ccmain/imgscale.cpp File Reference

#include "mfcpch.h"
#include <stdio.h>
#include <stdlib.h>
#include "errcode.h"

Go to the source code of this file.

Defines

• #define f(xc, yc)   ((xc - factor*yc)*(xc - factor*yc))
• #define g(oldyc, yc, oldxc, xc)   (factor*factor*(oldyc - yc)*(oldyc - yc)/(abs(oldxc - xc) + 1))

Functions

• void dyn_exit (const char s[])
• void dyn_prog (int n, int *x, int *y, int ymax, int *oldx, int *oldy, int oldn, float factor)

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Define Documentation

#define f	(	xc,
		yc		)	((xc - factor*yc)*(xc - factor*yc))

Note:

File: imgscale.cpp (Formerly dyn_prog.c)
Dynamic programming for smart scaling of images.

Author:

Phil Cheatle

Date:

Wed Nov 18 16:12:03 GMT 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.

Definition at line 26 of file imgscale.cpp.

Referenced by AdaptiveClassifier(), assign_blobs_to_rows(), WERD::baseline_normalise_x(), block_occ(), ClassPruner(), compute_row_descdrop(), compute_row_xheight(), dyn_prog(), float_read(), float_write(), make_rows(), make_words(), mark_gap(), median_block_xheight(), old_first_xheight(), print_background(), ReadTrainingSamples(), recog_word(), resegment_box(), save_summary(), show_all_in(), show_all_tr_in(), WEIRD_BLOCK::show_attrs(), SCRIBBLE_BLOCK::show_attrs(), IMAGE_BLOCK::show_attrs(), GRAPHICS_BLOCK::show_attrs(), RULE_BLOCK::show_attrs(), TEXT_BLOCK::show_attrs(), Solve(), streamtofloat(), strtofloat(), vertical_outline_projection(), and word_bln_display().

#define g	(	oldyc,
		yc,
		oldxc,
		xc		)	(factor*factor*(oldyc - yc)*(oldyc - yc)/(abs(oldxc - xc) + 1))

Definition at line 28 of file imgscale.cpp.

Referenced by dyn_prog().

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Function Documentation

void dyn_exit

(

const char

s[]

)

Definition at line 31 of file imgscale.cpp.

References err_exit().

Referenced by dyn_prog().

                          {
  fprintf (stderr, "%s", s);
  err_exit(); 
}

void dyn_prog	(	int	n,
		int *	x,
		int *	y,
		int	ymax,
		int *	oldx,
		int *	oldy,
		int	oldn,
		float	factor
	)

The clever bit

Phil Cheatle: This is really Sheelagh's code that I've hacked into a more usable form. It is used by scaleimg.cpp

All I did to it was to change "factor" from int to float.

This version uses the result of the previous row to influence the current row's calculation.

Definition at line 48 of file imgscale.cpp.

References dyn_exit(), f, g, NULL, and ymin.

Referenced by scale_image().

                            {
  int i, z, j, matchflag;
  int **ymin;
  float **F, fz;

  /* F[i][z] gives minimum over y <= z */

  F = (float **) calloc (n, sizeof (float *));
  ymin = (int **) calloc (n, sizeof (int *));
  if ((F == NULL) || (ymin == NULL))
    dyn_exit ("Error in calloc\n");

  for (i = 0; i < n; i++) {
    F[i] = (float *) calloc (ymax - n + i + 1, sizeof (float));
    ymin[i] = (int *) calloc (ymax - n + i + 1, sizeof (int));
    if ((F[i] == NULL) || (ymin[i] == NULL))
      dyn_exit ("Error in calloc\n");
  }

  F[0][0] = f (x[0], 0);
  /* find nearest transition of same sign (white to black) */
  j = 0;
  while ((j < oldn) && (oldx[j] < x[0]))
    j += 2;
  if (j >= oldn)
    j -= 2;
  else if ((j - 2 >= 0) && ((x[0] - oldx[j - 2]) < (oldx[j] - x[0])))
    j -= 2;
  if (abs (oldx[j] - x[0]) < factor) {
    matchflag = 1;
    F[0][0] += g (oldy[j], 0, oldx[j], x[0]);
  }
  else
    matchflag = 0;
  ymin[0][0] = 0;

  for (z = 1; z < ymax - n + 1; z++) {
    fz = f (x[0], z);
    /* add penalty for deviating from previous row if necessary */
    if (matchflag)
      fz += g (oldy[j], z, oldx[j], x[0]);
    if (fz < F[0][z - 1]) {
      F[0][z] = fz;
      ymin[0][z] = z;
    }
    else {
      F[0][z] = F[0][z - 1];
      ymin[0][z] = ymin[0][z - 1];
    }
  }

  for (i = 1; i < n; i++) {
    F[i][i] = f (x[i], i) + F[i - 1][i - 1];
    /* add penalty for deviating from previous row if necessary */
    if (j > 0)
      j--;
    else
      j++;
    while ((j < oldn) && (oldx[j] < x[i]))
      j += 2;
    if (j >= oldn)
      j -= 2;
    else if ((j - 2 >= 0) && ((x[i] - oldx[j - 2]) < (oldx[j] - x[i])))
      j -= 2;
    if (abs (oldx[j] - x[i]) < factor) {
      matchflag = 1;
      F[i][i] += g (oldy[j], i, oldx[j], x[i]);
    }
    else
      matchflag = 0;
    ymin[i][i] = i;
    for (z = i + 1; z < ymax - n + i + 1; z++) {
      fz = f (x[i], z) + F[i - 1][z - 1];
      /* add penalty for deviating from previous row if necessary */
      if (matchflag)
        fz += g (oldy[j], z, oldx[j], x[i]);
      if (fz < F[i][z - 1]) {
        F[i][z] = fz;
        ymin[i][z] = z;
      }
      else {
        F[i][z] = F[i][z - 1];
        ymin[i][z] = ymin[i][z - 1];
      }
    }
  }

  y[n - 1] = ymin[n - 1][ymax - 1];
  for (i = n - 2; i >= 0; i--)
    y[i] = ymin[i][y[i + 1] - 1];

  for (i = 0; i < n; i++) {
    free (F[i]);
    free (ymin[i]);
  }
  free(F); 
  free(ymin); 

  return;
}

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