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

/*
 * Map widget.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Hans Petter Jansson <hpj@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#include <config.h>
#include <math.h>
#include <stdlib.h>
#include <gdk/gdkkeysyms.h>
#include <glib/gi18n.h>

#include "e-util/e-util-private.h"
#include "e-util/e-util.h"

#include "e-map.h"

/* backward-compatibility cruft */
#include "e-util/gtk-compat.h"

/* Scroll step increment */

#define SCROLL_STEP_SIZE 32

/* */

#define E_MAP_GET_WIDTH(map) gdk_pixbuf_get_width(((EMapPrivate *) E_MAP(map)->priv)->map_render_pixbuf)
#define E_MAP_GET_HEIGHT(map) gdk_pixbuf_get_height(((EMapPrivate *) E_MAP(map)->priv)->map_render_pixbuf)

/* Zoom state - keeps track of animation hacks */

typedef enum
{
    E_MAP_ZOOMED_IN,
    E_MAP_ZOOMED_OUT,
    E_MAP_ZOOMING_IN,
    E_MAP_ZOOMING_OUT
}
EMapZoomState;

/* Private part of the EMap structure */

struct _EMapPrivate {
    /* Pointer to map image */
    GdkPixbuf *map_pixbuf, *map_render_pixbuf;

    /* Settings */
    gboolean frozen, smooth_zoom;

    /* Adjustments for scrolling */
    GtkAdjustment *hadj;
    GtkAdjustment *vadj;

    /* Current scrolling offsets */
    gint xofs, yofs;

    /* Realtime zoom data */
    EMapZoomState zoom_state;
    gdouble zoom_target_long, zoom_target_lat;

    /* Dots */
    GPtrArray *points;
};

/* Internal prototypes */

static void e_map_finalize (GObject *object);
static void e_map_realize (GtkWidget *widget);
static void e_map_size_request (GtkWidget *widget, GtkRequisition *requisition);
static void e_map_size_allocate (GtkWidget *widget, GtkAllocation *allocation);
static gint e_map_button_press (GtkWidget *widget, GdkEventButton *event);
static gint e_map_button_release (GtkWidget *widget, GdkEventButton *event);
static gint e_map_motion (GtkWidget *widget, GdkEventMotion *event);
static gint e_map_expose (GtkWidget *widget, GdkEventExpose *event);
static gint e_map_key_press (GtkWidget *widget, GdkEventKey *event);
static void e_map_set_scroll_adjustments (GtkWidget *widget, GtkAdjustment *hadj, GtkAdjustment *vadj);

static void update_render_pixbuf (EMap *map, GdkInterpType interp, gboolean render_overlays);
static void set_scroll_area (EMap *view);
static void request_paint_area (EMap *view, GdkRectangle *area);
static void center_at (EMap *map, gint x, gint y, gboolean scroll);
static void smooth_center_at (EMap *map, gint x, gint y);
static void scroll_to (EMap *view, gint x, gint y);
static void zoom_do (EMap *map);
static gint load_map_background (EMap *view, gchar *name);
static void adjustment_changed_cb (GtkAdjustment *adj, gpointer data);
static void update_and_paint (EMap *map);
static void update_render_point (EMap *map, EMapPoint *point);
static void repaint_point (EMap *map, EMapPoint *point);

G_DEFINE_TYPE (
    EMap,
    e_map,
    GTK_TYPE_WIDGET)

/* ----------------- *
 * Widget management *
 * ----------------- */

/* Class initialization function for the map view */

static void
e_map_class_init (EMapClass *class)
{
    GObjectClass *gobject_class;
    GtkWidgetClass *widget_class;

    gobject_class = (GObjectClass *) class;
    widget_class = (GtkWidgetClass *) class;

    gobject_class->finalize = e_map_finalize;

    class->set_scroll_adjustments = e_map_set_scroll_adjustments;
    widget_class->set_scroll_adjustments_signal = g_signal_new ("set_scroll_adjustments",
                                    G_OBJECT_CLASS_TYPE (gobject_class),
                                    G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
                                    G_STRUCT_OFFSET (EMapClass, set_scroll_adjustments),
                                    NULL, NULL,
                                    e_marshal_NONE__OBJECT_OBJECT,
                                    G_TYPE_NONE, 2,
                                    GTK_TYPE_ADJUSTMENT,
                                    GTK_TYPE_ADJUSTMENT);

    widget_class->realize = e_map_realize;
    widget_class->size_request = e_map_size_request;
    widget_class->size_allocate = e_map_size_allocate;
    widget_class->button_press_event = e_map_button_press;
    widget_class->button_release_event = e_map_button_release;
    widget_class->motion_notify_event = e_map_motion;
    widget_class->expose_event = e_map_expose;
    widget_class->key_press_event = e_map_key_press;
}

/* Object initialization function for the map view */

static void
e_map_init (EMap *view)
{
    EMapPrivate *priv;
    GtkWidget *widget;
    gchar *map_file_name = g_build_filename (EVOLUTION_IMAGESDIR, "world_map-960.png", NULL);

    widget = GTK_WIDGET (view);

    priv = g_new0 (EMapPrivate, 1);
    view->priv = priv;

    load_map_background (view, map_file_name);
    g_free (map_file_name);
    priv->frozen = FALSE;
    priv->smooth_zoom = TRUE;
    priv->zoom_state = E_MAP_ZOOMED_OUT;
        priv->points = g_ptr_array_new ();

    gtk_widget_set_can_focus (widget, TRUE);
    gtk_widget_set_has_window (widget, TRUE);
}

/* Finalize handler for the map view */

static void
e_map_finalize (GObject *object)
{
    EMap *view;
    EMapPrivate *priv;

    g_return_if_fail (object != NULL);
    g_return_if_fail (E_IS_MAP (object));

    view = E_MAP (object);
    priv = view->priv;

    g_signal_handlers_disconnect_by_func (priv->hadj, adjustment_changed_cb, view);
    g_signal_handlers_disconnect_by_func (priv->vadj, adjustment_changed_cb, view);

    g_object_unref ((priv->hadj));
    priv->hadj = NULL;

    g_object_unref ((priv->vadj));
    priv->vadj = NULL;

    if (priv->map_pixbuf)
    {
        g_object_unref (priv->map_pixbuf);
        priv->map_pixbuf = NULL;
    }

    if (priv->map_render_pixbuf)
    {
        g_object_unref (priv->map_render_pixbuf);
        priv->map_render_pixbuf = NULL;
    }

    g_free (priv);
    view->priv = NULL;

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

/* Realize handler for the map view */

static void
e_map_realize (GtkWidget *widget)
{
    GtkAllocation allocation;
    GdkWindowAttr attr;
    GdkWindow *window;
    GtkStyle *style;
    gint attr_mask;

    g_return_if_fail (widget != NULL);
    g_return_if_fail (E_IS_MAP (widget));

    gtk_widget_set_realized (widget, TRUE);

    gtk_widget_get_allocation (widget, &allocation);

    attr.window_type = GDK_WINDOW_CHILD;
    attr.x = allocation.x;
    attr.y = allocation.y;
    attr.width = allocation.width;
    attr.height = allocation.height;
    attr.wclass = GDK_INPUT_OUTPUT;
    attr.visual = gdk_rgb_get_visual ();
    attr.colormap = gdk_rgb_get_colormap ();
    attr.event_mask = gtk_widget_get_events (widget) |
      GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK | GDK_KEY_PRESS_MASK |
      GDK_POINTER_MOTION_MASK;

    attr_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;

    window = gdk_window_new (
        gtk_widget_get_parent_window (widget), &attr, attr_mask);
    gtk_widget_set_window (widget, window);
    gdk_window_set_user_data (window, widget);

    style = gtk_widget_get_style (widget);
    style = gtk_style_attach (style, window);
    gtk_widget_set_style (widget, style);

    gdk_window_set_back_pixmap (window, NULL, FALSE);
    update_render_pixbuf (E_MAP (widget), GDK_INTERP_BILINEAR, TRUE);
}

/* Size_request handler for the map view */

static void
e_map_size_request (GtkWidget *widget, GtkRequisition *requisition)
{
    EMap *view;
    EMapPrivate *priv;

    g_return_if_fail (widget != NULL);
    g_return_if_fail (E_IS_MAP (widget));
    g_return_if_fail (requisition != NULL);

    view = E_MAP (widget);
    priv = view->priv;

    /* TODO: Put real sizes here. */

    requisition->width = gdk_pixbuf_get_width (priv->map_pixbuf);
    requisition->height = gdk_pixbuf_get_height (priv->map_pixbuf);
}

/* Size_allocate handler for the map view */

static void
e_map_size_allocate (GtkWidget *widget, GtkAllocation *allocation)
{
    EMap *view;
    GdkRectangle area;

    g_return_if_fail (widget != NULL);
    g_return_if_fail (E_IS_MAP (widget));
    g_return_if_fail (allocation != NULL);

    view = E_MAP (widget);

    /* Resize the window */

    gtk_widget_set_allocation (widget, allocation);

    if (gtk_widget_get_realized (widget)) {
        GdkWindow *window;

        window = gtk_widget_get_window (widget);

        gdk_window_move_resize (
            window, allocation->x, allocation->y,
            allocation->width, allocation->height);

        area.x = 0;
        area.y = 0;
        area.width = allocation->width;
        area.height = allocation->height;
        request_paint_area (E_MAP (widget), &area);
    }

    update_render_pixbuf (view, GDK_INTERP_BILINEAR, TRUE);
}

/* Button press handler for the map view */

static gint
e_map_button_press (GtkWidget *widget, GdkEventButton *event)
{
    if (!gtk_widget_has_focus (widget)) gtk_widget_grab_focus (widget);
        return TRUE;
}

/* Button release handler for the map view */

static gint
e_map_button_release (GtkWidget *widget, GdkEventButton *event)
{
    if (event->button != 1) return FALSE;

    gdk_pointer_ungrab (event->time);
    return TRUE;
}

/* Motion handler for the map view */

static gint
e_map_motion (GtkWidget *widget, GdkEventMotion *event)
{
    return FALSE;

/*
 * if (event->is_hint)
 *   gdk_window_get_pointer(widget->window, &x, &y, &mods);
 * else
 * {
 *   x = event->x;
 *   y = event->y;
 * }
 *
 * return TRUE;
 */
}

/* Expose handler for the map view */

static gint
e_map_expose (GtkWidget *widget, GdkEventExpose *event)
{
    EMap *view;

    g_return_val_if_fail (widget != NULL, FALSE);
    g_return_val_if_fail (E_IS_MAP (widget), FALSE);
    g_return_val_if_fail (event != NULL, FALSE);

    view = E_MAP (widget);

    request_paint_area (view, &event->area);
    return TRUE;
}

/* Set_scroll_adjustments handler for the map view */

static void
e_map_set_scroll_adjustments (GtkWidget *widget, GtkAdjustment *hadj, GtkAdjustment *vadj)
{
    EMap *view;
    EMapPrivate *priv;
    gboolean need_adjust;

    g_return_if_fail (widget != NULL);
    g_return_if_fail (E_IS_MAP (widget));

    view = E_MAP (widget);
    priv = view->priv;

    if (hadj) g_return_if_fail (GTK_IS_ADJUSTMENT (hadj));
    else hadj = GTK_ADJUSTMENT (gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0));

    if (vadj) g_return_if_fail (GTK_IS_ADJUSTMENT (vadj));
    else vadj = GTK_ADJUSTMENT (gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0));

    if (priv->hadj && priv->hadj != hadj)
    {
        g_signal_handlers_disconnect_by_func (priv->hadj,
                              adjustment_changed_cb,
                              view);
        g_object_unref (priv->hadj);
    }

    if (priv->vadj && priv->vadj != vadj)
    {
        g_signal_handlers_disconnect_by_func (priv->vadj,
                              adjustment_changed_cb,
                              view);
        g_object_unref (priv->vadj);
    }

    need_adjust = FALSE;

    if (priv->hadj != hadj)
    {
        priv->hadj = hadj;
        g_object_ref_sink (priv->hadj);

        g_signal_connect (priv->hadj, "value_changed",
                  G_CALLBACK (adjustment_changed_cb), view);

        need_adjust = TRUE;
    }

    if (priv->vadj != vadj)
    {
        priv->vadj = vadj;
        g_object_ref_sink (priv->vadj);

        g_signal_connect (priv->vadj, "value_changed",
                  G_CALLBACK (adjustment_changed_cb), view);

        need_adjust = TRUE;
    }

    if (need_adjust) adjustment_changed_cb (NULL, view);
}

/* Key press handler for the map view */

static gint
e_map_key_press (GtkWidget *widget, GdkEventKey *event)
{
    EMap *view;
    EMapPrivate *priv;
    gboolean do_scroll;
    gint xofs, yofs;

    view = E_MAP (widget);
    priv = view->priv;

    switch (event->keyval)
    {
        case GDK_KEY_Up:
            do_scroll = TRUE;
            xofs = 0;
            yofs = -SCROLL_STEP_SIZE;
            break;

        case GDK_KEY_Down:
            do_scroll = TRUE;
            xofs = 0;
            yofs = SCROLL_STEP_SIZE;
            break;

        case GDK_KEY_Left:
            do_scroll = TRUE;
            xofs = -SCROLL_STEP_SIZE;
            yofs = 0;
            break;

        case GDK_KEY_Right:
            do_scroll = TRUE;
            xofs = SCROLL_STEP_SIZE;
            yofs = 0;
            break;

        default:
            return FALSE;
    }

    if (do_scroll)
    {
        gint page_size;
        gint upper;
        gint x, y;

        page_size = gtk_adjustment_get_page_size (priv->hadj);
        upper = gtk_adjustment_get_upper (priv->hadj);
        x = CLAMP (priv->xofs + xofs, 0, upper - page_size);

        page_size = gtk_adjustment_get_page_size (priv->vadj);
        upper = gtk_adjustment_get_upper (priv->vadj);
        y = CLAMP (priv->yofs + yofs, 0, upper - page_size);

        scroll_to (view, x, y);

        g_signal_handlers_block_matched (priv->hadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);
        g_signal_handlers_block_matched (priv->vadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);

        gtk_adjustment_set_value (priv->hadj, x);
        gtk_adjustment_set_value (priv->vadj, y);

        g_signal_emit_by_name (priv->hadj, "value_changed");
        g_signal_emit_by_name (priv->vadj, "value_changed");

        g_signal_handlers_unblock_matched (priv->hadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);
        g_signal_handlers_unblock_matched (priv->vadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);
    }

    return TRUE;
}

/* ---------------- *
 * Widget interface *
 * ---------------- */

/**
 * e_map_new:
 * @void:
 *
 * Creates a new empty map widget.
 *
 * Return value: A newly-created map widget.
 **/

EMap *
e_map_new (void)
{
    GtkWidget *widget;
    AtkObject *a11y;

    widget = g_object_new (E_TYPE_MAP, NULL);
    a11y = gtk_widget_get_accessible (widget);
    atk_object_set_name (a11y, _("World Map"));
    atk_object_set_role (a11y, ATK_ROLE_IMAGE);
    atk_object_set_description (a11y, _("Mouse-based interactive map widget for selecting timezone. Keyboard users should instead select the timezone from the drop-down combination box below."));
    return (E_MAP (widget));
}

/* --- Coordinate translation --- */

/* These functions translate coordinates between longitude/latitude and
 * the image x/y offsets, using the equidistant cylindrical projection.
 *
 * Longitude E <-180, 180]
 * Latitude  E <-90, 90]   */

void
e_map_window_to_world (EMap *map, gdouble win_x, gdouble win_y, gdouble *world_longitude, gdouble *world_latitude)
{
    EMapPrivate *priv;
    gint width, height;

    g_return_if_fail (map);

    priv = map->priv;
    g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (map)));

    width = gdk_pixbuf_get_width (priv->map_render_pixbuf);
    height = gdk_pixbuf_get_height (priv->map_render_pixbuf);

    *world_longitude = (win_x + priv->xofs - (gdouble) width / 2.0) /
        ((gdouble) width / 2.0) * 180.0;
    *world_latitude = ((gdouble) height / 2.0 - win_y - priv->yofs) /
        ((gdouble) height / 2.0) * 90.0;
}

void
e_map_world_to_window (EMap *map, gdouble world_longitude, gdouble world_latitude, gdouble *win_x, gdouble *win_y)
{
    EMapPrivate *priv;
    gint width, height;

    g_return_if_fail (map);

    priv = map->priv;
    g_return_if_fail (priv->map_render_pixbuf);
    g_return_if_fail (world_longitude >= -180.0 && world_longitude <= 180.0);
    g_return_if_fail (world_latitude >= -90.0 && world_latitude <= 90.0);

    width = gdk_pixbuf_get_width (priv->map_render_pixbuf);
    height = gdk_pixbuf_get_height (priv->map_render_pixbuf);

    *win_x = (width / 2.0 + (width / 2.0) * world_longitude / 180.0) - priv->xofs;
    *win_y = (height / 2.0 - (height / 2.0) * world_latitude / 90.0) - priv->yofs;

#ifdef DEBUG
    printf ("Map size: (%d, %d)\nCoords: (%.1f, %.1f) -> (%.1f, %.1f)\n---\n", width, height, world_longitude, world_latitude, *win_x, *win_y);
#endif
}

/* --- Zoom --- */

gdouble
e_map_get_magnification (EMap *map)
{
    EMapPrivate *priv;

    priv = map->priv;
    if (priv->zoom_state == E_MAP_ZOOMED_IN) return 2.0;
    else return 1.0;
}

void
e_map_zoom_to_location (EMap *map, gdouble longitude, gdouble latitude)
{
    EMapPrivate *priv;

    g_return_if_fail (map);
    g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (map)));

    priv = map->priv;

    if (priv->zoom_state == E_MAP_ZOOMED_IN) e_map_zoom_out (map);
    else if (priv->zoom_state != E_MAP_ZOOMED_OUT) return;

    priv->zoom_state = E_MAP_ZOOMING_IN;
    priv->zoom_target_long = longitude;
    priv->zoom_target_lat = latitude;

    zoom_do (map);
}

void
e_map_zoom_out (EMap *map)
{
    EMapPrivate *priv;

    g_return_if_fail (map);
    g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (map)));

    priv = map->priv;

    if (priv->zoom_state != E_MAP_ZOOMED_IN) return;

    priv->zoom_state = E_MAP_ZOOMING_OUT;
    zoom_do (map);
    priv->zoom_state = E_MAP_ZOOMED_OUT;
}

void
e_map_set_smooth_zoom (EMap *map, gboolean state)
{
    ((EMapPrivate *) map->priv)->smooth_zoom = state;
}

gboolean
e_map_get_smooth_zoom (EMap *map)
{
    return (((EMapPrivate *) map->priv)->smooth_zoom);
}

void
e_map_freeze (EMap *map)
{
    ((EMapPrivate *) map->priv)->frozen = TRUE;
}

void
e_map_thaw (EMap *map)
{
    ((EMapPrivate *) map->priv)->frozen = FALSE;
    update_and_paint (map);
}

/* --- Point manipulation --- */

EMapPoint *
e_map_add_point (EMap *map, gchar *name, gdouble longitude, gdouble latitude, guint32 color_rgba)
{
    EMapPrivate *priv;
    EMapPoint *point;

    priv = map->priv;
    point = g_new0 (EMapPoint, 1);

    point->name = name;  /* Can be NULL */
    point->longitude = longitude;
    point->latitude = latitude;
    point->rgba = color_rgba;

    g_ptr_array_add (priv->points, (gpointer) point);

    if (!priv->frozen)
    {
        update_render_point (map, point);
        repaint_point (map, point);
    }

    return point;
}

void
e_map_remove_point (EMap *map, EMapPoint *point)
{
    EMapPrivate *priv;

    priv = map->priv;
    g_ptr_array_remove (priv->points, point);

    if (!((EMapPrivate *) map->priv)->frozen)
    {
        /* FIXME: Re-scaling the whole pixbuf is more than a little
         * overkill when just one point is removed */

        update_render_pixbuf (map, GDK_INTERP_BILINEAR, TRUE);
        repaint_point (map, point);
    }

    g_free (point);
}

void
e_map_point_get_location (EMapPoint *point, gdouble *longitude, gdouble *latitude)
{
    *longitude = point->longitude;
    *latitude = point->latitude;
}

gchar *
e_map_point_get_name (EMapPoint *point)
{
    return point->name;
}

guint32
e_map_point_get_color_rgba (EMapPoint *point)
{
    return point->rgba;
}

void
e_map_point_set_color_rgba (EMap *map, EMapPoint *point, guint32 color_rgba)
{
    point->rgba = color_rgba;

    if (!((EMapPrivate *) map->priv)->frozen)
    {
        /* TODO: Redraw area around point only */

        update_render_point (map, point);
        repaint_point (map, point);
    }
}

void
e_map_point_set_data (EMapPoint *point, gpointer data)
{
    point->user_data = data;
}

gpointer
e_map_point_get_data (EMapPoint *point)
{
    return point->user_data;
}

gboolean
e_map_point_is_in_view (EMap *map, EMapPoint *point)
{
    EMapPrivate *priv;
    GtkAllocation allocation;
    gdouble x, y;

    priv = map->priv;
    if (!priv->map_render_pixbuf) return FALSE;

    e_map_world_to_window (map, point->longitude, point->latitude, &x, &y);
    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    if (x >= 0 && x < allocation.width &&
        y >= 0 && y < allocation.height)
        return TRUE;

    return FALSE;
}

EMapPoint *
e_map_get_closest_point (EMap *map, gdouble longitude, gdouble latitude, gboolean in_view)
{
    EMapPrivate *priv;
    EMapPoint *point_chosen = NULL, *point;
    gdouble min_dist = 0.0, dist;
    gdouble dx, dy;
    gint i;

    priv = map->priv;

    for (i = 0; i < priv->points->len; i++)
    {
        point = g_ptr_array_index (priv->points, i);
        if (in_view && !e_map_point_is_in_view (map, point)) continue;

        dx = point->longitude - longitude;
        dy = point->latitude - latitude;
        dist = dx * dx + dy * dy;

        if (!point_chosen || dist < min_dist)
        {
            min_dist = dist;
            point_chosen = point;
        }
    }

    return point_chosen;
}

/* ------------------ *
 * Internal functions *
 * ------------------ */

static void
repaint_visible (EMap *map)
{
    GdkRectangle area;
    GtkAllocation allocation;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    area.x = 0;
    area.y = 0;
    area.width = allocation.width;
    area.height = allocation.height;

    request_paint_area (map, &area);
}

static void
update_and_paint (EMap *map)
{
    update_render_pixbuf (map, GDK_INTERP_BILINEAR, TRUE);
    repaint_visible (map);
}

static gint
load_map_background (EMap *view, gchar *name)
{
    EMapPrivate *priv;
    GdkPixbuf *pb0;

    priv = view->priv;

    pb0 = gdk_pixbuf_new_from_file (name, NULL);
    if (!pb0)
        return FALSE;

    if (priv->map_pixbuf) g_object_unref (priv->map_pixbuf);
    priv->map_pixbuf = pb0;
    update_render_pixbuf (view, GDK_INTERP_BILINEAR, TRUE);

    return TRUE;
}

static void
update_render_pixbuf (EMap *map,
                      GdkInterpType interp,
                      gboolean render_overlays)
{
    EMapPrivate *priv;
    EMapPoint *point;
    GtkAllocation allocation;
    gint width, height, orig_width, orig_height;
    gdouble zoom;
    gint i;

    if (!gtk_widget_get_realized (GTK_WIDGET (map)))
        return;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    /* Set up value shortcuts */

    priv = map->priv;
    width = allocation.width;
    height = allocation.height;
    orig_width = gdk_pixbuf_get_width (priv->map_pixbuf);
    orig_height = gdk_pixbuf_get_height (priv->map_pixbuf);

    /* Compute scaled width and height based on the extreme dimension */

    if ((gdouble) width / orig_width > (gdouble) height / orig_height)
        zoom = (gdouble) width / (gdouble) orig_width;
    else
        zoom = (gdouble) height / (gdouble) orig_height;

    if (priv->zoom_state == E_MAP_ZOOMED_IN)
        zoom *= 2.0;
    height = (orig_height * zoom) + 0.5;
    width = (orig_width * zoom) + 0.5;

    /* Reallocate the pixbuf */

    if (priv->map_render_pixbuf) g_object_unref (priv->map_render_pixbuf);
    priv->map_render_pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE,    /* No alpha */
                          8, width, height);

    /* Scale the original map into the rendering pixbuf */

    if (width > 1 && height > 1)
    {
        gdk_pixbuf_scale (priv->map_pixbuf, priv->map_render_pixbuf, 0, 0,  /* Dest (x, y) */
                  width, height, 0, 0,                  /* Offset (x, y) */
                  zoom, zoom,                       /* Scale (x, y) */
                  interp);
    }

    if (render_overlays)
    {
        /* Add points */

        for (i = 0; i < priv->points->len; i++)
        {
            point = g_ptr_array_index (priv->points, i);
            update_render_point (map, point);
        }
    }

    /* Compute image offsets with respect to window */

    set_scroll_area (map);
}

/* Queues a repaint of the specified area in window coordinates */

static void
request_paint_area (EMap *view, GdkRectangle *area)
{
    EMapPrivate *priv;
    gint width, height;

    if (!gtk_widget_is_drawable (GTK_WIDGET (view)) ||
        !gtk_widget_get_realized (GTK_WIDGET (view))) return;

    priv = view->priv;
    if (!priv->map_render_pixbuf) return;

    width = MIN (area->width, E_MAP_GET_WIDTH (view));
    height = MIN (area->height, E_MAP_GET_HEIGHT (view));

    /* This satisfies paranoia. To be removed */

    if (priv->xofs + width > gdk_pixbuf_get_width (priv->map_render_pixbuf))
        width = gdk_pixbuf_get_width (priv->map_render_pixbuf) - priv->xofs;

    if (priv->yofs + height > gdk_pixbuf_get_height (priv->map_render_pixbuf))
        height = gdk_pixbuf_get_height (priv->map_render_pixbuf) - priv->yofs;

    /* We rely on the fast case always being the case, since we load and
   * preprocess the source pixbuf ourselves */

    if (gdk_pixbuf_get_colorspace (priv->map_render_pixbuf) == GDK_COLORSPACE_RGB && !gdk_pixbuf_get_has_alpha (priv->map_render_pixbuf) &&
        gdk_pixbuf_get_bits_per_sample (priv->map_render_pixbuf) == 8)
    {
        GtkStyle *style;
        GdkWindow *window;
        guchar *pixels;
        gint rowstride;

        style = gtk_widget_get_style (GTK_WIDGET (view));
        window = gtk_widget_get_window (GTK_WIDGET (view));

        rowstride = gdk_pixbuf_get_rowstride (priv->map_render_pixbuf);
        pixels = gdk_pixbuf_get_pixels (priv->map_render_pixbuf) +
            (area->y + priv->yofs) * rowstride + 3 *
            (area->x + priv->xofs);
        gdk_draw_rgb_image_dithalign (
            window, style->black_gc, area->x, area->y,
            width, height, GDK_RGB_DITHER_NORMAL, pixels,
            rowstride, 0, 0);
        return;
    }

#ifdef DEBUG
    g_print ("Doing hard redraw.\n");
#endif
}

static void
put_pixel_with_clipping (GdkPixbuf *pixbuf, gint x, gint y, guint rgba)
{
    gint    width, height;
    gint    rowstride, n_channels;
    guchar *pixels, *pixel;

    width      = gdk_pixbuf_get_width      (pixbuf);
    height     = gdk_pixbuf_get_height     (pixbuf);
    rowstride  = gdk_pixbuf_get_rowstride  (pixbuf);
    n_channels = gdk_pixbuf_get_n_channels (pixbuf);
    pixels     = gdk_pixbuf_get_pixels     (pixbuf);

    if (x < 0 || x >= width || y < 0 || y >= height)
        return;

    pixel = pixels + (y * rowstride) + (x * n_channels);

    *pixel       = (rgba >> 24);
    *(pixel + 1) = (rgba >> 16) & 0x000000ff;
    *(pixel + 2) = (rgba >>  8) & 0x000000ff;

    if (n_channels > 3)
    {
        *(pixel + 3) = rgba & 0x000000ff;
    }
}

/* Redraw point in client pixbuf */

static void
update_render_point (EMap *map, EMapPoint *point)
{
    EMapPrivate *priv;
    GdkPixbuf *pb;
    gdouble px, py;

    priv = map->priv;
    pb = priv->map_render_pixbuf;
    if (!pb) return;

    e_map_world_to_window (map, point->longitude, point->latitude, &px, &py);
    px += priv->xofs;
    py += priv->yofs;

    put_pixel_with_clipping (pb, px,     py,     point->rgba);
    put_pixel_with_clipping (pb, px - 1, py,     point->rgba);
    put_pixel_with_clipping (pb, px + 1, py,     point->rgba);
    put_pixel_with_clipping (pb, px,     py - 1, point->rgba);
    put_pixel_with_clipping (pb, px,     py + 1, point->rgba);

    put_pixel_with_clipping (pb, px - 2, py,     0x000000ff);
    put_pixel_with_clipping (pb, px + 2, py,     0x000000ff);
    put_pixel_with_clipping (pb, px,     py - 2, 0x000000ff);
    put_pixel_with_clipping (pb, px,     py + 2, 0x000000ff);
    put_pixel_with_clipping (pb, px - 1, py - 1, 0x000000ff);
    put_pixel_with_clipping (pb, px - 1, py + 1, 0x000000ff);
    put_pixel_with_clipping (pb, px + 1, py - 1, 0x000000ff);
    put_pixel_with_clipping (pb, px + 1, py + 1, 0x000000ff);
}

/* Repaint point on X server */

static void
repaint_point (EMap *map, EMapPoint *point)
{
    GdkRectangle area;
    gdouble px, py;

    if (!e_map_point_is_in_view (map, point)) return;

    e_map_world_to_window (map, point->longitude, point->latitude, &px, &py);

    area.x = (gint) px - 2;
    area.y = (gint) py - 2;
    area.width = 5;
    area.height = 5;
    request_paint_area (map, &area);
}

static void
center_at (EMap *map, gint x, gint y, gboolean scroll)
{
    EMapPrivate *priv;
    GtkAllocation allocation;
    gint pb_width, pb_height;

    priv = map->priv;

    pb_width = E_MAP_GET_WIDTH (map);
    pb_height = E_MAP_GET_HEIGHT (map);

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    x = CLAMP (x - (allocation.width / 2), 0, pb_width - allocation.width);
    y = CLAMP (y - (allocation.height / 2), 0, pb_height - allocation.height);

    if (scroll)
        scroll_to (map, x, y);
    else {
        priv->xofs = x;
        priv->yofs = y;
    }
}

static void
smooth_center_at (EMap *map, gint x, gint y)
{
    EMapPrivate *priv;
    GtkAllocation allocation;
    gint pb_width, pb_height;
    gint dx, dy;

    priv = map->priv;

    pb_width = E_MAP_GET_WIDTH (map);
    pb_height = E_MAP_GET_HEIGHT (map);

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    x = CLAMP (x - (allocation.width / 2), 0, pb_width - allocation.width);
    y = CLAMP (y - (allocation.height / 2), 0, pb_height - allocation.height);

    for (;;)
    {
        if (priv->xofs == x && priv->yofs == y)
            break;

        dx = (x < priv->xofs) ? -1 : (x > priv->xofs) ? 1 : 0;
        dy = (y < priv->yofs) ? -1 : (y > priv->yofs) ? 1 : 0;

        scroll_to (map, priv->xofs + dx, priv->yofs + dy);
    }
}

/* Scrolls the view to the specified offsets.  Does not perform range checking!  */

static void
scroll_to (EMap *view, gint x, gint y)
{
    EMapPrivate *priv;
    gint xofs, yofs;
    GdkWindow *window;
    GtkAllocation allocation;
    GdkGC *gc;
    gint src_x, src_y;
    gint dest_x, dest_y;
#if 0  /* see comment below */
    GdkEvent *event;
#endif

    priv = view->priv;

    /* Compute offsets and check bounds */

    xofs = x - priv->xofs;
    yofs = y - priv->yofs;

    if (xofs == 0 && yofs == 0)
        return;

    priv->xofs = x;
    priv->yofs = y;

    if (!gtk_widget_is_drawable (GTK_WIDGET (view)))
        return;

    gtk_widget_get_allocation (GTK_WIDGET (view), &allocation);

    if (abs (xofs) >= allocation.width || abs (yofs) >= allocation.height)
    {
        GdkRectangle area;

        area.x = 0;
        area.y = 0;
        area.width = allocation.width;
        area.height = allocation.height;

        request_paint_area (view, &area);
        return;
    }

    window = gtk_widget_get_window (GTK_WIDGET (view));

    /* Copy the window area */

    src_x = xofs < 0 ? 0 : xofs;
    src_y = yofs < 0 ? 0 : yofs;
    dest_x = xofs < 0 ? -xofs : 0;
    dest_y = yofs < 0 ? -yofs : 0;

    gc = gdk_gc_new (window);
    gdk_gc_set_exposures (gc, TRUE);

    gdk_draw_drawable (
        GDK_DRAWABLE (window),
        gc, GDK_DRAWABLE (window),
        src_x, src_y, dest_x, dest_y,
        allocation.width - abs (xofs),
        allocation.height - abs (yofs));

    g_object_unref (gc);

    /* Add the scrolled-in region */

    if (xofs)
    {
        GdkRectangle r;

        r.x = xofs < 0 ? 0 : allocation.width - xofs;
        r.y = 0;
        r.width = abs (xofs);
        r.height = allocation.height;

        request_paint_area (view, &r);
    }

    if (yofs)
    {
        GdkRectangle r;

        r.x = 0;
        r.y = yofs < 0 ? 0 : allocation.height - yofs;
        r.width = allocation.width;
        r.height = abs (yofs);

        request_paint_area (view, &r);
    }

    /* Process graphics exposures */

    /* XXX gdk_event_get_graphics_expose() is deprecated now.
     *     The map widget seems to work fine without this logic
     *     (I think it was just an optimization) but leaving it
     *     intact in case I'm wrong and we need to rewrite it. */
#if 0
    while ((event = gdk_event_get_graphics_expose (window)) != NULL)
    {
        gtk_widget_event (GTK_WIDGET (view), event);

        if (event->expose.count == 0)
        {
            gdk_event_free (event);
            break;
        }

        gdk_event_free (event);
    }
#endif
}

static gint divide_seq[] =
{
    /* Dividends for divisor of 2 */

    -2,

    1,

    /* Dividends for divisor of 4 */

    -4,

    1, 3,

    /* Dividends for divisor of 8 */

    -8,

    1, 5, 3, 7,

    /* Dividends for divisor of 16 */

    -16,

    1, 9, 5, 13, 3, 11, 7, 15,

    /* Dividends for divisor of 32 */

    -32,

    1, 17, 9, 25, 5, 21, 13, 29, 3, 19,
    11, 27, 7, 23, 15, 31,

    /* Dividends for divisor of 64 */

    -64,

    1, 33, 17, 49, 9, 41, 25, 57, 5, 37,
    21, 53, 13, 45, 29, 61, 3, 35, 19, 51,
    11, 43, 27, 59, 7, 39, 23, 55, 15, 47,
    31, 63,

    /* Dividends for divisor of 128 */

    -128,

    1, 65, 33, 97, 17, 81, 49, 113, 9, 73,
    41, 105, 25, 89, 57, 121, 5, 69, 37, 101,
    21, 85, 53, 117, 13, 77, 45, 109, 29, 93,
    61, 125, 3, 67, 35, 99, 19, 83, 51, 115,
    11, 75, 43, 107, 27, 91, 59, 123, 7, 71,
    39, 103, 23, 87, 55, 119, 15, 79, 47, 111,
    31, 95, 63, 127,

    /* Dividends for divisor of 256 */

    -256,

    1, 129, 65, 193, 33, 161, 97, 225, 17, 145,
    81, 209, 49, 177, 113, 241, 9, 137, 73, 201,
    41, 169, 105, 233, 25, 153, 89, 217, 57, 185,
    121, 249, 5, 133, 69, 197, 37, 165, 101, 229,
    21, 149, 85, 213, 53, 181, 117, 245, 13, 141,
    77, 205, 45, 173, 109, 237, 29, 157, 93, 221,
    61, 189, 125, 253, 3, 131, 67, 195, 35, 163,
    99, 227, 19, 147, 83, 211, 51, 179, 115, 243,
    11, 139, 75, 203, 43, 171, 107, 235, 27, 155,
    91, 219, 59, 187, 123, 251, 7, 135, 71, 199,
    39, 167, 103, 231, 23, 151, 87, 215, 55, 183,
    119, 247, 15, 143, 79, 207, 47, 175, 111, 239,
    31, 159, 95, 223, 63, 191, 127, 255,

    0
};

typedef enum
{
    AXIS_X,
    AXIS_Y
}
AxisType;

static void
blowup_window_area (GdkWindow *window, gint area_x, gint area_y, gint target_x, gint target_y, gint total_width, gint total_height, gfloat zoom_factor)
{
    GdkGC *gc;
    AxisType strong_axis;
    gfloat axis_factor, axis_counter;
    gint zoom_chunk;
    gint divisor_width = 0, divisor_height = 0;
    gint divide_width_index, divide_height_index;
    gint area_width, area_height;
    gint i, j;
    gint line;

    /* Set up the GC we'll be using */

    gc = gdk_gc_new (window);
    gdk_gc_set_exposures (gc, FALSE);

    /* Get area constraints */

    gdk_drawable_get_size (GDK_DRAWABLE (window), &area_width, &area_height);

    /* Initialize area division array indexes */

    divide_width_index = divide_height_index = 0;

    /* Initialize axis counter */

    axis_counter = 0.0;

    /* Find the strong axis (which is the basis for iteration) and the ratio
     * at which the other axis will be scaled.
     *
     * Also determine how many lines to expand in one fell swoop, and store
     * this figure in zoom_chunk. */

    if (area_width > area_height)
    {
        strong_axis = AXIS_X;
        axis_factor = (gdouble) area_height / (gdouble) area_width;
        zoom_chunk = MAX (1, area_width / 250);
        i = (area_width * (zoom_factor - 1.0)) / zoom_chunk;
    }
    else
    {
        strong_axis = AXIS_Y;
        axis_factor = (gdouble) area_width / (gdouble) area_height;
        zoom_chunk = MAX (1, area_height / 250);
        i = (area_height * (zoom_factor - 1.0)) / zoom_chunk;
    }

    /* Go, go, devil bunnies! Gogo devil bunnies! */

    for (; i > 0; i--)
    {
        /* Reset division sequence table indexes as necessary */

        if (!divide_seq[divide_width_index]) divide_width_index = 0;
        if (!divide_seq[divide_height_index]) divide_height_index = 0;

        /* Set new divisor if found in table */

        if (divide_seq[divide_width_index] < 0)
            divisor_width = abs (divide_seq[divide_width_index++]);
        if (divide_seq[divide_height_index] < 0)
            divisor_height = abs (divide_seq[divide_height_index++]);

        /* Widen */

        if (strong_axis == AXIS_X || axis_counter >= 1.0)
        {
            line = ((divide_seq[divide_width_index] * area_width) / divisor_width) + 0.5;

            if ((line < target_x && target_x > area_width / 2) || (line > target_x && target_x > (area_width / 2) + zoom_chunk))
            {
                /* Push left */

                for (j = 0; j < zoom_chunk - 1; j++)
                    gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), line, 0, line + j + 1, 0, 1, area_height);

                gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), zoom_chunk, 0, 0, 0, line, area_height);
                if (line > target_x) target_x -= zoom_chunk;
            }
            else
            {
                /* Push right */

                for (j = 0; j < zoom_chunk - 1; j++)
                    gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), line - zoom_chunk, 0, line + j - (zoom_chunk - 1), 0, 1, area_height);

                gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), line - zoom_chunk, 0, line, 0, area_width - line, area_height);
                if (line < target_x) target_x += zoom_chunk;
            }
        }

        if (strong_axis == AXIS_Y || axis_counter >= 1.0)
        {
            /* Heighten */

            line = ((divide_seq[divide_height_index] * area_height) / divisor_height) + 0.5;

            if ((line < target_y && target_y > area_height / 2) || (line > target_y && target_y > (area_height / 2) + zoom_chunk))
            {
                /* Push up */

                for (j = 0; j < zoom_chunk - 1; j++)
                    gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), 0, line, 0, line + j + 1, area_width, 1);

                gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), 0, zoom_chunk, 0, 0, area_width, line);
                if (line > target_y) target_y -= zoom_chunk;
            }
            else
            {
                /* Push down */

                for (j = 0; j < zoom_chunk - 1; j++)
                    gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_WINDOW (window), 0, line - zoom_chunk, 0, line + j - (zoom_chunk - 1), area_width, 1);

                gdk_draw_drawable (GDK_DRAWABLE (window), gc, GDK_DRAWABLE (window), 0, line - zoom_chunk, 0, line, area_width, area_height - line);
                if (line < target_y) target_y += zoom_chunk;
            }
        }

        divide_width_index++;
        divide_height_index++;
        if (axis_counter >= 1.0) axis_counter -= 1.0;
        axis_counter += axis_factor;
    }

    /* Free our GC */

    g_object_unref (gc);
}

static void
zoom_in_smooth (EMap *map)
{
    GtkAllocation allocation;
    GdkRectangle area;
    EMapPrivate *priv;
    GdkWindow *window;
    gint width, height;
    gdouble x, y;

    g_return_if_fail (map);
    g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (map)));

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    area.x = 0;
    area.y = 0;
    area.width = allocation.width;
    area.height = allocation.height;

    priv = map->priv;
    window = gtk_widget_get_window (GTK_WIDGET (map));
    width = gdk_pixbuf_get_width (priv->map_render_pixbuf);
    height = gdk_pixbuf_get_height (priv->map_render_pixbuf);

    /* Center the target point as much as possible */

    e_map_world_to_window (map, priv->zoom_target_long, priv->zoom_target_lat, &x, &y);
    smooth_center_at (map, x + priv->xofs, y + priv->yofs);

    /* Render and paint a temporary map without overlays, so they don't get in
     * the way (look ugly) while zooming */

    update_render_pixbuf (map, GDK_INTERP_BILINEAR, FALSE);
    request_paint_area (map, &area);

    /* Find out where in the area we're going to zoom to */

    e_map_world_to_window (map, priv->zoom_target_long, priv->zoom_target_lat, &x, &y);

    /* Pre-render the zoomed-in map, so we can put it there quickly when the
     * blowup sequence ends */

    priv->zoom_state = E_MAP_ZOOMED_IN;
    update_render_pixbuf (map, GDK_INTERP_BILINEAR, TRUE);

    /* Do the blowup */

    blowup_window_area (window, priv->xofs, priv->yofs, x, y, width, height, 1.68);

    /* Set new scroll offsets and paint the zoomed map */

    e_map_world_to_window (map, priv->zoom_target_long, priv->zoom_target_lat, &x, &y);
    priv->xofs = CLAMP (priv->xofs + x - area.width / 2.0, 0, E_MAP_GET_WIDTH (map) - area.width);
    priv->yofs = CLAMP (priv->yofs + y - area.height / 2.0, 0, E_MAP_GET_HEIGHT (map) - area.height);

    request_paint_area (map, &area);
}

static void
zoom_in (EMap *map)
{
    GtkAllocation allocation;
    GdkRectangle area;
    EMapPrivate *priv;
    gdouble x, y;

    priv = map->priv;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    area.x = 0;
    area.y = 0;
    area.width = allocation.width;
    area.height = allocation.height;

    priv->zoom_state = E_MAP_ZOOMED_IN;

    update_render_pixbuf (map, GDK_INTERP_BILINEAR, TRUE);

    e_map_world_to_window (
        map, priv->zoom_target_long,
        priv->zoom_target_lat, &x, &y);
    priv->xofs = CLAMP (
        priv->xofs + x - area.width / 2.0,
        0, E_MAP_GET_WIDTH (map) - area.width);
    priv->yofs = CLAMP (
        priv->yofs + y - area.height / 2.0,
        0, E_MAP_GET_HEIGHT (map) - area.height);

    request_paint_area (map, &area);
}

static void
zoom_out (EMap *map)
{
    GtkAllocation allocation;
    GdkRectangle area;
    EMapPrivate *priv;
    gdouble longitude, latitude;
    gdouble x, y;

    priv = map->priv;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    area.x = 0;
    area.y = 0;
    area.width = allocation.width;
    area.height = allocation.height;

    /* Must be done before update_render_pixbuf() */

    e_map_window_to_world (
        map, area.width / 2, area.height / 2,
        &longitude, &latitude);

    priv->zoom_state = E_MAP_ZOOMED_OUT;
    update_render_pixbuf (map, GDK_INTERP_BILINEAR, TRUE);

    e_map_world_to_window (map, longitude, latitude, &x, &y);
    center_at (map, x + priv->xofs, y + priv->yofs, FALSE);
/*  request_paint_area (map, &area); */
    repaint_visible (map);
}

static void
zoom_do (EMap *map)
{
    EMapPrivate *priv;

    priv = map->priv;
    g_signal_handlers_block_matched (priv->hadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, map);
    g_signal_handlers_block_matched (priv->vadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, map);

    if (priv->zoom_state == E_MAP_ZOOMING_IN)
    {
        if (e_map_get_smooth_zoom (map)) zoom_in_smooth (map);
        else zoom_in (map);
    }
    else if (priv->zoom_state == E_MAP_ZOOMING_OUT)
    {
/*    if (e_map_get_smooth_zoom(map)) zoom_out_smooth(map); */
        zoom_out (map);
    }

    g_signal_handlers_unblock_matched (priv->hadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, map);
    g_signal_handlers_unblock_matched (priv->vadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, map);

    set_scroll_area (map);
}

/* Callback used when an adjustment is changed */

static void
adjustment_changed_cb (GtkAdjustment *adj, gpointer data)
{
    EMap *view;
    gint hadj_value;
    gint vadj_value;

    view = E_MAP (data);

    hadj_value = gtk_adjustment_get_value (view->priv->hadj);
    vadj_value = gtk_adjustment_get_value (view->priv->vadj);

    scroll_to (view, hadj_value, vadj_value);
}

static void
set_scroll_area (EMap *view)
{
    EMapPrivate *priv;
    GtkAllocation allocation;
    gint upper, page_size;

    priv = view->priv;

    if (!gtk_widget_get_realized (GTK_WIDGET (view))) return;
    if (!priv->hadj || !priv->vadj) return;

    g_object_freeze_notify (G_OBJECT (priv->hadj));
    g_object_freeze_notify (G_OBJECT (priv->vadj));

    gtk_widget_get_allocation (GTK_WIDGET (view), &allocation);

    /* Set scroll increments */

    gtk_adjustment_set_page_size (priv->hadj, allocation.width);
    gtk_adjustment_set_page_increment (priv->hadj, allocation.width / 2);
    gtk_adjustment_set_step_increment (priv->hadj, SCROLL_STEP_SIZE);

    gtk_adjustment_set_page_size (priv->vadj, allocation.height);
    gtk_adjustment_set_page_increment (priv->vadj, allocation.height / 2);
    gtk_adjustment_set_step_increment (priv->vadj, SCROLL_STEP_SIZE);

    /* Set scroll bounds and new offsets */

    gtk_adjustment_set_lower (priv->hadj, 0);
    if (priv->map_render_pixbuf) {
        gint width = gdk_pixbuf_get_width (priv->map_render_pixbuf);
        gtk_adjustment_set_upper (priv->hadj, width);
    }

    gtk_adjustment_set_lower (priv->vadj, 0);
    if (priv->map_render_pixbuf) {
        gint height = gdk_pixbuf_get_height (priv->map_render_pixbuf);
        gtk_adjustment_set_upper (priv->vadj, height);
    }

    g_object_thaw_notify (G_OBJECT (priv->hadj));
    g_object_thaw_notify (G_OBJECT (priv->vadj));

    upper = gtk_adjustment_get_upper (priv->hadj);
    page_size = gtk_adjustment_get_page_size (priv->hadj);
    priv->xofs = CLAMP (priv->xofs, 0, upper - page_size);

    upper = gtk_adjustment_get_upper (priv->vadj);
    page_size = gtk_adjustment_get_page_size (priv->vadj);
    priv->yofs = CLAMP (priv->yofs, 0, upper - page_size);

    g_signal_handlers_block_matched (
        priv->hadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);
    gtk_adjustment_set_value (priv->hadj, priv->xofs);
    g_signal_handlers_unblock_matched (
        priv->hadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);

    g_signal_handlers_block_matched (
        priv->vadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);
    gtk_adjustment_set_value (priv->vadj, priv->yofs);
    g_signal_handlers_unblock_matched (
        priv->vadj, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, view);
}