/*# proc: drawline8 - draws a line between two points in an 8-bit# proc:             grayscale image.# proc: drawline8_xor - draws a line using logical XOR onto an 8-bit per pixel# proc:                 binary image by interpolating between given endpoints.# proc:                 really flips the image pixels equal to XOR with 1.# proc: valid_point - determines if a point lies with the specified# proc:               dimensions.# proc: drawvertline8 - draws a vertically straight line in a binary char image.# proc:# proc: tstndrawvertline8 - draws a vertically straight line in a binary char# proc:              image and prempts itself is destination pixel already set# proc:              to non-zero.*/#include <stddef.h>#include <defs.h>/*************************************************************************/drawline8(image, width, height, x0, y0, x1, y1, barpix)unsigned char *image;int width, height, barpix, x0, y0, x1, y1;{  int num = 0, nbres = 0, *xlist, *ylist;  if (!valid_point(x0, y0, width, height))     fatalerr("drawline","Point x0, y0","Invalid");   if (!valid_point(x1, y1, width, height))     fatalerr("drawline","Point x1, y1","Invalid");   bres_line_alloc(x0, y0, x1, y1, &xlist, &ylist, &num, &nbres);  while (num--)     *(image + ylist[num]*width + xlist[num]) = barpix;  free(xlist); free(ylist);}	/*************************************************************************/drawline8_xor(image, width, height, depth, x0, y0, x1, y1)unsigned char *image;int width, height, depth, x0, y0, x1, y1;{  int num = 0, nbres = 0, *xlist, *ylist;  unsigned char *iptr;  if (!valid_point(x0, y0, width, height))     fatalerr("drawline","Point x0, y0","Invalid");   if (!valid_point(x1, y1, width, height))     fatalerr("drawline","Point x1, y1","Invalid");   bres_line_alloc(x0, y0, x1, y1, &xlist, &ylist, &num, &nbres);  while (num--)     iptr = image + ylist[num]*width + xlist[num],  *iptr = !*iptr;  free(xlist); free(ylist);}/*************************************************************************/int valid_point(x, y, w, h)int x, y, w, h;{  if (w < 1)  fatalerr("valid_point","w","Invalid");  if (h < 1)  fatalerr("valid_point","h","Invalid");  if (x < 0 ||  w <= x)  return(0);  if (y < 0 ||  h <= y)  return(0);  return(1);}/***************************************************************************/drawvertline8(cdata, w, h, x1, y1, x2, y2, pix)unsigned char *cdata;int w, h, x1, y1, x2, y2, pix;{   int y;   unsigned char *cptr;   cptr = cdata + (y1 * w) + x1;   for(y = y1; y <= y2; y++){      *cptr = pix;      cptr += w;   }}/***************************************************************************/tstndrawvertline8(cdata, w, h, x1, y1, x2, y2, pix)unsigned char *cdata;int w, h, x1, y1, x2, y2, pix;{   int y;   unsigned char *cptr;   cptr = cdata + (y1 * w) + x1;   for(y = y1; y <= y2; y++){      if(*cptr != 0)        return(FALSE);      *cptr = pix;      cptr += w;   }   return(TRUE);}