imgs.cpp File Reference

#include "mfcpch.h"
#include <unistd.h>
#include <string.h>
#include "allheaders.h"
#include "stderr.h"
#include "tprintf.h"
#include "imgerrs.h"
#include "memry.h"
#include "imgs.h"
#include "imgunpk.h"

Go to the source code of this file.

Macros
#define	FIXED_COLOURS   32 /*number of fixed colours */
#define	MIN_4BIT   48 /*4bpp range */
#define	MAX_4BIT   64
#define	MIN_6BIT   64 /*6bpp range */
#define	MAX_6BIT   128
#define	BLACK_PIX   0
#define	EXTERN

Functions
inT32	check_legal_image_size (inT32 x, inT32 y, inT8 bits_per_pixel)
DLLSYM void	copy_sub_image (IMAGE *source, inT32 xstart, inT32 ystart, inT32 xext, inT32 yext, IMAGE *dest, inT32 xdest, inT32 ydest, BOOL8 adjust_grey)
DLLSYM void	enlarge_sub_image (IMAGE *source, inT32 xstart, inT32 ystart, IMAGE *dest, inT32 xdest, inT32 ydest, inT32 xext, inT32 yext, inT32 scale, BOOL8 adjust_grey)
DLLSYM void	fast_reduce_sub_image (IMAGE *source, inT32 xstart, inT32 ystart, inT32 xext, inT32 yext, IMAGE *dest, inT32 xdest, inT32 ydest, inT32 scale, BOOL8 adjust_grey)
DLLSYM void	reduce_sub_image (IMAGE *source, inT32 xstart, inT32 ystart, inT32 xext, inT32 yext, IMAGE *dest, inT32 xdest, inT32 ydest, inT32 scale, BOOL8 adjust_grey)
DLLSYM void	invert_image (IMAGE *image)
DLLSYM void	bias_sub_image (IMAGE *source, inT32 xstart, inT32 ystart, inT32 xext, inT32 yext, uinT8 bias)
DLLSYM void	starbase_to_normal (IMAGE *source, inT32 xstart, inT32 ystart, inT32 xext, inT32 yext, IMAGE *dest, inT32 xdest, inT32 ydest, BOOL8 preserve_grey)

Variables
const uinT8	grey_scales [FIXED_COLOURS]
EXTERN int	image_default_resolution = 300

Macro Definition Documentation

#define BLACK_PIX   0

Definition at line 50 of file imgs.cpp.

#define EXTERN

Definition at line 60 of file imgs.cpp.

#define FIXED_COLOURS   32 /*number of fixed colours */

Definition at line 45 of file imgs.cpp.

#define MAX_4BIT   64

Definition at line 47 of file imgs.cpp.

#define MAX_6BIT   128

Definition at line 49 of file imgs.cpp.

#define MIN_4BIT   48 /*4bpp range */

Definition at line 46 of file imgs.cpp.

#define MIN_6BIT   64 /*6bpp range */

Definition at line 48 of file imgs.cpp.

Function Documentation

DLLSYM void bias_sub_image	(	IMAGE *	source,
		inT32	xstart,
		inT32	ystart,
		inT32	xext,
		inT32	yext,
		uinT8	bias
	)

Definition at line 832 of file imgs.cpp.

                            {
  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);
  }
}

inT32 check_legal_image_size	(	inT32	x,
		inT32	y,
		inT8	bits_per_pixel
	)

Definition at line 240 of file imgs.cpp.

                              {
  if (x <= 0 || y <= 0) {
    BADIMAGESIZE.error ("check_legal_image_size", TESSLOG, "(%d,%d)", x, y);
    return -1;                   //failed
  }
  if (bits_per_pixel != 1 && bits_per_pixel != 2 &&
      bits_per_pixel != 4 && bits_per_pixel != 5 &&
      bits_per_pixel != 6 && bits_per_pixel != 8 &&
      bits_per_pixel != 16 && bits_per_pixel != 24 &&
      bits_per_pixel != 32) {
    BADBPP.error ("check_legal_image_size", TESSLOG, "%d", bits_per_pixel);
    return -1;
  }
                                 //bytes per line
  return COMPUTE_IMAGE_XDIM (x, bits_per_pixel);
}

DLLSYM void copy_sub_image	(	IMAGE *	source,
		inT32	xstart,
		inT32	ystart,
		inT32	xext,
		inT32	yext,
		IMAGE *	dest,
		inT32	xdest,
		inT32	ydest,
		BOOL8	adjust_grey
	)

Definition at line 270 of file imgs.cpp.

                            {
  IMAGELINE copyline;            //copy of line
  uinT8 *copy;                   //source pointer
  inT8 shift;                    //shift factor
  inT32 pixel;                   //pixel index
  inT32 y;                       //line index
  inT32 yoffset;                 //current adjusted offset
  inT32 bytesize;                //no of bytes to copy
  inT32 srcppb;                  //pixels per byte
  BOOL8 aligned;

  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)
    xext = dest->xsize - xdest;
  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)
    yext = dest->ysize - ydest;
  if (xext <= 0 || yext <= 0)
    return;                      //nothing to do

  srcppb = 8 / source->bpp;      //pixels per byte
  if (source->bpp == dest->bpp || !adjust_grey)
    shift = 0;                   //no adjustment
  else {
    shift = source->bps - dest->bps;
    if (shift < 0)
      shift = -shift;            //keep positive
  }
  aligned = source->bpp == dest->bpp;
  if (aligned && srcppb != 0) {
    aligned = xstart % srcppb == 0
      && xdest % srcppb == 0
      && (xext % srcppb == 0 || xdest + xext == dest->xsize);
  }
  for (y = 0; y < yext; y++) {
    if (ystart >= ydest)
      yoffset = y;               //top down
    else
      yoffset = yext - y - 1;    //bottom up
    source->check_legal_access (xstart, ystart + yoffset, xext);
    dest->check_legal_access (xdest, ydest + yoffset, xext);
    if (aligned) {
      bytesize = COMPUTE_IMAGE_XDIM (xext, source->bpp);
      //get bytes per line
      if (srcppb == 0)
                                 //do cheap move
        memmove (dest->image + (dest->ymax - 1 - ydest - yoffset) * dest->xdim + xdest * 3, source->image + (source->ymax - 1 - ystart - yoffset) * source->xdim + xstart * 3, (unsigned) bytesize);
      else
                                 //do cheap move
        memmove (dest->image + (dest->ymax - 1 - ydest - yoffset) * dest->xdim + xdest / srcppb, source->image + (source->ymax - 1 - ystart - yoffset) * source->xdim + xstart / srcppb, (unsigned) bytesize);
    }
    else {
      if (shift == 0) {
        source->fast_get_line (xstart, ystart + yoffset, xext,
          &copyline);
      }
      else if (source->bpp < dest->bpp) {
        source->get_line (xstart, ystart + yoffset, xext, &copyline, 0);
        if (source->bpp <= shift
        && (source->bpp == 1 || source->bpp == 4)) {
          if (source->bpp == 1) {
            for (pixel = 0, copy = copyline.pixels; pixel < xext;
              pixel++, copy++)
            if (*copy)
              *copy = 0xff;
          }
          else {
            for (pixel = 0, copy = copyline.pixels; pixel < xext;
              pixel++, copy++)
                                 //scale up
            *copy = (*copy << shift) | *copy;
          }
        }
        else {
          for (pixel = 0, copy = copyline.pixels; pixel < xext;
            pixel++)
          *copy++ <<= shift;     //scale up
        }
      }
      else {
        source->get_line (xstart, ystart + yoffset, xext, &copyline, 0);
        if (source->bpp == 24) {
          for (pixel = 0, copy = copyline.pixels + 1; pixel < xext;
          pixel++) {
            *copy >>= shift;
            copy += 3;
          }
        }
        else {
          for (pixel = 0, copy = copyline.pixels; pixel < xext;
            pixel++)
          *copy++ >>= shift;     //scale down
        }
      }
      dest->put_line (xdest, ydest + yoffset, xext, &copyline, 0);
    }
  }
}

DLLSYM void enlarge_sub_image	(	IMAGE *	source,
		inT32	xstart,
		inT32	ystart,
		IMAGE *	dest,
		inT32	xdest,
		inT32	ydest,
		inT32	xext,
		inT32	yext,
		inT32	scale,
		BOOL8	adjust_grey
	)

Definition at line 398 of file imgs.cpp.

                               {
  inT8 shift;                    //shift factor
  uinT8 pixel;                   //current pixel
  inT32 srcext;                  //source extent
  inT32 xoffset;                 //column index
  inT32 yoffset;                 //line index
  inT32 xindex, yindex;          //index in super pixel
  inT32 startxindex;             //initial x index
  inT32 xscale;                  //x scale factor
  uinT8 *src;                    //source pixels
  uinT8 *destpix;                //dest pixels
  IMAGELINE copyline;            //copy of line
  IMAGELINE bigline;             //expanded line

  if (xstart < 0 || ystart < 0 || xdest < 0 || ydest < 0)
    return;

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

  xindex = xstart % scale;       //offset in super pixel
  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;
  }
}

DLLSYM void fast_reduce_sub_image	(	IMAGE *	source,
		inT32	xstart,
		inT32	ystart,
		inT32	xext,
		inT32	yext,
		IMAGE *	dest,
		inT32	xdest,
		inT32	ydest,
		inT32	scale,
		BOOL8	adjust_grey
	)

Definition at line 516 of file imgs.cpp.

                                   {
  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;
}

DLLSYM void invert_image

(

IMAGE *

image

)

Definition at line 797 of file imgs.cpp.

                          {
  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);
  }
}

DLLSYM void reduce_sub_image	(	IMAGE *	source,
		inT32	xstart,
		inT32	ystart,
		inT32	xext,
		inT32	yext,
		IMAGE *	dest,
		inT32	xdest,
		inT32	ydest,
		inT32	scale,
		BOOL8	adjust_grey
	)

Definition at line 658 of file imgs.cpp.

                              {
  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;
}

DLLSYM void starbase_to_normal	(	IMAGE *	source,
		inT32	xstart,
		inT32	ystart,
		inT32	xext,
		inT32	yext,
		IMAGE *	dest,
		inT32	xdest,
		inT32	ydest,
		BOOL8	preserve_grey
	)

Definition at line 882 of file imgs.cpp.

                                {
  IMAGELINE copyline;            //copy of line
  uinT8 *copy;                   //source pointer
  inT8 shift4;                   //shift factor
  inT8 shift6;                   //shift factor
  inT8 colour_shift;             //shift of colours
  uinT8 white_level;             //dest white value
  inT32 pixel;                   //pixel index
  inT32 y;                       //line index
  inT32 yoffset;                 //current adjusted offset
  inT8 srcppb;                   //pixels per byte

  if (xstart < 0 || ystart < 0 || xdest < 0 || ydest < 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 (xext > dest->get_xsize () - xdest)
    xext = dest->get_xsize () - xdest;
  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 (yext > dest->get_ysize () - ydest)
    yext = dest->get_ysize () - ydest;
  if (xext <= 0 || yext <= 0)
    return;                      //nothing to do

                                 //pixels per byte
  srcppb = 8 / source->get_bpp ();
  shift4 = 4 - dest->get_bpp (); //for different bpps
  shift6 = 6 - dest->get_bpp ();
                                 //for grey preserve
  colour_shift = 8 - dest->get_bpp ();
  white_level = dest->get_white_level ();
  for (y = 0; y < yext; y++) {
    if (ystart >= ydest)
      yoffset = y;               //top down
    else
      yoffset = yext - y - 1;    //bottom up
    source->check_legal_access (xstart, ystart + yoffset, xext);
    dest->check_legal_access (xdest, ydest + yoffset, xext);
    source->get_line (xstart, ystart + yoffset, xext, &copyline, 0);
    for (pixel = 0, copy = copyline.pixels; pixel < xext; pixel++) {
      if (*copy < FIXED_COLOURS && preserve_grey)
        *copy = grey_scales[*copy] >> colour_shift;
      else if (*copy < FIXED_COLOURS) {
        if (*copy == BLACK_PIX)
          *copy = white_level;   //black->white
        else
          *copy = 0;             //others->black
      }
      else if (*copy >= MIN_4BIT && *copy < MAX_4BIT) {
        if (shift4 < 0)
          *copy = (*copy - MIN_4BIT) << (-shift4);
        else
          *copy = (*copy - MIN_4BIT) >> shift4;
      }
      else if (*copy >= MIN_6BIT && *copy < MAX_6BIT) {
        if (shift6 < 0)
          *copy = (*copy - MIN_6BIT) << (-shift6);
        else
          *copy = (*copy - MIN_6BIT) >> shift6;
      }
      else {
        *copy = white_level;     //white the rest
      }
      copy++;
    }
    dest->put_line (xdest, ydest + yoffset, xext, &copyline, 0);
  }
}

Variable Documentation

const uinT8 grey_scales[FIXED_COLOURS]

Initial value:

= {
  0, 255, 76, 227, 151, 179, 28, 104,
  149, 72, 215, 67, 53, 44, 156, 137,
  110, 153, 79, 181, 166, 218, 55, 81,
  129, 105, 179, 149, 168, 69, 84, 126
}

Definition at line 52 of file imgs.cpp.

EXTERN int image_default_resolution = 300

"Image resolution dpi"

Definition at line 64 of file imgs.cpp.