/* MX LIBRARY FUNCTION:  mxip_image_s_open_f7
 *
 * PURPOSE:  Open a mxip_image_s structure.
 *
 * USAGE EXAMPLE:
 *
 *   struct mxip_image_s *image=NULL;
 *   int nx = 9;   ! number of rows (width) 
 *   int ny = 13;  ! number of columns (height) 
 *   int idx0 = 0; ! true X coordinate of lower left pixel 
 *   int idy0 = 0; ! true Y coordinate of lower left pixel 
 *   int mpx = 1; ! number of subpixels per pixel 
 *   int status;
 *   
 *   status = mxip_image_s_open_f7 (&image, nx, ny, idx0, idy0, mpx, "image");
 *
 * AUTHOR:  K. J. Mighell (mighell@noao.edu)
 *
 * LANGUAGE:  ANSI C
 *
 * DOCUMENTATION:  http://www.noao.edu/staff/mighell/mx
 *
 * DATE:  20000313
 *
 * MOD: 3
 * 
 * Copyleft (L) 2000 Kenneth John Mighell
 */

#include "mx.h"

int mxip_image_s_open_f7( 
  struct mxip_image_s **out,
  int nx,
  int ny,
  int idx0,
  int idy0,
  int mpx_,
  char *comment
) {

  char mxfunc[] = "mxip_image_s_open_f7";
  int status;

  struct mxip_image_s *image=NULL;
  int npix;
  int mpx = mpx_;
  int ix0;
  int iy0;
  int ix1;
  int iy1;
  int j0;

  status = 0;

  image = (struct mxip_image_s *)malloc(sizeof(struct mxip_image_s));

  if ((struct mxip_image_s *)NULL==image) { 
    status=1;
    sprintf (MX.tmpmsg, "#   could not allocate mxip_image_s structure!\n");
    goto error;
  }

  /* 
   * Initilize structure with dummy values 
   */
  image->openedi = 0;
  image->nxi = 0;
  image->nyi = 0;
  image->npxi = 0;
  image->llx0i = 0;
  image->lly0i = 0;
  image->mpxi = 0;
  image->comment[0] = '\0';
  image->vectord = (double *)NULL;
  image->matrixd = (double **)NULL;

  /* 
   * Set the number of pixels in the X direction (X -> columns)
   */
  if (nx>0) {
    image->nxi = nx;
  } else {
    status = 2;
    sprintf (MX.tmpmsg, "#   nx=%d < minimum=1 \n", nx);
    goto error;
  }

  /* 
   * Set the number of pixels in the Y direction (Y -> rows)
   */
  if (ny>0) {
    image->nyi = ny;
  } else {
    status = 3;
    sprintf (MX.tmpmsg, "#   ny=%d < minimum=1 \n", ny);
    goto error;
  }

  /* 
   * Set the total number of pixels 
   */
  image->npxi = nx * ny;

  /* 
   * Set the offset in the X direction 
   */
  image->llx0i = idx0;

  /* 
   * Set the offset in the Y direction
   */
  image->lly0i = idy0;

  /* 
   * Set the super/sub pixel sampling 
   *    normal case: 1 -> 1x1
   *      mpx < -1 : negative value indicates subsampling 
   *      mpx > +1 : postive value indicates supersampling 
   *   special case:  0 -> 1x1 
   *   special case: -1 -> 1x1
   */
  if (0==mpx) mpx = 1;
  if (-1==mpx) mpx = 1;
  image->mpxi = mpx;

  /* 
   * Set the comment of this data set
   */
  strncpy (image->comment, comment, sizeof(image->comment));

  /*
   * Allocate the data vector
   */
  npix = image->npxi;
  image->vectord = (double *)calloc (npix, sizeof(double));
  if ((double *)NULL==image->vectord) {
    status = 4;
    sprintf (
      MX.tmpmsg, 
      "#   Could not allocate data vector with %d pixels!\n",
      npix
    );
    goto error;
  } 
  /*
   * and initialize it
   */
  for (j0=0; j0<npix; ++j0) {
    image->vectord[j0] = (double)0.0;
  }

  /*
   * Allocate the data matrix
   */
  image->matrixd = (double **)calloc (ny, sizeof(double));
  if ((double **)NULL==image->matrixd) {
    status = 5;
    sprintf (MX.tmpmsg, "#   Could not allocate data matrix!\n");
    goto error;
  }
  /*
   * and initialize it
   */
  for (iy0=0; iy0<ny; ++iy0) {
    j0 = iy0*nx;
    iy1 = iy0 + 1;
    ix0 = j0 % nx;
    ix1 = ix0 + 1;
    image->matrixd[iy0] = &image->vectord[j0];
    if (image->matrixd[iy0][ix0]!=image->vectord[j0]) {
      status = 6;
      sprintf (
        MX.tmpmsg,
        "#   image->matrixd[%d][%d] = %g !="
        "image->vectord[%d] = %g <-- F77:(%d,%d)\n",
        iy0, ix0, image->matrixd[iy0][ix0],
	j0, image->vectord[j0], ix1, iy1
      );
      goto error;
    }
  }

  image->openedi = MX_OPENED;

ok:
  status = 0;
  goto bye;

error:
  mxp_errmsg_set_f3 (mxfunc, status, MX.tmpmsg);
  goto bye;

bye:
  *out = &*image;
  return (status);

}
/* end-of-file */