mirror of
https://github.com/tesseract-ocr/tesseract.git
synced 2024-12-12 23:49:06 +08:00
163 lines
5.7 KiB
C++
163 lines
5.7 KiB
C++
/**********************************************************************
|
|
* File: edgloop.cpp (Formerly edgeloop.c)
|
|
* Description: Functions to clean up an outline before approximation.
|
|
* Author: Ray Smith
|
|
*
|
|
* (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 automatically generated configuration file if running autoconf.
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config_auto.h"
|
|
#endif
|
|
|
|
#include "scanedg.h"
|
|
|
|
#include "edgloop.h"
|
|
|
|
namespace tesseract {
|
|
|
|
#define MINEDGELENGTH 8 // min decent length
|
|
|
|
/**********************************************************************
|
|
* complete_edge
|
|
*
|
|
* Complete the edge by cleaning it up.
|
|
**********************************************************************/
|
|
|
|
void complete_edge(CRACKEDGE *start, //start of loop
|
|
C_OUTLINE_IT* outline_it) {
|
|
ScrollView::Color colour; //colour to draw in
|
|
int16_t looplength; //steps in loop
|
|
ICOORD botleft; //bounding box
|
|
ICOORD topright;
|
|
C_OUTLINE *outline; //new outline
|
|
|
|
//check length etc.
|
|
colour = check_path_legal (start);
|
|
|
|
if (colour == ScrollView::RED || colour == ScrollView::BLUE) {
|
|
looplength = loop_bounding_box (start, botleft, topright);
|
|
outline = new C_OUTLINE (start, botleft, topright, looplength);
|
|
//add to list
|
|
outline_it->add_after_then_move (outline);
|
|
}
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* check_path_legal
|
|
*
|
|
* Check that the outline is legal for length and for chaincode sum.
|
|
* The return value is RED for a normal black-inside outline,
|
|
* BLUE for a white-inside outline, MAGENTA if it is too short,
|
|
* YELLOW if it is too long, and GREEN if it is illegal.
|
|
* These colours are used to draw the raw outline.
|
|
**********************************************************************/
|
|
|
|
ScrollView::Color check_path_legal( //certify outline
|
|
CRACKEDGE *start //start of loop
|
|
) {
|
|
int lastchain; //last chain code
|
|
int chaindiff; //chain code diff
|
|
int32_t length; //length of loop
|
|
int32_t chainsum; //sum of chain diffs
|
|
CRACKEDGE *edgept; //current point
|
|
constexpr ERRCODE ED_ILLEGAL_SUM("Illegal sum of chain codes");
|
|
|
|
length = 0;
|
|
chainsum = 0; //sum of chain codes
|
|
edgept = start;
|
|
lastchain = edgept->prev->stepdir; //previous chain code
|
|
do {
|
|
length++;
|
|
if (edgept->stepdir != lastchain) {
|
|
//chain code difference
|
|
chaindiff = edgept->stepdir - lastchain;
|
|
if (chaindiff > 2)
|
|
chaindiff -= 4;
|
|
else if (chaindiff < -2)
|
|
chaindiff += 4;
|
|
chainsum += chaindiff; //sum differences
|
|
lastchain = edgept->stepdir;
|
|
}
|
|
edgept = edgept->next;
|
|
}
|
|
while (edgept != start && length < C_OUTLINE::kMaxOutlineLength);
|
|
|
|
if ((chainsum != 4 && chainsum != -4)
|
|
|| edgept != start || length < MINEDGELENGTH) {
|
|
if (edgept != start) {
|
|
return ScrollView::YELLOW;
|
|
} else if (length < MINEDGELENGTH) {
|
|
return ScrollView::MAGENTA;
|
|
} else {
|
|
ED_ILLEGAL_SUM.error ("check_path_legal", TESSLOG, "chainsum=%d",
|
|
chainsum);
|
|
return ScrollView::GREEN;
|
|
}
|
|
}
|
|
//colour on inside
|
|
return chainsum < 0 ? ScrollView::BLUE : ScrollView::RED;
|
|
}
|
|
|
|
/**********************************************************************
|
|
* loop_bounding_box
|
|
*
|
|
* Find the bounding box of the edge loop.
|
|
**********************************************************************/
|
|
|
|
int16_t loop_bounding_box( //get bounding box
|
|
CRACKEDGE *&start, //edge loop
|
|
ICOORD &botleft, //bounding box
|
|
ICOORD &topright) {
|
|
int16_t length; //length of loop
|
|
int16_t leftmost; //on top row
|
|
CRACKEDGE *edgept; //current point
|
|
CRACKEDGE *realstart; //topleft start
|
|
|
|
edgept = start;
|
|
realstart = start;
|
|
botleft = topright = ICOORD (edgept->pos.x (), edgept->pos.y ());
|
|
leftmost = edgept->pos.x ();
|
|
length = 0; //coutn length
|
|
do {
|
|
edgept = edgept->next;
|
|
if (edgept->pos.x () < botleft.x ())
|
|
//get bounding box
|
|
botleft.set_x (edgept->pos.x ());
|
|
else if (edgept->pos.x () > topright.x ())
|
|
topright.set_x (edgept->pos.x ());
|
|
if (edgept->pos.y () < botleft.y ())
|
|
//get bounding box
|
|
botleft.set_y (edgept->pos.y ());
|
|
else if (edgept->pos.y () > topright.y ()) {
|
|
realstart = edgept;
|
|
leftmost = edgept->pos.x ();
|
|
topright.set_y (edgept->pos.y ());
|
|
}
|
|
else if (edgept->pos.y () == topright.y ()
|
|
&& edgept->pos.x () < leftmost) {
|
|
//leftmost on line
|
|
leftmost = edgept->pos.x ();
|
|
realstart = edgept;
|
|
}
|
|
length++; //count elements
|
|
}
|
|
while (edgept != start);
|
|
start = realstart; //shift it to topleft
|
|
return length;
|
|
}
|
|
|
|
} // namespace tesseract
|