polyaprx.cpp

一个google的OCR源码

/**********************************************************************
 * File:        polyaprx.cpp  (Formerly polygon.c)
 * Description: Code for polygonal approximation from old edgeprog.
 * Author:		Ray Smith
 * Created:		Thu Nov 25 11:42:04 GMT 1993
 *
 * (C) Copyright 1993, 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          <stdio.h>
#ifdef __UNIX__
#include          <assert.h>
#endif
//#include                                                      "edgeloop.h"
#define MAXEDGELENGTH    16000   //must replace
#include          "polyaprx.h"
#include          "varable.h"
#include          "tprintf.h"

#define EXTERN

EXTERN BOOL_VAR (poly_debug, FALSE, "Debug old poly");
EXTERN BOOL_VAR (poly_wide_objects_better, TRUE,
"More accurate approx on wide things");

static int par1, par2;

#define CONVEX        1          /*OUTLINE point is convex */
#define CONCAVE       2          /*used and set only in edges */
#define FIXED       4            /*OUTLINE point is fixed */
#define ONHULL        8          /*on convex hull */

#define RUNLENGTH     1          /*length of run */

#define DIR         2            /*direction of run */

#define CORRECTION      3        /*correction of run */
//#define MAXSHORT                      32767                                           /*max value of short*/
#define FLAGS       0

#define fixed_dist      20       //really an int_variable
#define approx_dist     15       //really an int_variable

#define point_diff(p,p1,p2) (p).x = (p1).x - (p2).x ; (p).y = (p1).y - (p2).y
#define CROSS(a,b) ((a).x * (b).y - (a).y * (b).x)
#define LENGTH(a) ((a).x * (a).x + (a).y * (a).y)

#define DISTANCE(a,b) (((b).x-(a).x) * ((b).x-(a).x) \
						+ ((b).y-(a).y) * ((b).y-(a).y))

/**********************************************************************
 * tesspoly_outline
 *
 * Approximate an outline from c form using the old tess algorithm.
 **********************************************************************/

OUTLINE *tesspoly_outline(                       //old approximation
                          C_OUTLINE *c_outline,  //input
                          float                  //xheight
                         ) {
  EDGEPT *edgept;                //converted steps
  EDGEPT *startpt;               //start of outline
  TBOX loop_box;                  //bounding box
  inT32 area;                    //loop area
  FCOORD pos;                    //vertex
  FCOORD vec;                    //vector
  POLYPT_LIST polypts;           //output polygon
  POLYPT *polypt;                //converted point
  POLYPT_IT poly_it = &polypts;  //iterator
  EDGEPT edgepts[MAXEDGELENGTH]; //converted path

  loop_box = c_outline->bounding_box ();
  area = loop_box.height ();
  if (!poly_wide_objects_better && loop_box.width () > area)
    area = loop_box.width ();
  area *= area;
  edgept = edgesteps_to_edgepts (c_outline, edgepts);
  fix2(edgepts, area);
  edgept = poly2 (edgepts, area);/*2nd approximation */
  startpt = edgept;
  do {
    pos = FCOORD (edgept->pos.x, edgept->pos.y);
    vec = FCOORD (edgept->vec.x, edgept->vec.y);
    polypt = new POLYPT (pos, vec);
                                 //add to list
    poly_it.add_after_then_move (polypt);
    edgept = edgept->next;
  }
  while (edgept != startpt);
  if (poly_it.length () <= 2)
    return NULL;
  else
                                 //turn to outline
      return new OUTLINE (&poly_it);
}


/**********************************************************************
 * edgesteps_to_edgepts
 *
 * Convert a C_OUTLINE to EDGEPTs.
 **********************************************************************/

EDGEPT *
edgesteps_to_edgepts (           //convert outline
C_OUTLINE * c_outline,           //input
EDGEPT edgepts[]                 //output is array
) {
  inT32 length;                  //steps in path
  ICOORD pos;                    //current coords
  inT32 stepindex;               //current step
  inT32 stepinc;                 //increment
  inT32 epindex;                 //current EDGEPT
  inT32 count;                   //repeated steps
  ICOORD vec;                    //for this 8 step
  ICOORD prev_vec;
  inT8 epdir;                    //of this step
  DIR128 prevdir;                //prvious dir
  DIR128 dir;                    //of this step

  pos = c_outline->start_pos (); //start of loop
  length = c_outline->pathlength ();
  stepindex = 0;
  epindex = 0;
  prevdir = -1;
  count = 0;
  do {
    dir = c_outline->step_dir (stepindex);
    vec = c_outline->step (stepindex);
    if (stepindex < length - 1
    && c_outline->step_dir (stepindex + 1) - dir == -32) {
      dir += 128 - 16;
      vec += c_outline->step (stepindex + 1);
      stepinc = 2;
    }
    else
      stepinc = 1;
    if (count == 0) {
      prevdir = dir;
      prev_vec = vec;
    }
    if (prevdir.get_dir () != dir.get_dir ()) {
      edgepts[epindex].pos.x = pos.x ();
      edgepts[epindex].pos.y = pos.y ();
      prev_vec *= count;
      edgepts[epindex].vec.x = prev_vec.x ();
      edgepts[epindex].vec.y = prev_vec.y ();
      pos += prev_vec;
      edgepts[epindex].flags[RUNLENGTH] = count;
      edgepts[epindex].prev = &edgepts[epindex - 1];
      edgepts[epindex].flags[FLAGS] = 0;
      edgepts[epindex].next = &edgepts[epindex + 1];
      prevdir += 64;
      epdir = (DIR128) 0 - prevdir;
      epdir >>= 4;
      epdir &= 7;
      edgepts[epindex].flags[DIR] = epdir;
      epindex++;
      prevdir = dir;
      prev_vec = vec;
      count = 1;
    }
    else
      count++;
    stepindex += stepinc;
  }
  while (stepindex < length);
  edgepts[epindex].pos.x = pos.x ();
  edgepts[epindex].pos.y = pos.y ();
  prev_vec *= count;
  edgepts[epindex].vec.x = prev_vec.x ();
  edgepts[epindex].vec.y = prev_vec.y ();
  pos += prev_vec;
  edgepts[epindex].flags[RUNLENGTH] = count;
  edgepts[epindex].flags[FLAGS] = 0;
  edgepts[epindex].prev = &edgepts[epindex - 1];
  edgepts[epindex].next = &edgepts[0];
  prevdir += 64;
  epdir = (DIR128) 0 - prevdir;
  epdir >>= 4;
  epdir &= 7;
  edgepts[epindex].flags[DIR] = epdir;
  edgepts[0].prev = &edgepts[epindex];
  ASSERT_HOST (pos.x () == c_outline->start_pos ().x ()
    && pos.y () == c_outline->start_pos ().y ());
  return &edgepts[0];
}


/**********************************************************************
 *fix2(start,area) fixes points on the outline according to a trial method*
 **********************************************************************/

//#pragma OPT_LEVEL 1                                                                           /*stop compiler bugs*/

void fix2(                //polygonal approx
          EDGEPT *start,  /*loop to approimate */
          int area) {
  register EDGEPT *edgept;       /*current point */
  register EDGEPT *edgept1;
  register EDGEPT *loopstart;    /*modified start of loop */
  register EDGEPT *linestart;    /*start of line segment */
  register int dir1, dir2;       /*directions of line */
  register int sum1, sum2;       /*lengths in dir1,dir2 */
  int stopped;                   /*completed flag */
  int fixed_count;               //no of fixed points
  int d01, d12, d23, gapmin;
  TPOINT d01vec, d12vec, d23vec;
  register EDGEPT *edgefix, *startfix;
  register EDGEPT *edgefix0, *edgefix1, *edgefix2, *edgefix3;

  edgept = start;                /*start of loop */
  while (((edgept->flags[DIR] - edgept->prev->flags[DIR] + 1) & 7) < 3
    && (dir1 =
    (edgept->prev->flags[DIR] - edgept->next->flags[DIR]) & 7) != 2
    && dir1 != 6)
    edgept = edgept->next;       /*find suitable start */
  loopstart = edgept;            /*remember start */

  stopped = 0;                   /*not finished yet */
  edgept->flags[FLAGS] |= FIXED; /*fix it */
  do {
    linestart = edgept;          /*possible start of line */
    dir1 = edgept->flags[DIR];   /*first direction */
                                 /*length of dir1 */
    sum1 = edgept->flags[RUNLENGTH];
    edgept = edgept->next;
    dir2 = edgept->flags[DIR];   /*2nd direction */
                                 /*length in dir2 */
    sum2 = edgept->flags[RUNLENGTH];
    if (((dir1 - dir2 + 1) & 7) < 3) {
      while (edgept->prev->flags[DIR] == edgept->next->flags[DIR]) {
        edgept = edgept->next;   /*look at next */
        if (edgept->flags[DIR] == dir1)
                                 /*sum lengths */
          sum1 += edgept->flags[RUNLENGTH];
        else
          sum2 += edgept->flags[RUNLENGTH];
      }

      if (edgept == loopstart)
        stopped = 1;             /*finished */
      if (sum2 + sum1 > 2
        && linestart->prev->flags[DIR] == dir2
        && (linestart->prev->flags[RUNLENGTH] >
      linestart->flags[RUNLENGTH] || sum2 > sum1)) {
                                 /*start is back one */
        linestart = linestart->prev;
        linestart->flags[FLAGS] |= FIXED;
      }

      if (((edgept->next->flags[DIR] - edgept->flags[DIR] + 1) & 7) >= 3
        || (edgept->flags[DIR] == dir1 && sum1 >= sum2)
        || ((edgept->prev->flags[RUNLENGTH] < edgept->flags[RUNLENGTH]
        || (edgept->flags[DIR] == dir2 && sum2 >= sum1))
          && linestart->next != edgept))
        edgept = edgept->next;
    }
                                 /*sharp bend */
    edgept->flags[FLAGS] |= FIXED;
  }
                                 /*do whole loop */
  while (edgept != loopstart && !stopped);

  edgept = start;
  do {
    if (((edgept->flags[RUNLENGTH] >= 8) &&
      (edgept->flags[DIR] != 2) && (edgept->flags[DIR] != 6)) ||
      ((edgept->flags[RUNLENGTH] >= 8) &&
    ((edgept->flags[DIR] == 2) || (edgept->flags[DIR] == 6)))) {
      edgept->flags[FLAGS] |= FIXED;
      edgept1 = edgept->next;
      edgept1->flags[FLAGS] |= FIXED;
    }
    edgept = edgept->next;
  }
  while (edgept != start);

  edgept = start;
  do {
                                 /*single fixed step */