/*
 * Animation Playback plug-in version 0.99.1
 *
 * (c) Adam D. Moss : 1997-2000 : adam@gimp.org : adam@foxbox.org
 * (c) Mircea Purdea : 2009 : someone_else@exhalus.net
 * (c) Jehan : 2012 : jehan at girinstud.io
 *
 * PIKA - Photo and Image Kooker Application
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * 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 <https://www.gnu.org/licenses/>.
 */

/*
 * TODO:
 *  pdb interface - should we bother?
 *
 *  speedups (caching?  most bottlenecks seem to be in pixelrgns)
 *    -> do pixelrgns properly!
 */

#include "config.h"

#include <string.h>

#include <libpika/pika.h>
#undef GDK_DISABLE_DEPRECATED
#include <libpika/pikaui.h>

#include "libpika/stdplugins-intl.h"


#define PLUG_IN_PROC   "plug-in-animationplay"
#define PLUG_IN_BINARY "animation-play"
#define PLUG_IN_ROLE   "pika-animation-play"
#define DITHERTYPE     GDK_RGB_DITHER_NORMAL


typedef enum
{
  DISPOSE_COMBINE   = 0x00,
  DISPOSE_REPLACE   = 0x01
} DisposeType;

typedef struct
{
  gint        duration_index;
  DisposeType default_frame_disposal;
  guint32     default_frame_duration;
}
AnimationSettings;

/* for shaping */
typedef struct
{
  gint x, y;
} CursorOffset;

struct _PikaPlay
{
  PikaPlugIn      parent_instance;

  GtkApplication *app;

  GtkWidget      *play_button;
  GtkWidget      *step_back_button;
  GtkWidget      *step_button;
  GtkWidget      *rewind_button;

  GMenu          *menu;
};


#define PIKA_TYPE_PLAY (pika_play_get_type ())
G_DECLARE_FINAL_TYPE (PikaPlay, pika_play, PIKA, PLAY, PikaPlugIn)


GType                   play_get_type         (void) G_GNUC_CONST;

static void             pika_play_finalize    (GObject              *object);

static GList          * play_query_procedures (PikaPlugIn           *plug_in);
static PikaProcedure  * play_create_procedure (PikaPlugIn           *plug_in,
                                               const gchar          *name);

static PikaValueArray * play_run              (PikaProcedure        *procedure,
                                               PikaRunMode           run_mode,
                                               PikaImage            *image,
                                               gint                  n_drawables,
                                               PikaDrawable        **drawables,
                                               PikaProcedureConfig  *config,
                                               gpointer              run_data);

static void        initialize                (PikaPlay        *play);
static void        on_app_activate           (GApplication    *gapp,
                                              gpointer         user_data);

static GtkWidget * build_dialog              (PikaPlay        *play,
                                              gchar           *imagename);
static void        refresh_dialog            (gchar           *imagename);

static void        da_size_callback          (GtkWidget       *widget,
                                              GtkAllocation   *allocation,
                                              gpointer         data);

static void        sda_realize_callback      (GtkWidget       *widget,
                                              gpointer         data);
static void        sda_size_callback         (GtkWidget       *widget,
                                              GtkAllocation   *allocation,
                                              gpointer         data);

static void        window_destroy            (GtkWidget       *widget,
                                              PikaPlay        *play);
static void        step_back_action          (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);

static void        play_change_state         (GSimpleAction  *action,
                                              GVariant       *new_state,
                                              gpointer        user_data);
static void        detach_change_state       (GSimpleAction  *action,
                                              GVariant       *new_state,
                                              gpointer        user_data);

static void        step_action               (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        rewind_action             (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        refresh_action            (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        help_action               (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        close_action              (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        speed_up_action           (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        speed_down_action         (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        speed_reset_action        (GSimpleAction   *action,
                                              GVariant        *parameter,
                                              gpointer         user_data);
static void        framecombo_changed        (GtkWidget       *combo,
                                              gpointer         data);
static void        speedcombo_changed        (GtkWidget       *combo,
                                              gpointer         data);
static void        fpscombo_changed          (GtkWidget       *combo,
                                              gpointer         data);
static void        zoomcombo_activated       (GtkEntry        *combo,
                                              gpointer         data);
static void        zoomcombo_changed         (GtkWidget       *combo,
                                              gpointer         data);
static gboolean    repaint_sda               (GtkWidget       *darea,
                                              cairo_t         *cr,
                                              gpointer         data);
static gboolean    repaint_da                (GtkWidget       *darea,
                                              cairo_t         *cr,
                                              gpointer         data);

static void        init_frames               (PikaPlay        *play);
static void        render_frame              (gint32           whichframe);
static void        show_frame                (void);
static void        update_combobox           (void);
static gdouble     get_duration_factor       (gint             index);
static gint        get_fps                   (gint             index);
static gdouble     get_scale                 (gint             index);
static void        update_scale              (gdouble          scale);


/* tag util functions*/
static gint        parse_ms_tag              (const gchar     *str);
static DisposeType parse_disposal_tag        (const gchar     *str);
static gboolean    is_disposal_tag           (const gchar     *str,
                                              DisposeType     *disposal,
                                              gint            *taglength);
static gboolean    is_ms_tag                 (const gchar     *str,
                                              gint            *duration,
                                              gint            *taglength);

static GtkWidget * add_tool_button           (GtkWidget       *toolbar,
                                              const char      *action,
                                              const char      *icon,
                                              const char      *label,
                                              const char      *tooltip);
static void        add_tool_separator        (GtkWidget       *toolbar,
                                              gboolean         expand);


G_DEFINE_TYPE (PikaPlay, pika_play, PIKA_TYPE_PLUG_IN)

PIKA_MAIN (PIKA_TYPE_PLAY)
DEFINE_STD_SET_I18N


/* Global widgets'n'stuff */
static GtkWidget         *window                    = NULL;
static GdkWindow         *root_win                  = NULL;
static GtkWidget         *progress;
static GtkWidget         *speedcombo                = NULL;
static GtkWidget         *fpscombo                  = NULL;
static GtkWidget         *zoomcombo                 = NULL;
static GtkWidget         *frame_disposal_combo      = NULL;

static PikaImage         *image                     = NULL;
static guint              width                     = -1;
static guint              height                    = -1;
static GList             *layers                    = NULL;

static GtkWidget         *drawing_area              = NULL;
static cairo_surface_t   *drawing_area_surface      = NULL;
static guint              drawing_area_width        = -1;
static guint              drawing_area_height       = -1;

static GtkWidget         *shape_window              = NULL;
static cairo_surface_t   *shape_drawing_area_surface= NULL;
static guint              shape_drawing_area_width  = -1;
static guint              shape_drawing_area_height = -1;

static gint32             total_frames              = 0;
static PikaLayer        **frames                    = NULL;
static guint32           *frame_durations           = NULL;
static guint              frame_number              = 0;

static gboolean           playing                   = FALSE;
static guint              timer                     = 0;
static gboolean           detached                  = FALSE;
static gdouble            scale, shape_scale;

static const GActionEntry ACTIONS[] =
{
  { "play", NULL, NULL, "false", play_change_state },
  { "detach", NULL, NULL, "false", detach_change_state },

  { "step-back", step_back_action },
  { "step", step_action },
  { "rewind", rewind_action },

  { "refresh", refresh_action },

  { "help", help_action },

  { "close", close_action },
  { "quit", close_action },

  { "speed-up", speed_up_action },
  { "speed-down", speed_down_action },
  { "speed-reset", speed_reset_action },
};

/* Default settings. */
static AnimationSettings settings =
{
  3,
  DISPOSE_COMBINE,
  100 /* ms */
};

static PikaImage *frames_image = NULL;


static void
pika_play_class_init (PikaPlayClass *klass)
{
  PikaPlugInClass *plug_in_class = PIKA_PLUG_IN_CLASS (klass);
  GObjectClass    *object_class  = G_OBJECT_CLASS (klass);

  object_class->finalize          = pika_play_finalize;

  plug_in_class->query_procedures = play_query_procedures;
  plug_in_class->create_procedure = play_create_procedure;
  plug_in_class->set_i18n         = STD_SET_I18N;
}

static void
pika_play_init (PikaPlay *play)
{
}

static void
pika_play_finalize (GObject *object)
{
  PikaPlay *play = PIKA_PLAY (object);

  G_OBJECT_CLASS (pika_play_parent_class)->finalize (object);

  g_clear_object (&play->menu);
}

static GList *
play_query_procedures (PikaPlugIn *plug_in)
{
  return g_list_append (NULL, g_strdup (PLUG_IN_PROC));
}

static PikaProcedure *
play_create_procedure (PikaPlugIn  *plug_in,
                       const gchar *name)
{
  PikaProcedure *procedure = NULL;

  if (! strcmp (name, PLUG_IN_PROC))
    {
      procedure = pika_image_procedure_new (plug_in, name,
                                            PIKA_PDB_PROC_TYPE_PLUGIN,
                                            play_run, NULL, NULL);

      pika_procedure_set_image_types (procedure, "*");
      pika_procedure_set_sensitivity_mask (procedure,
                                           PIKA_PROCEDURE_SENSITIVE_DRAWABLE  |
                                           PIKA_PROCEDURE_SENSITIVE_DRAWABLES |
                                           PIKA_PROCEDURE_SENSITIVE_NO_DRAWABLES);

      pika_procedure_set_menu_label (procedure, _("_Playback..."));
      pika_procedure_set_icon_name (procedure, "media-playback-start");
      pika_procedure_add_menu_path (procedure, "<Image>/Filters/Animation/");

      pika_procedure_set_documentation (procedure,
                                        _("Preview a PIKA layer-based "
                                          "animation"),
                                        "",
                                        name);
      pika_procedure_set_attribution (procedure,
                                      "Adam D. Moss <adam@gimp.org>",
                                      "Adam D. Moss <adam@gimp.org>",
                                      "1997, 1998...");

      PIKA_PROC_AUX_ARG_BYTES (procedure, "settings-data",
                               "Settings data",
                               "TODO: eventually we must implement proper args for every settings",
                               PIKA_PARAM_READWRITE);
    }

  return procedure;
}

static PikaValueArray *
play_run (PikaProcedure        *procedure,
          PikaRunMode           run_mode,
          PikaImage            *_image,
          gint                  n_drawables,
          PikaDrawable        **drawables,
          PikaProcedureConfig  *config,
          gpointer              run_data)
{
  GBytes   *settings_bytes = NULL;
  GMenu    *section;
  PikaPlay *play;

  if (run_mode != PIKA_RUN_INTERACTIVE)
    {
      GError *error = NULL;

      g_set_error (&error, PIKA_PLUG_IN_ERROR, 0,
                   _("Procedure '%s' only works in interactive mode."),
                   pika_procedure_get_name (procedure));

      return pika_procedure_new_return_values (procedure,
                                               PIKA_PDB_CALLING_ERROR,
                                               error);
    }

  play = PIKA_PLAY (pika_procedure_get_plug_in (procedure));
#if GLIB_CHECK_VERSION(2,74,0)
  play->app = gtk_application_new (NULL, G_APPLICATION_DEFAULT_FLAGS);
#else
  play->app = gtk_application_new (NULL, G_APPLICATION_FLAGS_NONE);
#endif

  play->menu = g_menu_new ();

  section = g_menu_new ();
  g_menu_append (section, _("Start playback"), "win.play");
  g_menu_append (section, _("Step back to previous frame"), "win.step-back");
  g_menu_append (section, _("Step to next frame"), "win.step");
  g_menu_append (section, _("Rewind the animation"), "win.rewind");
  g_menu_append_section (play->menu, NULL, G_MENU_MODEL (section));
  g_clear_object (&section);

  section = g_menu_new ();
  g_menu_append (section, _("Increase the speed of the animation"), "win.speed-down");
  g_menu_append (section, _("Decrease the speed of the animation"), "win.speed-up");
  g_menu_append (section, _("Reset the speed of the animation"), "win.speed-reset");
  g_menu_append_section (play->menu, NULL, G_MENU_MODEL (section));
  g_clear_object (&section);

  section = g_menu_new ();
  g_menu_append (section, _("Detach the animation from the dialog window"), "win.detach");
  g_menu_append (section, _("Reload the image"), "win.refresh");
  g_menu_append (section, _("Quit"), "win.close");
  g_menu_append_section (play->menu, NULL, G_MENU_MODEL (section));
  g_clear_object (&section);

  gegl_init (NULL, NULL);

  image = _image;

  /* Temporary code replacing legacy pika_[gs]et_data() using an AUX argument.
   * This doesn't actually fix the "Reset to initial values|factory defaults"
   * features, but at least makes per-run value storage work.
   * TODO: eventually we want proper separate arguments as a complete fix.
   */
  g_object_get (config, "settings-data", &settings_bytes, NULL);
  if (settings_bytes != NULL && g_bytes_get_size (settings_bytes) == sizeof (AnimationSettings))
    settings = *((AnimationSettings *) g_bytes_get_data (settings_bytes, NULL));
  g_bytes_unref (settings_bytes);

  g_signal_connect (play->app, "activate", G_CALLBACK (on_app_activate), play);

  g_application_run (G_APPLICATION (play->app), 0, NULL);

  g_clear_object (&play->app);

  settings_bytes = g_bytes_new (&settings, sizeof (AnimationSettings));
  g_object_set (config, "settings-data", settings_bytes, NULL);
  g_bytes_unref (settings_bytes);

  if (run_mode != PIKA_RUN_NONINTERACTIVE)
    pika_displays_flush ();

  pika_image_delete (frames_image);
  gegl_exit ();

  return pika_procedure_new_return_values (procedure, PIKA_PDB_SUCCESS, NULL);
}

static gboolean
popup_menu (GtkWidget      *widget,
            GdkEventButton *event,
            PikaPlay       *play)
{
  GtkWidget  *menu;

  menu = gtk_menu_new_from_model (G_MENU_MODEL (play->menu));

  gtk_menu_attach_to_widget (GTK_MENU (menu), window, NULL);
  gtk_menu_popup_at_pointer (GTK_MENU (menu), (GdkEvent *) event);

  return TRUE;
}

static gboolean
button_press (GtkWidget      *widget,
              GdkEventButton *event,
              PikaPlay       *play)
{
  if (gdk_event_triggers_context_menu ((GdkEvent *) event))
    return popup_menu (widget, event, play);

  return FALSE;
}

/*
 * Update the actual drawing area metrics, which may be different as requested,
 * because there is no full control of the WM.
 * data is always NULL. */
static void
da_size_callback (GtkWidget     *widget,
                  GtkAllocation *allocation,
                  gpointer       data)
{
  if (allocation->width  == drawing_area_width &&
      allocation->height == drawing_area_height)
    return;

  drawing_area_width  = allocation->width;
  drawing_area_height = allocation->height;

  scale = MIN ((gdouble) drawing_area_width  / (gdouble) width,
               (gdouble) drawing_area_height / (gdouble) height);

  if (! detached)
    {
      /* Update the zoom information. */
      GtkEntry *zoomcombo_text_child;

      zoomcombo_text_child = GTK_ENTRY (gtk_bin_get_child (GTK_BIN (zoomcombo)));
      if (zoomcombo_text_child)
        {
          char* new_entry_text = g_strdup_printf  (_("%.1f %%"), scale * 100.0);

          gtk_entry_set_text (zoomcombo_text_child, new_entry_text);
          g_free (new_entry_text);
        }

      /* As we re-allocated the drawn data, let's render it again. */
      if (frame_number < total_frames)
        render_frame (frame_number);
    }
  else
    {
      /* Set "alpha grid" background. */
      gtk_widget_queue_draw (drawing_area);
    }
}

static void
sda_realize_callback (GtkWidget *widget,
                      gpointer   data)
{
  GdkCursor *cursor;

  cursor = gdk_cursor_new_for_display (gtk_widget_get_display (widget),
                                       GDK_HAND2);
  gdk_window_set_cursor (gtk_widget_get_window (widget), cursor);
  g_object_unref (cursor);
}

/*
 * Update the actual shape drawing area metrics, which may be
 * different as requested, They *should* be the same as the drawing
 * area, but the safe way is to make sure and process it separately.
 * data is always NULL.
 */
static void
sda_size_callback (GtkWidget     *widget,
                   GtkAllocation *allocation,
                   gpointer       data)
{
  if (allocation->width  == shape_drawing_area_width &&
      allocation->height == shape_drawing_area_height)
    return;

  shape_drawing_area_width  = allocation->width;
  shape_drawing_area_height = allocation->height;

  shape_scale = MIN ((gdouble) shape_drawing_area_width  / (gdouble) width,
                     (gdouble) shape_drawing_area_height / (gdouble) height);

  if (detached)
    {
      /* Update the zoom information. */
      GtkEntry *zoomcombo_text_child;

      zoomcombo_text_child = GTK_ENTRY (gtk_bin_get_child (GTK_BIN (zoomcombo)));
      if (zoomcombo_text_child)
        {
          char* new_entry_text = g_strdup_printf  (_("%.1f %%"),
                                                   shape_scale * 100.0);

          gtk_entry_set_text (zoomcombo_text_child, new_entry_text);
          g_free (new_entry_text);
        }

      if (frame_number < total_frames)
        render_frame (frame_number);
    }
}

static gboolean
shape_pressed (GtkWidget      *widget,
               GdkEventButton *event,
               PikaPlay       *play)
{
  if (button_press (widget, event, play))
    return TRUE;

  /* ignore double and triple click */
  if (event->type == GDK_BUTTON_PRESS)
    {
      CursorOffset *p = g_object_get_data (G_OBJECT(widget), "cursor-offset");

      if (!p)
        return FALSE;

      p->x = (gint) event->x;
      p->y = (gint) event->y;

      gtk_grab_add (widget);
      gdk_pointer_grab (gtk_widget_get_window (widget), TRUE,
                        GDK_BUTTON_RELEASE_MASK |
                        GDK_BUTTON_MOTION_MASK  |
                        GDK_POINTER_MOTION_HINT_MASK,
                        NULL, NULL, 0);
      gdk_window_raise (gtk_widget_get_window (widget));
    }

  return FALSE;
}

static gboolean
shape_released (GtkWidget *widget)
{
  gtk_grab_remove (widget);
  gdk_display_pointer_ungrab (gtk_widget_get_display (widget), 0);
  gdk_display_flush (gtk_widget_get_display (widget));

  return FALSE;
}

static gboolean
shape_motion (GtkWidget      *widget,
              GdkEventMotion *event)
{
  GdkModifierType  mask;
  gint             xp, yp;

  gdk_window_get_device_position (root_win,
                                  gdk_event_get_device ((GdkEvent *) event),
                                  &xp, &yp, &mask);

  /* if a button is still held by the time we process this event... */
  if (mask & GDK_BUTTON1_MASK)
    {
      CursorOffset *p = g_object_get_data (G_OBJECT (widget), "cursor-offset");

      if (!p)
        return FALSE;

      gtk_window_move (GTK_WINDOW (widget), xp  - p->x, yp  - p->y);
    }
  else /* the user has released all buttons */
    {
      shape_released (widget);
    }

  return FALSE;
}

static gboolean
repaint_da (GtkWidget *darea,
            cairo_t   *cr,
            gpointer   data)
{
  cairo_pattern_t *check;
  PikaRGB          light = *(pika_check_custom_color1 ());
  PikaRGB          dark  = *(pika_check_custom_color2 ());

  pika_checks_get_colors (pika_check_type (), &light, &dark);

  check = pika_cairo_checkerboard_create (cr, 32, &light, &dark);

  cairo_set_source (cr, check);
  cairo_paint (cr);
  cairo_pattern_destroy (check);

  cairo_set_source_surface (cr, drawing_area_surface, 0, 0);
  cairo_paint (cr);

  return FALSE;
}

static gboolean
repaint_sda (GtkWidget *darea,
             cairo_t   *cr,
             gpointer   data)
{
  gboolean rgba;

  rgba = gdk_screen_get_rgba_visual (gtk_widget_get_screen (darea)) != NULL;

  if (rgba)
    cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);

  cairo_set_source_surface (cr, shape_drawing_area_surface, 0, 0);

  cairo_paint (cr);

  return FALSE;
}

static void
refresh_dialog (gchar *imagename)
{
  gchar        *name;
  GdkMonitor   *monitor;
  GdkRectangle  workarea;
  gint          window_width, window_height;

  /* Image Name */
  name = g_strconcat (_("Animation Playback:"), " ", imagename, NULL);
  gtk_window_set_title (GTK_WINDOW (window), name);
  g_free (name);

  /* Update GUI size. */
  monitor = pika_widget_get_monitor (window);
  gdk_monitor_get_workarea (monitor, &workarea);
  gtk_window_get_size (GTK_WINDOW (window), &window_width, &window_height);

  /* if the *window* size is bigger than the screen size,
   * diminish the drawing area by as much, then compute the corresponding scale. */
  if (window_width  + 50 > workarea.width ||
      window_height + 50 > workarea.height)
    {
      guint expected_drawing_area_width  = MAX (1,
                                                width -
                                                window_width + workarea.width);
      guint expected_drawing_area_height = MAX (1,
                                                height -
                                                window_height + workarea.height);
      gdouble expected_scale = MIN ((gdouble) expected_drawing_area_width /
                                    (gdouble) width,
                                    (gdouble) expected_drawing_area_height /
                                    (gdouble) height);

      update_scale (expected_scale);

      /* There is unfortunately no good way to know the size of the decorations, taskbars, etc.
       * So we take a wild guess by making the window slightly smaller to fit into any case. */
      gtk_window_set_default_size (GTK_WINDOW (window),
                                   MIN (expected_drawing_area_width + 20,
                                        workarea.width - 60),
                                   MIN (expected_drawing_area_height + 90,
                                        workarea.height - 60));

      gtk_widget_show (window);
    }
}

static GtkWidget *
build_dialog (PikaPlay *play,
              gchar    *imagename)
{
  GtkWidget *toolbar;
  GtkWidget *frame;
  GtkWidget *viewport;
  GtkWidget *main_vbox;
  GtkWidget *vbox;
  GtkWidget *hbox;
  GdkVisual *rgba;
  GAction   *action;
  gint       index;
  gchar     *text;

  pika_ui_init (PLUG_IN_BINARY);

  window = gtk_application_window_new (play->app);
  gtk_window_set_role (GTK_WINDOW (window), "animation-playback");

  g_signal_connect (window, "destroy",
                    G_CALLBACK (window_destroy),
                    play);
  g_signal_connect (window, "popup-menu",
                    G_CALLBACK (popup_menu),
                    play);

  g_action_map_add_action_entries (G_ACTION_MAP (window),
                                   ACTIONS, G_N_ELEMENTS (ACTIONS),
                                   play);

  pika_help_connect (window, pika_standard_help_func, PLUG_IN_PROC, NULL, NULL);

  main_vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
  gtk_container_add (GTK_CONTAINER (window), main_vbox);
  gtk_widget_show (main_vbox);

  toolbar = gtk_toolbar_new ();
  play->play_button = add_tool_button (toolbar, "win.play", "media-playback-start",
                                       NULL, _("Start playback"));
  play->step_back_button = add_tool_button (toolbar, "win.step-back", "media-skip-backward",
                                            _("Step _back"), _("Step back to previous frame"));
  play->step_button = add_tool_button (toolbar, "win.step", "media-skip-forward",
                                       _("_Step"), _("Step to next frame"));
  play->rewind_button = add_tool_button (toolbar, "win.rewind", "media-seek-backward",
                                         NULL, _("Rewind the animation"));
  add_tool_separator (toolbar, FALSE);
  add_tool_button (toolbar, "win.detach", PIKA_ICON_DETACH,
                   _("Detach"), _("Detach the animation from the dialog window"));
  add_tool_button (toolbar, "win.refresh", PIKA_ICON_VIEW_REFRESH,
                   NULL, _("Reload the image"));
  add_tool_separator (toolbar, TRUE);
  add_tool_button (toolbar, "win.help", "help-browser",
                   NULL, NULL);

  gtk_box_pack_start (GTK_BOX (main_vbox), toolbar, FALSE, FALSE, 0);
  gtk_widget_show (toolbar);

  vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 2);
  gtk_box_pack_start (GTK_BOX (main_vbox), vbox, TRUE, TRUE, 0);
  gtk_widget_show (vbox);

  frame = gtk_scrolled_window_new (NULL, NULL);
  gtk_widget_set_hexpand (frame, TRUE);
  gtk_widget_set_vexpand (frame, TRUE);
  gtk_container_add (GTK_CONTAINER (vbox), frame);
  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (frame),
                                  GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
  gtk_widget_show (frame);

  viewport = gtk_viewport_new (NULL, NULL);
  gtk_container_add (GTK_CONTAINER (frame), viewport);
  gtk_widget_show (viewport);

  /* Build a drawing area, with a default size same as the image */
  drawing_area = gtk_drawing_area_new ();
  gtk_widget_add_events (drawing_area, GDK_BUTTON_PRESS_MASK);
  gtk_container_add (GTK_CONTAINER (viewport), drawing_area);
  gtk_widget_show (drawing_area);

  g_signal_connect (drawing_area, "size-allocate",
                    G_CALLBACK(da_size_callback),
                    NULL);
  g_signal_connect (drawing_area, "button-press-event",
                    G_CALLBACK (button_press),
                    play);

  /* Lower option bar. */

  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  /* Progress bar. */

  progress = gtk_progress_bar_new ();
  gtk_box_pack_end (GTK_BOX (hbox), progress, TRUE, TRUE, 0);
  gtk_widget_show (progress);

  /* Zoom */
  zoomcombo = gtk_combo_box_text_new_with_entry ();
  gtk_box_pack_end (GTK_BOX (hbox), zoomcombo, FALSE, FALSE, 0);
  gtk_widget_show (zoomcombo);
  for (index = 0; index < 5; index++)
    {
      /* list is given in "fps" - frames per second */
      text = g_strdup_printf  (_("%.1f %%"), get_scale (index) * 100.0);
      gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (zoomcombo), text);
      g_free (text);
    }

  gtk_combo_box_set_active (GTK_COMBO_BOX (zoomcombo), 2); /* 1.0 by default. */

  g_signal_connect (GTK_ENTRY (gtk_bin_get_child (GTK_BIN (zoomcombo))),
                    "activate",
                    G_CALLBACK (zoomcombo_activated),
                    NULL);
  g_signal_connect (zoomcombo, "changed",
                    G_CALLBACK (zoomcombo_changed),
                    NULL);

  pika_help_set_help_data (zoomcombo, _("Zoom"), NULL);

  /* fps combo */
  fpscombo = gtk_combo_box_text_new ();
  gtk_box_pack_end (GTK_BOX (hbox), fpscombo, FALSE, FALSE, 0);
  gtk_widget_show (fpscombo);

  for (index = 0; index < 9; index++)
    {
      /* list is given in "fps" - frames per second */
      text = g_strdup_printf  (_("%d fps"), get_fps (index));
      gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (fpscombo), text);
      g_free (text);
      if (settings.default_frame_duration == 1000 / get_fps(index))
        gtk_combo_box_set_active (GTK_COMBO_BOX (fpscombo), index);
    }

  g_signal_connect (fpscombo, "changed",
                    G_CALLBACK (fpscombo_changed),
                    NULL);

  pika_help_set_help_data (fpscombo, _("Default framerate"), NULL);

  /* Speed Combo */
  speedcombo = gtk_combo_box_text_new ();
  gtk_box_pack_end (GTK_BOX (hbox), speedcombo, FALSE, FALSE, 0);
  gtk_widget_show (speedcombo);

  for (index = 0; index < 7; index++)
    {
      text = g_strdup_printf  ("%g\303\227", (100 / get_duration_factor (index)) / 100);
      gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (speedcombo), text);
      g_free (text);
    }

  gtk_combo_box_set_active (GTK_COMBO_BOX (speedcombo), settings.duration_index);

  g_signal_connect (speedcombo, "changed",
                    G_CALLBACK (speedcombo_changed),
                    NULL);

  pika_help_set_help_data (speedcombo, _("Playback speed"), NULL);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-reset");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action), FALSE);

  /* Set up the frame disposal combo. */
  frame_disposal_combo = gtk_combo_box_text_new ();

  /* 2 styles of default frame disposals: cumulative layers and one
   * frame per layer.
   */
  text = g_strdup (_("Cumulative layers (combine)"));
  gtk_combo_box_text_insert_text (GTK_COMBO_BOX_TEXT (frame_disposal_combo),
                                  DISPOSE_COMBINE, text);
  g_free (text);

  text = g_strdup (_("One frame per layer (replace)"));
  gtk_combo_box_text_insert_text (GTK_COMBO_BOX_TEXT (frame_disposal_combo),
                                  DISPOSE_REPLACE, text);
  g_free (text);

  gtk_combo_box_set_active (GTK_COMBO_BOX (frame_disposal_combo),
                            settings.default_frame_disposal);

  g_signal_connect (frame_disposal_combo, "changed",
                    G_CALLBACK (framecombo_changed),
                    play);

  gtk_box_pack_end (GTK_BOX (hbox), frame_disposal_combo, FALSE, FALSE, 0);
  gtk_widget_show (frame_disposal_combo);

  gtk_window_set_resizable (GTK_WINDOW (window), TRUE);
  gtk_window_set_default_size (GTK_WINDOW (window), width + 20, height + 90);
  gtk_widget_show (window);

  /* shape_drawing_area for detached feature. */
  shape_window = gtk_window_new (GTK_WINDOW_POPUP);
  gtk_widget_set_app_paintable (shape_window, TRUE);
  gtk_window_set_resizable (GTK_WINDOW (shape_window), FALSE);
  gtk_window_set_decorated (GTK_WINDOW (shape_window), FALSE);
  gtk_widget_add_events (shape_window, GDK_BUTTON_PRESS_MASK);

  rgba = gdk_screen_get_rgba_visual (gdk_screen_get_default ());

  if (rgba && gdk_screen_is_composited (gdk_screen_get_default ()))
    gtk_widget_set_visual (shape_window, rgba);

  g_signal_connect (shape_window, "realize",
                    G_CALLBACK (sda_realize_callback),
                    NULL);
  g_signal_connect (shape_window, "size-allocate",
                    G_CALLBACK (sda_size_callback),
                    NULL);
  g_signal_connect (shape_window, "button-press-event",
                    G_CALLBACK (shape_pressed),
                    play);
  g_signal_connect (shape_window, "button-release-event",
                    G_CALLBACK (shape_released),
                    NULL);
  g_signal_connect (shape_window, "motion-notify-event",
                    G_CALLBACK (shape_motion),
                    NULL);

  g_object_set_data (G_OBJECT (shape_window),
                     "cursor-offset", g_new0 (CursorOffset, 1));

  g_signal_connect (drawing_area, "draw",
                    G_CALLBACK (repaint_da),
                    NULL);

  g_signal_connect (shape_window, "draw",
                    G_CALLBACK (repaint_sda),
                    NULL);

  /* We request a minimum size *after* having connecting the
   * size-allocate signal for correct initialization.
   */
  gtk_widget_set_size_request (drawing_area, width, height);
  gtk_widget_set_size_request (shape_window, width, height);

  root_win = gdk_get_default_root_window ();

  return window;
}

static void
init_frames (PikaPlay *play)
{
  /* Frames are associated to an unused image. */
  gint          i;
  PikaLayer    *new_frame;
  PikaLayer    *previous_frame;
  PikaLayer    *new_layer;
  gboolean      animated;
  gint          duration = 0;
  DisposeType   disposal = settings.default_frame_disposal;
  gchar        *layer_name;
  GList        *iter;

  total_frames = g_list_length (layers);

  /* Cleanup before re-generation. */
  if (frames)
    {
      pika_image_delete (frames_image);
      g_free (frames);
      g_free (frame_durations);
    }
  frames = g_try_malloc0_n (total_frames, sizeof (PikaLayer *));
  frame_durations = g_try_malloc0_n (total_frames, sizeof (guint32));
  if (! frames || ! frame_durations)
    {
      pika_message (_("Memory could not be allocated to the frame container."));
      gtk_widget_destroy (GTK_WIDGET (window));
      pika_quit ();
      return;
    }

  /* We only use RGB images for display because indexed images would
   * somehow render terrible colors. Layers from other types will be
   * automatically converted.
   */
  frames_image = pika_image_new (width, height, PIKA_RGB);

  /* Save processing time and memory by not saving history and merged frames. */
  pika_image_undo_disable (frames_image);

  for (iter = layers, i = 0;
       iter;
       iter = g_list_next (iter), i++)
    {
      layer_name = pika_item_get_name (iter->data);
      if (layer_name)
        {
          duration = parse_ms_tag (layer_name);
          disposal = parse_disposal_tag (layer_name);
          g_free (layer_name);
        }

      if (i > 0 && disposal != DISPOSE_REPLACE)
        {
          previous_frame = pika_layer_copy (frames[i - 1]);
          pika_image_insert_layer (frames_image, previous_frame, NULL, -1);
          pika_item_set_visible (PIKA_ITEM (previous_frame), TRUE);
        }
      new_layer = pika_layer_new_from_drawable (iter->data, frames_image);
      pika_image_insert_layer (frames_image, new_layer, NULL, -1);
      pika_item_set_visible (PIKA_ITEM (new_layer), TRUE);
      new_frame = pika_image_merge_visible_layers (frames_image,
                                                   PIKA_CLIP_TO_IMAGE);
      frames[i] = new_frame;
      pika_item_set_visible (PIKA_ITEM (new_frame), FALSE);

      if (duration <= 0)
        duration = settings.default_frame_duration;
      frame_durations[i] = (guint32) duration;
    }

  /* Update the UI. */
  animated = total_frames >= 2;
  gtk_widget_set_sensitive (play->play_button, animated);
  gtk_widget_set_sensitive (play->step_back_button, animated);
  gtk_widget_set_sensitive (play->step_button, animated);
  gtk_widget_set_sensitive (play->rewind_button, animated);

  /* Keep the same frame number, unless it is now invalid. */
  if (frame_number >= total_frames)
    frame_number = 0;
}

static void
initialize (PikaPlay *play)
{
  /* Freeing existing data after a refresh. */
  g_list_free (layers);

  /* Catch the case when the user has closed the image in the meantime. */
  if (! pika_image_is_valid (image))
    {
      pika_message (_("Invalid image. Did you close it?"));
      if (window)
        gtk_widget_destroy (GTK_WIDGET (window));
      return;
    }

  width  = pika_image_get_width (image);
  height = pika_image_get_height (image);

  layers = pika_image_list_layers (image);
  layers = g_list_reverse (layers);

  if (!window)
    build_dialog (play, pika_image_get_name (image));
  refresh_dialog (pika_image_get_name (image));

  init_frames (play);
  render_frame (frame_number);
  show_frame ();
}

static void
on_app_activate (GApplication *gapp,
                 gpointer      user_data)
{
  PikaPlay       *play = PIKA_PLAY (user_data);
  GtkApplication *app  = GTK_APPLICATION (gapp);

  initialize (play);

  gtk_application_set_accels_for_action (app, "win.play", (const char*[]) { "space", NULL });
  gtk_application_set_accels_for_action (app, "win.detach", (const char*[]) { NULL });

  gtk_application_set_accels_for_action (app, "win.step-back", (const char*[]) { "d", NULL });
  gtk_application_set_accels_for_action (app, "win.step", (const char*[]) { "f", NULL });
  gtk_application_set_accels_for_action (app, "win.rewind", (const char*[]) { NULL });
  gtk_application_set_accels_for_action (app, "win.refresh", (const char*[]) { "<control>R", NULL });
  gtk_application_set_accels_for_action (app, "win.help", (const char*[]) {  NULL });
  gtk_application_set_accels_for_action (app, "win.close", (const char*[]) { "<control>W", NULL });
  gtk_application_set_accels_for_action (app, "win.quit", (const char*[]) { "<control>Q", NULL });
  gtk_application_set_accels_for_action (app, "win.speed-up", (const char*[]) { "<control>L", NULL });
  gtk_application_set_accels_for_action (app, "win.speed-down", (const char*[]) { "<control>J", NULL });
  gtk_application_set_accels_for_action (app, "win.speed-reset", (const char*[]) { "<control>K", NULL });
}

/* Rendering Functions */

static void
render_frame (gint32 whichframe)
{
  GeglBuffer       *buffer;
  GtkWidget        *da;
  cairo_surface_t **drawing_surface;
  guint             drawing_width, drawing_height;
  gdouble           drawing_scale;

  g_assert (whichframe < total_frames);

  if (detached)
    {
      da              = shape_window;
      drawing_surface = &shape_drawing_area_surface;
      drawing_width   = shape_drawing_area_width;
      drawing_height  = shape_drawing_area_height;
      drawing_scale   = shape_scale;
    }
  else
    {
      da              = drawing_area;
      drawing_surface = &drawing_area_surface;
      drawing_width   = drawing_area_width;
      drawing_height  = drawing_area_height;
      drawing_scale   = scale;
    }

  buffer = pika_drawable_get_buffer (PIKA_DRAWABLE (frames[whichframe]));

  if (*drawing_surface)
    cairo_surface_destroy (*drawing_surface);

  *drawing_surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
                                                 drawing_width,
                                                 drawing_height);

  cairo_surface_flush (*drawing_surface);

  /* Fetch and scale the whole raw new frame */
  gegl_buffer_get (buffer, GEGL_RECTANGLE (0, 0, drawing_width, drawing_height),
                   drawing_scale, babl_format ("cairo-ARGB32"),
                   cairo_image_surface_get_data (*drawing_surface),
                   cairo_image_surface_get_stride (*drawing_surface),
                   GEGL_ABYSS_CLAMP);

  cairo_surface_mark_dirty (*drawing_surface);

  /* Display the preview buffer. */
  gtk_widget_queue_draw (da);

  /* clean up */
  g_object_unref (buffer);
}

static void
show_frame (void)
{
  gchar *text;

  /* update the dialog's progress bar */
  gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (progress),
                                 ((gfloat) frame_number /
                                  (gfloat) (total_frames - 0.999)));

  text = g_strdup_printf (_("Frame %d of %d"), frame_number + 1, total_frames);
  gtk_progress_bar_set_text (GTK_PROGRESS_BAR (progress), text);
  g_free (text);
}


/* Util. */

static void
remove_timer (void)
{
  if (timer)
    {
      g_source_remove (timer);
      timer = 0;
    }
}

static void
do_back_step (void)
{
  if (frame_number == 0)
    frame_number = total_frames - 1;
  else
    frame_number = (frame_number - 1) % total_frames;
  render_frame (frame_number);
}

static void
do_step (void)
{
  frame_number = (frame_number + 1) % total_frames;
  render_frame (frame_number);
}


/*  Callbacks  */

static void
window_destroy (GtkWidget *widget,
                PikaPlay  *play)
{
  if (playing)
    remove_timer ();

  if (shape_window)
    gtk_widget_destroy (GTK_WIDGET (shape_window));

  gtk_widget_destroy (GTK_WIDGET (window));
}


static gint
advance_frame_callback (gpointer data)
{
  gdouble duration;

  remove_timer();

  duration = frame_durations[(frame_number + 1) % total_frames];

  timer = g_timeout_add (duration * get_duration_factor (settings.duration_index),
                         advance_frame_callback, NULL);

  do_step ();
  show_frame ();

  return FALSE;
}

static gdouble
get_duration_factor (gint index)
{
  switch (index)
    {
    case 0:
      return 0.125;
    case 1:
      return 0.25;
    case 2:
      return 0.5;
    case 3:
      return 1.0;
    case 4:
      return 2.0;
    case 5:
      return 4.0;
    case 6:
      return 8.0;
    default:
      return 1.0;
    }
}

static gint
get_fps (gint index)
{
  switch (index)
    {
    case 0:
      return 10;
    case 1:
      return 12;
    case 2:
      return 15;
    case 3:
      return 24;
    case 4:
      return 25;
    case 5:
      return 30;
    case 6:
      return 50;
    case 7:
      return 60;
    case 8:
      return 72;
    default:
      return 10;
    }
}

static gdouble
get_scale (gint index)
{
  switch (index)
    {
    case 0:
      return 0.51;
    case 1:
      return 1.0;
    case 2:
      return 1.25;
    case 3:
      return 1.5;
    case 4:
      return 2.0;
    default:
      {
        /* likely -1 returned if there is no active item from the list.
         * Try a text conversion, locale-aware in such a case, assuming people write in percent. */
        gchar* active_text = gtk_combo_box_text_get_active_text (GTK_COMBO_BOX_TEXT (zoomcombo));
        gdouble zoom = g_strtod (active_text, NULL);

        /* Negative scales are inconsistent. And we want to avoid huge scaling. */
        if (zoom > 400.0)
          zoom = 400.0;
        else if (zoom <= 50.0)
          /* FIXME: scales under 0.5 are broken. See bug 690265. */
          zoom = 50.1;
        g_free (active_text);
        return zoom / 100.0;
      }
    }
}

static void
step_back_action (GSimpleAction *action,
                  GVariant      *parameter,
                  gpointer       user_data)
{
  if (playing)
    g_action_group_activate_action (G_ACTION_GROUP (window),
                                    "play", NULL);
  do_back_step();
  show_frame();
}

static void
play_change_state (GSimpleAction *action,
                   GVariant      *new_state,
                   gpointer       user_data)
{
  GtkToolButton *play_button;
  GtkWidget     *tool_icon;

  if (playing)
    remove_timer ();

  playing = g_variant_get_boolean (new_state);
  g_simple_action_set_state (action, new_state);

  play_button = GTK_TOOL_BUTTON (PIKA_PLAY (user_data)->play_button);
  tool_icon   = gtk_tool_button_get_icon_widget (play_button);
  if (playing)
    {
      timer = g_timeout_add ((gdouble) frame_durations[frame_number] *
                             get_duration_factor (settings.duration_index),
                             advance_frame_callback, NULL);

      gtk_image_set_from_icon_name (GTK_IMAGE (tool_icon),
                                    "media-playback-pause",
                                    GTK_ICON_SIZE_BUTTON);
    }
  else
    {
      gtk_image_set_from_icon_name (GTK_IMAGE (tool_icon),
                                    "media-playback-start",
                                    GTK_ICON_SIZE_BUTTON);
    }

  gtk_tool_item_set_tooltip_text (GTK_TOOL_ITEM (play_button),
                                  playing ? _("Stop playback") : _("Start playback"));
}

static void
detach_change_state (GSimpleAction *action,
                     GVariant      *new_state,
                     gpointer       user_data)
{
  gboolean active = g_variant_get_boolean (new_state);

  if (active == detached)
    {
      g_warning ("detached state and toggle action got out of sync");
      return;
    }

  g_simple_action_set_state (action, new_state);
  detached = active;

  if (detached)
    {
      gint x, y;

      /* Create a total-alpha buffer merely for the not-shaped
         drawing area to now display. */

      gtk_window_set_screen (GTK_WINDOW (shape_window),
                             gtk_widget_get_screen (drawing_area));

      gtk_widget_show (shape_window);

      if (! gtk_widget_get_realized (drawing_area))
        gtk_widget_realize (drawing_area);

      if (! gtk_widget_get_realized (shape_window))
        gtk_widget_realize (shape_window);

      gdk_window_get_origin (gtk_widget_get_window (drawing_area), &x, &y);

      gtk_window_move (GTK_WINDOW (shape_window), x + 6, y + 6);

      gtk_widget_queue_draw (drawing_area);
    }
  else
    gtk_widget_hide (shape_window);

  render_frame (frame_number);
}

static void
step_action (GSimpleAction *action,
             GVariant      *parameter,
             gpointer       user_data)
{
  if (playing)
    g_action_group_activate_action (G_ACTION_GROUP (window),
                                    "play", NULL);
  do_step();
  show_frame();
}

static void
rewind_action (GSimpleAction *action,
               GVariant      *parameter,
               gpointer       user_data)
{
  if (playing)
    g_action_group_activate_action (G_ACTION_GROUP (window),
                                    "play", NULL);
  frame_number = 0;
  render_frame (frame_number);
  show_frame ();
}

static void
refresh_action (GSimpleAction *action,
                GVariant      *parameter,
                gpointer       user_data)
{
  initialize (PIKA_PLAY (user_data));
}

static void
close_action (GSimpleAction *action,
              GVariant      *parameter,
              gpointer       user_data)
{
  gtk_widget_destroy (GTK_WIDGET (window));
}

static void
help_action (GSimpleAction *action,
             GVariant      *parameter,
             gpointer       user_data)
{
  pika_standard_help_func (PLUG_IN_PROC, window);
}

static void
speed_up_action (GSimpleAction *saction,
                 GVariant      *parameter,
                 gpointer       user_data)
{
  GAction *action;

  if (settings.duration_index > 0)
    --settings.duration_index;

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-up");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index > 0);


  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-reset");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index != 3);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-down");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action), TRUE);

  update_combobox ();
}

static void
speed_down_action (GSimpleAction *saction,
                   GVariant      *parameter,
                   gpointer       user_data)
{
  GAction *action;

  if (settings.duration_index < 6)
    ++settings.duration_index;

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-down");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index < 6);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-reset");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index != 3);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-up");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action), TRUE);

  update_combobox ();
}

static void
speed_reset_action (GSimpleAction *saction,
                    GVariant      *parameter,
                    gpointer       user_data)
{
  GAction *action;

  settings.duration_index = 3;

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-reset");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action), FALSE);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-down");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action), TRUE);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-up");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action), TRUE);

  update_combobox ();
}

static void
framecombo_changed (GtkWidget *combo,
                    gpointer   data)
{
  settings.default_frame_disposal =
    gtk_combo_box_get_active (GTK_COMBO_BOX (combo));
  init_frames (PIKA_PLAY (data));
  render_frame (frame_number);
}

static void
speedcombo_changed (GtkWidget *combo,
                    gpointer   data)
{
  GAction *action;

  settings.duration_index = gtk_combo_box_get_active (GTK_COMBO_BOX (combo));

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-reset");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index != 3);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-down");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index < 6);

  action = g_action_map_lookup_action (G_ACTION_MAP (window), "speed-up");
  g_simple_action_set_enabled (G_SIMPLE_ACTION (action),
                               settings.duration_index > 0);
}

static void
update_scale (gdouble scale)
{
  guint expected_drawing_area_width;
  guint expected_drawing_area_height;

  /* FIXME: scales under 0.5 are broken. See bug 690265. */
  if (scale <= 0.5)
    scale = 0.501;

  expected_drawing_area_width  = width  * scale;
  expected_drawing_area_height = height * scale;

  gtk_widget_set_size_request (drawing_area,
                               expected_drawing_area_width,
                               expected_drawing_area_height);
  gtk_widget_set_size_request (shape_window,
                               expected_drawing_area_width,
                               expected_drawing_area_height);

  /* I force the shape window to a smaller size if we scale down. */
  if (detached)
    {
      gint x, y;

      gdk_window_get_origin (gtk_widget_get_window (shape_window), &x, &y);
      gtk_window_move (GTK_WINDOW (shape_window), x, y);
      gtk_widget_show (shape_window);
    }
}

/*
 * Callback emitted when the user hits the Enter key of the zoom combo.
 */
static void
zoomcombo_activated (GtkEntry *combo,
                     gpointer  data)
{
  update_scale (get_scale (-1));
}

/*
 * Callback emitted when the user selects a zoom in the dropdown,
 * or edits the text entry.
 * We don't want to process manual edits because it greedily emits
 * signals after each character deleted or added.
 */
static void
zoomcombo_changed (GtkWidget *combo,
                   gpointer   data)
{
  gint index = gtk_combo_box_get_active (GTK_COMBO_BOX (combo));

  /* If no index, user is probably editing by hand. We wait for them to click "Enter". */
  if (index != -1)
    update_scale (get_scale (index));
}

static void
fpscombo_changed (GtkWidget *combo,
                  gpointer   data)
{
  settings.default_frame_duration =
    1000 / get_fps (gtk_combo_box_get_active (GTK_COMBO_BOX (combo)));
}

static void
update_combobox (void)
{
  gtk_combo_box_set_active (GTK_COMBO_BOX (speedcombo), settings.duration_index);
}

/* tag util. */

static gboolean
is_ms_tag (const gchar *str,
           gint        *duration,
           gint        *taglength)
{
  gint sum = 0;
  gint offset;
  gint length;

  length = strlen(str);

  if (str[0] != '(')
    return FALSE;

  offset = 1;

  /* eat any spaces between open-parenthesis and number */
  while ((offset < length) && (str[offset] == ' '))
    offset++;

  if ((offset>=length) || (!g_ascii_isdigit (str[offset])))
    return FALSE;

  do
    {
      sum *= 10;
      sum += str[offset] - '0';
      offset++;
    }
  while ((offset<length) && (g_ascii_isdigit (str[offset])));

  if (length - offset <= 2)
    return FALSE;

  /* eat any spaces between number and 'ms' */
  while ((offset < length) && (str[offset] == ' '))
    offset++;

  if (length - offset <= 2                     ||
      g_ascii_toupper (str[offset])     != 'M' ||
      g_ascii_toupper (str[offset + 1]) != 'S')
    return FALSE;

  offset += 2;

  /* eat any spaces between 'ms' and close-parenthesis */
  while ((offset < length) && (str[offset] == ' '))
    offset++;

  if ((length - offset < 1) || (str[offset] != ')'))
    return FALSE;

  offset++;

  *duration = sum;
  *taglength = offset;

  return TRUE;
}

static gint
parse_ms_tag (const gchar *str)
{
  gint i;
  gint length = strlen (str);

  for (i = 0; i < length; i++)
    {
      gint rtn;
      gint dummy;

      if (is_ms_tag (&str[i], &rtn, &dummy))
        return rtn;
    }

  return -1;
}

static gboolean
is_disposal_tag (const gchar *str,
                 DisposeType *disposal,
                 gint        *taglength)
{
  if (strlen (str) != 9)
    return FALSE;

  if (strncmp (str, "(combine)", 9) == 0)
    {
      *taglength = 9;
      *disposal = DISPOSE_COMBINE;
      return TRUE;
    }
  else if (strncmp (str, "(replace)", 9) == 0)
    {
      *taglength = 9;
      *disposal = DISPOSE_REPLACE;
      return TRUE;
    }

  return FALSE;
}

static DisposeType
parse_disposal_tag (const gchar *str)
{
  gint i;
  gint length = strlen (str);

  for (i = 0; i < length; i++)
    {
      DisposeType rtn;
      gint        dummy;

      if (is_disposal_tag (&str[i], &rtn, &dummy))
        return rtn;
    }

  return settings.default_frame_disposal;
}

static GtkWidget *
add_tool_button (GtkWidget  *toolbar,
                 const char *action,
                 const char *icon,
                 const char *label,
                 const char *tooltip)
{
  GtkWidget   *tool_icon;
  GtkToolItem *tool_button;

  tool_icon = gtk_image_new_from_icon_name (icon, GTK_ICON_SIZE_BUTTON);
  gtk_widget_show (GTK_WIDGET (tool_icon));
  tool_button = gtk_tool_button_new (tool_icon, label);
  gtk_widget_show (GTK_WIDGET (tool_button));
  gtk_tool_item_set_tooltip_text (tool_button, tooltip);
  gtk_actionable_set_detailed_action_name (GTK_ACTIONABLE (tool_button), action);

  gtk_toolbar_insert (GTK_TOOLBAR (toolbar), tool_button, -1);

  return GTK_WIDGET (tool_button);
}

static void
add_tool_separator (GtkWidget *toolbar,
                    gboolean   expand)
{
  GtkToolItem *item;

  item = gtk_separator_tool_item_new ();
  gtk_toolbar_insert (GTK_TOOLBAR (toolbar), item, -1);
  gtk_separator_tool_item_set_draw (GTK_SEPARATOR_TOOL_ITEM (item), FALSE);
  gtk_tool_item_set_expand (item, expand);
  gtk_widget_show (GTK_WIDGET (item));
}
