/* convolve twice, rotating the mask

 *

 * 23/10/13

 *  - from vips_convsep()

 * 8/5/17

 *      - default to float ... int will often lose precision and should not be

 *        the default

 */

/*

  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

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif /*HAVE_CONFIG_H*/

#include <glib/gi18n-lib.h>

#include <stdio.h>

#include <vips/vips.h>

#include "pconvolution.h"

typedef struct {

  VipsConvolution parent_instance;

  VipsPrecision precision;

  int layers;

  int cluster;

} VipsConvsep;

typedef VipsConvolutionClass VipsConvsepClass;

G_DEFINE_TYPE(VipsConvsep, vips_convsep, VIPS_TYPE_CONVOLUTION);

static int

vips_convsep_build(VipsObject *object)

{

  VipsObjectClass *class = VIPS_OBJECT_GET_CLASS(object);

  VipsConvolution *convolution = (VipsConvolution *) object;

  VipsConvsep *convsep = (VipsConvsep *) object;

  VipsImage **t = (VipsImage **) vips_object_local_array(object, 4);

  VipsImage *in;

  g_object_set(convsep, "out", vips_image_new(), NULL);

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

    return -1;

  if (vips_check_separable(class->nickname, convolution->M))

    return -1;

  in = convolution->in;

  if (convsep->precision == VIPS_PRECISION_APPROXIMATE) {

    if (vips_convasep(in, &t[0], convolution->M,

        "layers", convsep->layers,

        NULL))

      return -1;

    in = t[0];

  }

  else {

    /* Take a copy, since we must set the offset.

     */

    if (vips_rot(convolution->M, &t[0], VIPS_ANGLE_D90, NULL) ||

      vips_copy(t[0], &t[3], NULL))

      return -1;

    vips_image_set_double(t[3], "offset", 0);

    if (vips_conv(in, &t[1], convolution->M,

        "precision", convsep->precision,

        "layers", convsep->layers,

        "cluster", convsep->cluster,

        NULL) ||

      vips_conv(t[1], &t[2], t[3],

        "precision", convsep->precision,

        "layers", convsep->layers,

        "cluster", convsep->cluster,

        NULL))

      return -1;

    in = t[2];

  }

  if (vips_image_write(in, convolution->out))

    return -1;

  return 0;

}

static void

vips_convsep_class_init(VipsConvsepClass *class)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS(class);

  VipsObjectClass *object_class = (VipsObjectClass *) class;

  gobject_class->set_property = vips_object_set_property;

  gobject_class->get_property = vips_object_get_property;

  object_class->nickname = "convsep";

  object_class->description = _("separable convolution operation");

  object_class->build = vips_convsep_build;

  VIPS_ARG_ENUM(class, "precision", 203,

    _("Precision"),

    _("Convolve with this precision"),

    VIPS_ARGUMENT_OPTIONAL_INPUT,

    G_STRUCT_OFFSET(VipsConvsep, precision),

    VIPS_TYPE_PRECISION, VIPS_PRECISION_FLOAT);

  VIPS_ARG_INT(class, "layers", 204,

    _("Layers"),

    _("Use this many layers in approximation"),

    VIPS_ARGUMENT_OPTIONAL_INPUT,

    G_STRUCT_OFFSET(VipsConvsep, layers),

    1, 1000, 5);

  VIPS_ARG_INT(class, "cluster", 205,

    _("Cluster"),

    _("Cluster lines closer than this in approximation"),

    VIPS_ARGUMENT_OPTIONAL_INPUT,

    G_STRUCT_OFFSET(VipsConvsep, cluster),

    1, 100, 1);

}

static void

vips_convsep_init(VipsConvsep *convsep)

{

  convsep->precision = VIPS_PRECISION_FLOAT;

  convsep->layers = 5;

  convsep->cluster = 1;

}

/**

 * vips_convsep: (method)

 * @in: input image

 * @out: (out): output image

 * @mask: convolution mask

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

 *

 * Perform a separable convolution of @in with @mask.

 * See [method@Image.conv] for a detailed description.

 *

 * The mask must be 1xn or nx1 elements.

 *

 * The image is convolved twice: once with @mask and then again with @mask

 * rotated by 90 degrees. This is much faster for certain types of mask

 * (gaussian blur, for example) than doing a full 2D convolution.

 *

 * ::: tip "Optional arguments"

 *     * @precision: [enum@Precision], calculation accuracy

 *     * @layers: `gint`, number of layers for approximation

 *     * @cluster: `gint`, cluster lines closer than this distance

 *

 * ::: seealso

 *     [method@Image.conv], [ctor@Image.gaussmat].

 *

 * Returns: 0 on success, -1 on error

 */

int

vips_convsep(VipsImage *in, VipsImage **out, VipsImage *mask, ...)

{

  va_list ap;

  int result;

  va_start(ap, mask);

  result = vips_call_split("convsep", ap, in, out, mask);

  va_end(ap);

  return result;

}