Pick GPS coordinates of dive location via map widget

I have some concerns about the way this is implemented - especially the
use of gtk_grab_add to make the map widget work has me worried. But it
seems to work and survived some test cases that I threw at it.

The GtkButton with the Pixmap looks a little off on my screen, but this
way it was easy to implement. Feel free to come up with a better design.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

display-gtk.h

@@ -71,6 +71,7 @@ extern GtkWidget *weightsystem_list_widget(int w_idx);
 
 extern GtkWidget *dive_list_create(void);
 extern void dive_list_destroy(void);
+extern GdkPixbuf *get_gps_icon(void);
 
 extern gboolean icon_click_cb(GtkWidget *w, GdkEventButton *event, gpointer data);
 

dive.h

@@ -486,7 +486,7 @@ extern void show_dive_stats(struct dive *);
 extern void clear_stats_widgets(void);
 
 extern void show_gps_locations(void);
-extern void show_gps_location(struct dive *);
+extern void show_gps_location(struct dive *, void (*callback)(float, float));
 
 extern void show_yearly_stats(void);
 

divelist.c

@@ -980,10 +980,15 @@ static void get_suit(struct dive *dive, char **str)
 	get_string(str, dive->suit);
 }
 
-static GdkPixbuf *get_gps_icon(struct dive *dive)
+GdkPixbuf *get_gps_icon(void)
+{
+	return gdk_pixbuf_from_pixdata(&my_pixbuf, TRUE, NULL);
+}
+
+GdkPixbuf *get_gps_icon_for_dive(struct dive *dive)
 {
 	if (dive_has_location(dive))
-		return gdk_pixbuf_from_pixdata(&my_pixbuf, TRUE, NULL);
+		return get_gps_icon();
 	else
 		return NULL;
 }
@@ -1010,7 +1015,7 @@ static void fill_one_dive(struct dive *dive,
 	get_cylinder(dive, &cylinder);
 	get_location(dive, &location);
 	get_suit(dive, &suit);
-	icon = get_gps_icon(dive);
+	icon = get_gps_icon_for_dive(dive);
 	gtk_tree_store_set(GTK_TREE_STORE(model), iter,
 		DIVE_NR, dive->number,
 		DIVE_LOCATION, location,
@@ -1413,7 +1418,7 @@ static void fill_dive_list(void)
 		/* store dive */
 		update_cylinder_related_info(dive);
 		gtk_tree_store_append(treestore, &iter, parent_ptr);
-		icon = get_gps_icon(dive);
+		icon = get_gps_icon_for_dive(dive);
 		gtk_tree_store_set(treestore, &iter,
 			DIVE_INDEX, i,
 			DIVE_NR, dive->number,
@@ -1694,7 +1699,7 @@ void edit_dive_when_cb(GtkWidget *menuitem, struct dive *dive)
 #if HAVE_OSM_GPS_MAP
 static void show_gps_location_cb(GtkWidget *menuitem, struct dive *dive)
 {
-	show_gps_location(dive);
+	show_gps_location(dive, NULL);
 }
 #endif
 
@@ -1716,7 +1721,7 @@ gboolean icon_click_cb(GtkWidget *w, GdkEventButton *event, gpointer data)
 			gtk_tree_model_get(MODEL(dive_list), &iter, DIVE_INDEX, &idx, -1);
 			dive = get_dive(idx);
 			if (dive && dive_has_location(dive))
-				show_gps_location(dive);
+				show_gps_location(dive, NULL);
 		}
 		if (path)
 			gtk_tree_path_free(path);

gps.c

@@ -20,10 +20,60 @@ static OsmGpsMapSource_t opt_map_provider = OSM_GPS_MAP_SOURCE_GOOGLE_STREET;
 static void on_close(GtkWidget *widget, gpointer user_data)
 {
 	GtkWidget **window = user_data;
+	gtk_grab_remove(widget);
 	gtk_widget_destroy(widget);
 	*window = NULL;
 }
 
+struct maplocation {
+	OsmGpsMap *map;
+	double x,y;
+	void (* callback)(float, float);
+	GtkWidget *mapwindow;
+};
+
+static void add_location_cb(GtkWidget *widget, gpointer data)
+{
+	struct maplocation *maplocation = data;
+	OsmGpsMap *map = maplocation->map;
+	OsmGpsMapPoint *pt = osm_gps_map_point_new_degrees(0.0, 0.0);
+	float mark_lat, mark_lon;
+
+	osm_gps_map_convert_screen_to_geographic(map, maplocation->x, maplocation->y, pt);
+	osm_gps_map_point_get_degrees(pt, &mark_lat, &mark_lon);
+	maplocation->callback(mark_lat, mark_lon);
+	gtk_widget_destroy(gtk_widget_get_parent(maplocation->mapwindow));
+}
+
+static void map_popup_menu_cb(GtkWidget *w, gpointer data)
+{
+	GtkWidget *menu, *menuitem, *image;
+
+	menu = gtk_menu_new();
+	menuitem = gtk_image_menu_item_new_with_label(_("Mark location here"));
+	image = gtk_image_new_from_stock(GTK_STOCK_ADD, GTK_ICON_SIZE_MENU);
+	gtk_image_menu_item_set_image(GTK_IMAGE_MENU_ITEM(menuitem), image);
+	g_signal_connect(menuitem, "activate", G_CALLBACK(add_location_cb), data);
+	gtk_menu_shell_append(GTK_MENU_SHELL(menu), menuitem);
+	gtk_widget_show_all(menu);
+	gtk_menu_popup(GTK_MENU(menu), NULL, NULL, NULL, NULL,
+		3, gtk_get_current_event_time());
+}
+
+static gboolean button_cb(GtkWidget *widget, GdkEventButton *event, gpointer data)
+{
+	static struct maplocation maplocation = {};
+	if (data && event->type == GDK_BUTTON_PRESS && event->button == 3) {
+		maplocation.map = (OsmGpsMap *)widget;
+		maplocation.x = event->x;
+		maplocation.y = event->y;
+		maplocation.callback = data;
+		maplocation.mapwindow = widget;
+		map_popup_menu_cb(widget, &maplocation);
+	}
+	return FALSE;
+}
+
 /* the osm gps map default is to scroll-and-recenter around the mouse position
  * that is BAT SHIT CRAZY.
  * So let's do our own scroll handling instead */
@@ -85,7 +135,6 @@ static void add_gps_point(OsmGpsMap *map, float latitude, float longitude)
 	osm_gps_map_track_add(map, track);
 }
 
-
 OsmGpsMap *init_map(void)
 {
 	OsmGpsMap *map;
@@ -117,7 +166,7 @@ OsmGpsMap *init_map(void)
 	return map;
 }
 
-void show_map(OsmGpsMap *map, GtkWidget **window)
+void show_map(OsmGpsMap *map, GtkWidget **window, struct dive *dive, void (*callback)(float, float))
 {
 	if (!*window) {
 		/* Enable keyboard navigation */
@@ -137,19 +186,23 @@ void show_map(OsmGpsMap *map, GtkWidget **window)
 		g_signal_connect(*window, "destroy", G_CALLBACK(on_close), (gpointer)window);
 		g_signal_connect(G_OBJECT(map), "scroll-event", G_CALLBACK(scroll_cb), NULL);
 	}
+	if (callback)
+		g_signal_connect(G_OBJECT(map), "button-press-event", G_CALLBACK(button_cb), callback);
 	gtk_widget_show_all(*window);
 	gtk_window_present(GTK_WINDOW(*window));
+	if (callback)
+		gtk_grab_add(*window);
 }
 
-void show_gps_location(struct dive *dp)
+void show_gps_location(struct dive *dive, void (*callback)(float, float))
 {
 	static GtkWidget *window = NULL;
 	static OsmGpsMap *map = NULL;
 	GdkPixbuf *picture;
 	GError *gerror = NULL;
 
-	double lat = dp->latitude.udeg / 1000000.0;
+	double lat = dive->latitude.udeg / 1000000.0;
-	double lng = dp->longitude.udeg / 1000000.0;
+	double lng = dive->longitude.udeg / 1000000.0;
 
 	if (!map || !window)
 		map = init_map();
@@ -165,26 +218,26 @@ void show_gps_location(struct dive *dp)
 	} else {
 		osm_gps_map_set_center_and_zoom(map, 0, 0, 2);
 	}
-	show_map(map, &window);
+	show_map(map, &window, dive, callback);
 }
 
 void show_gps_locations()
 {
 	static OsmGpsMap *map = NULL;
 	static GtkWidget *window = NULL;
-	struct dive *dp;
+	struct dive *dive;
 	int idx;
 
 	if (!window || !map)
 		map = init_map();
 
-	for_each_dive(idx, dp) {
+	for_each_dive(idx, dive) {
-		if (dive_has_location(dp)) {
+		if (dive_has_location(dive)) {
-			add_gps_point(map, dp->latitude.udeg / 1000000.0,
+			add_gps_point(map, dive->latitude.udeg / 1000000.0,
-				dp->longitude.udeg / 1000000.0);
+				dive->longitude.udeg / 1000000.0);
 		}
 	}
 	osm_gps_map_set_center_and_zoom(map, 0, 0, 2);
 
-	show_map(map, &window);
+	show_map(map, &window, NULL, NULL);
 }

info.c

@@ -520,6 +520,7 @@ static gboolean gps_changed(struct dive *dive, struct dive *master, const char *
 struct dive_info {
 	GtkComboBoxEntry *location, *divemaster, *buddy, *rating, *suit, *viz;
 	GtkEntry *airtemp, *gps;
+	GtkWidget *gps_icon;
 	GtkTextView *notes;
 };
 
@@ -626,12 +627,52 @@ static void dive_trip_widget(GtkWidget *box, dive_trip_t *trip, struct dive_info
 		gtk_text_buffer_set_text(gtk_text_view_get_buffer(info->notes), trip->notes, -1);
 }
 
+struct location_update {
+	GtkEntry *entry;
+	struct dive *dive;
+	void (*callback)(float, float);
+} location_update;
+
+void print_gps_coordinates(char *buffer, int len, float lat, float lon)
+{
+	unsigned int latdeg, londeg;
+	float latmin, lonmin;
+	char *lath, *lonh;
+
+	lath = lat >= 0.0 ? "N" : "S";
+	lonh = lon >= 0.0 ? "E" : "W";
+	lat = fabs(lat);
+	lon = fabs(lon);
+	latdeg = lat;
+	londeg = lon;
+	latmin = (lat - latdeg) * 60.0;
+	lonmin = (lon - londeg) * 60.0;
+	snprintf(buffer, len, "%s%u%s %6.3f\' , %s%u%s %6.3f\'",
+		lath, latdeg, UTF8_DEGREE, latmin,
+		lonh, londeg, UTF8_DEGREE, lonmin);
+}
+
+void update_gps_entry(float lat, float lon)
+{
+	char gps_text[45];
+
+	print_gps_coordinates(gps_text, 45, lat, lon);
+	gtk_entry_set_text(location_update.entry, gps_text);
+}
+
+static gboolean gps_map_callback(GtkWidget *w, gpointer data)
+{
+	struct dive *dive = location_update.dive;
+	show_gps_location(dive, update_gps_entry);
+	return TRUE;
+}
+
 static void dive_info_widget(GtkWidget *box, struct dive *dive, struct dive_info *info, gboolean multi)
 {
-	GtkWidget *hbox, *label, *frame, *equipment;
+	GtkWidget *hbox, *label, *frame, *equipment, *image;
 	char buffer[128];
 	char airtemp[6];
-	char gps_text[25] = "";
+	char gps_text[45] = "";
 	const char *unit;
 	double value;
 
@@ -645,9 +686,21 @@ static void dive_info_widget(GtkWidget *box, struct dive *dive, struct dive_info
 	info->location = text_entry(box, _("Location"), location_list, dive->location);
 
 	if (dive_has_location(dive))
-		snprintf(gps_text, sizeof(gps_text), "%3.5lf;%3.5lf", dive->latitude.udeg / 1000000.0,
+		print_gps_coordinates(gps_text, sizeof(gps_text), dive->latitude.udeg / 1000000.0,
-								      dive->longitude.udeg / 1000000.0);
+								  dive->longitude.udeg / 1000000.0);
-	info->gps = single_text_entry(box, _("GPS (WGS84 or GPS format - use ';' as separator)"), gps_text);
+	hbox = gtk_hbox_new(FALSE, 2);
+	gtk_box_pack_start(GTK_BOX(box), hbox, FALSE, TRUE, 0);
+	info->gps = single_text_entry(hbox, _("GPS (WGS84 or GPS format)"), gps_text);
+	gtk_entry_set_width_chars(info->gps, 30);
+	info->gps_icon = gtk_button_new_with_label(_("Pick on map"));
+	gtk_box_pack_start(GTK_BOX(hbox), info->gps_icon, FALSE, FALSE, 6);
+	image = gtk_image_new_from_pixbuf(get_gps_icon());
+	gtk_image_set_pixel_size(GTK_IMAGE(image), 128);
+	gtk_button_set_image(GTK_BUTTON(info->gps_icon), image);
+
+	location_update.entry = info->gps;
+	location_update.dive = dive;
+	g_signal_connect(G_OBJECT(info->gps_icon), "clicked", G_CALLBACK(gps_map_callback), NULL);
 
 	hbox = gtk_hbox_new(FALSE, 3);
 	gtk_box_pack_start(GTK_BOX(box), hbox, FALSE, TRUE, 0);