rotate.c

This is code tutorial for image processing include:histogram,sketon....

    /***********************************************
    *
    *       file d:\cips\rotate.c
    *
    *       Functions: This file contains
    *          rotate_flip_image_array
    *
    *       Purpose:
    *          This function rotates or flips an image
    *          array in one of five ways.
    *
    *       External Calls:
    *          wtiff.c - round_off_image_size
    *                    create_file_if_needed
    *                    write_array_into_tiff_image
    *          tiff.c - read_tiff_header
    *          rtiff.c - read_tiff_image
    *
    *
    *       Modifications:
    *          1 April 1992 - created
    *
    *************************************************/

#include "cips.h"

     /*******************************************
     *
     *   rotate_flip_image_array(...
     *
     *   This function rotates an image array
     *   in one of three ways or flips an image
     *   array either vertically or horizontally.
     *   The rotation_type parameter specifies
     *   the operation.  When rotation_type is
     *   1, 2, or 3 you rotate.  When it is
     *   4 or 5 you flip.
     *
     *   I define rotation as this:  Pin down the
     *   lower left hand corner of the image array
     *   and rotate the image 90 degrees clockwise.
     *   1 rotation is 90 degrees, 2 rotations are
     *   180 degrees, and 3 rotations are 270 degrees.
     *   4 rotations bring you back to where you
     *   started.
     *
     *   The cases are:
     *
     *   If the input image array is:
     *        1 2 3
     *        4 5 6
     *        7 8 9
     *
     *   Rotate # 1 - the result is:
     *        7 4 1
     *        8 5 2
     *        9 6 3
     *
     *   Rotate # 2 - the result is:
     *        9 8 7
     *        6 5 4
     *        3 2 1
     *
     *   Rotate # 3 - the result is:
     *        3 6 9
     *        2 5 8
     *        1 4 7
     *
     *   Flip # 4 - horizontal the result is:
     *        3 2 1
     *        6 5 4
     *        9 8 7
     *
     *   Flip # 5 - vertical the result is:
     *        7 8 9
     *        4 5 6
     *        1 2 3
     *
     *
     *   The in_file is the source image with
     *   parameters given by il1, ie1, ll1, le1.
     *
     *   The out_file is the destination image with
     *   parameters given by il2, ie2, ll2, le2.
     *
     *******************************************/


rotate_flip_image_array(in_name, out_name, the_image,
                   out_image, il1, ie1, ll1, le1,
                   il2, ie2, ll2, le2, rotation_type)
   char  in_name[], out_name[];
   int   il1, ie1, ll1, le1,
         il2, ie2, ll2, le2, rotation_type;
   short the_image[ROWS][COLS],
         out_image[ROWS][COLS];
{
   int    cd2, i, j, length, rd2, type, width;
   struct tiff_header_struct image_header;

   create_file_if_needed(in_name, out_name, out_image);

     /*******************************************
     *
     *   Check the rotation_type.  If it is not
     *   a valid value, set it to 1.
     *
     *******************************************/

   type = rotation_type;
   if(type != 1  &&
      type != 2  &&
      type != 3  &&
      type != 4  &&
      type != 5) type = 1;

   read_tiff_image(in_name, the_image, 
                   il1, ie1, ll1, le1);

     /*******************************************
     *
     *   Rotate the image array as desired.
     *
     *******************************************/

     /*******************************************
     *
     *   1 90 degree rotation
     *
     *******************************************/

   if(type == 1  ||  type == 2  ||  type == 3){
      for(i=0; i<ROWS; i++){
         for(j=0; j<COLS; j++)
            out_image[j][COLS-1-i] = the_image[i][j];
      }  /* ends loop over i */
   }  /* ends if type == 1 or 2 or 3 */


     /*******************************************
     *
     *   a second 90 degree rotation
     *
     *******************************************/

   if(type == 2  ||  type == 3){
      for(i=0; i<ROWS; i++)
         for(j=0; j<COLS; j++)
            the_image[i][j] = out_image[i][j];
      for(i=0; i<ROWS; i++){
         for(j=0; j<COLS; j++)
            out_image[j][COLS-1-i] = the_image[i][j];
      }  /* ends loop over i */
   }  /* ends if type == 2 or 3 */


     /*******************************************
     *
     *   a third 90 degree rotation
     *
     *******************************************/

   if(type == 3){
      for(i=0; i<ROWS; i++)
         for(j=0; j<COLS; j++)
            the_image[i][j] = out_image[i][j];
      for(i=0; i<ROWS; i++){
         for(j=0; j<COLS; j++)
            out_image[j][COLS-1-i] = the_image[i][j];
      }  /* ends loop over i */
   }  /* ends if type == 3 */


     /*******************************************
     *
     *   Flip the image array horizontally
     *   about the center vertical axis.
     *
     *******************************************/

   if(type == 4){
      cd2 = COLS/2;
      for(j=0; j<cd2; j++){
         for(i=0; i<ROWS; i++){
            out_image[i][COLS-1-j] = the_image[i][j];
         }  /* ends loop over i */
      }  /* ends loop over j */

      for(j=cd2; j<COLS; j++){
         for(i=0; i<ROWS; i++){
            out_image[i][COLS-1-j] = the_image[i][j];
         }  /* ends loop over i */
      }  /* ends loop over j */
   }  /* ends if type == 4 */


     /*******************************************
     *
     *   Flip the image array vertically
     *   about the center horizontal axis.
     *
     *******************************************/

   if(type == 5){
      rd2 = ROWS/2;
      for(i=0; i<rd2; i++){
         for(j=0; j<COLS; j++){
            out_image[ROWS-1-i][j] = the_image[i][j];
         }  /* ends loop over j */
      }  /* ends loop over i */

      for(i=rd2; i<ROWS; i++){
         for(j=0; j<COLS; j++){
            out_image[ROWS-1-i][j] = the_image[i][j];
         }  /* ends loop over j */
      }  /* ends loop over i */
   }  /* ends if type == 5 */

   write_array_into_tiff_image(out_name, out_image,
                               il2, ie2, ll2, le2);

}  /* ends rotate_flip_image_array */