/* GIMP - The GNU Image Manipulation Program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * gimpoverlayframe.c
 * Copyright (C) 2010  Michael Natterer <mitch@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 <gtk/gtk.h>

#include "widgets-types.h"

#include "gimpoverlayframe.h"


static gboolean   gimp_overlay_frame_expose (GtkWidget      *widget,
                                             GdkEventExpose *eevent);


G_DEFINE_TYPE (GimpOverlayFrame, gimp_overlay_frame, GTK_TYPE_BIN)

#define parent_class gimp_overlay_frame_parent_class


static void
gimp_overlay_frame_class_init (GimpOverlayFrameClass *klass)
{
  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);

  widget_class->expose_event = gimp_overlay_frame_expose;
}

static void
gimp_overlay_frame_init (GimpOverlayFrame *frame)
{
  GtkWidget   *widget = GTK_WIDGET (frame);

#if 0 /* crashes badly beause gtk+ doesn't support offscreen windows
       * with colormap != parent_colormap yet
       */
  GdkScreen   *screen = gtk_widget_get_screen (widget);
  GdkColormap *rgba   = gdk_screen_get_rgba_colormap (screen);

  if (rgba)
    gtk_widget_set_colormap (widget, rgba);
#endif

  gtk_widget_set_app_paintable (widget, TRUE);
}

static gboolean
gimp_overlay_frame_expose (GtkWidget      *widget,
                           GdkEventExpose *eevent)
{
  cairo_t       *cr = gdk_cairo_create (gtk_widget_get_window (widget));
  GtkStyle      *style;
  GtkAllocation  allocation;
  gint           border_width;
  gint           inner_width;
  gint           inner_height;

  style = gtk_widget_get_style (widget);
  gtk_widget_get_allocation (widget, &allocation);

  border_width = gtk_container_get_border_width (GTK_CONTAINER (widget));

  inner_width  = allocation.width  - border_width / 2;
  inner_height = allocation.height - border_width / 2;

  cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
  gdk_cairo_region (cr, eevent->region);
  cairo_clip_preserve (cr);
  cairo_fill (cr);

  cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
  gdk_cairo_set_source_color (cr, &style->bg[GTK_STATE_NORMAL]);

#define TO_RAD(deg) (deg * (G_PI / 180.0))

  cairo_arc (cr,
             border_width,
             border_width,
             border_width,
             TO_RAD (180),
             TO_RAD (270));
  cairo_line_to (cr,
                 allocation.width - border_width,
                 0);

  cairo_arc (cr,
             allocation.width - border_width,
             border_width,
             border_width,
             TO_RAD (270),
             TO_RAD (0));
  cairo_line_to (cr,
                 allocation.width,
                 allocation.height - border_width);

  cairo_arc (cr,
             allocation.width  - border_width,
             allocation.height - border_width,
             border_width,
             TO_RAD (0),
             TO_RAD (90));
  cairo_line_to (cr,
                 border_width,
                 allocation.height);

  cairo_arc (cr,
             border_width,
             allocation.height - border_width,
             border_width,
             TO_RAD (90),
             TO_RAD (180));
  cairo_close_path (cr);

  cairo_fill (cr);

  cairo_destroy (cr);

  return GTK_WIDGET_CLASS (parent_class)->expose_event (widget, eevent);
}

GtkWidget *
gimp_overlay_frame_new (void)
{
  return g_object_new (GIMP_TYPE_OVERLAY_FRAME, NULL);
}