/* $Id: overscan.c,v 1.3 2002/01/11 16:22:57 fors Exp $
 * ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * COPYRIGHT (c) 2001 European Southern Observatory
 * LICENSE: GNU General Public License version 2 or later
 *
 * PROJECT:   VLT Data Flow System
 * AUTHOR:    Ralf Palsa -- ESO/DMD/DPG
 * SUBSYSTEM: Instrument pipelines
 *
 * PURPOSE:
 * DESCRIPTION:
 *
 * $Name: fsmosaic-1_0 $
 * $Revision: 1.3 $
 * ----------------------------------------------------------------------------
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "overscan.h"
#include "qfits_ext.h"


/**
 * @memo
 *   Remove prescan areas from an image.
 *
 * @return The function returns #EXIT_SUCCESS# if the prescan areas were
 *   properly removed, otherwise the return value is #EXIT_FAILURE#.
 *
 * @param header  FITS header corresponding to the image.
 * @param image   Image from which the prescan areas should be removed.
 * @param flag    Selector of prescan area to be removed.
 *
 * @doc
 *   The function gets the configuration of the prescan area from the
 *   image header \textbf{header} and removes the correspondig pixels
 *   from the image \textbf{image}, therby modifying the input image.
 *   The switch \textbf{flag} controls if the prescan area along the X,
 *   Y or both axes.
 *
 *   If the image does not contain any prescan areas, i.e. the FITS keyword
 *   characterizing the size of the prescan area are zero the function does
 *   nothing.
 *
 *   After removing the prescan areas the FITS keywords describing the
 *   size of the prescan areas are set to zero.
 *
 * @author R. Palsa
 */

int trim_prescan(qfits_header *header, image_t *image, unsigned int flag)
{

  char card[FITS_CARD_SIZE + 1];

  register int i;
  int npixel;
  
  size_t size, offset;

  double crpix;


  assert(header != 0);
  assert(image != 0);
  assert(flag <= 2);


  /*
   * Remove prescan along x-axis
   */

  if (flag != 1) {
    if ((npixel = qfits_header_getint(header, PRESCAN_X, -1)) > 0) {

      unsigned char *start;
      size_t step;

      if ((crpix = qfits_header_getdouble(header, "CRPIX1", -1)) < 0)
	return EXIT_FAILURE;

      image->hsize -= npixel;
      size = image->hsize * sizeof(pixel_t);

      start = (unsigned char *)image->data;
      step = npixel * sizeof(pixel_t);

      offset = step;

      for (i = 0; i < image->vsize; i++) {
	memmove(start, start + offset, size);
	start += size;
	offset += step;
      }

      if (!(image->data = realloc(image->data, size * image->vsize)))
	return EXIT_FAILURE;


      /*
       * Update the FITS header
       */

      sprintf(card, "%d", image->hsize);
      fits_header_set_value(header, "NAXIS1", card);
  
      sprintf(card, "%.1f", crpix - npixel);
      fits_header_set_value(header, "CRPIX1", card);

      fits_header_set_value(header, PRESCAN_X, "0");
    }      
  }


  /*
   * Remove prescan along y-axis
   */

  if (flag >= 1) {
    if ((npixel = qfits_header_getint(header, PRESCAN_Y, -1)) > 0) {

      if ((crpix = qfits_header_getdouble(header, "CRPIX2", -1)) < 0)
	return EXIT_FAILURE;

      image->vsize -= npixel;
      size = image->vsize * image->hsize * sizeof(pixel_t);
      offset = npixel * image->hsize;

      memmove(image->data, image->data + offset, size);

      if (!(image->data = realloc(image->data, size)))
	return EXIT_FAILURE;


      /*
       * Update the FITS header
       */

      sprintf(card, "%d", image->vsize);
      fits_header_set_value(header, "NAXIS2", card);
  
      sprintf(card, "%.1f", crpix - npixel);
      fits_header_set_value(header, "CRPIX2", card);

      fits_header_set_value(header, PRESCAN_Y, "0");
    }
  }
      
  return EXIT_SUCCESS;

}


/**
 * @memo
 *   Remove overscan areas from an image.
 *
 * @return The function returns #EXIT_SUCCESS# if the overscan areas were
 *   properly removed, otherwise the return value is #EXIT_FAILURE#.
 *
 * @param header  FITS header corresponding to the image.
 * @param image   Image from which the overscan areas should be removed.
 * @param flag    Selector of overscan area to be removed.
 *
 * @doc
 *   The function gets the configuration of the overscan area from the
 *   image header \textbf{header} and removes the correspondig pixels
 *   from the image \textbf{image}, therby modifying the input image.
 *   The switch \textbf{flag} controls if the overscan area along the X,
 *   Y or both axes.
 *
 *   If the image does not contain any overscan areas, i.e. the FITS keyword
 *   characterizing the size of the overscan area are zero the function does
 *   nothing.
 *
 *   After removing the overscan areas the FITS keywords describing the
 *   size of the overscan areas are set to zero.
 *
 * @author R. Palsa
 */

int trim_overscan(qfits_header *header, image_t *image, unsigned int flag)
{

  char card[FITS_CARD_SIZE + 1];

  register int i;
  int npixel;
  
  size_t size, offset;


  assert(header != 0);
  assert(image != 0);
  assert(flag <= 2);


  /*
   * Remove overscan along x-axis
   */

  if (flag != 1) {
    if ((npixel = qfits_header_getint(header, OVERSCAN_X, -1)) > 0) {

      unsigned char *start;
      size_t step;

      image->hsize -= npixel;
      size = image->hsize * sizeof(pixel_t);

      start = (unsigned char *)image->data + size;
      step = npixel * sizeof(pixel_t);

      offset = step;

      for (i = 0; i < image->vsize - 1; i++) {
	memmove(start, start + offset, size);
	start += size;
	offset += step;
      }

      if (!(image->data = realloc(image->data, size * image->vsize)))
	return EXIT_FAILURE;


      /*
       * Update the FITS header
       */

      sprintf(card, "%d", image->hsize);
      fits_header_set_value(header, "NAXIS1", card);
  
      fits_header_set_value(header, OVERSCAN_X, "0");
    }      
  }


  /*
   * Remove overscan along y-axis
   */

  if (flag >= 1) {
    if ((npixel = qfits_header_getint(header, OVERSCAN_Y, -1)) > 0) {

      image->vsize -= npixel;
      size = image->vsize * image->hsize * sizeof(pixel_t);

      if (!(image->data = realloc(image->data, size)))
	return EXIT_FAILURE;


      /*
       * Update the FITS header
       */

      sprintf(card, "%d", image->vsize);
      fits_header_set_value(header, "NAXIS2", card);
  
      fits_header_set_value(header, OVERSCAN_Y, "0");
    }
  }
      
  return EXIT_SUCCESS;

}