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1 /*
2  * Copyright (C) 2009-2010 Andy Spencer <andy753421@gmail.com>
3  *
4  * This program is free software: you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation, either version 3 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17
18 /**
19  * SECTION:gis-viewer
20  * @short_description: Virtual globe base class
21  *
22  * #GisViewer is the base class for the virtual globe widget. It handles
23  * everything not directly related to drawing the globe. Plugins and
24  * applications using the viewer should normally talk to the viewer and not care
25  * how it is implemented. 
26  */
27
28 #include <config.h>
29 #include <math.h>
30 #include <gtk/gtk.h>
31 #include <gdk/gdkkeysyms.h>
32
33 #include "gis-marshal.h"
34 #include "gis-viewer.h"
35
36 #include "gis-util.h"
37
38
39 /* Constants */
40 enum {
41         SIG_TIME_CHANGED,
42         SIG_LOCATION_CHANGED,
43         SIG_ROTATION_CHANGED,
44         SIG_REFRESH,
45         SIG_OFFLINE,
46         NUM_SIGNALS,
47 };
48 static guint signals[NUM_SIGNALS];
49
50
51 /***********
52  * Helpers *
53  ***********/
54 /* Misc helpers */
55 static void _gis_viewer_fix_location(GisViewer *viewer)
56 {
57         while (viewer->location[0] <  -90) viewer->location[0] += 180;
58         while (viewer->location[0] >   90) viewer->location[0] -= 180;
59         while (viewer->location[1] < -180) viewer->location[1] += 360;
60         while (viewer->location[1] >  180) viewer->location[1] -= 360;
61         viewer->location[2] = ABS(viewer->location[2]);
62 }
63
64 /* Signal helpers */
65 static void _gis_viewer_emit_location_changed(GisViewer *viewer)
66 {
67         g_signal_emit(viewer, signals[SIG_LOCATION_CHANGED], 0,
68                         viewer->location[0],
69                         viewer->location[1],
70                         viewer->location[2]);
71 }
72 static void _gis_viewer_emit_rotation_changed(GisViewer *viewer)
73 {
74         g_signal_emit(viewer, signals[SIG_ROTATION_CHANGED], 0,
75                         viewer->rotation[0],
76                         viewer->rotation[1],
77                         viewer->rotation[2]);
78 }
79 static void _gis_viewer_emit_time_changed(GisViewer *viewer)
80 {
81         g_signal_emit(viewer, signals[SIG_TIME_CHANGED], 0,
82                         viewer->time);
83 }
84 static void _gis_viewer_emit_refresh(GisViewer *viewer)
85 {
86         g_signal_emit(viewer, signals[SIG_REFRESH], 0);
87 }
88 static void _gis_viewer_emit_offline(GisViewer *viewer)
89 {
90         g_signal_emit(viewer, signals[SIG_OFFLINE], 0,
91                         viewer->offline);
92 }
93
94 /*************
95  * Callbacks *
96  *************/
97 static gboolean on_key_press(GisViewer *viewer, GdkEventKey *event, gpointer _)
98 {
99         g_debug("GisViewer: on_key_press - key=%x, state=%x, plus=%x",
100                         event->keyval, event->state, GDK_plus);
101
102         double lat, lon, elev, pan;
103         gis_viewer_get_location(viewer, &lat, &lon, &elev);
104         pan = MIN(elev/(EARTH_R/2), 30);
105         gdk_threads_leave();
106         switch (event->keyval) {
107         case GDK_Left:  case GDK_h: gis_viewer_pan(viewer,  0,  -pan, 0); break;
108         case GDK_Down:  case GDK_j: gis_viewer_pan(viewer, -pan, 0,   0); break;
109         case GDK_Up:    case GDK_k: gis_viewer_pan(viewer,  pan, 0,   0); break;
110         case GDK_Right: case GDK_l: gis_viewer_pan(viewer,  0,   pan, 0); break;
111         case GDK_minus: case GDK_o: gis_viewer_zoom(viewer, 10./9); break;
112         case GDK_plus:  case GDK_i: gis_viewer_zoom(viewer, 9./10); break;
113         case GDK_H: gis_viewer_rotate(viewer,  0, 0, -2); break;
114         case GDK_J: gis_viewer_rotate(viewer,  2, 0,  0); break;
115         case GDK_K: gis_viewer_rotate(viewer, -2, 0,  0); break;
116         case GDK_L: gis_viewer_rotate(viewer,  0, 0,  2); break;
117         }
118         return FALSE;
119 }
120
121 static gboolean on_scroll(GisViewer *viewer, GdkEventScroll *event, gpointer _)
122 {
123         switch (event->direction) {
124         case GDK_SCROLL_DOWN: gis_viewer_zoom(viewer, 10./9); break;
125         case GDK_SCROLL_UP:   gis_viewer_zoom(viewer, 9./10); break;
126         default: break;
127         }
128         return FALSE;
129 }
130
131 enum {
132         GIS_DRAG_NONE,
133         GIS_DRAG_PAN,
134         GIS_DRAG_ZOOM,
135         GIS_DRAG_TILT,
136 };
137
138 static gboolean on_button_press(GisViewer *viewer, GdkEventButton *event, gpointer _)
139 {
140         g_debug("GisViewer: on_button_press - %d", event->button);
141         gtk_widget_grab_focus(GTK_WIDGET(viewer));
142         switch (event->button) {
143         case 1:  viewer->drag_mode = GIS_DRAG_PAN;  break;
144         case 2:  viewer->drag_mode = GIS_DRAG_ZOOM; break;
145         case 3:  viewer->drag_mode = GIS_DRAG_TILT; break;
146         defualt: viewer->drag_mode = GIS_DRAG_NONE; break;
147         }
148         viewer->drag_x = event->x;
149         viewer->drag_y = event->y;
150         return FALSE;
151 }
152
153 static gboolean on_button_release(GisViewer *viewer, GdkEventButton *event, gpointer _)
154 {
155         g_debug("GisViewer: on_button_release");
156         viewer->drag_mode = GIS_DRAG_NONE;
157         return FALSE;
158 }
159
160 static gboolean on_motion_notify(GisViewer *viewer, GdkEventMotion *event, gpointer _)
161 {
162         gdouble x = viewer->drag_x - event->x;
163         gdouble y = viewer->drag_y - event->y;
164         gdouble lat, lon, elev, scale;
165         gis_viewer_get_location(GIS_VIEWER(viewer), &lat, &lon, &elev);
166         scale = elev/EARTH_R/15;
167         switch (viewer->drag_mode) {
168         case GIS_DRAG_PAN:  gis_viewer_pan(viewer, -y*scale, x*scale, 0); break;
169         case GIS_DRAG_ZOOM: gis_viewer_zoom(viewer, pow(2, -y/500)); break;
170         case GIS_DRAG_TILT: gis_viewer_rotate(viewer, y/10, 0, x/10); break;
171         }
172         viewer->drag_x = event->x;
173         viewer->drag_y = event->y;
174         return FALSE;
175 }
176
177 static void on_view_changed(GisViewer *viewer,
178                 gdouble _1, gdouble _2, gdouble _3)
179 {
180         gtk_widget_queue_draw(GTK_WIDGET(viewer));
181 }
182
183 static void on_realize(GisViewer *viewer)
184 {
185         GdkCursor *cursor = gdk_cursor_new(GDK_FLEUR);
186         GdkWindow *window = gtk_widget_get_window(GTK_WIDGET(viewer));
187         gdk_window_set_cursor(window, cursor);
188 }
189
190 /***********
191  * Methods *
192  ***********/
193 /**
194  * gis_viewer_setup:
195  * @viewer:  the viewer
196  * @plugins: a plugins store
197  * @prefs:   a prefs store
198  *
199  * This should be called by objects which implement GisViewer somewhere in their
200  * constructor.
201  */
202 void gis_viewer_setup(GisViewer *viewer, GisPlugins *plugins, GisPrefs *prefs)
203 {
204         viewer->plugins = plugins;
205         viewer->prefs   = prefs;
206         viewer->offline = gis_prefs_get_boolean(prefs, "gis/offline", NULL);
207 }
208
209 /**
210  * gis_viewer_set_time:
211  * @viewer: the viewer
212  * @time: the time to set the view to
213  *
214  * Set the current time for the view
215  */
216 void gis_viewer_set_time(GisViewer *viewer, const char *time)
217 {
218         g_assert(GIS_IS_VIEWER(viewer));
219         g_debug("GisViewer: set_time - time=%s", time);
220         g_free(viewer->time);
221         viewer->time = g_strdup(time);
222         _gis_viewer_emit_time_changed(viewer);
223 }
224
225 /**
226  * gis_viewer_get_time:
227  * @viewer: the viewer
228  * 
229  * Get the time that is being viewed
230  *
231  * Returns: the current time
232  */
233 gchar *gis_viewer_get_time(GisViewer *viewer)
234 {
235         g_assert(GIS_IS_VIEWER(viewer));
236         g_debug("GisViewer: get_time");
237         return viewer->time;
238 }
239
240 /**
241  * gis_viewer_set_location:
242  * @viewer: the viewer
243  * @lat:  the new latitude
244  * @lon:  the new longitude
245  * @elev: the new elevation
246  *
247  * Set the location for the camera
248  */
249 void gis_viewer_set_location(GisViewer *viewer, gdouble lat, gdouble lon, gdouble elev)
250 {
251         g_assert(GIS_IS_VIEWER(viewer));
252         g_debug("GisViewer: set_location");
253         viewer->location[0] = lat;
254         viewer->location[1] = lon;
255         viewer->location[2] = elev;
256         _gis_viewer_fix_location(viewer);
257         _gis_viewer_emit_location_changed(viewer);
258 }
259
260 /**
261  * gis_viewer_get_location:
262  * @viewer: the viewer
263  * @lat:  the location to store the latitude
264  * @lon:  the location to store the longitude
265  * @elev: the location to store the elevation
266  *
267  * Get the location of the camera
268  */
269 void gis_viewer_get_location(GisViewer *viewer, gdouble *lat, gdouble *lon, gdouble *elev)
270 {
271         g_assert(GIS_IS_VIEWER(viewer));
272         //g_debug("GisViewer: get_location");
273         *lat  = viewer->location[0];
274         *lon  = viewer->location[1];
275         *elev = viewer->location[2];
276 }
277
278 /**
279  * gis_viewer_pan:
280  * @viewer: the viewer
281  * @forward:  distance to move forward in meters
282  * @right:    distance to move right in meters
283  * @up:       distance to move up in meters
284  *
285  * Pan the location by a number of meters long the surface.
286  *
287  * Bugs: the distances are not in meters
288  * Bugs: panning does not move in strait lines
289  */
290 void gis_viewer_pan(GisViewer *viewer, gdouble forward, gdouble sideways, gdouble up)
291 {
292         g_assert(GIS_IS_VIEWER(viewer));
293         g_debug("GisViewer: pan - forward=%8.3f, sideways=%8.3f, up=%8.3f",
294                         forward, sideways, up);
295         gdouble dist   = sqrt(forward*forward + sideways*sideways);
296         gdouble angle1 = deg2rad(viewer->rotation[2]);
297         gdouble angle2 = atan2(sideways, forward);
298         gdouble angle  = angle1 + angle2;
299         /* This isn't accurate, but it's usable */
300         viewer->location[0] += dist*cos(angle);
301         viewer->location[1] += dist*sin(angle);
302         viewer->location[2] += up;
303         _gis_viewer_fix_location(viewer);
304         _gis_viewer_emit_location_changed(viewer);
305 }
306
307 /**
308  * gis_viewer_zoom:
309  * @viewer: the viewer
310  * @scale: the scale to multiple the elevation by
311  *
312  * Multiple the elevation by a scale.
313  */
314 void gis_viewer_zoom(GisViewer *viewer, gdouble scale)
315 {
316         g_assert(GIS_IS_VIEWER(viewer));
317         g_debug("GisViewer: zoom");
318         viewer->location[2] *= scale;
319         _gis_viewer_emit_location_changed(viewer);
320 }
321
322 /**
323  * gis_viewer_set_rotation:
324  * @viewer: the viewer
325  * @x: rotation new around the x axes
326  * @y: rotation new around the y axes
327  * @z: rotation new around the z axes
328  *
329  * Set the rotations in degrees around the x, y, and z axes.
330  */
331 void gis_viewer_set_rotation(GisViewer *viewer, gdouble x, gdouble y, gdouble z)
332 {
333         g_assert(GIS_IS_VIEWER(viewer));
334         g_debug("GisViewer: set_rotation");
335         viewer->rotation[0] = x;
336         viewer->rotation[1] = y;
337         viewer->rotation[2] = z;
338         _gis_viewer_emit_rotation_changed(viewer);
339 }
340
341 /**
342  * gis_viewer_get_rotation:
343  * @viewer: the viewer
344  * @x: rotation around the x axes
345  * @y: rotation around the y axes
346  * @z: rotation around the z axes
347  *
348  * Get the rotations in degrees around the x, y, and z axes.
349  */
350 void gis_viewer_get_rotation(GisViewer *viewer, gdouble *x, gdouble *y, gdouble *z)
351 {
352         g_assert(GIS_IS_VIEWER(viewer));
353         g_debug("GisViewer: get_rotation");
354         *x = viewer->rotation[0];
355         *y = viewer->rotation[1];
356         *z = viewer->rotation[2];
357 }
358
359 /**
360  * gis_viewer_rotate:
361  * @viewer: the viewer
362  * @x: rotation around the x axes
363  * @y: rotation around the y axes
364  * @z: rotation around the z axes
365  *
366  * Add to the rotation around the x, y, and z axes.
367  */
368 void gis_viewer_rotate(GisViewer *viewer, gdouble x, gdouble y, gdouble z)
369 {
370         g_assert(GIS_IS_VIEWER(viewer));
371         g_debug("GisViewer: rotate - x=%.0f, y=%.0f, z=%.0f", x, y, z);
372         viewer->rotation[0] += x;
373         viewer->rotation[1] += y;
374         viewer->rotation[2] += z;
375         _gis_viewer_emit_rotation_changed(viewer);
376 }
377
378 /**
379  * gis_viewer_refresh:
380  * @viewer: the viewer
381  *
382  * Trigger the refresh signal. This will cause any remote data to be checked for
383  * updates. 
384  */
385 void gis_viewer_refresh(GisViewer *viewer)
386 {
387         g_debug("GisViewer: refresh");
388         _gis_viewer_emit_refresh(viewer);
389 }
390
391 /**
392  * gis_viewer_set_offline:
393  * @viewer: the viewer
394  * @offline: %TRUE to enter offline mode
395  *
396  * Set the offline mode. If @offline is %TRUE, only locally cached data will be
397  * used.
398  */
399 void gis_viewer_set_offline(GisViewer *viewer, gboolean offline)
400 {
401         g_assert(GIS_IS_VIEWER(viewer));
402         g_debug("GisViewer: set_offline - %d", offline);
403         gis_prefs_set_boolean(viewer->prefs, "gis/offline", offline);
404         viewer->offline = offline;
405         _gis_viewer_emit_offline(viewer);
406 }
407
408 /**
409  * gis_viewer_get_offline:
410  * @viewer: the viewer
411  *
412  * Check if the viewer is in offline mode.
413  *
414  * Returns: %TRUE if the viewer is in offline mode.
415  */
416 gboolean gis_viewer_get_offline(GisViewer *viewer)
417 {
418         g_assert(GIS_IS_VIEWER(viewer));
419         g_debug("GisViewer: get_offline - %d", viewer->offline);
420         return viewer->offline;
421 }
422
423 /***********************************
424  * To be implemented by subclasses *
425  ***********************************/
426 /**
427  * gis_viewer_center_position:
428  * @viewer: the viewer
429  * @lat:  the latitude
430  * @lon:  the longitude
431  * @elev: the elevation
432  *
433  * Center the viewer on a point. This can be used before drawing operations to
434  * center the items a particular location.
435  */
436 void gis_viewer_center_position(GisViewer *viewer,
437                 gdouble lat, gdouble lon, gdouble elev)
438 {
439         GisViewerClass *klass = GIS_VIEWER_GET_CLASS(viewer);
440         if (!klass->center_position)
441                 g_warning("GisViewer: center_position - Unimplemented");
442         klass->center_position(viewer, lat, lon, elev);
443 }
444
445 /**
446  * gis_viewer_project:
447  * @viewer: the viewer
448  * @lat:  the latitude
449  * @lon:  the latitude
450  * @elev: the latitude
451  * @px:   the project x coordinate
452  * @py:   the project y coordinate
453  * @pz:   the project z coordinate
454  *
455  * Project a latitude, longitude, elevation point to to x, y, and z coordinates
456  * in screen space. Useful for drawing orthographic data over a particular point
457  * in space. E.g. #GisMarker.
458  */
459 void gis_viewer_project(GisViewer *viewer,
460                 gdouble lat, gdouble lon, gdouble elev,
461                 gdouble *px, gdouble *py, gdouble *pz)
462 {
463         GisViewerClass *klass = GIS_VIEWER_GET_CLASS(viewer);
464         if (!klass->project)
465                 g_warning("GisViewer: project - Unimplemented");
466         klass->project(viewer, lat, lon, elev, px, py, pz);
467 }
468
469 /**
470  * gis_viewer_clear_height_func:
471  * @viewer: the viewer
472  *
473  * Clears the height function for the entire viewer. Useful when an elevation
474  * plugin is unloaded.
475  */
476 void gis_viewer_clear_height_func(GisViewer *viewer)
477 {
478         GisViewerClass *klass = GIS_VIEWER_GET_CLASS(viewer);
479         if (!klass->clear_height_func)
480                 g_warning("GisViewer: clear_height_func - Unimplemented");
481         klass->clear_height_func(viewer);
482 }
483
484 /**
485  * gis_viewer_set_height_func:
486  * @viewer:      the viewer
487  * @tile:        the area to set the height function for
488  * @height_func: the height function 
489  * @user_data:   user data to pass to the height function
490  * @update:      %TRUE if the heights inside the tile should be updated.
491  *
492  * Set the height function to be used for a given part of the surface..
493  */
494 void gis_viewer_set_height_func(GisViewer *viewer, GisTile *tile,
495                 GisHeightFunc height_func, gpointer user_data,
496                 gboolean update)
497 {
498         GisViewerClass *klass = GIS_VIEWER_GET_CLASS(viewer);
499         if (!klass->set_height_func)
500                 g_warning("GisViewer: set_height_func - Unimplemented");
501         klass->set_height_func(viewer, tile, height_func, user_data, update);
502 }
503
504 /**
505  * gis_viewer_add:
506  * @viewer: the viewer
507  * @object: the object to add
508  * @level:  the level to add the object to
509  * @sort:   %TRUE if the object should be depth-sorted prior to being drawn
510  *
511  * Objects which are added to the viewer will be drawn on subsequent renderings
512  * if their level of details is adequate.
513  *
514  * The @level represents the order the object should be drawn in, this is
515  * unrelated to the objects actual position in the world.
516  *
517  * Semi-transparent objects should set @sort to %TRUE so that they are rendered
518  * correctly when they overlap other semi-transparent objects.
519  *
520  * The viewer steals the objects reference. Call g_object_ref if you plan on
521  * holding a reference as well.
522  *
523  * Returns: a handle to be pass to gis_viewer_remove()
524  */
525 gpointer gis_viewer_add(GisViewer *viewer, GisObject *object,
526                 gint level, gboolean sort)
527 {
528         GisViewerClass *klass = GIS_VIEWER_GET_CLASS(viewer);
529         if (!klass->add)
530                 g_warning("GisViewer: add - Unimplemented");
531         return klass->add(viewer, object, level, sort);
532 }
533
534 /**
535  * gis_viewer_remove:
536  * @viewer: the viewer
537  * @ref:    the handle obtained from gis_viewer_add()
538  *
539  * Remove an object from the viewer. The objects reference count is decremented
540  * prior to being removed.
541  *
542  * Returns: the #GisObject referenced by the handle
543  */
544 GisObject *gis_viewer_remove(GisViewer *viewer, gpointer ref)
545 {
546         GisViewerClass *klass = GIS_VIEWER_GET_CLASS(viewer);
547         if (!klass->remove)
548                 g_warning("GisViewer: remove - Unimplemented");
549         return klass->remove(viewer, ref);
550 }
551
552 /****************
553  * GObject code *
554  ****************/
555 G_DEFINE_ABSTRACT_TYPE(GisViewer, gis_viewer, GTK_TYPE_DRAWING_AREA);
556 static void gis_viewer_init(GisViewer *viewer)
557 {
558         g_debug("GisViewer: init");
559         /* Default values */
560         viewer->time = g_strdup("");
561         viewer->location[0] = 40;
562         viewer->location[1] = -100;
563         viewer->location[2] = 1.5*EARTH_R;
564         viewer->rotation[0] = 0;
565         viewer->rotation[1] = 0;
566         viewer->rotation[2] = 0;
567
568         g_object_set(viewer, "can-focus", TRUE, NULL);
569         gtk_widget_add_events(GTK_WIDGET(viewer),
570                         GDK_BUTTON_PRESS_MASK |
571                         GDK_BUTTON_RELEASE_MASK |
572                         GDK_POINTER_MOTION_MASK |
573                         GDK_KEY_PRESS_MASK);
574
575         g_signal_connect(viewer, "key-press-event",      G_CALLBACK(on_key_press),      NULL);
576         g_signal_connect(viewer, "scroll-event",         G_CALLBACK(on_scroll),         NULL);
577
578         g_signal_connect(viewer, "button-press-event",   G_CALLBACK(on_button_press),   NULL);
579         g_signal_connect(viewer, "button-release-event", G_CALLBACK(on_button_release), NULL);
580         g_signal_connect(viewer, "motion-notify-event",  G_CALLBACK(on_motion_notify),  NULL);
581
582         g_signal_connect(viewer, "location-changed",     G_CALLBACK(on_view_changed),   NULL);
583         g_signal_connect(viewer, "rotation-changed",     G_CALLBACK(on_view_changed),   NULL);
584
585         g_signal_connect(viewer, "realize",              G_CALLBACK(on_realize),        NULL);
586 }
587 static void gis_viewer_finalize(GObject *gobject)
588 {
589         g_debug("GisViewer: finalize");
590         GisViewer *viewer = GIS_VIEWER(gobject);
591         g_free(viewer->time);
592         G_OBJECT_CLASS(gis_viewer_parent_class)->finalize(gobject);
593 }
594 static void gis_viewer_class_init(GisViewerClass *klass)
595 {
596         g_debug("GisViewer: class_init");
597         GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
598         gobject_class->finalize     = gis_viewer_finalize;
599
600         /**
601          * GisViewer::time-changed:
602          * @viewer: the viewer.
603          * @time:   a string representation of the time.
604          *
605          * The ::time-changed signal is emitted when the viewers current time
606          * changers.
607          */
608         signals[SIG_TIME_CHANGED] = g_signal_new(
609                         "time-changed",
610                         G_TYPE_FROM_CLASS(gobject_class),
611                         G_SIGNAL_RUN_LAST,
612                         0,
613                         NULL,
614                         NULL,
615                         g_cclosure_marshal_VOID__STRING,
616                         G_TYPE_NONE,
617                         1,
618                         G_TYPE_STRING);
619
620         /**
621          * GisViewer::location-changed:
622          * @viewer: the viewer.
623          * @lat:    the new latitude.
624          * @lon:    the new longitude.
625          * @elev:   the new elevation.
626          *
627          * The ::location-changed signal is emitted when the viewers camera
628          * location changes.
629          */
630         signals[SIG_LOCATION_CHANGED] = g_signal_new(
631                         "location-changed",
632                         G_TYPE_FROM_CLASS(gobject_class),
633                         G_SIGNAL_RUN_LAST,
634                         0,
635                         NULL,
636                         NULL,
637                         gis_cclosure_marshal_VOID__DOUBLE_DOUBLE_DOUBLE,
638                         G_TYPE_NONE,
639                         3,
640                         G_TYPE_DOUBLE,
641                         G_TYPE_DOUBLE,
642                         G_TYPE_DOUBLE);
643
644         /**
645          * GisViewer::rotation-changed:
646          * @viewer: the viewer.
647          * @x: rotation new around the x axes.
648          * @y: rotation new around the y axes.
649          * @z: rotation new around the z axes.
650          *
651          * The ::rotation-changed signal is emitted when the viewers cameras
652          * rotation changes.
653          */
654         signals[SIG_ROTATION_CHANGED] = g_signal_new(
655                         "rotation-changed",
656                         G_TYPE_FROM_CLASS(gobject_class),
657                         G_SIGNAL_RUN_LAST,
658                         0,
659                         NULL,
660                         NULL,
661                         gis_cclosure_marshal_VOID__DOUBLE_DOUBLE_DOUBLE,
662                         G_TYPE_NONE,
663                         3,
664                         G_TYPE_DOUBLE,
665                         G_TYPE_DOUBLE,
666                         G_TYPE_DOUBLE);
667
668         /**
669          * GisViewer::refresh:
670          * @viewer: the viewer.
671          *
672          * The ::refresh signal is emitted when a refresh is needed. If you are
673          * using real-time data from a remote server, you should connect to the
674          * refresh signal and update the data when necessary.
675          */
676         signals[SIG_REFRESH] = g_signal_new(
677                         "refresh",
678                         G_TYPE_FROM_CLASS(gobject_class),
679                         G_SIGNAL_RUN_LAST,
680                         0,
681                         NULL,
682                         NULL,
683                         g_cclosure_marshal_VOID__VOID,
684                         G_TYPE_NONE,
685                         0);
686
687         /**
688          * GisViewer::offline:
689          * @viewer:  the viewer.
690          * @offline: %TRUE if the viewer going offline.
691          *
692          * The ::offline signal is emitted when the viewers offline mode
693          * changes.
694          */
695         signals[SIG_OFFLINE] = g_signal_new(
696                         "offline",
697                         G_TYPE_FROM_CLASS(gobject_class),
698                         G_SIGNAL_RUN_LAST,
699                         0,
700                         NULL,
701                         NULL,
702                         g_cclosure_marshal_VOID__BOOLEAN,
703                         G_TYPE_NONE,
704                         1,
705                         G_TYPE_BOOLEAN);
706 }