/*# proc: erode_charimage - set true pixel to zero if any of 4 neighbors is zero# proc:                   in a character image.# proc: dilate_charimage - set false pixel to one if any of 4 neighbors is one# proc:                    in a character image.# proc: get_south8 - return value of char image pixel 1 below of current pixel# proc:              if defined else return (char)0# proc: get_north8 - return value of char image pixel 1 above of current pixel# proc:              if defined else return (char)0# proc: get_east8  - return value of char image pixel 1 right of current pixel# proc:              if defined else return (char)0# proc: get_west8  - return value of char image pixel 1 left  of current pixel# proc:              if defined else return (char)0*/#include <memory.h>/******************************************************************//* erode a one bit per byte char image, inp. Result is out which  *//* must be disjoint with inp. The data in out before the call is  *//* irrelevant, and is zeroed and filled by this routine. iw and   *//* ih are the width and height of the image in pixels. Both inp   *//* and out point to iw*ih bytes                                   *//******************************************************************/ erode_charimage(inp, out, iw, ih)unsigned char *inp, *out; int iw, ih;{int row, col;unsigned char *itr = inp, *otr = out;    memcpy(out, inp, iw*ih);    /* for true pixels. kill pixel if there is at least one false neighbor */   for ( row = 0 ; row < ih ; row++ )      for ( col = 0 ; col < iw ; col++ )      {           if (*itr)      /* erode only operates on true pixels */         {            /* more efficient with C's left to right evaluation of     */            /* conjuctions. E N S functions not executed if W is false */            if (!(get_west8 (itr, col        ) &&                  get_east8 (itr, col, iw    ) &&                  get_north8(itr, row, iw    ) &&                  get_south8(itr, row, iw, ih)))               *otr = 0;         }         itr++ ; otr++;      }  }/******************************************************************//* dilate a one bit per byte char image, inp. Result is out which  *//* must be disjoint with inp. The data in out before the call is  *//* irrelevant, and is zeroed and filled by this routine. iw and   *//* ih are the width and height of the image in pixels. Both inp   *//* and out point to iw*ih bytes                                   *//******************************************************************/ dilate_charimage(inp, out, iw, ih)unsigned char *inp, *out; int iw, ih;{int row, col;unsigned char *itr = inp, *otr = out;    memcpy(out, inp, iw*ih);    /* for all pixels. set pixel if there is at least one true neighbor */   for ( row = 0 ; row < ih ; row++ )      for ( col = 0 ; col < iw ; col++ )      {           if (!*itr)     /* pixel is already true, neighbors irrelevant */         {            /* more efficient with C's left to right evaluation of     */            /* conjuctions. E N S functions not executed if W is false */            if (get_west8 (itr, col        ) ||                get_east8 (itr, col, iw    ) ||                get_north8(itr, row, iw    ) ||                get_south8(itr, row, iw, ih))               *otr = 1;         }         itr++ ; otr++;      }  }/************************************************************************//* routines for accessing individual neighbors of pixel at (row,col) 	*//* row and pixel are zero oriented. That is 0 <= row < ih and           *//* 0 <= col < iw. ptr points to the (row,col) element of the ih by iw 	*//* sized char image which contains as many >bytes< as there are pixels  *//* in the image. 							*//************************************************************************/get_south8(ptr, row, iw, ih)unsigned char *ptr; int row, iw, ih;{   if (row >= ih-1) /* catch case where image is undefined southwards   */      return 0;     /* use plane geometry and return false.             */      return *(ptr+iw);}get_north8(ptr, row, iw)unsigned char *ptr; int row, iw;{   if (row < 1)     /* catch case where image is undefined northwards   */      return 0;     /* use plane geometry and return false.             */      return *(ptr-iw);}get_east8(ptr, col, iw)unsigned char *ptr; int col, iw;{   if (col >= iw-1) /* catch case where image is undefined eastwards    */      return 0;     /* use plane geometry and return false.             */      return *(ptr+ 1);}get_west8(ptr, col)unsigned char *ptr; int col;{   if (col < 1)     /* catch case where image is undefined westwards     */      return 0;     /* use plane geometry and return false.              */      return *(ptr- 1);}