/* $Id: image.c,v 1.2 2001/10/26 13:29:49 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: 1.2 $
 * ----------------------------------------------------------------------------
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

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

#include "image.h"


inline void image_del(image_t *);


/**
 * @memo
 *   Allocate a new image object.
 *
 * @return The function returns a pointer to the created image object if no
 *   error occurs, otherwise a #NULL# pointer is returned.
 *
 * @param hsize  Horizontal image size in pixels.
 * @param vsize  Vertical image size in pixels.
 *
 * @doc
 *   The function creates an image object with the pixel buffer large enough
 *   to store an image having a horizontal size of \textbf{hsize} and a
 *   vertical size of \textbf{vsize} pixels. The pixel buffer is initialized
 *   with 0.
 *
 * @author R. Palsa
 */

inline image_t *image_new(int hsize, int vsize)
{

  size_t sz;
  image_t *image = 0;


  if (hsize < 1 || hsize > IMAGE_HSIZE_MAX ||
      vsize < 1 || vsize > IMAGE_VSIZE_MAX)
    return 0;

  if ((image = (image_t *)malloc(sizeof(image_t)))) {
    image->hsize = hsize;
    image->vsize = vsize;

    sz = image->hsize * image->vsize;

    if (!(image->data = (pixel_t *)malloc(sz * sizeof(pixel_t)))) {
      image_del(image);
      return 0;
    }

    memset(image->data, 0, sz * sizeof(pixel_t));
  }

  return image;

}


/**
 * @memo
 *   Destroy an image object.
 *
 * @return Nothing.
 *
 * @param image  Image object.
 *
 * @doc
 *   The function deallocates the image object \textbf{image}. If a pixel
 *   buffer is present, i.e. the pointer to the pixel data is not #NULL#
 *   the pixel buffer is deallocated before the image object is destroyed.
 *
 *   If \textbf{image} is a #NULL# pointer, no operation is performed.
 *
 * @author R. Palsa
 */

inline void image_del(image_t *image)
{

  if (!image)
    return;

  if (image->data) {
    free(image->data);
    image->data = 0;
  }

  free(image);
  return;

}


/**
 * @memo
 *   Insert an image into another.
 *
 * @return The function returns #EXIT_SUCCESS# if no error occurred, otherwise
 *   the return value is #EXIT_FAILURE#.
 *
 * @param target  Target image object.
 * @param source  Source image object.
 * @param xstart  Start position along the x axis.
 * @param ystart  Start position along the y axis.
 *
 * @doc
 *   The function replaces the pixels of the target image \textbf{target}
 *   with the pixel data from the source image \textbf{source}. The
 *   source image is inserted at the pixel position specified by
 *   \textbf{xstart} and \textbf{ystart}.
 *
 *   The source image must completely fit into the target image when it is
 *   inserted at the given position.
 *
 * @author R. Palsa
 */

inline int image_insert(image_t *target, image_t *source, int xstart,
			int ystart)
{

    register int i, j, k;


    /*
     * Check if the source fits into the target image.
     */

    if (xstart + source->hsize - 1 > target->hsize ||
	ystart + source->vsize - 1 > target->vsize)
      return EXIT_FAILURE;
    

    /*
     * Copy the pixel data
     */

    for (i = 0; i < source->vsize; i++) {
	k = (i + ystart) * target->hsize;

	for (j = 0; j < source->hsize; j++)
	    target->data[k + j + xstart] = source->data[i * source->hsize + j];
    }

    return EXIT_SUCCESS;

}