path: root/widgets/misc/e-spinner.c

/*
 * Copyright © 2000 Eazel, Inc.
 * Copyright © 2002-2004 Marco Pesenti Gritti
 * Copyright © 2004, 2006 Christian Persch
 *
 * Nautilus 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 2 of the License, or
 * (at your option) any later version.
 *
 * Nautilus 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Author: Andy Hertzfeld <andy@eazel.com>
 *
 * Ephy port by Marco Pesenti Gritti <marco@it.gnome.org>
 *
 * $Id: e-spinner.c 12639 2006-12-12 17:06:55Z chpe $
 */

/*
 * From Nautilus ephy-spinner.c
 */

#include "config.h"

#include "e-spinner.h"

#define LOG(msg, args...)
#define START_PROFILER(name)
#define STOP_PROFILER(name)

#include "e-util/e-icon-factory.h"

/* Spinner cache implementation */

#define E_TYPE_SPINNER_CACHE            (e_spinner_cache_get_type())
#define E_SPINNER_CACHE(object)     (G_TYPE_CHECK_INSTANCE_CAST((object), E_TYPE_SPINNER_CACHE, ESpinnerCache))
#define E_SPINNER_CACHE_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass), E_TYPE_SPINNER_CACHE, ESpinnerCacheClass))
#define E_IS_SPINNER_CACHE(object)      (G_TYPE_CHECK_INSTANCE_TYPE((object), E_TYPE_SPINNER_CACHE))
#define E_IS_SPINNER_CACHE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass), E_TYPE_SPINNER_CACHE))
#define E_SPINNER_CACHE_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj), E_TYPE_SPINNER_CACHE, ESpinnerCacheClass))

typedef struct _ESpinnerCache   ESpinnerCache;
typedef struct _ESpinnerCacheClass  ESpinnerCacheClass;
typedef struct _ESpinnerCachePrivate    ESpinnerCachePrivate;

struct _ESpinnerCacheClass
{
    GObjectClass parent_class;
};

struct _ESpinnerCache
{
    GObject parent_object;

    /*< private >*/
    ESpinnerCachePrivate *priv;
};

#define E_SPINNER_CACHE_GET_PRIVATE(object)(G_TYPE_INSTANCE_GET_PRIVATE ((object), E_TYPE_SPINNER_CACHE, ESpinnerCachePrivate))

struct _ESpinnerCachePrivate
{
    /* Hash table of GdkScreen -> ESpinnerCacheData */
    GHashTable *hash;
};

typedef struct
{
    guint ref_count;
    GtkIconSize size;
    int width;
    int height;
    GdkPixbuf **animation_pixbufs;
    guint n_animation_pixbufs;
} ESpinnerImages;

#define LAST_ICON_SIZE          GTK_ICON_SIZE_DIALOG + 1
#define SPINNER_ICON_NAME       "process-working"
#define SPINNER_FALLBACK_ICON_NAME  "gnome-spinner"
#define E_SPINNER_IMAGES_INVALID    ((ESpinnerImages *) 0x1)

typedef struct
{
    GdkScreen *screen;
    GtkIconTheme *icon_theme;
    ESpinnerImages *images[LAST_ICON_SIZE];
} ESpinnerCacheData;

static void e_spinner_cache_class_init (ESpinnerCacheClass *klass);
static void e_spinner_cache_init      (ESpinnerCache *cache);

static GObjectClass *e_spinner_cache_parent_class;
static gpointer spinner_cache = NULL;

static GType
e_spinner_cache_get_type (void)
{
    static GType type = 0;

    if (G_UNLIKELY (type == 0))
    {
        const GTypeInfo our_info =
        {
            sizeof (ESpinnerCacheClass),
            NULL,
            NULL,
            (GClassInitFunc) e_spinner_cache_class_init,
            NULL,
            NULL,
            sizeof (ESpinnerCache),
            0,
            (GInstanceInitFunc) e_spinner_cache_init
        };

        type = g_type_register_static (G_TYPE_OBJECT,
                           "ESpinnerCache",
                           &our_info, 0);
    }

    return type;
}

static ESpinnerImages *
e_spinner_images_ref (ESpinnerImages *images)
{
    g_return_val_if_fail (images != NULL, NULL);

    images->ref_count++;

    return images;
}

static void
e_spinner_images_unref (ESpinnerImages *images)
{
    g_return_if_fail (images != NULL);

    images->ref_count--;
    if (images->ref_count == 0)
    {
        guint i;

        LOG ("Freeing spinner images %p for size %d", images, images->size);

        for (i = 0; i < images->n_animation_pixbufs; ++i)
        {
            g_object_unref (images->animation_pixbufs[i]);
        }
        g_free (images->animation_pixbufs);

        g_free (images);
    }
}

static void
e_spinner_cache_data_unload (ESpinnerCacheData *data)
{
    GtkIconSize size;
    ESpinnerImages *images;

    g_return_if_fail (data != NULL);

    LOG ("ESpinnerDataCache unload for screen %p", data->screen);

    for (size = GTK_ICON_SIZE_INVALID; size < LAST_ICON_SIZE; ++size)
    {
        images = data->images[size];
        data->images[size] = NULL;

        if (images != NULL && images != E_SPINNER_IMAGES_INVALID)
        {
            e_spinner_images_unref (images);
        }
    }
}

static GdkPixbuf *
extract_frame (GdkPixbuf *grid_pixbuf,
           int x,
           int y,
           int size)
{
    GdkPixbuf *pixbuf;

    if (x + size > gdk_pixbuf_get_width (grid_pixbuf) ||
        y + size > gdk_pixbuf_get_height (grid_pixbuf))
    {
        return NULL;
    }

    pixbuf = gdk_pixbuf_new_subpixbuf (grid_pixbuf,
                       x, y,
                       size, size);
    g_return_val_if_fail (pixbuf != NULL, NULL);

    return pixbuf;
}

static GdkPixbuf *
scale_to_size (GdkPixbuf *pixbuf,
           int dw,
           int dh)
{
    GdkPixbuf *result;
    int pw, ph;

    g_return_val_if_fail (pixbuf != NULL, NULL);

    pw = gdk_pixbuf_get_width (pixbuf);
    ph = gdk_pixbuf_get_height (pixbuf);

    if (pw != dw || ph != dh)
    {
        result = e_icon_factory_pixbuf_scale (pixbuf, dw, dh);
        g_object_unref (pixbuf);
        return result;
    }

    return pixbuf;
}

static ESpinnerImages *
e_spinner_images_load (GdkScreen *screen,
              GtkIconTheme *icon_theme,
              GtkIconSize icon_size)
{
    ESpinnerImages *images;
    GdkPixbuf *icon_pixbuf, *pixbuf;
    GtkIconInfo *icon_info = NULL;
    int grid_width, grid_height, x, y, requested_size, size, isw, ish, n;
    const char *icon;
    GSList *list = NULL, *l;

    LOG ("ESpinnerCacheData loading for screen %p at size %d", screen, icon_size);

    START_PROFILER ("loading spinner animation")

    if (!gtk_icon_size_lookup_for_settings (gtk_settings_get_for_screen (screen),
                        icon_size, &isw, &ish)) goto loser;

    requested_size = MAX (ish, isw);

    /* Load the animation. The 'rest icon' is the 0th frame */
    icon_info = gtk_icon_theme_lookup_icon (icon_theme,
                        SPINNER_ICON_NAME,
                            requested_size, 0);
    if (icon_info == NULL)
    {
        g_warning ("Throbber animation not found");

        /* If the icon naming spec compliant name wasn't found, try the old name */
        icon_info = gtk_icon_theme_lookup_icon (icon_theme,
                            SPINNER_FALLBACK_ICON_NAME,
                            requested_size, 0);
        if (icon_info == NULL)
        {
            g_warning ("Throbber fallback animation not found either");
            goto loser;
        }
    }
    if (icon_info == NULL) {
        g_warning ("icon_info is NULL");
        goto loser;
    }

    size = gtk_icon_info_get_base_size (icon_info);
    icon = gtk_icon_info_get_filename (icon_info);
    if (icon == NULL) goto loser;

    icon_pixbuf = gdk_pixbuf_new_from_file (icon, NULL);
    gtk_icon_info_free (icon_info);
    icon_info = NULL;

    if (icon_pixbuf == NULL)
    {
        g_warning ("Could not load the spinner file");
        goto loser;
    }

    grid_width = gdk_pixbuf_get_width (icon_pixbuf);
    grid_height = gdk_pixbuf_get_height (icon_pixbuf);

    n = 0;
    for (y = 0; y < grid_height; y += size)
    {
        for (x = 0; x < grid_width ; x += size)
        {
            pixbuf = extract_frame (icon_pixbuf, x, y, size);

            if (pixbuf)
            {
                list = g_slist_prepend (list, pixbuf);
                ++n;
            }
            else
            {
                g_warning ("Cannot extract frame (%d, %d) from the grid\n", x, y);
            }
        }
    }

    g_object_unref (icon_pixbuf);

    if (list == NULL || n <= 0) goto loser;

    if (size > requested_size)
    {
        for (l = list; l != NULL; l = l->next)
        {
            l->data = scale_to_size (l->data, isw, ish);
        }
    }

    /* Now we've successfully got all the data */
    images = g_new (ESpinnerImages, 1);
    images->ref_count = 1;

    images->size = icon_size;
    images->width = images->height = requested_size;

    images->n_animation_pixbufs = n;
    images->animation_pixbufs = g_new (GdkPixbuf *, n);

    for (l = list; l != NULL; l = l->next)
    {
        if (l->data)
            images->animation_pixbufs[--n] = l->data;
    }
    if (n != 0) {
        g_warning ("n != 0 \n");
    }

    g_slist_free (list);

    STOP_PROFILER ("loading spinner animation")

    return images;

loser:
    if (icon_info)
    {
        gtk_icon_info_free (icon_info);
    }
    g_slist_foreach (list, (GFunc) g_object_unref, NULL);

    STOP_PROFILER ("loading spinner animation")

    return NULL;
}

static ESpinnerCacheData *
e_spinner_cache_data_new (GdkScreen *screen)
{
    ESpinnerCacheData *data;

    data = g_new0 (ESpinnerCacheData, 1);

    data->screen = screen;
    data->icon_theme = gtk_icon_theme_get_for_screen (screen);
    g_signal_connect_swapped (data->icon_theme, "changed",
                  G_CALLBACK (e_spinner_cache_data_unload),
                  data);

    return data;
}

static void
e_spinner_cache_data_free (ESpinnerCacheData *data)
{
    g_return_if_fail (data != NULL);
    g_return_if_fail (data->icon_theme != NULL);

    g_signal_handlers_disconnect_by_func
        (data->icon_theme,
         G_CALLBACK (e_spinner_cache_data_unload), data);

    e_spinner_cache_data_unload (data);

    g_free (data);
}

static ESpinnerImages *
e_spinner_cache_get_images (ESpinnerCache *cache,
                   GdkScreen *screen,
                   GtkIconSize icon_size)
{
    ESpinnerCachePrivate *priv = cache->priv;
    ESpinnerCacheData *data;
    ESpinnerImages *images;

    LOG ("Getting animation images for screen %p at size %d", screen, icon_size);

    g_return_val_if_fail (icon_size >= 0 && icon_size < LAST_ICON_SIZE, NULL);

    /* Backward compat: "invalid" meant "native" size which doesn't exist anymore */
    if (icon_size == GTK_ICON_SIZE_INVALID)
    {
        icon_size = GTK_ICON_SIZE_DIALOG;
    }

    data = g_hash_table_lookup (priv->hash, screen);
    if (data == NULL)
    {
        data = e_spinner_cache_data_new (screen);
        /* FIXME: think about what happens when the screen's display is closed later on */
        g_hash_table_insert (priv->hash, screen, data);
    }

    images = data->images[icon_size];
    if (images == E_SPINNER_IMAGES_INVALID)
    {
        /* Load failed, but don't try endlessly again! */
        return NULL;
    }

    if (images != NULL)
    {
        /* Return cached data */
        return e_spinner_images_ref (images);
    }

    images = e_spinner_images_load (screen, data->icon_theme, icon_size);

    if (images == NULL)
    {
        /* Mark as failed-to-load */
        data->images[icon_size] = E_SPINNER_IMAGES_INVALID;

        return NULL;
    }

    data->images[icon_size] = images;

    return e_spinner_images_ref (images);
}

static void
e_spinner_cache_init (ESpinnerCache *cache)
{
    ESpinnerCachePrivate *priv;

    priv = cache->priv = E_SPINNER_CACHE_GET_PRIVATE (cache);

    LOG ("ESpinnerCache initialising");

    priv->hash = g_hash_table_new_full (g_direct_hash, g_direct_equal,
                        NULL,
                        (GDestroyNotify) e_spinner_cache_data_free);
}

static void
e_spinner_cache_finalize (GObject *object)
{
    ESpinnerCache *cache = E_SPINNER_CACHE (object);
    ESpinnerCachePrivate *priv = cache->priv;

    g_hash_table_destroy (priv->hash);

    LOG ("ESpinnerCache finalised");

    G_OBJECT_CLASS (e_spinner_cache_parent_class)->finalize (object);
}

static void
e_spinner_cache_class_init (ESpinnerCacheClass *klass)
{
    GObjectClass *object_class = G_OBJECT_CLASS (klass);

    e_spinner_cache_parent_class = g_type_class_peek_parent (klass);

    object_class->finalize = e_spinner_cache_finalize;

    g_type_class_add_private (object_class, sizeof (ESpinnerCachePrivate));
}

static ESpinnerCache *
e_spinner_cache_ref (void)
{
    if (G_UNLIKELY (spinner_cache == NULL))
    {
        spinner_cache = g_object_new (E_TYPE_SPINNER_CACHE, NULL);
        g_object_add_weak_pointer (
                        G_OBJECT (spinner_cache), &spinner_cache);
    }

    return g_object_ref_sink (spinner_cache);
}

/* Spinner implementation */

#define SPINNER_TIMEOUT 125 /* ms */

#define E_SPINNER_GET_PRIVATE(object)(G_TYPE_INSTANCE_GET_PRIVATE ((object), E_TYPE_SPINNER, ESpinnerDetails))

struct _ESpinnerDetails
{
    GtkIconTheme *icon_theme;
    ESpinnerCache *cache;
    GtkIconSize size;
    ESpinnerImages *images;
    guint current_image;
    guint timeout;
    guint timer_task;
    guint spinning : 1;
    guint need_load : 1;
};

static void e_spinner_class_init (ESpinnerClass *class);
static void e_spinner_init      (ESpinner *spinner);

static GObjectClass *parent_class;

GType
e_spinner_get_type (void)
{
    static GType type = 0;

    if (G_UNLIKELY (type == 0))
    {
        const GTypeInfo our_info =
        {
            sizeof (ESpinnerClass),
            NULL, /* base_init */
            NULL, /* base_finalize */
            (GClassInitFunc) e_spinner_class_init,
            NULL,
            NULL, /* class_data */
            sizeof (ESpinner),
            0, /* n_preallocs */
            (GInstanceInitFunc) e_spinner_init
        };

        type = g_type_register_static (GTK_TYPE_WIDGET,
                           "ESpinner",
                           &our_info, 0);
    }

    return type;
}

static gboolean
e_spinner_load_images (ESpinner *spinner)
{
    ESpinnerDetails *details = spinner->details;

    if (details->need_load)
    {
        START_PROFILER ("e_spinner_load_images")

        details->images =
            e_spinner_cache_get_images
                (details->cache,
                 gtk_widget_get_screen (GTK_WIDGET (spinner)),
                 details->size);

        STOP_PROFILER ("e_spinner_load_images")

        details->current_image = 0; /* 'rest' icon */
        details->need_load = FALSE;
    }

    return details->images != NULL;
}

static void
e_spinner_unload_images (ESpinner *spinner)
{
    ESpinnerDetails *details = spinner->details;

    if (details->images != NULL)
    {
        e_spinner_images_unref (details->images);
        details->images = NULL;
    }

    details->current_image = 0;
    details->need_load = TRUE;
}

static void
icon_theme_changed_cb (GtkIconTheme *icon_theme,
               ESpinner *spinner)
{
    e_spinner_unload_images (spinner);
    gtk_widget_queue_resize (GTK_WIDGET (spinner));
}

static void
e_spinner_init (ESpinner *spinner)
{
    ESpinnerDetails *details;

    details = spinner->details = E_SPINNER_GET_PRIVATE (spinner);

    GTK_WIDGET_SET_FLAGS (GTK_WIDGET (spinner), GTK_NO_WINDOW);

    details->cache = e_spinner_cache_ref ();
    details->size = GTK_ICON_SIZE_DIALOG;
    details->spinning = FALSE;
    details->timeout = SPINNER_TIMEOUT;
    details->need_load = TRUE;
}

static int
e_spinner_expose (GtkWidget *widget,
             GdkEventExpose *event)
{
    ESpinner *spinner = E_SPINNER (widget);
    ESpinnerDetails *details = spinner->details;
    ESpinnerImages *images;
    GdkPixbuf *pixbuf;
    GdkGC *gc;
    int x_offset, y_offset, width, height;
    GdkRectangle pix_area, dest;

    if (!GTK_WIDGET_DRAWABLE (spinner))
    {
        return FALSE;
    }

    if (details->need_load &&
        !e_spinner_load_images (spinner))
    {
        return FALSE;
    }

    images = details->images;
    if (images == NULL)
    {
        return FALSE;
    }

    /* Otherwise |images| will be NULL anyway */
    g_return_val_if_fail (images->n_animation_pixbufs > 0, FALSE);

    g_return_val_if_fail (details->current_image >= 0 &&
          details->current_image < images->n_animation_pixbufs, FALSE);

    pixbuf = images->animation_pixbufs[details->current_image];

    g_return_val_if_fail (pixbuf != NULL, FALSE);

    width = gdk_pixbuf_get_width (pixbuf);
    height = gdk_pixbuf_get_height (pixbuf);

    /* Compute the offsets for the image centered on our allocation */
    x_offset = (widget->allocation.width - width) / 2;
    y_offset = (widget->allocation.height - height) / 2;

    pix_area.x = x_offset + widget->allocation.x;
    pix_area.y = y_offset + widget->allocation.y;
    pix_area.width = width;
    pix_area.height = height;

    if (!gdk_rectangle_intersect (&event->area, &pix_area, &dest))
    {
        return FALSE;
    }

    gc = gdk_gc_new (widget->window);
    gdk_draw_pixbuf (widget->window, gc, pixbuf,
             dest.x - x_offset - widget->allocation.x,
             dest.y - y_offset - widget->allocation.y,
             dest.x, dest.y,
             dest.width, dest.height,
             GDK_RGB_DITHER_MAX, 0, 0);
    g_object_unref (gc);

    return FALSE;
}

static gboolean
bump_spinner_frame_cb (ESpinner *spinner)
{
    ESpinnerDetails *details = spinner->details;

    /* This can happen when we've unloaded the images on a theme
     * change, but haven't been in the queued size request yet.
     * Just skip this update.
     */
    if (details->images == NULL) return TRUE;

    details->current_image++;
    if (details->current_image >= details->images->n_animation_pixbufs)
    {
        /* the 0th frame is the 'rest' icon */
        details->current_image = MIN (1, details->images->n_animation_pixbufs);
    }

    gtk_widget_queue_draw (GTK_WIDGET (spinner));

    /* run again */
    return TRUE;
}

/**
 * e_spinner_start:
 * @spinner: a #ESpinner
 *
 * Start the spinner animation.
 **/
void
e_spinner_start (ESpinner *spinner)
{
    ESpinnerDetails *details = spinner->details;

    details->spinning = TRUE;

    if (GTK_WIDGET_MAPPED (GTK_WIDGET (spinner)) &&
        details->timer_task == 0 &&
        e_spinner_load_images (spinner))
    {
        /* the 0th frame is the 'rest' icon */
        details->current_image = MIN (1, details->images->n_animation_pixbufs);

        details->timer_task =
            g_timeout_add_full (G_PRIORITY_LOW,
                                details->timeout,
                            (GSourceFunc) bump_spinner_frame_cb,
                            spinner,
                            NULL);
    }
}

static void
e_spinner_remove_update_callback (ESpinner *spinner)
{
    ESpinnerDetails *details = spinner->details;

    if (details->timer_task != 0)
    {
        g_source_remove (details->timer_task);
        details->timer_task = 0;
    }
}

/**
 * e_spinner_stop:
 * @spinner: a #ESpinner
 *
 * Stop the spinner animation.
 **/
void
e_spinner_stop (ESpinner *spinner)
{
    ESpinnerDetails *details = spinner->details;

    details->spinning = FALSE;
    details->current_image = 0;

    if (details->timer_task != 0)
    {
        e_spinner_remove_update_callback (spinner);

        if (GTK_WIDGET_MAPPED (GTK_WIDGET (spinner)))
        {
            gtk_widget_queue_draw (GTK_WIDGET (spinner));
        }
    }
}

/*
 * e_spinner_set_size:
 * @spinner: a #ESpinner
 * @size: the size of type %GtkIconSize
 *
 * Set the size of the spinner.
 **/
void
e_spinner_set_size (ESpinner *spinner,
               GtkIconSize size)
{
    if (size == GTK_ICON_SIZE_INVALID)
    {
        size = GTK_ICON_SIZE_DIALOG;
    }

    if (size != spinner->details->size)
    {
        e_spinner_unload_images (spinner);

        spinner->details->size = size;

        gtk_widget_queue_resize (GTK_WIDGET (spinner));
    }
}

#if 0
/*
 * e_spinner_set_timeout:
 * @spinner: a #ESpinner
 * @timeout: time delay between updates to the spinner.
 *
 * Sets the timeout delay for spinner updates.
 **/
void
e_spinner_set_timeout (ESpinner *spinner,
              guint timeout)
{
    ESpinnerDetails *details = spinner->details;

    if (timeout != details->timeout)
    {
        e_spinner_stop (spinner);

        details->timeout = timeout;

        if (details->spinning)
        {
            e_spinner_start (spinner);
        }
    }
}
#endif

static void
e_spinner_size_request (GtkWidget *widget,
               GtkRequisition *requisition)
{
    ESpinner *spinner = E_SPINNER (widget);
    ESpinnerDetails *details = spinner->details;

    if ((details->need_load &&
         !e_spinner_load_images (spinner)) ||
            details->images == NULL)
    {
        requisition->width = requisition->height = 0;
        gtk_icon_size_lookup_for_settings (gtk_widget_get_settings (widget),
                           details->size,
                           &requisition->width,
                               &requisition->height);
        return;
    }

    requisition->width = details->images->width;
    requisition->height = details->images->height;

    /* FIXME fix this hack */
    /* allocate some extra margin so we don't butt up against toolbar edges */
    if (details->size != GTK_ICON_SIZE_MENU)
    {
        requisition->width += 2;
        requisition->height += 2;
    }
}

static void
e_spinner_map (GtkWidget *widget)
{
    ESpinner *spinner = E_SPINNER (widget);
    ESpinnerDetails *details = spinner->details;

    GTK_WIDGET_CLASS (parent_class)->map (widget);

    if (details->spinning)
    {
        e_spinner_start (spinner);
    }
}

static void
e_spinner_unmap (GtkWidget *widget)
{
    ESpinner *spinner = E_SPINNER (widget);

    e_spinner_remove_update_callback (spinner);

    GTK_WIDGET_CLASS (parent_class)->unmap (widget);
}

static void
e_spinner_dispose (GObject *object)
{
    ESpinner *spinner = E_SPINNER (object);

    g_signal_handlers_disconnect_by_func
            (spinner->details->icon_theme,
         G_CALLBACK (icon_theme_changed_cb), spinner);

    G_OBJECT_CLASS (parent_class)->dispose (object);
}

static void
e_spinner_finalize (GObject *object)
{
    ESpinner *spinner = E_SPINNER (object);

    e_spinner_remove_update_callback (spinner);
    e_spinner_unload_images (spinner);

    g_object_unref (spinner->details->cache);

    G_OBJECT_CLASS (parent_class)->finalize (object);
}

static void
e_spinner_screen_changed (GtkWidget *widget,
                 GdkScreen *old_screen)
{
    ESpinner *spinner = E_SPINNER (widget);
    ESpinnerDetails *details = spinner->details;
    GdkScreen *screen;

    if (GTK_WIDGET_CLASS (parent_class)->screen_changed)
    {
        GTK_WIDGET_CLASS (parent_class)->screen_changed (widget, old_screen);
    }

    screen = gtk_widget_get_screen (widget);

    /* FIXME: this seems to be happening when then spinner is destroyed!? */
    if (old_screen == screen) return;

    /* We'll get mapped again on the new screen, but not unmapped from
     * the old screen, so remove timeout here.
     */
    e_spinner_remove_update_callback (spinner);

    e_spinner_unload_images (spinner);

    if (old_screen != NULL)
    {
        g_signal_handlers_disconnect_by_func
            (gtk_icon_theme_get_for_screen (old_screen),
             G_CALLBACK (icon_theme_changed_cb), spinner);
    }

    details->icon_theme = gtk_icon_theme_get_for_screen (screen);
    g_signal_connect (details->icon_theme, "changed",
              G_CALLBACK (icon_theme_changed_cb), spinner);
}

static void
e_spinner_class_init (ESpinnerClass *class)
{
    GObjectClass *object_class =  G_OBJECT_CLASS (class);
    GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);

    parent_class = g_type_class_peek_parent (class);

    object_class->dispose = e_spinner_dispose;
    object_class->finalize = e_spinner_finalize;

    widget_class->expose_event = e_spinner_expose;
    widget_class->size_request = e_spinner_size_request;
    widget_class->map = e_spinner_map;
    widget_class->unmap = e_spinner_unmap;
    widget_class->screen_changed = e_spinner_screen_changed;

    g_type_class_add_private (object_class, sizeof (ESpinnerDetails));
}

/*
 * e_spinner_new:
 *
 * Create a new #ESpinner. The spinner is a widget
 * that gives the user feedback about network status with
 * an animated image.
 *
 * Return Value: the spinner #GtkWidget
 **/
GtkWidget *
e_spinner_new (void)
{
    return GTK_WIDGET (g_object_new (E_TYPE_SPINNER, NULL));
}