/* Fold up x into bands.

 *

 * 5/6/15

 *  - from copy.c

 * 10/6/15

 *  - add @factor option

 */

/*

  This file is part of VIPS.

  VIPS is free software; you can redistribute it and/or modify

  it under the terms of the GNU Lesser General Public License as published by

  the Free Software Foundation; either version 2 of the License, or

  (at your option) any later version.

  This program is distributed in the hope that it will be useful,

  but WITHOUT ANY WARRANTY; without even the implied warranty of

  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License

  along with this program; if not, write to the Free Software

  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

  02110-1301  USA

 */

/*

  These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */

/*

#define VIPS_DEBUG

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif /*HAVE_CONFIG_H*/

#include <glib/gi18n-lib.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <math.h>

#include <vips/vips.h>

#include <vips/internal.h>

#include <vips/debug.h>

#include "pconversion.h"

typedef struct _VipsBandfold {

  VipsConversion parent_instance;

  /* The input image.

   */

  VipsImage *in;

  int factor;

} VipsBandfold;

typedef VipsConversionClass VipsBandfoldClass;

G_DEFINE_TYPE(VipsBandfold, vips_bandfold, VIPS_TYPE_CONVERSION);

static int

vips_bandfold_gen(VipsRegion *out_region,

  void *seq, void *a, void *b, gboolean *stop)

{

  VipsBandfold *bandfold = (VipsBandfold *) b;

  VipsRegion *ir = (VipsRegion *) seq;

  VipsImage *out = out_region->im;

  VipsRect *r = &out_region->valid;

  int psize = VIPS_IMAGE_SIZEOF_PEL(out);

  VipsRect need;

  int y;

  need.left = r->left * bandfold->factor;

  need.top = r->top;

  need.width = r->width * bandfold->factor;

  need.height = r->height;

  if (vips_region_prepare(ir, &need))

    return -1;

  for (y = 0; y < r->height; y++) {

    VipsPel *p = VIPS_REGION_ADDR(ir,

      r->left * bandfold->factor, r->top + y);

    VipsPel *q = VIPS_REGION_ADDR(out_region, r->left, r->top + y);

    /* We can't use vips_region_region() since we change pixel

     * coordinates.

     */

    memcpy(q, p, psize * r->width);

  }

  return 0;

}

static int

vips_bandfold_build(VipsObject *object)

{

  VipsObjectClass *class = VIPS_OBJECT_GET_CLASS(object);

  VipsConversion *conversion = VIPS_CONVERSION(object);

  VipsBandfold *bandfold = (VipsBandfold *) object;

  if (VIPS_OBJECT_CLASS(vips_bandfold_parent_class)->build(object))

    return -1;

  if (vips_image_pio_input(bandfold->in))

    return -1;

  if (bandfold->factor == 0)

    bandfold->factor = bandfold->in->Xsize; // FIXME: Invalidates operation cache

  if (bandfold->in->Xsize % bandfold->factor != 0) {

    vips_error(class->nickname,

      "%s", _("@factor must be a factor of image width"));

    return -1;

  }

  if (vips_image_pipelinev(conversion->out,

      VIPS_DEMAND_STYLE_THINSTRIP, bandfold->in, NULL))

    return -1;

  conversion->out->Xsize /= bandfold->factor;

  conversion->out->Bands *= bandfold->factor;

  if (vips_image_generate(conversion->out,

      vips_start_one, vips_bandfold_gen, vips_stop_one,

      bandfold->in, bandfold))

    return -1;

  return 0;

}

static void

vips_bandfold_class_init(VipsBandfoldClass *class)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS(class);

  VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS(class);

  VipsOperationClass *operation_class = VIPS_OPERATION_CLASS(class);

  VIPS_DEBUG_MSG("vips_bandfold_class_init\n");

  gobject_class->set_property = vips_object_set_property;

  gobject_class->get_property = vips_object_get_property;

  vobject_class->nickname = "bandfold";

  vobject_class->description = _("fold up x axis into bands");

  vobject_class->build = vips_bandfold_build;

  operation_class->flags = VIPS_OPERATION_SEQUENTIAL;

  VIPS_ARG_IMAGE(class, "in", 1,

    _("Input"),

    _("Input image"),

    VIPS_ARGUMENT_REQUIRED_INPUT,

    G_STRUCT_OFFSET(VipsBandfold, in));

  VIPS_ARG_INT(class, "factor", 11,

    _("Factor"),

    _("Fold by this factor"),

    VIPS_ARGUMENT_OPTIONAL_INPUT,

    G_STRUCT_OFFSET(VipsBandfold, factor),

    0, 10000000, 0);

}

static void

vips_bandfold_init(VipsBandfold *bandfold)

{

  /* 0 means fold by width, see above.

   */

  bandfold->factor = 0;

}

/**

 * vips_bandfold: (method)

 * @in: input image

 * @out: (out): output image

 * @...: %NULL-terminated list of optional named arguments

 *

 * Optional arguments:

 *

 * * @factor: fold by this factor

 *

 * Fold up an image horizontally: width is collapsed into bands.

 * Use @factor to set how much to fold by: @factor 3, for example, will make

 * the output image three times narrower than the input, and with three times

 * as many bands. By default the whole of the input width is folded up.

 *

 * See also: vips_csvload(), vips_bandunfold().

 *

 * Returns: 0 on success, -1 on error.

 */

int

vips_bandfold(VipsImage *in, VipsImage **out, ...)

{

  va_list ap;

  int result;

  va_start(ap, out);

  result = vips_call_split("bandfold", ap, in, out);

  va_end(ap);

  return result;

}