;
y_ = y_origin_;
SetIterator();
previous_return_ = NULL;
next_return_ = it_.empty() ? NULL : it_.data();
}
// Factored out helper to complete a next search.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::CommonNext() {
previous_return_ = it_.data();
it_.forward();
next_return_ = it_.cycled_list() ? NULL : it_.data();
return previous_return_;
}
// Factored out final return when search is exhausted.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
BBC* GridSearch<BBC, BBC_CLIST, BBC_C_IT>::CommonEnd() {
previous_return_ = NULL;
next_return_ = NULL;
return NULL;
}
// Factored out function to set the iterator to the current x_, y_
// grid coords and mark the cycle pt.
template<class BBC, class BBC_CLIST, class BBC_C_IT>
void GridSearch<BBC, BBC_CLIST, BBC_C_IT>::SetIterator() {
it_= &(grid_->grid_[y_ * grid_->gridwidth_ + x_]);
it_.mark_cycle_pt();
}
} // namespace tesseract.
#endif // TESSERACT_TEXTORD_BBGRID_H__