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tesseract/ccstruct/ocrblock.cpp

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/**********************************************************************
* File: ocrblock.cpp (Formerly block.c)
* Description: BLOCK member functions and iterator functions.
* Author: Ray Smith
* Created: Fri Mar 15 09:41:28 GMT 1991
*
* (C) Copyright 1991, 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 "ocrblock.h"
#include <stdlib.h>
#include <memory> // std::unique_ptr
#include "blckerr.h"
#include "stepblob.h"
#include "tprintf.h"
#define BLOCK_LABEL_HEIGHT 150 //char height of block id
ELISTIZE (BLOCK)
/**
* BLOCK::BLOCK
*
* Constructor for a simple rectangular block.
*/
BLOCK::BLOCK(const char *name, //< filename
BOOL8 prop, //< proportional
inT16 kern, //< kerning
inT16 space, //< spacing
inT16 xmin, //< bottom left
inT16 ymin, inT16 xmax, //< top right
inT16 ymax)
: PDBLK (xmin, ymin, xmax, ymax),
filename(name),
re_rotation_(1.0f, 0.0f),
classify_rotation_(1.0f, 0.0f),
skew_(1.0f, 0.0f) {
ICOORDELT_IT left_it = &leftside;
ICOORDELT_IT right_it = &rightside;
proportional = prop;
right_to_left_ = false;
kerning = kern;
spacing = space;
font_class = -1; //not assigned
cell_over_xheight_ = 2.0f;
hand_poly = NULL;
left_it.set_to_list (&leftside);
right_it.set_to_list (&rightside);
//make default box
left_it.add_to_end (new ICOORDELT (xmin, ymin));
left_it.add_to_end (new ICOORDELT (xmin, ymax));
right_it.add_to_end (new ICOORDELT (xmax, ymin));
right_it.add_to_end (new ICOORDELT (xmax, ymax));
}
/**
* decreasing_top_order
*
* Sort Comparator: Return <0 if row1 top < row2 top
*/
int decreasing_top_order( //
const void *row1,
const void *row2) {
return (*(ROW **) row2)->bounding_box ().top () -
(*(ROW **) row1)->bounding_box ().top ();
}
/**
* BLOCK::rotate
*
* Rotate the polygon by the given rotation and recompute the bounding_box.
*/
void BLOCK::rotate(const FCOORD& rotation) {
poly_block()->rotate(rotation);
box = *poly_block()->bounding_box();
}
// Returns the bounding box including the desired combination of upper and
// lower noise/diacritic elements.
TBOX BLOCK::restricted_bounding_box(bool upper_dots, bool lower_dots) const {
TBOX box;
// This is a read-only iteration of the rows in the block.
ROW_IT it(const_cast<ROW_LIST*>(&rows));
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
box += it.data()->restricted_bounding_box(upper_dots, lower_dots);
}
return box;
}
/**
* BLOCK::reflect_polygon_in_y_axis
*
* Reflects the polygon in the y-axis and recompute the bounding_box.
* Does nothing to any contained rows/words/blobs etc.
*/
void BLOCK::reflect_polygon_in_y_axis() {
poly_block()->reflect_in_y_axis();
box = *poly_block()->bounding_box();
}
/**
* BLOCK::sort_rows
*
* Order rows so that they are in order of decreasing Y coordinate
*/
void BLOCK::sort_rows() { // order on "top"
ROW_IT row_it(&rows);
row_it.sort (decreasing_top_order);
}
/**
* BLOCK::compress
*
* Delete space between the rows. (And maybe one day, compress the rows)
* Fill space of block from top down, left aligning rows.
*/
void BLOCK::compress() { // squash it up
#define ROW_SPACING 5
ROW_IT row_it(&rows);
ROW *row;
ICOORD row_spacing (0, ROW_SPACING);
ICOORDELT_IT icoordelt_it;
sort_rows();
box = TBOX (box.topleft (), box.topleft ());
box.move_bottom_edge (ROW_SPACING);
for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) {
row = row_it.data ();
row->move (box.botleft () - row_spacing -
row->bounding_box ().topleft ());
box += row->bounding_box ();
}
leftside.clear ();
icoordelt_it.set_to_list (&leftside);
icoordelt_it.add_to_end (new ICOORDELT (box.left (), box.bottom ()));
icoordelt_it.add_to_end (new ICOORDELT (box.left (), box.top ()));
rightside.clear ();
icoordelt_it.set_to_list (&rightside);
icoordelt_it.add_to_end (new ICOORDELT (box.right (), box.bottom ()));
icoordelt_it.add_to_end (new ICOORDELT (box.right (), box.top ()));
}
/**
* BLOCK::check_pitch
*
* Check whether the block is fixed or prop, set the flag, and set
* the pitch if it is fixed.
*/
void BLOCK::check_pitch() { // check prop
// tprintf("Missing FFT fixed pitch stuff!\n");
pitch = -1;
}
/**
* BLOCK::compress
*
* Compress and move in a single operation.
*/
void BLOCK::compress( // squash it up
const ICOORD vec // and move
) {
box.move (vec);
compress();
}
/**
* BLOCK::print
*
* Print the info on a block
*/
void BLOCK::print( //print list of sides
FILE *, //< file to print on
BOOL8 dump //< print full detail
) {
ICOORDELT_IT it = &leftside; //iterator
box.print ();
tprintf ("Proportional= %s\n", proportional ? "TRUE" : "FALSE");
tprintf ("Kerning= %d\n", kerning);
tprintf ("Spacing= %d\n", spacing);
tprintf ("Fixed_pitch=%d\n", pitch);
tprintf ("Filename= %s\n", filename.string ());
if (dump) {
tprintf ("Left side coords are:\n");
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ())
tprintf ("(%d,%d) ", it.data ()->x (), it.data ()->y ());
tprintf ("\n");
tprintf ("Right side coords are:\n");
it.set_to_list (&rightside);
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ())
tprintf ("(%d,%d) ", it.data ()->x (), it.data ()->y ());
tprintf ("\n");
}
}
/**
* BLOCK::operator=
*
* Assignment - duplicate the block structure, but with an EMPTY row list.
*/
BLOCK & BLOCK::operator= ( //assignment
const BLOCK & source //from this
) {
this->ELIST_LINK::operator= (source);
this->PDBLK::operator= (source);
proportional = source.proportional;
kerning = source.kerning;
spacing = source.spacing;
filename = source.filename; //STRINGs assign ok
if (!rows.empty ())
rows.clear ();
re_rotation_ = source.re_rotation_;
classify_rotation_ = source.classify_rotation_;
skew_ = source.skew_;
return *this;
}
// This function is for finding the approximate (horizontal) distance from
// the x-coordinate of the left edge of a symbol to the left edge of the
// text block which contains it. We are passed:
// segments - output of PB_LINE_IT::get_line() which contains x-coordinate
// intervals for the scan line going through the symbol's y-coordinate.
// Each element of segments is of the form (x()=start_x, y()=length).
// x - the x coordinate of the symbol we're interested in.
// margin - return value, the distance from x,y to the left margin of the
// block containing it.
// If all segments were to the right of x, we return false and 0.
bool LeftMargin(ICOORDELT_LIST *segments, int x, int *margin) {
bool found = false;
*margin = 0;
if (segments->empty())
return found;
ICOORDELT_IT seg_it(segments);
for (seg_it.mark_cycle_pt(); !seg_it.cycled_list(); seg_it.forward()) {
int cur_margin = x - seg_it.data()->x();
if (cur_margin >= 0) {
if (!found) {
*margin = cur_margin;
} else if (cur_margin < *margin) {
*margin = cur_margin;
}
found = true;
}
}
return found;
}
// This function is for finding the approximate (horizontal) distance from
// the x-coordinate of the right edge of a symbol to the right edge of the
// text block which contains it. We are passed:
// segments - output of PB_LINE_IT::get_line() which contains x-coordinate
// intervals for the scan line going through the symbol's y-coordinate.
// Each element of segments is of the form (x()=start_x, y()=length).
// x - the x coordinate of the symbol we're interested in.
// margin - return value, the distance from x,y to the right margin of the
// block containing it.
// If all segments were to the left of x, we return false and 0.
bool RightMargin(ICOORDELT_LIST *segments, int x, int *margin) {
bool found = false;
*margin = 0;
if (segments->empty())
return found;
ICOORDELT_IT seg_it(segments);
for (seg_it.mark_cycle_pt(); !seg_it.cycled_list(); seg_it.forward()) {
int cur_margin = seg_it.data()->x() + seg_it.data()->y() - x;
if (cur_margin >= 0) {
if (!found) {
*margin = cur_margin;
} else if (cur_margin < *margin) {
*margin = cur_margin;
}
found = true;
}
}
return found;
}
// Compute the distance from the left and right ends of each row to the
// left and right edges of the block's polyblock. Illustration:
// ____________________________ _______________________
// | Howdy neighbor! | |rectangular blocks look|
// | This text is written to| |more like stacked pizza|
// |illustrate how useful poly- |boxes. |
// |blobs are in ----------- ------ The polyblob|
// |dealing with| _________ |for a BLOCK rec-|
// |harder layout| /===========\ |ords the possibly|
// |issues. | | _ _ | |skewed pseudo-|
// | You see this| | |_| \|_| | |rectangular |
// |text is flowed| | } | |boundary that|
// |around a mid-| \ ____ | |forms the ideal-|
// |cloumn portrait._____ \ / __|ized text margin|
// | Polyblobs exist| \ / |from which we should|
// |to account for insets| | | |measure paragraph|
// |which make otherwise| ----- |indentation. |
// ----------------------- ----------------------
//
// If we identify a drop-cap, we measure the left margin for the lines
// below the first line relative to one space past the drop cap. The
// first line's margin and those past the drop cap area are measured
// relative to the enclosing polyblock.
//
// TODO(rays): Before this will work well, we'll need to adjust the
// polyblob tighter around the text near images, as in:
// UNLV_AUTO:mag.3G0 page 2
// UNLV_AUTO:mag.3G4 page 16
void BLOCK::compute_row_margins() {
if (row_list()->empty() || row_list()->singleton()) {
return;
}
// If Layout analysis was not called, default to this.
POLY_BLOCK rect_block(bounding_box(), PT_FLOWING_TEXT);
POLY_BLOCK *pblock = &rect_block;
if (poly_block() != NULL) {
pblock = poly_block();
}
// Step One: Determine if there is a drop-cap.
// TODO(eger): Fix up drop cap code for RTL languages.
ROW_IT r_it(row_list());
ROW *first_row = r_it.data();
ROW *second_row = r_it.data_relative(1);
// initialize the bottom of a fictitious drop cap far above the first line.
int drop_cap_bottom = first_row->bounding_box().top() +
first_row->bounding_box().height();
int drop_cap_right = first_row->bounding_box().left();
int mid_second_line = second_row->bounding_box().top() -
second_row->bounding_box().height() / 2;
WERD_IT werd_it(r_it.data()->word_list()); // words of line one
if (!werd_it.empty()) {
C_BLOB_IT cblob_it(werd_it.data()->cblob_list());
for (cblob_it.mark_cycle_pt(); !cblob_it.cycled_list();
cblob_it.forward()) {
TBOX bbox = cblob_it.data()->bounding_box();
if (bbox.bottom() <= mid_second_line) {
// we found a real drop cap
first_row->set_has_drop_cap(true);
if (drop_cap_bottom > bbox.bottom())
drop_cap_bottom = bbox.bottom();
if (drop_cap_right < bbox.right())
drop_cap_right = bbox.right();
}
}
}
// Step Two: Calculate the margin from the text of each row to the block
// (or drop-cap) boundaries.
PB_LINE_IT lines(pblock);
r_it.set_to_list(row_list());
for (r_it.mark_cycle_pt(); !r_it.cycled_list(); r_it.forward()) {
ROW *row = r_it.data();
TBOX row_box = row->bounding_box();
int left_y = row->base_line(row_box.left()) + row->x_height();
int left_margin;
const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments_left(
lines.get_line(left_y));
LeftMargin(segments_left.get(), row_box.left(), &left_margin);
if (row_box.top() >= drop_cap_bottom) {
int drop_cap_distance = row_box.left() - row->space() - drop_cap_right;
if (drop_cap_distance < 0)
drop_cap_distance = 0;
if (drop_cap_distance < left_margin)
left_margin = drop_cap_distance;
}
int right_y = row->base_line(row_box.right()) + row->x_height();
int right_margin;
const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments_right(
lines.get_line(right_y));
RightMargin(segments_right.get(), row_box.right(), &right_margin);
row->set_lmargin(left_margin);
row->set_rmargin(right_margin);
}
}
/**********************************************************************
* PrintSegmentationStats
*
* Prints segmentation stats for the given block list.
**********************************************************************/
void PrintSegmentationStats(BLOCK_LIST* block_list) {
int num_blocks = 0;
int num_rows = 0;
int num_words = 0;
int num_blobs = 0;
BLOCK_IT block_it(block_list);
for (block_it.mark_cycle_pt(); !block_it.cycled_list(); block_it.forward()) {
BLOCK* block = block_it.data();
++num_blocks;
ROW_IT row_it(block->row_list());
for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) {
++num_rows;
ROW* row = row_it.data();
// Iterate over all werds in the row.
WERD_IT werd_it(row->word_list());
for (werd_it.mark_cycle_pt(); !werd_it.cycled_list(); werd_it.forward()) {
WERD* werd = werd_it.data();
++num_words;
num_blobs += werd->cblob_list()->length();
}
}
}
tprintf("Block list stats:\nBlocks = %d\nRows = %d\nWords = %d\nBlobs = %d\n",
num_blocks, num_rows, num_words, num_blobs);
}
/**********************************************************************
* ExtractBlobsFromSegmentation
*
* Extracts blobs from the given block list and adds them to the output list.
* The block list must have been created by performing a page segmentation.
**********************************************************************/
void ExtractBlobsFromSegmentation(BLOCK_LIST* blocks,
C_BLOB_LIST* output_blob_list) {
C_BLOB_IT return_list_it(output_blob_list);
BLOCK_IT block_it(blocks);
for (block_it.mark_cycle_pt(); !block_it.cycled_list(); block_it.forward()) {
BLOCK* block = block_it.data();
ROW_IT row_it(block->row_list());
for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) {
ROW* row = row_it.data();
// Iterate over all werds in the row.
WERD_IT werd_it(row->word_list());
for (werd_it.mark_cycle_pt(); !werd_it.cycled_list(); werd_it.forward()) {
WERD* werd = werd_it.data();
return_list_it.move_to_last();
return_list_it.add_list_after(werd->cblob_list());
return_list_it.move_to_last();
return_list_it.add_list_after(werd->rej_cblob_list());
}
}
}
}
/**********************************************************************
* RefreshWordBlobsFromNewBlobs()
*
* Refreshes the words in the block_list by using blobs in the
* new_blobs list.
* Block list must have word segmentation in it.
* It consumes the blobs provided in the new_blobs list. The blobs leftover in
* the new_blobs list after the call weren't matched to any blobs of the words
* in block list.
* The output not_found_blobs is a list of blobs from the original segmentation
* in the block_list for which no corresponding new blobs were found.
**********************************************************************/
void RefreshWordBlobsFromNewBlobs(BLOCK_LIST* block_list,
C_BLOB_LIST* new_blobs,
C_BLOB_LIST* not_found_blobs) {
// Now iterate over all the blobs in the segmentation_block_list_, and just
// replace the corresponding c-blobs inside the werds.
BLOCK_IT block_it(block_list);
for (block_it.mark_cycle_pt(); !block_it.cycled_list(); block_it.forward()) {
BLOCK* block = block_it.data();
if (block->poly_block() != NULL && !block->poly_block()->IsText())
continue; // Don't touch non-text blocks.
// Iterate over all rows in the block.
ROW_IT row_it(block->row_list());
for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) {
ROW* row = row_it.data();
// Iterate over all werds in the row.
WERD_IT werd_it(row->word_list());
WERD_LIST new_words;
WERD_IT new_words_it(&new_words);
for (werd_it.mark_cycle_pt(); !werd_it.cycled_list(); werd_it.forward()) {
WERD* werd = werd_it.extract();
WERD* new_werd = werd->ConstructWerdWithNewBlobs(new_blobs,
not_found_blobs);
if (new_werd) {
// Insert this new werd into the actual row's werd-list. Remove the
// existing one.
new_words_it.add_after_then_move(new_werd);
delete werd;
} else {
// Reinsert the older word back, for lack of better options.
// This is critical since dropping the words messes up segmentation:
// eg. 1st word in the row might otherwise have W_FUZZY_NON turned on.
new_words_it.add_after_then_move(werd);
}
}
// Get rid of the old word list & replace it with the new one.
row->word_list()->clear();
werd_it.move_to_first();
werd_it.add_list_after(&new_words);
}
}
}
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