* viking -- GPS Data and Topo Analyzer, Explorer, and Manager
*
* Copyright (C) 2003-2007, Evan Battaglia <gtoevan@gmx.net>
+ * Copyright (C) 2013, Rob Norris <rw_norris@hotmail.com>
*
* Lat/Lon plotting functions calcxy* are from GPSDrive
* GPSDrive Copyright (C) 2001-2004 Fritz Ganter <ganter@ganter.at>
#include "vikcoord.h"
#include "vikwindow.h"
#include "vikviewport.h"
-
#include "mapcoord.h"
/* for ALTI_TO_MPP */
#include "globals.h"
#include "settings.h"
+#include "dialog.h"
#define MERCATOR_FACTOR(x) ( (65536.0 / 180 / (x)) * 256.0 )
static void viewport_finalize ( GObject *gob );
static void viewport_utm_zone_check ( VikViewport *vvp );
+static void update_centers ( VikViewport *vvp );
+static void free_centers ( VikViewport *vvp, guint start );
static gboolean calcxy(double *x, double *y, double lg, double lt, double zero_long, double zero_lat, double pixelfact_x, double pixelfact_y, gint mapSizeX2, gint mapSizeY2 );
static gboolean calcxy_rev(double *lg, double *lt, gint x, gint y, double zero_long, double zero_lat, double pixelfact_x, double pixelfact_y, gint mapSizeX2, gint mapSizeY2 );
static GObjectClass *parent_class;
-
struct _VikViewport {
GtkDrawingArea drawing_area;
GdkPixmap *scr_buffer;
VikCoordMode coord_mode;
gdouble xmpp, ympp;
gdouble xmfactor, ymfactor;
-
- GdkPixbuf *alpha_pixbuf;
- guint8 alpha_pixbuf_width;
- guint8 alpha_pixbuf_height;
+ GList *centers; // The history of requested positions (of VikCoord type)
+ guint centers_index; // current position within the history list
+ guint centers_max; // configurable maximum size of the history list
+ guint centers_radius; // Metres
gdouble utm_zone_width;
gboolean one_utm_zone;
return 0.0;
}
+enum {
+ VW_UPDATED_CENTER_SIGNAL = 0,
+ VW_LAST_SIGNAL,
+};
+static guint viewport_signals[VW_LAST_SIGNAL] = { 0 };
+
G_DEFINE_TYPE (VikViewport, vik_viewport, GTK_TYPE_DRAWING_AREA)
static void
object_class->finalize = viewport_finalize;
parent_class = g_type_class_peek_parent (klass);
+
+ viewport_signals[VW_UPDATED_CENTER_SIGNAL] = g_signal_new ( "updated_center", G_TYPE_FROM_CLASS (klass),
+ G_SIGNAL_RUN_FIRST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (VikViewportClass, updated_center), NULL, NULL,
+ g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
}
VikViewport *vik_viewport_new ()
#define VIK_SETTINGS_VIEW_LAST_LONGITUDE "viewport_last_longitude"
#define VIK_SETTINGS_VIEW_LAST_ZOOM_X "viewport_last_zoom_xpp"
#define VIK_SETTINGS_VIEW_LAST_ZOOM_Y "viewport_last_zoom_ypp"
+#define VIK_SETTINGS_VIEW_HISTORY_SIZE "viewport_history_size"
+#define VIK_SETTINGS_VIEW_HISTORY_DIFF_DIST "viewport_history_diff_dist"
static void
vik_viewport_init ( VikViewport *vvp )
a_coords_latlon_to_utm ( &ll, &utm );
- /* TODO: not static */
vvp->xmpp = zoom_x;
vvp->ympp = zoom_y;
vvp->xmfactor = MERCATOR_FACTOR (vvp->xmpp);
vvp->center.utm_zone = (int)utm.zone;
vvp->center.utm_letter = utm.letter;
vvp->scr_buffer = NULL;
- vvp->alpha_pixbuf = NULL;
- vvp->alpha_pixbuf_width = vvp->alpha_pixbuf_height = 0;
vvp->utm_zone_width = 0.0;
vvp->background_gc = NULL;
vvp->highlight_gc = NULL;
vvp->scale_bg_gc = NULL;
vvp->copyrights = NULL;
+ vvp->centers = NULL;
+ vvp->centers_index = 0;
+ vvp->centers_max = 20;
+ gint tmp = vvp->centers_max;
+ if ( a_settings_get_integer ( VIK_SETTINGS_VIEW_HISTORY_SIZE, &tmp ) )
+ vvp->centers_max = tmp;
+ vvp->centers_radius = 500;
+ if ( a_settings_get_integer ( VIK_SETTINGS_VIEW_HISTORY_DIFF_DIST, &tmp ) )
+ vvp->centers_radius = tmp;
vvp->draw_scale = TRUE;
vvp->draw_centermark = TRUE;
vvp->snapshot_buffer = NULL;
vvp->half_drawn = FALSE;
+ // Initiate center history
+ update_centers ( vvp );
+
g_signal_connect (G_OBJECT(vvp), "configure_event", G_CALLBACK(vik_viewport_configure), NULL);
#if GTK_CHECK_VERSION (2,18,0)
{
g_return_val_if_fail ( vvp != NULL, TRUE );
- vvp->width = GTK_WIDGET(vvp)->allocation.width;
- vvp->height = GTK_WIDGET(vvp)->allocation.height;
+ GtkAllocation allocation;
+ gtk_widget_get_allocation ( GTK_WIDGET(vvp), &allocation );
+ vvp->width = allocation.width;
+ vvp->height = allocation.height;
vvp->width_2 = vvp->width/2;
vvp->height_2 = vvp->height/2;
a_settings_set_double ( VIK_SETTINGS_VIEW_LAST_ZOOM_Y, vvp->ympp );
}
+ if ( vvp->centers )
+ free_centers ( vvp, 0 );
+
if ( vvp->scr_buffer )
g_object_unref ( G_OBJECT ( vvp->scr_buffer ) );
if ( vvp->snapshot_buffer )
g_object_unref ( G_OBJECT ( vvp->snapshot_buffer ) );
- if ( vvp->alpha_pixbuf )
- g_object_unref ( G_OBJECT ( vvp->alpha_pixbuf ) );
-
if ( vvp->background_gc )
g_object_unref ( G_OBJECT ( vvp->background_gc ) );
PangoLayout *pl;
gchar s[128];
- vik_viewport_screen_to_coord ( vvp, 0, vvp->height, &left );
- vik_viewport_screen_to_coord ( vvp, vvp->width/SCSIZE, vvp->height, &right );
+ vik_viewport_screen_to_coord ( vvp, 0, vvp->height/2, &left );
+ vik_viewport_screen_to_coord ( vvp, vvp->width/SCSIZE, vvp->height/2, &right );
vik_units_distance_t dist_units = a_vik_get_units_distance ();
switch (dist_units) {
// in 0.1 miles (copes better when zoomed in as 1 mile can be too big)
base = VIK_METERS_TO_MILES(vik_coord_diff ( &left, &right )) * 10.0;
break;
+ case VIK_UNITS_DISTANCE_NAUTICAL_MILES:
+ // in 0.1 NM (copes better when zoomed in as 1 NM can be too big)
+ base = VIK_METERS_TO_NAUTICAL_MILES(vik_coord_diff ( &left, &right )) * 10.0;
+ break;
default:
base = 1; // Keep the compiler happy
g_critical("Houston, we've had a problem. distance=%d", dist_units);
int i;
for (i=1; i<5; i++) {
vik_viewport_draw_line(vvp, vvp->scale_bg_gc,
- PAD+i*len/5, vvp->height-PAD, PAD+i*len/5, vvp->height-PAD-((i==5)?(2*HEIGHT/3):(HEIGHT/2)));
+ PAD+i*len/5, vvp->height-PAD, PAD+i*len/5, vvp->height-PAD-(HEIGHT/2));
vik_viewport_draw_line(vvp, gtk_widget_get_style(GTK_WIDGET(&vvp->drawing_area))->black_gc,
- PAD+i*len/5, vvp->height-PAD, PAD+i*len/5, vvp->height-PAD-((i==5)?(2*HEIGHT/3):(HEIGHT/2)));
+ PAD+i*len/5, vvp->height-PAD, PAD+i*len/5, vvp->height-PAD-(HEIGHT/2));
}
} else {
int i;
switch (dist_units) {
case VIK_UNITS_DISTANCE_KILOMETRES:
if (unit >= 1000) {
- sprintf(s, "%d km", (int)unit/1000);
+ sprintf(s, "%d km", (int)unit/1000);
} else {
- sprintf(s, "%d m", (int)unit);
+ sprintf(s, "%d m", (int)unit);
}
break;
case VIK_UNITS_DISTANCE_MILES:
// Handle units in 0.1 miles
if (unit < 10.0) {
- sprintf(s, "%0.1f miles", unit/10.0);
+ sprintf(s, "%0.1f miles", unit/10.0);
}
else if ((int)unit == 10.0) {
- sprintf(s, "1 mile");
+ sprintf(s, "1 mile");
}
else {
- sprintf(s, "%d miles", (int)(unit/10.0));
+ sprintf(s, "%d miles", (int)(unit/10.0));
+ }
+ break;
+ case VIK_UNITS_DISTANCE_NAUTICAL_MILES:
+ // Handle units in 0.1 NM
+ if (unit < 10.0) {
+ sprintf(s, "%0.1f NM", unit/10.0);
+ }
+ else if ((int)unit == 10.0) {
+ sprintf(s, "1 NM");
+ }
+ else {
+ sprintf(s, "%d NMs", (int)(unit/10.0));
}
break;
default:
}
}
-void vik_viewport_set_center_latlon ( VikViewport *vvp, const struct LatLon *ll )
+/**
+ * Free an individual center position in the history list
+ */
+static void free_center ( VikViewport *vvp, guint index )
+{
+ VikCoord *coord = g_list_nth_data ( vvp->centers, index );
+ if ( coord )
+ g_free ( coord );
+ GList *gl = g_list_nth ( vvp->centers, index );
+ if ( gl )
+ vvp->centers = g_list_delete_link ( vvp->centers, gl );
+}
+
+/**
+ * Free a set of center positions in the history list,
+ * from the indicated start index to the end of the list
+ */
+static void free_centers ( VikViewport *vvp, guint start )
+{
+ // Have to work backward since we delete items referenced by the '_nth()' values,
+ // otherwise if processed forward - removing the lower nth index entries would change the subsequent indexing
+ for ( guint i = g_list_length(vvp->centers)-1; i > start; i-- )
+ free_center ( vvp, i );
+}
+
+/**
+ * Store the current center position into the history list
+ * and emit a signal to notify clients the list has been updated
+ */
+static void update_centers ( VikViewport *vvp )
+{
+ VikCoord *new_center = g_malloc(sizeof (VikCoord));
+ *new_center = vvp->center;
+
+ if ( vvp->centers_index ) {
+
+ if ( vvp->centers_index == vvp->centers_max-1 ) {
+ // List is full, so drop the oldest value to make room for the new one
+ free_center ( vvp, 0 );
+ vvp->centers_index--;
+ }
+ else {
+ // Reset the now unused section of the list
+ // Free from the index to the end
+ free_centers ( vvp, vvp->centers_index+1 );
+ }
+
+ }
+
+ // Store new position
+ // NB ATM this can be the same location as the last one in the list
+ vvp->centers = g_list_append ( vvp->centers, new_center );
+
+ // Reset to the end (NB should be same as centers_index++)
+ vvp->centers_index = g_list_length ( vvp->centers ) - 1;
+
+ // Inform interested subscribers that this change has occurred
+ g_signal_emit ( G_OBJECT(vvp), viewport_signals[VW_UPDATED_CENTER_SIGNAL], 0 );
+}
+
+/**
+ * Show the list of forward/backward positions
+ * ATM only for debug usage
+ */
+void vik_viewport_show_centers ( VikViewport *vvp, GtkWindow *parent )
+{
+ GList* node = NULL;
+ GList* texts = NULL;
+ gint index = 0;
+ for (node = vvp->centers; node != NULL; node = g_list_next(node)) {
+ gchar *lat = NULL, *lon = NULL;
+ struct LatLon ll;
+ vik_coord_to_latlon (node->data, &ll);
+ a_coords_latlon_to_string ( &ll, &lat, &lon );
+ gchar *extra = NULL;
+ if ( index == vvp->centers_index-1 )
+ extra = g_strdup ( " [Back]" );
+ else if ( index == vvp->centers_index+1 )
+ extra = g_strdup ( " [Forward]" );
+ else
+ extra = g_strdup ( "" );
+ texts = g_list_prepend ( texts , g_strdup_printf ( "%s %s%s", lat, lon, extra ) );
+ g_free ( lat );
+ g_free ( lon );
+ g_free ( extra );
+ index++;
+ }
+
+ // NB: No i18n as this is just for debug
+ // Using this function the dialog allows sorting of the list which isn't appropriate here
+ // but this doesn't matter much for debug purposes of showing stuff...
+ GList *ans = a_dialog_select_from_list(parent,
+ texts,
+ FALSE,
+ "Back/Forward Locations",
+ "Back/Forward Locations");
+ for (node = ans; node != NULL; node = g_list_next(node))
+ g_free(node->data);
+ g_list_free(ans);
+ for (node = texts; node != NULL; node = g_list_next(node))
+ g_free(node->data);
+ g_list_free(texts);
+}
+
+/**
+ * vik_viewport_go_back:
+ *
+ * Move back in the position history
+ *
+ * Returns: %TRUE one success
+ */
+gboolean vik_viewport_go_back ( VikViewport *vvp )
+{
+ // see if the current position is different from the last saved center position within a certain radius
+ VikCoord *center = g_list_nth_data ( vvp->centers, vvp->centers_index );
+ if ( center ) {
+ // Consider an exclusion size (should it zoom level dependent, rather than a fixed value?)
+ // When still near to the last saved position we'll jump over it to the one before
+ if ( vik_coord_diff ( center, &vvp->center ) > vvp->centers_radius ) {
+
+ if ( vvp->centers_index == g_list_length(vvp->centers)-1 ) {
+ // Only when we haven't already moved back in the list
+ // Remember where this request came from
+ // (alternatively we could insert in the list on every back attempt)
+ update_centers ( vvp );
+ }
+
+ }
+ // 'Go back' if possible
+ // NB if we inserted a position above, then this will then move to the last saved position
+ // otherwise this will skip to the previous saved position, as it's probably somewhere else.
+ if ( vvp->centers_index > 0 )
+ vvp->centers_index--;
+ }
+ else {
+ return FALSE;
+ }
+
+ VikCoord *new_center = g_list_nth_data ( vvp->centers, vvp->centers_index );
+ if ( new_center ) {
+ vik_viewport_set_center_coord ( vvp, new_center, FALSE );
+ return TRUE;
+ }
+ return FALSE;
+}
+
+/**
+ * vik_viewport_go_forward:
+ *
+ * Move forward in the position history
+ *
+ * Returns: %TRUE one success
+ */
+gboolean vik_viewport_go_forward ( VikViewport *vvp )
+{
+ if ( vvp->centers_index == vvp->centers_max-1 )
+ return FALSE;
+
+ vvp->centers_index++;
+ VikCoord *new_center = g_list_nth_data ( vvp->centers, vvp->centers_index );
+ if ( new_center ) {
+ vik_viewport_set_center_coord ( vvp, new_center, FALSE );
+ return TRUE;
+ }
+ else
+ // Set to end of list
+ vvp->centers_index = g_list_length(vvp->centers) - 1;
+
+ return FALSE;
+}
+
+/**
+ * vik_viewport_back_available:
+ *
+ * Returns: %TRUE when a previous position in the history is available
+ */
+gboolean vik_viewport_back_available ( const VikViewport *vvp )
+{
+ return ( vvp->centers_index > 0 );
+}
+
+/**
+ * vik_viewport_forward_available:
+ *
+ * Returns: %TRUE when a next position in the history is available
+ */
+gboolean vik_viewport_forward_available ( const VikViewport *vvp )
+{
+ return ( vvp->centers_index < g_list_length(vvp->centers)-1 );
+}
+
+/**
+ * vik_viewport_set_center_latlon:
+ * @vvp: The viewport to reposition.
+ * @ll: The new center position in Lat/Lon format
+ * @save_position: Whether this new position should be saved into the history of positions
+ * Normally only specific user requests should be saved (i.e. to not include Pan and Zoom repositions)
+ */
+void vik_viewport_set_center_latlon ( VikViewport *vvp, const struct LatLon *ll, gboolean save_position )
{
vik_coord_load_from_latlon ( &(vvp->center), vvp->coord_mode, ll );
+ if ( save_position )
+ update_centers ( vvp );
if ( vvp->coord_mode == VIK_COORD_UTM )
viewport_utm_zone_check ( vvp );
}
-void vik_viewport_set_center_utm ( VikViewport *vvp, const struct UTM *utm )
+/**
+ * vik_viewport_set_center_utm:
+ * @vvp: The viewport to reposition.
+ * @utm: The new center position in UTM format
+ * @save_position: Whether this new position should be saved into the history of positions
+ * Normally only specific user requests should be saved (i.e. to not include Pan and Zoom repositions)
+ */
+void vik_viewport_set_center_utm ( VikViewport *vvp, const struct UTM *utm, gboolean save_position )
{
vik_coord_load_from_utm ( &(vvp->center), vvp->coord_mode, utm );
+ if ( save_position )
+ update_centers ( vvp );
if ( vvp->coord_mode == VIK_COORD_UTM )
viewport_utm_zone_check ( vvp );
}
-void vik_viewport_set_center_coord ( VikViewport *vvp, const VikCoord *coord )
+/**
+ * vik_viewport_set_center_coord:
+ * @vvp: The viewport to reposition.
+ * @coord: The new center position in a VikCoord type
+ * @save_position: Whether this new position should be saved into the history of positions
+ * Normally only specific user requests should be saved (i.e. to not include Pan and Zoom repositions)
+ */
+void vik_viewport_set_center_coord ( VikViewport *vvp, const VikCoord *coord, gboolean save_position )
{
vvp->center = *coord;
+ if ( save_position )
+ update_centers ( vvp );
if ( vvp->coord_mode == VIK_COORD_UTM )
viewport_utm_zone_check ( vvp );
}
} else {
VikCoord tmp;
vik_viewport_screen_to_coord ( vvp, x, y, &tmp );
- vik_viewport_set_center_coord ( vvp, &tmp );
+ vik_viewport_set_center_coord ( vvp, &tmp, FALSE );
}
}
}
}
-void a_viewport_clip_line ( gint *x1, gint *y1, gint *x2, gint *y2 )
+// Clip functions continually reduce the value by a factor until it is in the acceptable range
+// whilst also scaling the other coordinate value.
+static void clip_x ( gint *x1, gint *y1, gint *x2, gint *y2 )
{
- if ( *x1 > 20000 || *x1 < -20000 ) {
- gdouble shrinkfactor = ABS(20000.0 / *x1);
- *x1 = *x2 + (shrinkfactor * (*x1-*x2));
- *y1 = *y2 + (shrinkfactor * (*y1-*y2));
- } else if ( *y1 > 20000 || *y1 < -20000 ) {
- gdouble shrinkfactor = ABS(20000.0 / *x1);
- *x1 = *x2 + (shrinkfactor * (*x1-*x2));
- *y1 = *y2 + (shrinkfactor * (*y1-*y2));
- } else if ( *x2 > 20000 || *x2 < -20000 ) {
- gdouble shrinkfactor = ABS(20000.0 / (gdouble)*x2);
- *x2 = *x1 + (shrinkfactor * (*x2-*x1));
- *y2 = *y1 + (shrinkfactor * (*y2-*y1));
- } else if ( *y2 > 20000 || *y2 < -20000 ) {
- gdouble shrinkfactor = ABS(20000.0 / (gdouble)*x2);
- *x2 = *x1 + (shrinkfactor * (*x2-*x1));
- *y2 = *y1 + (shrinkfactor * (*y2-*y1));
+ while ( ABS(*x1) > 32768 ) {
+ *x1 = *x2 + (0.5 * (*x1-*x2));
+ *y1 = *y2 + (0.5 * (*y1-*y2));
}
}
+static void clip_y ( gint *x1, gint *y1, gint *x2, gint *y2 )
+{
+ while ( ABS(*y1) > 32767 ) {
+ *x1 = *x2 + (0.5 * (*x1-*x2));
+ *y1 = *y2 + (0.5 * (*y1-*y2));
+ }
+}
+
+/**
+ * a_viewport_clip_line:
+ * @x1: screen coord
+ * @y1: screen coord
+ * @x2: screen coord
+ * @y2: screen coord
+ *
+ * Due to the seemingly undocumented behaviour of gdk_draw_line(), we need to restrict the range of values passed in.
+ * So despite it accepting gints, the effective range seems to be the actually the minimum C int range (2^16).
+ * This seems to be limitations coming from the X Window System.
+ *
+ * See http://www.rahul.net/kenton/40errs.html
+ * ERROR 7. Boundary conditions.
+ * "The X coordinate space is not infinite.
+ * Most drawing functions limit position, width, and height to 16 bit integers (sometimes signed, sometimes unsigned) of accuracy.
+ * Because most C compilers use 32 bit integers, Xlib will not complain if you exceed the 16 bit limit, but your results will usually not be what you expected.
+ * You should be especially careful of this if you are implementing higher level scalable graphics packages."
+ *
+ * This function should be called before calling gdk_draw_line().
+ */
+void a_viewport_clip_line ( gint *x1, gint *y1, gint *x2, gint *y2 )
+{
+ if ( *x1 > 32768 || *x1 < -32767 )
+ clip_x ( x1, y1, x2, y2 );
+ if ( *y1 > 32768 || *y1 < -32767 )
+ clip_y ( x1, y1, x2, y2 );
+ if ( *x2 > 32768 || *x2 < -32767 )
+ clip_x ( x2, y2, x1, y1 );
+ if ( *y2 > 32768 || *y2 < -32767 )
+ clip_y ( x2, y2, x1, y1 );
+}
+
void vik_viewport_draw_line ( VikViewport *vvp, GdkGC *gc, gint x1, gint y1, gint x2, gint y2 )
{
if ( ! ( ( x1 < 0 && x2 < 0 ) || ( y1 < 0 && y2 < 0 ) ||
gdk_draw_string ( vvp->scr_buffer, font, gc, x1, y1, string );
}
-/* shouldn't use this -- slow -- change the alpha channel instead. */
-void vik_viewport_draw_pixbuf_with_alpha ( VikViewport *vvp, GdkPixbuf *pixbuf, gint alpha,
- gint src_x, gint src_y, gint dest_x, gint dest_y, gint w, gint h )
-{
- gint real_dest_x = MAX(dest_x,0);
- gint real_dest_y = MAX(dest_y,0);
-
- if ( alpha == 0 )
- return; /* don't waste your time */
-
- if ( w > vvp->alpha_pixbuf_width || h > vvp->alpha_pixbuf_height )
- {
- if ( vvp->alpha_pixbuf )
- g_object_unref ( G_OBJECT ( vvp->alpha_pixbuf ) );
- vvp->alpha_pixbuf_width = MAX(w,vvp->alpha_pixbuf_width);
- vvp->alpha_pixbuf_height = MAX(h,vvp->alpha_pixbuf_height);
- vvp->alpha_pixbuf = gdk_pixbuf_new ( GDK_COLORSPACE_RGB, FALSE, 8, vvp->alpha_pixbuf_width, vvp->alpha_pixbuf_height );
- }
-
- w = MIN(w,vvp->width - dest_x);
- h = MIN(h,vvp->height - dest_y);
-
- /* check that we are drawing within boundaries. */
- src_x += (real_dest_x - dest_x);
- src_y += (real_dest_y - dest_y);
- w -= (real_dest_x - dest_x);
- h -= (real_dest_y - dest_y);
-
- gdk_pixbuf_get_from_drawable ( vvp->alpha_pixbuf, vvp->scr_buffer, NULL,
- real_dest_x, real_dest_y, 0, 0, w, h );
-
- /* do a composite */
- gdk_pixbuf_composite ( pixbuf, vvp->alpha_pixbuf, 0, 0, w, h, -src_x, -src_y, 1, 1, 0, alpha );
-
- /* draw pixbuf_tmp */
- vik_viewport_draw_pixbuf ( vvp, vvp->alpha_pixbuf, 0, 0, real_dest_x, real_dest_y, w, h );
-}
-
void vik_viewport_draw_pixbuf ( VikViewport *vvp, GdkPixbuf *pixbuf, gint src_x, gint src_y,
gint dest_x, gint dest_y, gint w, gint h )
{
px = (mapSizeX2 - x) * pixelfact_x;
py = (-mapSizeY2 + y) * pixelfact_y;
- lat = zero_lat - py / Ra;
lat = zero_lat - py / Ra;
lon =
zero_long -