/* GIMP - The GNU Image Manipulation Program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * gimpcanvaspassepartout.c
 * Copyright (C) 2010 Sven Neumann <sven@gimp.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <gegl.h>
#include <gtk/gtk.h>

#include "display-types.h"

#include "gimpcanvas-style.h"
#include "gimpcanvaspassepartout.h"
#include "gimpdisplayshell.h"
#include "gimpdisplayshell-scale.h"


enum
{
  PROP_0,
  PROP_OPACITY,
};


typedef struct _GimpCanvasPassePartoutPrivate GimpCanvasPassePartoutPrivate;

struct _GimpCanvasPassePartoutPrivate
{
  gdouble opacity;
};

#define GET_PRIVATE(item) \
        G_TYPE_INSTANCE_GET_PRIVATE (item, \
                                     GIMP_TYPE_CANVAS_PASSE_PARTOUT, \
                                     GimpCanvasPassePartoutPrivate)


/*  local function prototypes  */

static void             gimp_canvas_passe_partout_set_property (GObject        *object,
                                                                guint           property_id,
                                                                const GValue   *value,
                                                                GParamSpec     *pspec);
static void             gimp_canvas_passe_partout_get_property (GObject        *object,
                                                                guint           property_id,
                                                                GValue         *value,
                                                                GParamSpec     *pspec);
static void             gimp_canvas_passe_partout_draw         (GimpCanvasItem *item,
                                                                cairo_t        *cr);
static cairo_region_t * gimp_canvas_passe_partout_get_extents  (GimpCanvasItem *item);
static void             gimp_canvas_passe_partout_fill         (GimpCanvasItem *item,
                                                                cairo_t        *cr);


G_DEFINE_TYPE (GimpCanvasPassePartout, gimp_canvas_passe_partout,
               GIMP_TYPE_CANVAS_RECTANGLE)

#define parent_class gimp_canvas_passe_partout_parent_class


static void
gimp_canvas_passe_partout_class_init (GimpCanvasPassePartoutClass *klass)
{
  GObjectClass        *object_class = G_OBJECT_CLASS (klass);
  GimpCanvasItemClass *item_class   = GIMP_CANVAS_ITEM_CLASS (klass);

  object_class->set_property = gimp_canvas_passe_partout_set_property;
  object_class->get_property = gimp_canvas_passe_partout_get_property;

  item_class->draw           = gimp_canvas_passe_partout_draw;
  item_class->get_extents    = gimp_canvas_passe_partout_get_extents;
  item_class->fill           = gimp_canvas_passe_partout_fill;

  g_object_class_install_property (object_class, PROP_OPACITY,
                                   g_param_spec_double ("opacity", NULL, NULL,
                                                        0.0,
                                                        1.0, 0.5,
                                                        GIMP_PARAM_READWRITE));

  g_type_class_add_private (klass, sizeof (GimpCanvasPassePartoutPrivate));
}

static void
gimp_canvas_passe_partout_init (GimpCanvasPassePartout *passe_partout)
{
}

static void
gimp_canvas_passe_partout_set_property (GObject      *object,
                                        guint         property_id,
                                        const GValue *value,
                                        GParamSpec   *pspec)
{
  GimpCanvasPassePartoutPrivate *priv = GET_PRIVATE (object);

  switch (property_id)
    {
    case PROP_OPACITY:
      priv->opacity = g_value_get_double (value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
    }
}

static void
gimp_canvas_passe_partout_get_property (GObject    *object,
                                        guint       property_id,
                                        GValue     *value,
                                        GParamSpec *pspec)
{
  GimpCanvasPassePartoutPrivate *priv = GET_PRIVATE (object);

  switch (property_id)
    {
    case PROP_OPACITY:
      g_value_set_double (value, priv->opacity);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
    }
}

static void
gimp_canvas_passe_partout_draw (GimpCanvasItem *item,
                                cairo_t        *cr)
{
  GimpDisplayShell *shell = gimp_canvas_item_get_shell (item);
  gint              w, h;

  gimp_display_shell_scale_get_image_size (shell, &w, &h);
  cairo_rectangle (cr, - shell->offset_x, - shell->offset_y, w, h);

  GIMP_CANVAS_ITEM_CLASS (parent_class)->draw (item, cr);
}

static cairo_region_t *
gimp_canvas_passe_partout_get_extents (GimpCanvasItem *item)
{
  GimpDisplayShell      *shell = gimp_canvas_item_get_shell (item);
  cairo_rectangle_int_t  rectangle;
  cairo_region_t        *inner;
  cairo_region_t        *outer;

  rectangle.x = - shell->offset_x;
  rectangle.y = - shell->offset_y;
  gimp_display_shell_scale_get_image_size (shell,
                                           &rectangle.width,
                                           &rectangle.height);

  outer = cairo_region_create_rectangle (&rectangle);

  inner = GIMP_CANVAS_ITEM_CLASS (parent_class)->get_extents (item);

  cairo_region_xor (outer, inner);

  return outer;
}

static void
gimp_canvas_passe_partout_fill (GimpCanvasItem *item,
                                cairo_t        *cr)
{
  GimpCanvasPassePartoutPrivate *priv = GET_PRIVATE (item);

  cairo_set_fill_rule (cr, CAIRO_FILL_RULE_EVEN_ODD);
  cairo_clip (cr);

  gimp_canvas_set_passe_partout_style (gimp_canvas_item_get_canvas (item), cr);
  cairo_paint_with_alpha (cr, priv->opacity);
}

GimpCanvasItem *
gimp_canvas_passe_partout_new (GimpDisplayShell *shell,
                               gdouble           x,
                               gdouble           y,
                               gdouble           width,
                               gdouble           height)
{
  g_return_val_if_fail (GIMP_IS_DISPLAY_SHELL (shell), NULL);

  return g_object_new (GIMP_TYPE_CANVAS_PASSE_PARTOUT,
                       "shell", shell,
                       "x",      x,
                       "y",      y,
                       "width",  width,
                       "height", height,
                       "filled", TRUE,
                       NULL);
}
