imgs.cpp

一个google的OCR源码

  startxindex = xindex;
  yindex = ystart % scale;
                                 //no of source pixels
  srcext = (xext + xindex + scale - 1) / scale;
  xstart /= scale;               //actual start
  ystart /= scale;
  if (adjust_grey) {
    shift = dest->bps - source->bps;
  }
  else
    shift = 0;                   //no adjustment
  bigline.init (xext * 3);
  bigline.bpp = dest->bpp == 24 ? source->bpp : dest->bpp;

  for (yoffset = 0; yoffset < yext; ystart++) {
    source->check_legal_access (xstart, ystart, srcext);
    dest->check_legal_access (xdest, ydest + yoffset, xext);
    source->fast_get_line (xstart, ystart, srcext, &copyline);
    src = copyline.pixels;
    destpix = bigline.pixels;
    xscale = scale;              //enlargement factor
    if (source->bpp == 24 && dest->bpp == 24) {
      for (xoffset = 0, xindex = startxindex; xoffset < xext;
      src += source->bytespp) {
        xoffset += xscale - xindex;
        if (xoffset > xext)
          xscale -= xoffset - xext;
        for (; xindex < xscale; xindex++) {
          *destpix++ = *src;
          *destpix++ = *(src + 1);
          *destpix++ = *(src + 2);
        }
        xindex = 0;
      }
    }
    else {
      if (source->bpp == 24)
        src++;
      for (xoffset = 0, xindex = startxindex; xoffset < xext;
      src += source->bytespp) {
        xoffset += xscale - xindex;
        if (xoffset > xext)
                                 //clip to dest limit
            xscale -= xoffset - xext;
        if (shift == 0)
          pixel = *src;
        else if (shift > 0)
          pixel = *src << shift;
        else
          pixel = *src >> (-shift);
        for (; xindex < xscale; xindex++)
          *destpix++ = pixel;    //duplicate pixel
        xindex = 0;
      }
    }
    for (; yoffset < yext && yindex < scale; yindex++, yoffset++) {
      dest->put_line (xdest, ydest + yoffset, xext, &bigline, 0);
    }
    yindex = 0;
  }
}


/**********************************************************************
 * fast_reduce_sub_image
 *
 * Reduce a portion of one image to a portion of another image.
 * If the bpps are different, the position of the most significant
 * bit is preserved.
 * This is a fast but dirty version, which simply sub-samples.
 * It does not smooth as it reduces.
 **********************************************************************/

DLLSYM void fast_reduce_sub_image(                   //reduce rectangle
                                  IMAGE *source,     //source image
                                  inT32 xstart,      //start coords
                                  inT32 ystart,
                                  inT32 xext,        //extent to copy
                                  inT32 yext,
                                  IMAGE *dest,       //destination image
                                  inT32 xdest,       //destination coords
                                  inT32 ydest,
                                  inT32 scale,       //reduction factor
                                  BOOL8 adjust_grey  //shift to new bpp
                                 ) {
  inT8 shift;                    //shift factor
  inT32 xfactor;                 //run on x coord
  inT32 divisor;                 //total cell area
  inT32 xindex, yindex;          //into averaging square
  inT32 xcoord;                  //current x coord
  inT32 destext;                 //destination size
  inT32 yoffset;                 //current adjusted offset
  uinT8 *pixel;                  //ptr to source pixels
  inT32 *sums;                   //ptr to sums array
  IMAGELINE copyline;            //copy of line
  inT32 *linesums;               //averaging sums

  if (xstart < 0 || ystart < 0 || xdest < 0 || ydest < 0)
    return;
  if (xext <= 0)
    xext = source->xsize;        //default to all
  if (xext > source->xsize - xstart)
                                 //clip to smallest
      xext = source->xsize - xstart;
  if (xext > (dest->xsize - xdest) * scale)
    xext = (dest->xsize - xdest) * scale;
  if (yext <= 0)
    yext = source->ysize;        //default to all
  if (yext > source->ysize - ystart)
                                 //clip to smallest
      yext = source->ysize - ystart;
  if (yext > (dest->ysize - ydest) * scale)
    yext = (dest->ysize - ydest) * scale;
  if (xext <= 0 || yext <= 0)
    return;                      //nothing to do

  xfactor = xext % scale;        //left overs
  if (xfactor == 0)
    xfactor = scale;
                                 //destination pixels
  destext = (xext + scale - 1) / scale;
  if (adjust_grey)
                                 //shift factor
    shift = dest->bps - source->bps;
  else
    shift = 0;                   //no adjustment
  linesums = new inT32[destext * source->bytespp];

  for (yoffset = 0; yoffset < yext; ydest++) {
    source->check_legal_access (xstart, ystart + yoffset, xext);
    dest->check_legal_access (xdest, ydest, destext);
    for (xindex = destext * source->bytespp - 1; xindex >= 0; xindex--)
      linesums[xindex] = 0;      //zero sums
    for (yindex = 0; yindex < scale
    && ystart + yoffset < source->ysize; yindex += 3) {
      source->fast_get_line (xstart, ystart + yoffset, xext, &copyline);
      pixel = copyline.pixels;   //start of line
      if (source->bpp == 24) {
        for (xcoord = 1, sums = linesums; xcoord < destext;
        xcoord++, sums += 3) {
          for (xindex = 0; xindex < scale; xindex += 2) {
            *sums += *pixel++;
            *(sums + 1) += *pixel++;
            *(sums + 2) += *pixel++;
            pixel += 3;
          }
          if (scale & 1)
            pixel -= 3;          //correct position
        }
        for (xindex = 0; xindex < xfactor; xindex += 2) {
          *sums += *pixel++;
          *(sums + 1) += *pixel++;
          *(sums + 2) += *pixel++;
          pixel += 3;
        }
      }
      else {
        for (xcoord = 1, sums = linesums; xcoord < destext;
        xcoord++, sums++) {
          for (xindex = 0; xindex < scale; xindex += 2) {
            *sums += *pixel;
            pixel += 2;
          }
          if (scale & 1)
            pixel--;             //correct position
        }
        for (xindex = 0; xindex < xfactor; xindex += 2) {
          *sums += *pixel;
          pixel += 2;
        }
      }
      yoffset += 3;              //every 3 lines
    }
    if (yindex > scale)
      yoffset -= yindex - scale; //back on right scale
    copyline.init ();            //set pixels back to array
    copyline.bpp = source->bpp;
    pixel = copyline.pixels;
                                 //pixels in block
    divisor = ((yindex + 2) / 3) * ((scale + 1) / 2);
    if (shift <= 0) {
      divisor <<= (-shift);      //do greyscale correction
      for (sums = linesums, xindex = (destext - 1) * source->bytespp;
        xindex > 0; xindex--)
                                 //turn to destination value
      *pixel++ = (uinT8) (*sums++ / divisor);
      for (xindex = source->bytespp; xindex > 0; xindex--)
        *pixel++ = *sums++
          / (((yindex + 2) / 3) * ((xfactor + 1) / 2) << (-shift));
      //lastone different
    }
    else {
      for (sums = linesums, xindex = (destext - 1) * source->bytespp;
        xindex > 0; xindex--)
      *pixel++ = (uinT8) ((*sums++ << shift) / divisor);
      //destination value
      for (xindex = source->bytespp; xindex > 0; xindex--)
                                 //last one different
        *pixel++ = (*(sums++) << shift) / (((yindex + 2) / 3) * ((xfactor + 1) / 2));
    }
                                 //put in destination
    dest->put_line (xdest, ydest, destext, &copyline, 0);
  }
  delete linesums;
}


/**********************************************************************
 * reduce_sub_image
 *
 * Reduce a portion of one image to a portion of another image.
 * If the bpps are different, the position of the most significant
 * bit is preserved.
 **********************************************************************/

DLLSYM void reduce_sub_image(                   //reduce rectangle
                             IMAGE *source,     //source image
                             inT32 xstart,      //start coords
                             inT32 ystart,
                             inT32 xext,        //extent to copy
                             inT32 yext,
                             IMAGE *dest,       //destination image
                             inT32 xdest,       //destination coords
                             inT32 ydest,
                             inT32 scale,       //reduction factor
                             BOOL8 adjust_grey  //shift to new bpp
                            ) {
  inT8 shift;                    //shift factor
  inT32 xfactor;                 //run on x coord
  inT32 divisor;                 //total cell area
  inT32 div2;                    //total cell area divided by 2
  inT32 xindex, yindex;          //into averaging square
  inT32 xcoord;                  //current x coord
  inT32 destext;                 //destination size
  inT32 yoffset;                 //current adjusted offset
  uinT8 *pixel;                  //ptr to source pixels
  inT32 *sums;                   //ptr to sums array
  IMAGELINE copyline;            //copy of line
  inT32 *linesums;               //averaging sums

  if (xstart < 0 || ystart < 0 || xdest < 0 || ydest < 0)
    return;
  if (xext <= 0)
    xext = source->xsize;        //default to all
  if (xext > source->xsize - xstart)
                                 //clip to smallest
      xext = source->xsize - xstart;
  if (xext > (dest->xsize - xdest) * scale)
    xext = (dest->xsize - xdest) * scale;
  if (yext <= 0)
    yext = source->ysize;        //default to all
  if (yext > source->ysize - ystart)
                                 //clip to smallest
      yext = source->ysize - ystart;
  if (yext > (dest->ysize - ydest) * scale)
    yext = (dest->ysize - ydest) * scale;
  if (xext <= 0 || yext <= 0)
    return;                      //nothing to do

  xfactor = xext % scale;        //left overs
  if (xfactor == 0)
    xfactor = scale;
                                 //destination pixels
  destext = (xext + scale - 1) / scale;
  if (adjust_grey)
                                 //shift factor
    shift = dest->bps - source->bps;
  else
    shift = 0;                   //no adjustment
  linesums = new inT32[destext * source->bytespp];

  for (yoffset = 0; yoffset < yext; ydest++) {
    source->check_legal_access (xstart, ystart + yoffset, xext);
    dest->check_legal_access (xdest, ydest, destext);
    for (xindex = 0; xindex < (destext) * source->bytespp; xindex++)
      linesums[xindex] = 0;      //zero sums
    for (yindex = 0; yindex < scale && ystart + yoffset < source->ysize;
    yindex++) {
      source->fast_get_line (xstart, ystart + yoffset, xext, &copyline);
      pixel = copyline.pixels;   //start of line
      if (source->bpp == 24) {
        for (xcoord = 1, sums = linesums; xcoord < destext;
        xcoord++, sums += 3) {
          for (xindex = 0; xindex < scale; xindex++) {
            *sums += *pixel++;
            *(sums + 1) += *pixel++;
            *(sums + 2) += *pixel++;
          }
        }
        for (xindex = 0; xindex < xfactor; xindex++) {
          *sums += *pixel++;
          *(sums + 1) += *pixel++;
          *(sums + 2) += *pixel++;
        }
      }
      else {
        for (xcoord = 1, sums = linesums; xcoord < destext;
        xcoord++, sums++) {
          for (xindex = 0; xindex < scale; xindex++)
            *sums += *pixel++;
        }
        for (xindex = 0; xindex < xfactor; xindex++)
          *sums += *pixel++;
      }
      yoffset++;                 //next line
    }
    copyline.init ();            //set pixels back to array
    copyline.set_bpp (source->bpp);
    pixel = copyline.pixels;
    divisor = yindex * scale;
    if (divisor == 0) {
      tprintf
        ("Impossible:divisor=0!, yindex=%d, scale=%d, yoffset=%d,yext=%d\n",
        yindex, scale, yoffset, yext);
      break;
    }
    if (shift <= 0) {
      divisor <<= (-shift);      //do greyscale correction
      div2 = divisor / 2;
      for (sums = linesums, xindex = (destext - 1) * source->bytespp;
        xindex > 0; xindex--)
      *pixel++ = (uinT8) ((div2 + *sums++) / divisor);
      //turn to destination value
      div2 = (yindex * xfactor << (-shift)) / 2;
      for (xindex = source->bytespp; xindex > 0; xindex--)
        *pixel++ =
          (uinT8) ((div2 + *sums++) / (yindex * xfactor << (-shift)));
      //lastone different
    }
    else {
      div2 = divisor / 2;
      for (sums = linesums, xindex = (destext - 1) * source->bytespp;
        xindex > 0; xindex--)
      *pixel++ = (uinT8) ((div2 + (*sums++ << shift)) / divisor);
      //destination value
      div2 = (yindex * xfactor) / 2;
      for (xindex = source->bytespp; xindex > 0; xindex--)
        *pixel++ =
          (uinT8) ((div2 + (*sums++ << shift)) / (yindex * xfactor));
      //last one different
    }
                                 //put in destination
    dest->put_line (xdest, ydest, destext, &copyline, 0);
  }
  delete linesums;
}


/**********************************************************************
 * invert_image
 *
 * Invert the given image (the slow way.)
 **********************************************************************/

DLLSYM void invert_image(              /*invert the image */
                         IMAGE *image  /*image ot invert */
                        ) {
  uinT8 mask;                    //bit mask
  uinT8 bytespp;                 //bytes per pixel
  inT32 xsize, ysize;            /*size of image */
  inT32 xindex, yindex;          /*index into image */
  uinT8 *pixel;                  /*current pixel */
  IMAGELINE line;                /*line of image */

  bytespp = image->get_bpp () == 24 ? 3 : 1;
  xsize = image->get_xsize ();   /*find sizes */
  ysize = image->get_ysize ();
                                 //pixel mask
  mask = (1 << image->get_bpp ()) - 1;
                                 /*do each line */
  for (yindex = ysize - 1; yindex >= 0; yindex--) {
    image->fast_get_line (0, yindex, xsize, &line);
    for (pixel = line.pixels, xindex = xsize * bytespp; xindex > 0;
      xindex--) {
      *pixel = (*pixel) ^ mask;  //invert image only
      ++pixel;
    }
                                 /*put it back */
    image->fast_put_line (0, yindex, xsize, &line);
  }
}


/**********************************************************************
 * bias_sub_image
 *
 * Add a constant to a portion of an image.
 **********************************************************************/

DLLSYM void bias_sub_image(                //bias rectangle
                           IMAGE *source,  //source image
                           inT32 xstart,   //start coords
                           inT32 ystart,
                           inT32 xext,     //extent to copy
                           inT32 yext,
                           uinT8 bias      //number to add
                          ) {
  IMAGELINE copyline;            //copy of line
  uinT8 *copy;                   //source pointer
  inT32 pixel;                   //pixel index
  inT32 y;                       //line index
  uinT8 bytespp;                 //bytes per pixel

  if (xstart < 0 || ystart < 0)
    return;
  if (xext <= 0)
    xext = source->get_xsize (); //default to all
  if (xext > source->get_xsize () - xstart)
                                 //clip to smallest
    xext = source->get_xsize () - xstart;
  if (yext <= 0)
    yext = source->get_ysize (); //default to all
  if (yext > source->get_ysize () - ystart)
                                 //clip to smallest
    yext = source->get_ysize () - ystart;
  if (xext <= 0 || yext <= 0)
    return;                      //nothing to do

  bytespp = source->get_bpp () == 24 ? 3 : 1;
  for (y = 0; y < yext; y++) {
    source->check_legal_access (xstart, ystart + y, xext);
    source->fast_get_line (xstart, ystart + y, xext, &copyline);
    for (pixel = xext * bytespp, copy = copyline.pixels; pixel > 0;
      pixel--, copy++)
    *copy += bias;               //add bias

    source->fast_put_line (xstart, ystart + y, xext, &copyline);
  }
}


/**********************************************************************
 * starbase_to_normal
 *
 * Copy a portion of one image to a portion of another image.
 * This function maps the colour tables used on the screen to
 * greyscale values in the way "normally" expected.
 **********************************************************************/

DLLSYM void starbase_to_normal(                     //copy rectangle
                               IMAGE *source,       //source image
                               inT32 xstart,        //start coords