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)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#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"

#define E_MAP_TWEEN_TIMEOUT_MSECS 25
#define E_MAP_TWEEN_DURATION_MSECS 150

/* Scroll step increment */

#define SCROLL_STEP_SIZE 32

/* */

#define E_MAP_GET_WIDTH(map) gtk_adjustment_get_upper((map)->priv->hadjustment)
#define E_MAP_GET_HEIGHT(map) gtk_adjustment_get_upper((map)->priv->vadjustment)

/* 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;

/* The Tween struct used for zooming */

typedef struct _EMapTween EMapTween;

struct _EMapTween {
    guint start_time;
    guint end_time;
    gdouble longitude_offset;
    gdouble latitude_offset;
    gdouble zoom_factor;
};

/* Private part of the EMap structure */

struct _EMapPrivate {
    /* Pointer to map image */
    GdkPixbuf *map_pixbuf;
    cairo_surface_t *map_render_surface;

    /* Settings */
    gboolean frozen, smooth_zoom;

    /* Adjustments for scrolling */
    GtkAdjustment *hadjustment;
    GtkAdjustment *vadjustment;

    /* GtkScrollablePolicy needs to be checked when
     * driving the scrollable adjustment values */
    guint hscroll_policy : 1;
    guint vscroll_policy : 1;

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

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

    /* Dots */
    GPtrArray *points;

    /* Tweens */
    GSList *tweens;
    GTimer *timer;
    guint timer_current_ms;
    guint tween_id;
};

/* Properties */

enum {
    PROP_0,

    /* For scrollable interface */
    PROP_HADJUSTMENT,
    PROP_VADJUSTMENT,
    PROP_HSCROLL_POLICY,
    PROP_VSCROLL_POLICY
};

/* Internal prototypes */

static void update_render_surface (EMap *map, gboolean render_overlays);
static void set_scroll_area (EMap *map, gint width, gint height);
static void center_at (EMap *map, gdouble longitude, gdouble latitude);
static void scroll_to (EMap *map, gint x, gint y);
static gint load_map_background (EMap *map, gchar *name);
static void update_and_paint (EMap *map);
static void update_render_point (EMap *map, EMapPoint *point);
static void repaint_point (EMap *map, EMapPoint *point);

/* ------ *
 * Tweens *
 * ------ */

static gboolean
e_map_is_tweening (EMap *map)
{
    return map->priv->timer != NULL;
}

static void
e_map_stop_tweening (EMap *map)
{
    g_assert (map->priv->tweens == NULL);

    if (!e_map_is_tweening (map))
        return;

    g_timer_destroy (map->priv->timer);
    map->priv->timer = NULL;
    g_source_remove (map->priv->tween_id);
    map->priv->tween_id = 0;
}

static void
e_map_tween_destroy (EMap *map,
                     EMapTween *tween)
{
    map->priv->tweens = g_slist_remove (map->priv->tweens, tween);
    g_slice_free (EMapTween, tween);

    if (map->priv->tweens == NULL)
        e_map_stop_tweening (map);
}

static gboolean
e_map_do_tween_cb (gpointer data)
{
    EMap *map = data;
    GSList *walk;

    map->priv->timer_current_ms =
        g_timer_elapsed (map->priv->timer, NULL) * 1000;
    gtk_widget_queue_draw (GTK_WIDGET (map));

    /* Can't use for loop here, because we need to advance 
     * the list before deleting.
     */
    walk = map->priv->tweens;
    while (walk)
    {
        EMapTween *tween = walk->data;

        walk = walk->next;

        if (tween->end_time <= map->priv->timer_current_ms)
            e_map_tween_destroy (map, tween);
    }

    return TRUE;
}

static void
e_map_start_tweening (EMap *map)
{
    if (e_map_is_tweening (map))
        return;

    map->priv->timer = g_timer_new ();
    map->priv->timer_current_ms = 0;
    map->priv->tween_id = gdk_threads_add_timeout (
        E_MAP_TWEEN_TIMEOUT_MSECS, e_map_do_tween_cb, map);
    g_timer_start (map->priv->timer);
}

static void
e_map_tween_new (EMap *map,
                 guint msecs,
                 gdouble longitude_offset,
                 gdouble latitude_offset,
                 gdouble zoom_factor)
{
    EMapTween *tween;

    if (!map->priv->smooth_zoom)
        return;

    e_map_start_tweening (map);

    tween = g_slice_new (EMapTween);

    tween->start_time = map->priv->timer_current_ms;
    tween->end_time = tween->start_time + msecs;
    tween->longitude_offset = longitude_offset;
    tween->latitude_offset = latitude_offset;
    tween->zoom_factor = zoom_factor;

    map->priv->tweens = g_slist_prepend (map->priv->tweens, tween);

    gtk_widget_queue_draw (GTK_WIDGET (map));
}

G_DEFINE_TYPE_WITH_CODE (
    EMap,
    e_map,
    GTK_TYPE_WIDGET,
    G_IMPLEMENT_INTERFACE (GTK_TYPE_SCROLLABLE, NULL))

static void
e_map_get_current_location (EMap *map,
                            gdouble *longitude,
                            gdouble *latitude)
{
    GtkAllocation allocation;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    e_map_window_to_world (
        map, allocation.width / 2.0,
        allocation.height / 2.0,
        longitude, latitude);
}

static void
e_map_world_to_render_surface (EMap *map,
                               gdouble world_longitude,
                               gdouble world_latitude,
                               gdouble *win_x,
                               gdouble *win_y)
{
    gint width, height;

    width = E_MAP_GET_WIDTH (map);
    height = E_MAP_GET_HEIGHT (map);

    *win_x = (width / 2.0 + (width / 2.0) * world_longitude / 180.0);
    *win_y = (height / 2.0 - (height / 2.0) * world_latitude / 90.0);
}

static void
e_map_tween_new_from (EMap *map,
                      guint msecs,
                      gdouble longitude,
                      gdouble latitude,
                      gdouble zoom)
{
    gdouble current_longitude, current_latitude;

    e_map_get_current_location (
        map, &current_longitude, &current_latitude);

    e_map_tween_new (
        map, msecs,
        longitude - current_longitude,
        latitude - current_latitude,
        zoom / e_map_get_magnification (map));
}

static gdouble
e_map_get_tween_effect (EMap *map,
                        EMapTween *tween)
{
    gdouble elapsed;

    elapsed = (gdouble)
        (map->priv->timer_current_ms - tween->start_time) /
        tween->end_time;

    return MAX (0.0, 1.0 - elapsed);
}

static void
e_map_apply_tween (EMapTween *tween,
                   gdouble effect,
                   gdouble *longitude,
                   gdouble *latitude,
                   gdouble *zoom)
{
    *zoom *= pow (tween->zoom_factor, effect);
    *longitude += tween->longitude_offset * effect;
    *latitude += tween->latitude_offset * effect;
}

static void
e_map_tweens_compute_matrix (EMap *map,
                             cairo_matrix_t *matrix)
{
    GSList *walk;
    gdouble zoom, x, y, latitude, longitude, effect;
    GtkAllocation allocation;

    if (!e_map_is_tweening (map)) {
        cairo_matrix_init_translate (
            matrix, -map->priv->xofs, -map->priv->yofs);
        return;
    }

    e_map_get_current_location (map, &longitude, &latitude);
    zoom = 1.0;

    for (walk = map->priv->tweens; walk; walk = walk->next) {
        EMapTween *tween = walk->data;

        effect = e_map_get_tween_effect (map, tween);
        e_map_apply_tween (tween, effect, &longitude, &latitude, &zoom);
    }

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);
    cairo_matrix_init_translate (matrix,
                allocation.width / 2.0,
                allocation.height / 2.0);

    e_map_world_to_render_surface (map, longitude, latitude, &x, &y);
    cairo_matrix_scale (matrix, zoom, zoom);
    cairo_matrix_translate (matrix, -x, -y);
}

/* GtkScrollable implementation */

static void
e_map_adjustment_changed (GtkAdjustment *adjustment,
                          EMap *map)
{
    EMapPrivate *priv = map->priv;

    if (gtk_widget_get_realized (GTK_WIDGET (map))) {
        gint hadj_value;
        gint vadj_value;

        hadj_value = gtk_adjustment_get_value (priv->hadjustment);
        vadj_value = gtk_adjustment_get_value (priv->vadjustment);

        scroll_to (map, hadj_value, vadj_value);
    }
}

static void
e_map_set_hadjustment_values (EMap *map)
{
    GtkAllocation  allocation;
    EMapPrivate *priv = map->priv;
    GtkAdjustment *adj = priv->hadjustment;
    gdouble old_value;
    gdouble new_value;
    gdouble new_upper;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    old_value = gtk_adjustment_get_value (adj);
    new_upper = MAX (allocation.width, gdk_pixbuf_get_width (priv->map_pixbuf));

    g_object_set (adj,
        "lower", 0.0,
        "upper", new_upper,
        "page-size", (gdouble)allocation.height,
        "step-increment", allocation.height * 0.1,
        "page-increment", allocation.height * 0.9,
        NULL);

    new_value = CLAMP (old_value, 0, new_upper - allocation.width);
    if (new_value != old_value)
        gtk_adjustment_set_value (adj, new_value);
}

static void
e_map_set_vadjustment_values (EMap *map)
{
    GtkAllocation  allocation;
    EMapPrivate *priv = map->priv;
    GtkAdjustment *adj = priv->vadjustment;
    gdouble old_value;
    gdouble new_value;
    gdouble new_upper;

    gtk_widget_get_allocation (GTK_WIDGET (map), &allocation);

    old_value = gtk_adjustment_get_value (adj);
    new_upper = MAX (allocation.height, gdk_pixbuf_get_height (priv->map_pixbuf));

    g_object_set (adj,
        "lower", 0.0,
        "upper", new_upper,
        "page-size", (gdouble)allocation.height,
        "step-increment", allocation.height * 0.1,
        "page-increment", allocation.height * 0.9,
        NULL);

    new_value = CLAMP (old_value, 0, new_upper - allocation.height);
    if (new_value != old_value)
        gtk_adjustment_set_value (adj, new_value);
}

static void
e_map_set_hadjustment (EMap *map,
                       GtkAdjustment *adjustment)
{
    EMapPrivate *priv = map->priv;

    if (adjustment && priv->hadjustment == adjustment)
        return;

    if (priv->hadjustment != NULL) {
        g_signal_handlers_disconnect_matched (
            priv->hadjustment, G_SIGNAL_MATCH_DATA,
            0, 0, NULL, NULL, map);
        g_object_unref (priv->hadjustment);
    }

    if (!adjustment)
        adjustment = gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0);

    g_signal_connect (
        adjustment, "value-changed",
        G_CALLBACK (e_map_adjustment_changed), map);
    priv->hadjustment = g_object_ref_sink (adjustment);
    e_map_set_hadjustment_values (map);

    g_object_notify (G_OBJECT (map), "hadjustment");
}

static void
e_map_set_vadjustment (EMap *map,
                       GtkAdjustment *adjustment)
{
    EMapPrivate *priv = map->priv;

    if (adjustment && priv->vadjustment == adjustment)
        return;

    if (priv->vadjustment != NULL) {
        g_signal_handlers_disconnect_matched (
            priv->vadjustment, G_SIGNAL_MATCH_DATA,
            0, 0, NULL, NULL, map);
        g_object_unref (priv->vadjustment);
    }

    if (!adjustment)
        adjustment = gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0);

    g_signal_connect (
        adjustment, "value-changed",
        G_CALLBACK (e_map_adjustment_changed), map);
    priv->vadjustment = g_object_ref_sink (adjustment);
    e_map_set_vadjustment_values (map);

    g_object_notify (G_OBJECT (map), "vadjustment");
}

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

static void
e_map_set_property (GObject *object,
                    guint property_id,
                    const GValue *value,
                    GParamSpec *pspec)
{
    EMap *map;

    map = E_MAP (object);

    switch (property_id) {
    case PROP_HADJUSTMENT:
        e_map_set_hadjustment (map, g_value_get_object (value));
        break;
    case PROP_VADJUSTMENT:
        e_map_set_vadjustment (map, g_value_get_object (value));
        break;
    case PROP_HSCROLL_POLICY:
        map->priv->hscroll_policy = g_value_get_enum (value);
        gtk_widget_queue_resize (GTK_WIDGET (map));
        break;
    case PROP_VSCROLL_POLICY:
        map->priv->vscroll_policy = g_value_get_enum (value);
        gtk_widget_queue_resize (GTK_WIDGET (map));
        break;

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

static void
e_map_get_property (GObject *object,
                    guint property_id,
                    GValue *value,
                    GParamSpec *pspec)
{
    EMap *map;

    map = E_MAP (object);

    switch (property_id) {
    case PROP_HADJUSTMENT:
        g_value_set_object (value, map->priv->hadjustment);
        break;
    case PROP_VADJUSTMENT:
        g_value_set_object (value, map->priv->vadjustment);
        break;
    case PROP_HSCROLL_POLICY:
        g_value_set_enum (value, map->priv->hscroll_policy);
        break;
    case PROP_VSCROLL_POLICY:
        g_value_set_enum (value, map->priv->vscroll_policy);
        break;

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

static void
e_map_finalize (GObject *object)
{
    EMap *map;

    map = E_MAP (object);

    while (map->priv->tweens)
        e_map_tween_destroy (map, map->priv->tweens->data);
    e_map_stop_tweening (map);

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

    /* gone in unrealize */
    g_assert (map->priv->map_render_surface == NULL);

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

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

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 = gtk_widget_get_visual (widget);
    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;

    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);

    update_render_surface (E_MAP (widget), TRUE);
}

static void
e_map_unrealize (GtkWidget *widget)
{
    EMap *map = E_MAP (widget);

    cairo_surface_destroy (map->priv->map_render_surface);
    map->priv->map_render_surface = NULL;

    if (GTK_WIDGET_CLASS (e_map_parent_class)->unrealize)
        (*GTK_WIDGET_CLASS (e_map_parent_class)->unrealize) (widget);
}

static void
e_map_get_preferred_width (GtkWidget *widget,
                           gint *minimum,
                           gint *natural)
{
    EMap *map;

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

    map = E_MAP (widget);

    /* TODO: Put real sizes here. */

    *minimum = *natural = gdk_pixbuf_get_width (map->priv->map_pixbuf);
}

static void
e_map_get_preferred_height (GtkWidget *widget,
                            gint *minimum,
                            gint *natural)
{
    EMap *view;
    EMapPrivate *priv;

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

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

    /* TODO: Put real sizes here. */

    *minimum = *natural = gdk_pixbuf_get_height (priv->map_pixbuf);
}

static void
e_map_size_allocate (GtkWidget *widget,
                     GtkAllocation *allocation)
{
    EMap *map;

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

    map = 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);

        gtk_widget_queue_draw (widget);
    }

    update_render_surface (map, TRUE);
}

static gboolean
e_map_draw (GtkWidget *widget,
            cairo_t *cr)
{
    EMap *map;
    cairo_matrix_t matrix;

    if (!gtk_widget_is_drawable (widget))
        return FALSE;

    map = E_MAP (widget);

    cairo_save (cr);

    e_map_tweens_compute_matrix (map, &matrix);
    cairo_transform (cr, &matrix);

    cairo_set_source_surface (cr, map->priv->map_render_surface, 0, 0);
    cairo_paint (cr);

    cairo_restore (cr);

    return FALSE;
}

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

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

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

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

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

    map = E_MAP (widget);

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

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

        scroll_to (map, x, y);

        gtk_adjustment_set_value (map->priv->hadjustment, x);
        gtk_adjustment_set_value (map->priv->vadjustment, y);
    }

    return TRUE;
}

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

    object_class = G_OBJECT_CLASS (class);
    object_class->finalize = e_map_finalize;
    object_class->set_property = e_map_set_property;
    object_class->get_property = e_map_get_property;

    /* Scrollable interface properties */
    g_object_class_override_property (
        object_class, PROP_HADJUSTMENT, "hadjustment");
    g_object_class_override_property (
        object_class, PROP_VADJUSTMENT, "vadjustment");
    g_object_class_override_property (
        object_class, PROP_HSCROLL_POLICY, "hscroll-policy");
    g_object_class_override_property (
        object_class, PROP_VSCROLL_POLICY, "vscroll-policy");

    widget_class = GTK_WIDGET_CLASS (class);
    widget_class->realize = e_map_realize;
    widget_class->unrealize = e_map_unrealize;
    widget_class->get_preferred_height = e_map_get_preferred_height;
    widget_class->get_preferred_width = e_map_get_preferred_width;
    widget_class->size_allocate = e_map_size_allocate;
    widget_class->draw = e_map_draw;
    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->key_press_event = e_map_key_press;
}

static void
e_map_init (EMap *map)
{
    GtkWidget *widget;
    gchar *map_file_name;

    map_file_name = g_build_filename (
        EVOLUTION_IMAGESDIR, "world_map-960.png", NULL);

    widget = GTK_WIDGET (map);

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

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

    gtk_widget_set_can_focus (widget, TRUE);
    gtk_widget_set_has_window (widget, 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)
{
    gint width, height;

    g_return_if_fail (map);

    g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (map)));

    width = E_MAP_GET_WIDTH (map);
    height = E_MAP_GET_HEIGHT (map);

    *world_longitude = (win_x + map->priv->xofs - (gdouble) width / 2.0) /
        ((gdouble) width / 2.0) * 180.0;
    *world_latitude = ((gdouble) height / 2.0 - win_y - map->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)
{
    g_return_if_fail (E_IS_MAP (map));
    g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (map)));
    g_return_if_fail (world_longitude >= -180.0 && world_longitude <= 180.0);
    g_return_if_fail (world_latitude >= -90.0 && world_latitude <= 90.0);

    e_map_world_to_render_surface (
        map, world_longitude, world_latitude, win_x, win_y);

    *win_x -= map->priv->xofs;
    *win_y -= map->priv->yofs;
}

/* --- Zoom --- */

gdouble
e_map_get_magnification (EMap *map)
{
    if (map->priv->zoom_state == E_MAP_ZOOMED_IN) return 2.0;
    else return 1.0;
}

static void
e_map_set_zoom (EMap *map,
                EMapZoomState zoom)
{
    if (map->priv->zoom_state == zoom)
        return;

    map->priv->zoom_state = zoom;
    update_render_surface (map, TRUE);
    gtk_widget_queue_draw (GTK_WIDGET (map));
}

void
e_map_zoom_to_location (EMap *map,
                        gdouble longitude,
                        gdouble latitude)
{
    gdouble prevlong, prevlat;
    gdouble prevzoom;

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

    e_map_get_current_location (map, &prevlong, &prevlat);
    prevzoom = e_map_get_magnification (map);

    e_map_set_zoom (map, E_MAP_ZOOMED_IN);
    center_at (map, longitude, latitude);

    e_map_tween_new_from (
        map, E_MAP_TWEEN_DURATION_MSECS,
        prevlong, prevlat, prevzoom);
}

void
e_map_zoom_out (EMap *map)
{
    gdouble longitude, latitude;
    gdouble prevzoom;

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

    e_map_get_current_location (map, &longitude, &latitude);
    prevzoom = e_map_get_magnification (map);
    e_map_set_zoom (map, E_MAP_ZOOMED_OUT);
    center_at (map, longitude, latitude);

    e_map_tween_new_from (
        map, E_MAP_TWEEN_DURATION_MSECS,
        longitude, latitude, prevzoom);
}

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)
{
    EMapPoint *point;

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

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

    return point;
}

void
e_map_remove_point (EMap *map,
                    EMapPoint *point)
{
    g_ptr_array_remove (map->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_surface (map, 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)
{
    GtkAllocation allocation;
    gdouble x, y;

    if (!map->priv->map_render_surface) 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)
{
    EMapPoint *point_chosen = NULL, *point;
    gdouble min_dist = 0.0, dist;
    gdouble dx, dy;
    gint i;

    for (i = 0; i < map->priv->points->len; i++)
    {
        point = g_ptr_array_index (map->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
update_and_paint (EMap *map)
{
    update_render_surface (map, TRUE);
    gtk_widget_queue_draw (GTK_WIDGET (map));
}

static gint
load_map_background (EMap *map,
                     gchar *name)
{
    GdkPixbuf *pb0;

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

    if (map->priv->map_pixbuf) g_object_unref (map->priv->map_pixbuf);
    map->priv->map_pixbuf = pb0;
    update_render_surface (map, TRUE);

    return TRUE;
}

static void
update_render_surface (EMap *map,
                       gboolean render_overlays)
{
    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 */

    width = allocation.width;
    height = allocation.height;
    orig_width = gdk_pixbuf_get_width (map->priv->map_pixbuf);
    orig_height = gdk_pixbuf_get_height (map->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 (map->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 (map->priv->map_render_surface)
        cairo_surface_destroy (map->priv->map_render_surface);
    map->priv->map_render_surface = gdk_window_create_similar_surface (
        gtk_widget_get_window (GTK_WIDGET (map)),
        CAIRO_CONTENT_COLOR, width, height);

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

    if (width > 1 && height > 1)
    {
        cairo_t *cr = cairo_create (map->priv->map_render_surface);
        cairo_scale (cr, (gdouble) width / orig_width, (gdouble) height / orig_height);
        gdk_cairo_set_source_pixbuf (cr, map->priv->map_pixbuf, 0, 0);
        cairo_paint (cr);
        cairo_destroy (cr);
    }

    /* Compute image offsets with respect to window */

    set_scroll_area (map, width, height);

    if (render_overlays) {
        /* Add points */

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

/* Redraw point in client surface */

static void
update_render_point (EMap *map,
                     EMapPoint *point)
{
    cairo_t *cr;
    gdouble px, py;
    static guchar mask1[] = { 0x00, 0x00, 0xff, 0x00, 0x00,  0x00, 0x00, 0x00,
                  0x00, 0xff, 0x00, 0xff, 0x00,  0x00, 0x00, 0x00,
                  0xff, 0x00, 0x00, 0x00, 0xff,  0x00, 0x00, 0x00,
                  0x00, 0xff, 0x00, 0xff, 0x00,  0x00, 0x00, 0x00,
                  0x00, 0x00, 0xff, 0x00, 0x00,  0x00, 0x00, 0x00 };
    static guchar mask2[] = { 0x00, 0xff, 0x00,  0x00,
                  0xff, 0xff, 0xff,  0x00,
                  0x00, 0xff, 0x00,  0x00 };
    cairo_surface_t *mask;

    if (map->priv->map_render_surface == NULL)
        return;

    cr = cairo_create (map->priv->map_render_surface);
    cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);

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

    cairo_set_source_rgb (cr, 0, 0, 0);
    mask = cairo_image_surface_create_for_data (mask1, CAIRO_FORMAT_A8, 5, 5, 8);
    cairo_mask_surface (cr, mask, px - 2, py - 2);
    cairo_surface_destroy (mask);

    cairo_set_source_rgba (cr,
                   ((point->rgba >> 24) & 0xff) / 255.0,
                   ((point->rgba >> 16) & 0xff) / 255.0,
                   ((point->rgba >>  8) & 0xff) / 255.0,
                   ( point->rgba    & 0xff) / 255.0);
    mask = cairo_image_surface_create_for_data (mask2, CAIRO_FORMAT_A8, 3, 3, 4);
    cairo_mask_surface (cr, mask, px - 1, py - 1);
    cairo_surface_destroy (mask);

    cairo_destroy (cr);
}

/* Repaint point on X server */

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

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

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

    gtk_widget_queue_draw_area (GTK_WIDGET (map),
                    (gint) px - 2, (gint) py - 2,
                    5, 5);
}

static void
center_at (EMap *map,
           gdouble longitude,
           gdouble latitude)
{
    GtkAllocation allocation;
    gint pb_width, pb_height;
    gdouble x, y;

    e_map_world_to_render_surface (map, longitude, latitude, &x, &y);

    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);

    gtk_adjustment_set_value (map->priv->hadjustment, x);
    gtk_adjustment_set_value (map->priv->vadjustment, y);

    gtk_widget_queue_draw (GTK_WIDGET (map));
}

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

static void
scroll_to (EMap *map,
           gint x,
           gint y)
{
    gint xofs, yofs;

    /* Compute offsets and check bounds */

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

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

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

    gtk_widget_queue_draw (GTK_WIDGET (map));
}

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

    priv = view->priv;

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

    if (!priv->hadjustment || !priv->vadjustment)
        return;

    g_object_freeze_notify (G_OBJECT (priv->hadjustment));
    g_object_freeze_notify (G_OBJECT (priv->vadjustment));

    gtk_widget_get_allocation (GTK_WIDGET (view), &allocation);

    priv->xofs = CLAMP (priv->xofs, 0, width - allocation.width);
    priv->yofs = CLAMP (priv->yofs, 0, height - allocation.height);

    gtk_adjustment_configure (priv->hadjustment,
                  priv->xofs,
                  0, width,
                  SCROLL_STEP_SIZE,
                  allocation.width / 2,
                  allocation.width);
    gtk_adjustment_configure (priv->vadjustment,
                  priv->yofs,
                  0, height,
                  SCROLL_STEP_SIZE,
                  allocation.height / 2,
                  allocation.height);

    g_object_thaw_notify (G_OBJECT (priv->hadjustment));
    g_object_thaw_notify (G_OBJECT (priv->vadjustment));
}