tesseract/ccstruct/blobbox.cpp

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/**********************************************************************
* File: blobbox.cpp (Formerly blobnbox.c)
* Description: Code for the textord blob class.
* Author: Ray Smith
* Created: Thu Jul 30 09:08:51 BST 1992
*
* (C) Copyright 1992, Hewlett-Packard Ltd.
** 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 "mfcpch.h"
#include "blobbox.h"
#define PROJECTION_MARGIN 10 //arbitrary
#define EXTERN
EXTERN double_VAR (textord_error_weight, 3,
"Weighting for error in believability");
EXTERN BOOL_VAR (pitsync_projection_fix, TRUE,
"Fix bug in projection profile");
ELISTIZE (BLOBNBOX) ELIST2IZE (TO_ROW) ELISTIZE (TO_BLOCK)
/**********************************************************************
* BLOBNBOX::merge
*
* Merge this blob with the given blob, which should be after this.
**********************************************************************/
void BLOBNBOX::merge( //merge blobs
BLOBNBOX *nextblob //blob to join with
) {
box += nextblob->box; //merge boxes
nextblob->joined = TRUE;
}
/**********************************************************************
* BLOBNBOX::chop
*
* Chop this blob into equal sized pieces using the x height as a guide.
* The blob is not actually chopped. Instead, fake blobs are inserted
* with the relevant bounding boxes.
**********************************************************************/
void BLOBNBOX::chop( //chop blobs
BLOBNBOX_IT *start_it, //location of this
BLOBNBOX_IT *end_it, //iterator
FCOORD rotation, //for landscape
float xheight //of line
) {
inT16 blobcount; //no of blobs
BLOBNBOX *newblob; //fake blob
BLOBNBOX *blob; //current blob
inT16 blobindex; //number of chop
inT16 leftx; //left edge of blob
float blobwidth; //width of each
float rightx; //right edge to scan
float ymin, ymax; //limits of new blob
float test_ymin, test_ymax; //limits of part blob
ICOORD bl, tr; //corners of box
BLOBNBOX_IT blob_it; //blob iterator
//get no of chops
blobcount = (inT16) floor (box.width () / xheight);
if (blobcount > 1 && (blob_ptr != NULL || cblob_ptr != NULL)) {
//width of each
blobwidth = (float) (box.width () + 1) / blobcount;
for (blobindex = blobcount - 1, rightx = box.right ();
blobindex >= 0; blobindex--, rightx -= blobwidth) {
ymin = (float) MAX_INT32;
ymax = (float) -MAX_INT32;
blob_it = *start_it;
do {
blob = blob_it.data ();
if (blob->blob_ptr != NULL)
find_blob_limits (blob->blob_ptr, rightx - blobwidth, rightx,
rotation, test_ymin, test_ymax);
else
find_cblob_vlimits (blob->cblob_ptr, rightx - blobwidth,
rightx,
/*rotation, */ test_ymin, test_ymax);
blob_it.forward ();
if (test_ymin < ymin)
ymin = test_ymin;
if (test_ymax > ymax)
ymax = test_ymax;
}
while (blob != end_it->data ());
if (ymin < ymax) {
leftx = (inT16) floor (rightx - blobwidth);
if (leftx < box.left ())
leftx = box.left (); //clip to real box
bl = ICOORD (leftx, (inT16) floor (ymin));
tr = ICOORD ((inT16) ceil (rightx), (inT16) ceil (ymax));
if (blobindex == 0)
box = TBOX (bl, tr); //change box
else {
newblob = new BLOBNBOX;
//box is all it has
newblob->box = TBOX (bl, tr);
//stay on current
end_it->add_after_stay_put (newblob);
}
}
}
}
}
/**********************************************************************
* find_blob_limits
*
* Scan the outlines of the blob to locate the y min and max
* between the given x limits.
**********************************************************************/
void find_blob_limits( //get y limits
PBLOB *blob, //blob to search
float leftx, //x limits
float rightx,
FCOORD rotation, //for landscape
float &ymin, //output y limits
float &ymax) {
float testy; //y intercept
FCOORD pos; //rotated
FCOORD vec;
POLYPT *polypt; //current point
//outlines
OUTLINE_IT out_it = blob->out_list ();
POLYPT_IT poly_it; //outline pts
ymin = (float) MAX_INT32;
ymax = (float) -MAX_INT32;
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
//get points
poly_it.set_to_list (out_it.data ()->polypts ());
for (poly_it.mark_cycle_pt (); !poly_it.cycled_list ();
poly_it.forward ()) {
polypt = poly_it.data ();
pos = polypt->pos;
pos.rotate (rotation);
vec = polypt->vec;
vec.rotate (rotation);
if ((pos.x () < leftx && pos.x () + vec.x () > leftx)
|| (pos.x () > leftx && pos.x () + vec.x () < leftx)) {
testy = pos.y () + vec.y () * (leftx - pos.x ()) / vec.x ();
//intercept of boundary
if (testy < ymin)
ymin = testy;
if (testy > ymax)
ymax = testy;
}
if (pos.x () >= leftx && pos.x () <= rightx) {
if (pos.y () > ymax)
ymax = pos.y ();
if (pos.y () < ymin)
ymin = pos.y ();
}
if ((pos.x () > rightx && pos.x () + vec.x () < rightx)
|| (pos.x () < rightx && pos.x () + vec.x () > rightx)) {
testy = pos.y () + vec.y () * (rightx - pos.x ()) / vec.x ();
//intercept of boundary
if (testy < ymin)
ymin = testy;
if (testy > ymax)
ymax = testy;
}
}
}
}
/**********************************************************************
* find_cblob_limits
*
* Scan the outlines of the cblob to locate the y min and max
* between the given x limits.
**********************************************************************/
void find_cblob_limits( //get y limits
C_BLOB *blob, //blob to search
float leftx, //x limits
float rightx,
FCOORD rotation, //for landscape
float &ymin, //output y limits
float &ymax) {
inT16 stepindex; //current point
ICOORD pos; //current coords
ICOORD vec; //rotated step
C_OUTLINE *outline; //current outline
//outlines
C_OUTLINE_IT out_it = blob->out_list ();
ymin = (float) MAX_INT32;
ymax = (float) -MAX_INT32;
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
outline = out_it.data ();
pos = outline->start_pos (); //get coords
pos.rotate (rotation);
for (stepindex = 0; stepindex < outline->pathlength (); stepindex++) {
//inside
if (pos.x () >= leftx && pos.x () <= rightx) {
if (pos.y () > ymax)
ymax = pos.y ();
if (pos.y () < ymin)
ymin = pos.y ();
}
vec = outline->step (stepindex);
vec.rotate (rotation);
pos += vec; //move to next
}
}
}
/**********************************************************************
* find_cblob_vlimits
*
* Scan the outlines of the cblob to locate the y min and max
* between the given x limits.
**********************************************************************/
void find_cblob_vlimits( //get y limits
C_BLOB *blob, //blob to search
float leftx, //x limits
float rightx,
float &ymin, //output y limits
float &ymax) {
inT16 stepindex; //current point
ICOORD pos; //current coords
ICOORD vec; //rotated step
C_OUTLINE *outline; //current outline
//outlines
C_OUTLINE_IT out_it = blob->out_list ();
ymin = (float) MAX_INT32;
ymax = (float) -MAX_INT32;
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
outline = out_it.data ();
pos = outline->start_pos (); //get coords
for (stepindex = 0; stepindex < outline->pathlength (); stepindex++) {
//inside
if (pos.x () >= leftx && pos.x () <= rightx) {
if (pos.y () > ymax)
ymax = pos.y ();
if (pos.y () < ymin)
ymin = pos.y ();
}
vec = outline->step (stepindex);
pos += vec; //move to next
}
}
}
/**********************************************************************
* find_cblob_hlimits
*
* Scan the outlines of the cblob to locate the x min and max
* between the given y limits.
**********************************************************************/
void find_cblob_hlimits( //get x limits
C_BLOB *blob, //blob to search
float bottomy, //y limits
float topy,
float &xmin, //output x limits
float &xmax) {
inT16 stepindex; //current point
ICOORD pos; //current coords
ICOORD vec; //rotated step
C_OUTLINE *outline; //current outline
//outlines
C_OUTLINE_IT out_it = blob->out_list ();
xmin = (float) MAX_INT32;
xmax = (float) -MAX_INT32;
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
outline = out_it.data ();
pos = outline->start_pos (); //get coords
for (stepindex = 0; stepindex < outline->pathlength (); stepindex++) {
//inside
if (pos.y () >= bottomy && pos.y () <= topy) {
if (pos.x () > xmax)
xmax = pos.x ();
if (pos.x () < xmin)
xmin = pos.x ();
}
vec = outline->step (stepindex);
pos += vec; //move to next
}
}
}
/**********************************************************************
* rotate_blob
*
* Poly copy the blob and rotate the copy by the given vector.
**********************************************************************/
PBLOB *rotate_blob( //get y limits
PBLOB *blob, //blob to search
FCOORD rotation //vector to rotate by
) {
PBLOB *copy; //copy of blob
POLYPT *polypt; //current point
OUTLINE_IT out_it;
POLYPT_IT poly_it; //outline pts
copy = new PBLOB;
*copy = *blob; //deep copy
out_it.set_to_list (copy->out_list ());
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
//get points
poly_it.set_to_list (out_it.data ()->polypts ());
for (poly_it.mark_cycle_pt (); !poly_it.cycled_list ();
poly_it.forward ()) {
polypt = poly_it.data ();
//rotate it
polypt->pos.rotate (rotation);
polypt->vec.rotate (rotation);
}
out_it.data ()->compute_bb ();
}
return copy;
}
/**********************************************************************
* rotate_cblob
*
* Poly copy the blob and rotate the copy by the given vector.
**********************************************************************/
PBLOB *rotate_cblob( //rotate it
C_BLOB *blob, //blob to search
float xheight, //for poly approx
FCOORD rotation //for landscape
) {
PBLOB *copy; //copy of blob
POLYPT *polypt; //current point
OUTLINE_IT out_it;
POLYPT_IT poly_it; //outline pts
copy = new PBLOB (blob, xheight);
out_it.set_to_list (copy->out_list ());
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
//get points
poly_it.set_to_list (out_it.data ()->polypts ());
for (poly_it.mark_cycle_pt (); !poly_it.cycled_list ();
poly_it.forward ()) {
polypt = poly_it.data ();
//rotate it
polypt->pos.rotate (rotation);
polypt->vec.rotate (rotation);
}
out_it.data ()->compute_bb ();
}
return copy;
}
/**********************************************************************
* crotate_cblob
*
* Rotate the copy by the given vector and return a C_BLOB.
**********************************************************************/
C_BLOB *crotate_cblob( //rotate it
C_BLOB *blob, //blob to search
FCOORD rotation //for landscape
) {
C_OUTLINE_LIST out_list; //output outlines
//input outlines
C_OUTLINE_IT in_it = blob->out_list ();
//output outlines
C_OUTLINE_IT out_it = &out_list;
for (in_it.mark_cycle_pt (); !in_it.cycled_list (); in_it.forward ()) {
out_it.add_after_then_move (new C_OUTLINE (in_it.data (), rotation));
}
return new C_BLOB (&out_list);
}
/**********************************************************************
* box_next
*
* Compute the bounding box of this blob with merging of x overlaps
* but no pre-chopping.
* Then move the iterator on to the start of the next blob.
**********************************************************************/
TBOX box_next( //get bounding box
BLOBNBOX_IT *it //iterator to blobds
) {
BLOBNBOX *blob; //current blob
TBOX result; //total box
blob = it->data ();
result = blob->bounding_box ();
do {
it->forward ();
blob = it->data ();
if (blob->blob () == NULL && blob->cblob () == NULL)
//was pre-chopped
result += blob->bounding_box ();
}
//until next real blob
while ((blob->blob () == NULL && blob->cblob () == NULL) || blob->joined_to_prev ());
return result;
}
/**********************************************************************
* box_next_pre_chopped
*
* Compute the bounding box of this blob with merging of x overlaps
* but WITH pre-chopping.
* Then move the iterator on to the start of the next pre-chopped blob.
**********************************************************************/
TBOX box_next_pre_chopped( //get bounding box
BLOBNBOX_IT *it //iterator to blobds
) {
BLOBNBOX *blob; //current blob
TBOX result; //total box
blob = it->data ();
result = blob->bounding_box ();
do {
it->forward ();
blob = it->data ();
}
//until next real blob
while (blob->joined_to_prev ());
return result;
}
/**********************************************************************
* TO_ROW::TO_ROW
*
* Constructor to make a row from a blob.
**********************************************************************/
TO_ROW::TO_ROW ( //constructor
BLOBNBOX * blob, //first blob
float top, //corrected top
float bottom, //of row
float row_size //ideal
): y_min(bottom), y_max(top), initial_y_min(bottom), num_repeated_sets_(-1) {
float diff; //in size
BLOBNBOX_IT it = &blobs; //list of blobs
it.add_to_end (blob);
diff = top - bottom - row_size;
if (diff > 0) {
y_max -= diff / 2;
y_min += diff / 2;
}
//very small object
else if ((top - bottom) * 3 < row_size) {
diff = row_size / 3 + bottom - top;
y_max += diff / 2;
y_min -= diff / 2;
}
}
/**********************************************************************
* TO_ROW:add_blob
*
* Add the blob to the end of the row.
**********************************************************************/
void TO_ROW::add_blob( //constructor
BLOBNBOX *blob, //first blob
float top, //corrected top
float bottom, //of row
float row_size //ideal
) {
float allowed; //allowed expansion
float available; //expansion
BLOBNBOX_IT it = &blobs; //list of blobs
it.add_to_end (blob);
allowed = row_size + y_min - y_max;
if (allowed > 0) {
available = top > y_max ? top - y_max : 0;
if (bottom < y_min)
//total available
available += y_min - bottom;
if (available > 0) {
available += available; //do it gradually
if (available < allowed)
available = allowed;
if (bottom < y_min)
y_min -= (y_min - bottom) * allowed / available;
if (top > y_max)
y_max += (top - y_max) * allowed / available;
}
}
}
/**********************************************************************
* TO_ROW:insert_blob
*
* Add the blob to the row in the correct position.
**********************************************************************/
void TO_ROW::insert_blob( //constructor
BLOBNBOX *blob //first blob
) {
BLOBNBOX_IT it = &blobs; //list of blobs
if (it.empty ())
it.add_before_then_move (blob);
else {
it.mark_cycle_pt ();
while (!it.cycled_list ()
&& it.data ()->bounding_box ().left () <=
blob->bounding_box ().left ())
it.forward ();
if (it.cycled_list ())
it.add_to_end (blob);
else
it.add_before_stay_put (blob);
}
}
/**********************************************************************
* TO_ROW::compute_vertical_projection
*
* Compute the vertical projection of a TO_ROW from its blobs.
**********************************************************************/
void TO_ROW::compute_vertical_projection() { //project whole row
TBOX row_box; //bound of row
BLOBNBOX *blob; //current blob
TBOX blob_box; //bounding box
BLOBNBOX_IT blob_it = blob_list ();
if (blob_it.empty ())
return;
row_box = blob_it.data ()->bounding_box ();
for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ())
row_box += blob_it.data ()->bounding_box ();
projection.set_range (row_box.left () - PROJECTION_MARGIN,
row_box.right () + PROJECTION_MARGIN);
projection_left = row_box.left () - PROJECTION_MARGIN;
projection_right = row_box.right () + PROJECTION_MARGIN;
for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ()) {
blob = blob_it.data ();
if (blob->blob () != NULL)
vertical_blob_projection (blob->blob (), &projection);
else if (blob->cblob () != NULL)
vertical_cblob_projection (blob->cblob (), &projection);
}
}
/**********************************************************************
* vertical_blob_projection
*
* Compute the vertical projection of a blob from its outlines
* and add to the given STATS.
**********************************************************************/
void vertical_blob_projection( //project outlines
PBLOB *blob, //blob to project
STATS *stats //output
) {
//outlines of blob
OUTLINE_IT out_it = blob->out_list ();
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
vertical_outline_projection (out_it.data (), stats);
}
}
/**********************************************************************
* vertical_outline_projection
*
* Compute the vertical projection of a outline from its outlines
* and add to the given STATS.
**********************************************************************/
void vertical_outline_projection( //project outlines
OUTLINE *outline, //outline to project
STATS *stats //output
) {
POLYPT *polypt; //current point
inT32 xcoord; //current pixel coord
float end_x; //end of vec
POLYPT_IT poly_it = outline->polypts ();
OUTLINE_IT out_it = outline->child ();
float ymean; //amount to add
float width; //amount of x
for (poly_it.mark_cycle_pt (); !poly_it.cycled_list (); poly_it.forward ()) {
polypt = poly_it.data ();
end_x = polypt->pos.x () + polypt->vec.x ();
if (polypt->vec.x () > 0) {
for (xcoord = (inT32) floor (polypt->pos.x ());
xcoord < end_x; xcoord++) {
if (polypt->pos.x () < xcoord) {
width = (float) xcoord;
ymean =
polypt->vec.y () * (xcoord -
polypt->pos.x ()) / polypt->vec.x () +
polypt->pos.y ();
}
else {
width = polypt->pos.x ();
ymean = polypt->pos.y ();
}
if (end_x > xcoord + 1) {
width -= xcoord + 1;
ymean +=
polypt->vec.y () * (xcoord + 1 -
polypt->pos.x ()) / polypt->vec.x () +
polypt->pos.y ();
}
else {
width -= end_x;
ymean += polypt->pos.y () + polypt->vec.y ();
}
ymean = ymean * width / 2;
stats->add (xcoord, (inT32) floor (ymean + 0.5));
}
}
else if (polypt->vec.x () < 0) {
for (xcoord = (inT32) floor (end_x);
xcoord < polypt->pos.x (); xcoord++) {
if (polypt->pos.x () > xcoord + 1) {
width = xcoord + 1.0f;
ymean =
polypt->vec.y () * (xcoord + 1 -
polypt->pos.x ()) / polypt->vec.x () +
polypt->pos.y ();
}
else {
width = polypt->pos.x ();
ymean = polypt->pos.y ();
}
if (end_x < xcoord) {
width -= xcoord;
ymean +=
polypt->vec.y () * (xcoord -
polypt->pos.x ()) / polypt->vec.x () +
polypt->pos.y ();
}
else {
width -= end_x;
ymean += polypt->pos.y () + polypt->vec.y ();
}
ymean = ymean * width / 2;
stats->add (xcoord, (inT32) floor (ymean + 0.5));
}
}
}
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
vertical_outline_projection (out_it.data (), stats);
}
}
/**********************************************************************
* vertical_cblob_projection
*
* Compute the vertical projection of a cblob from its outlines
* and add to the given STATS.
**********************************************************************/
void vertical_cblob_projection( //project outlines
C_BLOB *blob, //blob to project
STATS *stats //output
) {
//outlines of blob
C_OUTLINE_IT out_it = blob->out_list ();
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
vertical_coutline_projection (out_it.data (), stats);
}
}
/**********************************************************************
* vertical_coutline_projection
*
* Compute the vertical projection of a outline from its outlines
* and add to the given STATS.
**********************************************************************/
void vertical_coutline_projection( //project outlines
C_OUTLINE *outline, //outline to project
STATS *stats //output
) {
ICOORD pos; //current point
ICOORD step; //edge step
inT32 length; //of outline
inT16 stepindex; //current step
C_OUTLINE_IT out_it = outline->child ();
pos = outline->start_pos ();
length = outline->pathlength ();
for (stepindex = 0; stepindex < length; stepindex++) {
step = outline->step (stepindex);
if (step.x () > 0) {
if (pitsync_projection_fix)
stats->add (pos.x (), -pos.y ());
else
stats->add (pos.x (), pos.y ());
}
else if (step.x () < 0) {
if (pitsync_projection_fix)
stats->add (pos.x () - 1, pos.y ());
else
stats->add (pos.x () - 1, -pos.y ());
}
pos += step;
}
for (out_it.mark_cycle_pt (); !out_it.cycled_list (); out_it.forward ()) {
vertical_coutline_projection (out_it.data (), stats);
}
}
/**********************************************************************
* TO_BLOCK::TO_BLOCK
*
* Constructor to make a TO_BLOCK from a real block.
**********************************************************************/
TO_BLOCK::TO_BLOCK( //make a block
BLOCK *src_block //real block
) {
block = src_block;
}
static void clear_blobnboxes(BLOBNBOX_LIST* boxes) {
BLOBNBOX_IT it = boxes;
// A BLOBNBOX generally doesn't own its blobs, so if they do, you
// have to delete them explicitly.
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* box = it.data();
if (box->blob() != NULL)
delete box->blob();
if (box->cblob() != NULL)
delete box->cblob();
}
}
TO_BLOCK::~TO_BLOCK() {
// Any residual BLOBNBOXes at this stage own their blobs, so delete them.
clear_blobnboxes(&blobs);
clear_blobnboxes(&underlines);
clear_blobnboxes(&noise_blobs);
clear_blobnboxes(&small_blobs);
clear_blobnboxes(&large_blobs);
}
#ifndef GRAPHICS_DISABLED
// Draw the blobs on the various lists in the block in different colors.
void TO_BLOCK::plot_graded_blobs(ScrollView* to_win) {
plot_blob_list(to_win, &noise_blobs, ScrollView::CORAL, ScrollView::BLUE);
plot_blob_list(to_win, &small_blobs,
ScrollView::GOLDENROD, ScrollView::YELLOW);
plot_blob_list(to_win, &large_blobs,
ScrollView::DARK_GREEN, ScrollView::YELLOW);
plot_blob_list(to_win, &blobs, ScrollView::WHITE, ScrollView::BROWN);
}
/**********************************************************************
* plot_blob_list
*
* Draw a list of blobs.
**********************************************************************/
void plot_blob_list(ScrollView* win, // window to draw in
BLOBNBOX_LIST *list, // blob list
ScrollView::Color body_colour, // colour to draw
ScrollView::Color child_colour) { // colour of child
BLOBNBOX_IT it = list;
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
it.data()->plot(win, body_colour, child_colour);
}
}
#endif //GRAPHICS_DISABLED