double a_coords_utm_diff( const struct UTM *utm1, const struct UTM *utm2 )
{
static struct LatLon tmp1, tmp2;
if ( utm1->zone == utm2->zone ) {
return sqrt ( pow ( utm1->easting - utm2->easting, 2 ) + pow ( utm1->northing - utm2->northing, 2 ) );
} else {
a_coords_utm_to_latlon ( utm1, &tmp1 );
a_coords_utm_to_latlon ( utm2, &tmp2 );
return a_coords_latlon_diff ( &tmp1, &tmp2 );
}
}
void vik_coord_to_latlon ( const VikCoord *coord, struct LatLon *dest )
{
if ( coord->mode == VIK_COORD_LATLON )
*dest = *((const struct LatLon *)coord);
else
a_coords_utm_to_latlon ( (const struct UTM *) coord, dest );
}
void vik_coord_load_from_utm ( VikCoord *coord, VikCoordMode mode, const struct UTM *utm )
{
if ( mode == VIK_COORD_UTM )
*((struct UTM *)coord) = *utm;
else
a_coords_utm_to_latlon ( utm, (struct LatLon *) coord );
coord->mode = mode;
}
void vik_coord_copy_convert(const VikCoord *coord, VikCoordMode dest_mode, VikCoord *dest)
{
if ( coord->mode == dest_mode ) {
*dest = *coord;
} else {
if ( dest_mode == VIK_COORD_LATLON )
a_coords_utm_to_latlon ( (struct UTM *)coord, (struct LatLon *)dest );
else
a_coords_latlon_to_utm ( (struct LatLon *)coord, (struct UTM *)dest );
dest->mode = dest_mode;
}
}
void vik_coord_convert(VikCoord *coord, VikCoordMode dest_mode)
{
VikCoord tmp;
if ( coord->mode != dest_mode )
{
if ( dest_mode == VIK_COORD_LATLON ) {
a_coords_utm_to_latlon ( (struct UTM *)coord, (struct LatLon *)&tmp );
*((struct LatLon *)coord) = *((struct LatLon *)&tmp);
} else {
a_coords_latlon_to_utm ( (struct LatLon *)coord, (struct UTM *)&tmp );
*((struct UTM *)coord) = *((struct UTM *)&tmp);
}
coord->mode = dest_mode;
}
}
// Align displayed Lat/Lon values with displayed UTM values
static void align_ll2utm (VikGeorefLayer *vgl)
{
struct UTM corner;
const gchar *letter = gtk_entry_get_text ( GTK_ENTRY(vgl->cw.utm_letter_entry) );
if (*letter)
corner.letter = toupper(*letter);
corner.zone = gtk_spin_button_get_value_as_int ( GTK_SPIN_BUTTON(vgl->cw.utm_zone_spin) );
corner.easting = gtk_spin_button_get_value ( GTK_SPIN_BUTTON(vgl->cw.ce_spin) );
corner.northing = gtk_spin_button_get_value ( GTK_SPIN_BUTTON(vgl->cw.cn_spin) );
struct LatLon ll;
a_coords_utm_to_latlon ( &corner, &ll );
gtk_spin_button_set_value ( GTK_SPIN_BUTTON(vgl->cw.lat_tl_spin), ll.lat );
gtk_spin_button_set_value ( GTK_SPIN_BUTTON(vgl->cw.lon_tl_spin), ll.lon );
}
/* called every time we update coordinates/zoom */
static void viewport_utm_zone_check ( VikViewport *vvp )
{
if ( vvp->coord_mode == VIK_COORD_UTM )
{
struct UTM utm;
struct LatLon ll;
a_coords_utm_to_latlon ( (struct UTM *) &(vvp->center), &ll );
a_coords_latlon_to_utm ( &ll, &utm );
if ( utm.zone != vvp->center.utm_zone )
*((struct UTM *)(&vvp->center)) = utm;
/* misc. stuff so we don't have to check later */
vvp->utm_zone_width = viewport_utm_zone_width ( vvp );
vvp->one_utm_zone = ( vik_viewport_rightmost_zone(vvp) == vik_viewport_leftmost_zone(vvp) );
}
}
static gdouble
viewport_utm_zone_width ( VikViewport *vvp )
{
if ( vvp->coord_mode == VIK_COORD_UTM ) {
struct LatLon ll;
/* get latitude of screen bottom */
struct UTM utm = *((struct UTM *)(vik_viewport_get_center ( vvp )));
utm.northing -= vvp -> height * vvp -> ympp / 2;
a_coords_utm_to_latlon ( &utm, &ll );
/* boundary */
ll.lon = (utm.zone - 1) * 6 - 180 ;
a_coords_latlon_to_utm ( &ll, &utm);
return fabs ( utm.easting - EASTING_OFFSET ) * 2;
} else
return 0.0;
}
void vik_coord_layer_draw ( VikCoordLayer *vcl, gpointer data )
{
VikViewport *vp = (VikViewport *) data;
if ( !vcl->gc ) {
return;
}
if ( vik_viewport_get_coord_mode(vp) != VIK_COORD_UTM )
{
VikCoord left, right, left2, right2;
gdouble l, r, i, j;
gint x1, y1, x2, y2, smod = 1, mmod = 1;
gboolean mins = FALSE, secs = FALSE;
GdkGC *dgc = vik_viewport_new_gc_from_color(vp, vcl->color, vcl->line_thickness);
GdkGC *mgc = vik_viewport_new_gc_from_color(vp, vcl->color, MAX(vcl->line_thickness/2, 1));
GdkGC *sgc = vik_viewport_new_gc_from_color(vp, vcl->color, MAX(vcl->line_thickness/5, 1));
vik_viewport_screen_to_coord ( vp, 0, 0, &left );
vik_viewport_screen_to_coord ( vp, vik_viewport_get_width(vp), 0, &right );
vik_viewport_screen_to_coord ( vp, 0, vik_viewport_get_height(vp), &left2 );
vik_viewport_screen_to_coord ( vp, vik_viewport_get_width(vp), vik_viewport_get_height(vp), &right2 );
#define CLINE(gc, c1, c2) { \
vik_viewport_coord_to_screen(vp, (c1), &x1, &y1); \
vik_viewport_coord_to_screen(vp, (c2), &x2, &y2); \
vik_viewport_draw_line (vp, (gc), x1, y1, x2, y2); \
}
l = left.east_west;
r = right.east_west;
if (60*fabs(l-r) < 4) {
secs = TRUE;
smod = MIN(6, (int)ceil(3600*fabs(l-r)/30.0));
}
if (fabs(l-r) < 4) {
mins = TRUE;
mmod = MIN(6, (int)ceil(60*fabs(l-r)/30.0));
}
for (i=floor(l*60); i<ceil(r*60); i+=1.0) {
if (secs) {
for (j=i*60+1; j<(i+1)*60; j+=1.0) {
left.east_west = j/3600.0;
left2.east_west = j/3600.0;
if ((int)j % smod == 0) CLINE(sgc, &left, &left2);
}
}
if (mins) {
left.east_west = i/60.0;
left2.east_west = i/60.0;
if ((int)i % mmod == 0) CLINE(mgc, &left, &left2);
}
if ((int)i % 60 == 0) {
left.east_west = i/60.0;
left2.east_west = i/60.0;
CLINE(dgc, &left, &left2);
}
}
vik_viewport_screen_to_coord ( vp, 0, 0, &left );
l = left2.north_south;
r = left.north_south;
for (i=floor(l*60); i<ceil(r*60); i+=1.0) {
if (secs) {
for (j=i*60+1; j<(i+1)*60; j+=1.0) {
left.north_south = j/3600.0;
right.north_south = j/3600.0;
if ((int)j % smod == 0) CLINE(sgc, &left, &right);
}
}
if (mins) {
left.north_south = i/60.0;
right.north_south = i/60.0;
if ((int)i % mmod == 0) CLINE(mgc, &left, &right);
}
if ((int)i % 60 == 0) {
left.north_south = i/60.0;
right.north_south = i/60.0;
CLINE(dgc, &left, &right);
}
}
#undef CLINE
g_object_unref(dgc);
g_object_unref(sgc);
g_object_unref(mgc);
return;
}
if ( vik_viewport_get_coord_mode(vp) == VIK_COORD_UTM )
{
const struct UTM *center = (const struct UTM *)vik_viewport_get_center ( vp );
gdouble xmpp = vik_viewport_get_xmpp ( vp ), ympp = vik_viewport_get_ympp ( vp );
guint16 width = vik_viewport_get_width ( vp ), height = vik_viewport_get_height ( vp );
struct LatLon ll, ll2, min, max;
double lon;
int x1, x2;
struct UTM utm;
utm = *center;
utm.northing = center->northing - ( ympp * height / 2 );
a_coords_utm_to_latlon ( &utm, &ll );
utm.northing = center->northing + ( ympp * height / 2 );
a_coords_utm_to_latlon ( &utm, &ll2 );
{
/* find corner coords in lat/lon.
start at whichever is less: top or bottom left lon. goto whichever more: top or bottom right lon
*/
struct LatLon topleft, topright, bottomleft, bottomright;
struct UTM temp_utm;
temp_utm = *center;
temp_utm.easting -= (width/2)*xmpp;
temp_utm.northing += (height/2)*ympp;
a_coords_utm_to_latlon ( &temp_utm, &topleft );
temp_utm.easting += (width*xmpp);
a_coords_utm_to_latlon ( &temp_utm, &topright );
temp_utm.northing -= (height*ympp);
a_coords_utm_to_latlon ( &temp_utm, &bottomright );
temp_utm.easting -= (width*xmpp);
a_coords_utm_to_latlon ( &temp_utm, &bottomleft );
min.lon = (topleft.lon < bottomleft.lon) ? topleft.lon : bottomleft.lon;
max.lon = (topright.lon > bottomright.lon) ? topright.lon : bottomright.lon;
min.lat = (bottomleft.lat < bottomright.lat) ? bottomleft.lat : bottomright.lat;
max.lat = (topleft.lat > topright.lat) ? topleft.lat : topright.lat;
}
lon = ((double) ((long) ((min.lon)/ vcl->deg_inc))) * vcl->deg_inc;
ll.lon = ll2.lon = lon;
for (; ll.lon <= max.lon; ll.lon+=vcl->deg_inc, ll2.lon+=vcl->deg_inc )
{
a_coords_latlon_to_utm ( &ll, &utm );
x1 = ( (utm.easting - center->easting) / xmpp ) + (width / 2);
a_coords_latlon_to_utm ( &ll2, &utm );
x2 = ( (utm.easting - center->easting) / xmpp ) + (width / 2);
vik_viewport_draw_line (vp, vcl->gc, x1, height, x2, 0);
}
utm = *center;
utm.easting = center->easting - ( xmpp * width / 2 );
a_coords_utm_to_latlon ( &utm, &ll );
utm.easting = center->easting + ( xmpp * width / 2 );
a_coords_utm_to_latlon ( &utm, &ll2 );
/* really lat, just reusing a variable */
lon = ((double) ((long) ((min.lat)/ vcl->deg_inc))) * vcl->deg_inc;
ll.lat = ll2.lat = lon;
for (; ll.lat <= max.lat ; ll.lat+=vcl->deg_inc, ll2.lat+=vcl->deg_inc )
{
a_coords_latlon_to_utm ( &ll, &utm );
x1 = (height / 2) - ( (utm.northing - center->northing) / ympp );
a_coords_latlon_to_utm ( &ll2, &utm );
x2 = (height / 2) - ( (utm.northing - center->northing) / ympp );
vik_viewport_draw_line (vp, vcl->gc, width, x2, 0, x1);
}
}
}
static void vik_dem_layer_draw_dem ( VikDEMLayer *vdl, VikViewport *vp, VikDEM *dem )
{
VikDEMColumn *column, *prevcolumn, *nextcolumn;
struct LatLon dem_northeast, dem_southwest;
gdouble max_lat, max_lon, min_lat, min_lon;
/**** Check if viewport and DEM data overlap ****/
/* get min, max lat/lon of viewport */
vik_viewport_get_min_max_lat_lon ( vp, &min_lat, &max_lat, &min_lon, &max_lon );
/* get min, max lat/lon of DEM data */
if ( dem->horiz_units == VIK_DEM_HORIZ_LL_ARCSECONDS ) {
dem_northeast.lat = dem->max_north / 3600.0;
dem_northeast.lon = dem->max_east / 3600.0;
dem_southwest.lat = dem->min_north / 3600.0;
dem_southwest.lon = dem->min_east / 3600.0;
} else if ( dem->horiz_units == VIK_DEM_HORIZ_UTM_METERS ) {
struct UTM dem_northeast_utm, dem_southwest_utm;
dem_northeast_utm.northing = dem->max_north;
dem_northeast_utm.easting = dem->max_east;
dem_southwest_utm.northing = dem->min_north;
dem_southwest_utm.easting = dem->min_east;
dem_northeast_utm.zone = dem_southwest_utm.zone = dem->utm_zone;
dem_northeast_utm.letter = dem_southwest_utm.letter = dem->utm_letter;
a_coords_utm_to_latlon(&dem_northeast_utm, &dem_northeast);
a_coords_utm_to_latlon(&dem_southwest_utm, &dem_southwest);
}
if ( (max_lat > dem_northeast.lat && min_lat > dem_northeast.lat) ||
(max_lat < dem_southwest.lat && min_lat < dem_southwest.lat) )
return;
else if ( (max_lon > dem_northeast.lon && min_lon > dem_northeast.lon) ||
(max_lon < dem_southwest.lon && min_lon < dem_southwest.lon) )
return;
/* else they overlap */
/**** End Overlap Check ****/
/* boxes to show where we have DEM instead of actually drawing the DEM.
* useful if we want to see what areas we have coverage for (if we want
* to get elevation data for a track) but don't want to cover the map.
*/
#if 0
/* draw a box if a DEM is loaded. in future I'd like to add an option for this
* this is useful if we want to see what areas we have dem for but don't want to
* cover the map (or maybe we just need translucent DEM?) */
{
VikCoord demne, demsw;
gint x1, y1, x2, y2;
vik_coord_load_from_latlon(&demne, vik_viewport_get_coord_mode(vp), &dem_northeast);
vik_coord_load_from_latlon(&demsw, vik_viewport_get_coord_mode(vp), &dem_southwest);
vik_viewport_coord_to_screen ( vp, &demne, &x1, &y1 );
vik_viewport_coord_to_screen ( vp, &demsw, &x2, &y2 );
if ( x1 > vik_viewport_get_width(vp) ) x1=vik_viewport_get_width(vp);
if ( y2 > vik_viewport_get_height(vp) ) y2=vik_viewport_get_height(vp);
if ( x2 < 0 ) x2 = 0;
if ( y1 < 0 ) y1 = 0;
vik_viewport_draw_rectangle ( vp, gtk_widget_get_style(GTK_WIDGET(vp))->black_gc,
FALSE, x2, y1, x1-x2, y2-y1 );
return;
}
#endif
if ( dem->horiz_units == VIK_DEM_HORIZ_LL_ARCSECONDS ) {
VikCoord tmp; /* TODO: don't use coord_load_from_latlon, especially if in latlon drawing mode */
gdouble max_lat_as, max_lon_as, min_lat_as, min_lon_as;
gdouble start_lat_as, end_lat_as, start_lon_as, end_lon_as;
gdouble start_lat, end_lat, start_lon, end_lon;
struct LatLon counter;
guint x, y, start_x, start_y;
gint16 elev;
guint skip_factor = ceil ( vik_viewport_get_xmpp(vp) / 80 ); /* todo: smarter calculation. */
gdouble nscale_deg = dem->north_scale / ((gdouble) 3600);
gdouble escale_deg = dem->east_scale / ((gdouble) 3600);
max_lat_as = max_lat * 3600;
min_lat_as = min_lat * 3600;
max_lon_as = max_lon * 3600;
min_lon_as = min_lon * 3600;
start_lat_as = MAX(min_lat_as, dem->min_north);
end_lat_as = MIN(max_lat_as, dem->max_north);
start_lon_as = MAX(min_lon_as, dem->min_east);
end_lon_as = MIN(max_lon_as, dem->max_east);
start_lat = floor(start_lat_as / dem->north_scale) * nscale_deg;
end_lat = ceil (end_lat_as / dem->north_scale) * nscale_deg;
start_lon = floor(start_lon_as / dem->east_scale) * escale_deg;
end_lon = ceil (end_lon_as / dem->east_scale) * escale_deg;
vik_dem_east_north_to_xy ( dem, start_lon_as, start_lat_as, &start_x, &start_y );
guint gradient_skip_factor = 1;
if(vdl->type == DEM_TYPE_GRADIENT)
gradient_skip_factor = skip_factor;
/* verify sane elev interval */
if ( vdl->max_elev <= vdl->min_elev )
vdl->max_elev = vdl->min_elev + 1;
for ( x=start_x, counter.lon = start_lon; counter.lon <= end_lon+escale_deg*skip_factor; counter.lon += escale_deg * skip_factor, x += skip_factor ) {
// NOTE: ( counter.lon <= end_lon + ESCALE_DEG*SKIP_FACTOR ) is neccessary so in high zoom modes,
// the leftmost column does also get drawn, if the center point is out of viewport.
if ( x < dem->n_columns ) {
column = g_ptr_array_index ( dem->columns, x );
// get previous and next column. catch out-of-bound.
gint32 new_x = x;
new_x -= gradient_skip_factor;
if(new_x < 1)
prevcolumn = g_ptr_array_index ( dem->columns, x+1);
else
prevcolumn = g_ptr_array_index ( dem->columns, new_x);
new_x = x;
new_x += gradient_skip_factor;
if(new_x >= dem->n_columns)
nextcolumn = g_ptr_array_index ( dem->columns, x-1);
else
nextcolumn = g_ptr_array_index ( dem->columns, new_x);
for ( y=start_y, counter.lat = start_lat; counter.lat <= end_lat; counter.lat += nscale_deg * skip_factor, y += skip_factor ) {
if ( y > column->n_points )
break;
elev = column->points[y];
// calculate bounding box for drawing
gint box_x, box_y, box_width, box_height;
struct LatLon box_c;
box_c = counter;
box_c.lat += (nscale_deg * skip_factor)/2;
box_c.lon -= (escale_deg * skip_factor)/2;
vik_coord_load_from_latlon(&tmp, vik_viewport_get_coord_mode(vp), &box_c);
vik_viewport_coord_to_screen(vp, &tmp, &box_x, &box_y);
// catch box at borders
if(box_x < 0)
box_x = 0;
if(box_y < 0)
box_y = 0;
box_c.lat -= nscale_deg * skip_factor;
box_c.lon += escale_deg * skip_factor;
vik_coord_load_from_latlon(&tmp, vik_viewport_get_coord_mode(vp), &box_c);
vik_viewport_coord_to_screen(vp, &tmp, &box_width, &box_height);
box_width -= box_x;
box_height -= box_y;
// catch box at borders
if(box_width < 0 || box_height < 0)
continue; // skip this. this is out of our viewport anyway. FIXME: why?
gboolean below_minimum = FALSE;
if(vdl->type == DEM_TYPE_HEIGHT) {
if ( elev != VIK_DEM_INVALID_ELEVATION && elev < vdl->min_elev ) {
// Prevent 'elev - vdl->min_elev' from being negative so can safely use as array index
elev = ceil ( vdl->min_elev );
below_minimum = TRUE;
}
if ( elev != VIK_DEM_INVALID_ELEVATION && elev > vdl->max_elev )
elev = vdl->max_elev;
}
{
if(box_width < 0 || box_height < 0) // FIXME: why does this happen?
continue;
if(vdl->type == DEM_TYPE_GRADIENT) {
if( elev == VIK_DEM_INVALID_ELEVATION ) {
/* don't draw it */
} else {
// calculate and sum gradient in all directions
gint16 change = 0;
gint32 new_y;
// calculate gradient from height points all around the current one
new_y = y - gradient_skip_factor;
if(new_y < 0)
new_y = y;
change += get_height_difference(elev, prevcolumn->points[new_y]);
change += get_height_difference(elev, column->points[new_y]);
change += get_height_difference(elev, nextcolumn->points[new_y]);
change += get_height_difference(elev, prevcolumn->points[y]);
change += get_height_difference(elev, nextcolumn->points[y]);
new_y = y + gradient_skip_factor;
if(new_y >= column->n_points)
new_y = y;
change += get_height_difference(elev, prevcolumn->points[new_y]);
change += get_height_difference(elev, column->points[new_y]);
change += get_height_difference(elev, nextcolumn->points[new_y]);
change = change / ((skip_factor > 1) ? log(skip_factor) : 0.55); // FIXME: better calc.
if(change < vdl->min_elev)
// Prevent 'change - vdl->min_elev' from being negative so can safely use as array index
change = ceil ( vdl->min_elev );
if(change > vdl->max_elev)
change = vdl->max_elev;
// void vik_viewport_draw_rectangle ( VikViewport *vvp, GdkGC *gc, gboolean filled, gint x1, gint y1, gint x2, gint y2 );
vik_viewport_draw_rectangle(vp, vdl->gcsgradient[(gint)floor(((change - vdl->min_elev)/(vdl->max_elev - vdl->min_elev))*(DEM_N_GRADIENT_COLORS-2))+1], TRUE, box_x, box_y, box_width, box_height);
}
} else {
if(vdl->type == DEM_TYPE_HEIGHT) {
if ( elev == VIK_DEM_INVALID_ELEVATION )
; /* don't draw it */
else if ( elev <= 0 || below_minimum )
/* If 'sea' colour or below the defined mininum draw in the configurable colour */
vik_viewport_draw_rectangle(vp, vdl->gcs[0], TRUE, box_x, box_y, box_width, box_height);
else
vik_viewport_draw_rectangle(vp, vdl->gcs[(gint)floor(((elev - vdl->min_elev)/(vdl->max_elev - vdl->min_elev))*(DEM_N_HEIGHT_COLORS-2))+1], TRUE, box_x, box_y, box_width, box_height);
}
}
}
} /* for y= */
}
} /* for x= */
} else if ( dem->horiz_units == VIK_DEM_HORIZ_UTM_METERS ) {
gdouble max_nor, max_eas, min_nor, min_eas;
gdouble start_nor, start_eas, end_nor, end_eas;
gint16 elev;
guint x, y, start_x, start_y;
VikCoord tmp; /* TODO: don't use coord_load_from_latlon, especially if in latlon drawing mode */
struct UTM counter;
guint skip_factor = ceil ( vik_viewport_get_xmpp(vp) / 10 ); /* todo: smarter calculation. */
VikCoord tleft, tright, bleft, bright;
vik_viewport_screen_to_coord ( vp, 0, 0, &tleft );
vik_viewport_screen_to_coord ( vp, vik_viewport_get_width(vp), 0, &tright );
vik_viewport_screen_to_coord ( vp, 0, vik_viewport_get_height(vp), &bleft );
vik_viewport_screen_to_coord ( vp, vik_viewport_get_width(vp), vik_viewport_get_height(vp), &bright );
vik_coord_convert(&tleft, VIK_COORD_UTM);
vik_coord_convert(&tright, VIK_COORD_UTM);
vik_coord_convert(&bleft, VIK_COORD_UTM);
vik_coord_convert(&bright, VIK_COORD_UTM);
max_nor = MAX(tleft.north_south, tright.north_south);
min_nor = MIN(bleft.north_south, bright.north_south);
max_eas = MAX(bright.east_west, tright.east_west);
min_eas = MIN(bleft.east_west, tleft.east_west);
start_nor = MAX(min_nor, dem->min_north);
end_nor = MIN(max_nor, dem->max_north);
if ( tleft.utm_zone == dem->utm_zone && bleft.utm_zone == dem->utm_zone
&& (tleft.utm_letter >= 'N') == (dem->utm_letter >= 'N')
&& (bleft.utm_letter >= 'N') == (dem->utm_letter >= 'N') ) /* if the utm zones/hemispheres are different, min_eas will be bogus */
start_eas = MAX(min_eas, dem->min_east);
else
start_eas = dem->min_east;
if ( tright.utm_zone == dem->utm_zone && bright.utm_zone == dem->utm_zone
&& (tright.utm_letter >= 'N') == (dem->utm_letter >= 'N')
&& (bright.utm_letter >= 'N') == (dem->utm_letter >= 'N') ) /* if the utm zones/hemispheres are different, min_eas will be bogus */
end_eas = MIN(max_eas, dem->max_east);
else
end_eas = dem->max_east;
start_nor = floor(start_nor / dem->north_scale) * dem->north_scale;
end_nor = ceil (end_nor / dem->north_scale) * dem->north_scale;
start_eas = floor(start_eas / dem->east_scale) * dem->east_scale;
end_eas = ceil (end_eas / dem->east_scale) * dem->east_scale;
vik_dem_east_north_to_xy ( dem, start_eas, start_nor, &start_x, &start_y );
/* TODO: why start_x and start_y are -1 -- rounding error from above? */
counter.zone = dem->utm_zone;
counter.letter = dem->utm_letter;
for ( x=start_x, counter.easting = start_eas; counter.easting <= end_eas; counter.easting += dem->east_scale * skip_factor, x += skip_factor ) {
if ( x > 0 && x < dem->n_columns ) {
column = g_ptr_array_index ( dem->columns, x );
for ( y=start_y, counter.northing = start_nor; counter.northing <= end_nor; counter.northing += dem->north_scale * skip_factor, y += skip_factor ) {
if ( y > column->n_points )
continue;
elev = column->points[y];
if ( elev != VIK_DEM_INVALID_ELEVATION && elev < vdl->min_elev )
elev=vdl->min_elev;
if ( elev != VIK_DEM_INVALID_ELEVATION && elev > vdl->max_elev )
elev=vdl->max_elev;
{
gint a, b;
vik_coord_load_from_utm(&tmp, vik_viewport_get_coord_mode(vp), &counter);
vik_viewport_coord_to_screen(vp, &tmp, &a, &b);
if ( elev == VIK_DEM_INVALID_ELEVATION )
; /* don't draw it */
else if ( elev <= 0 )
vik_viewport_draw_rectangle(vp, vdl->gcs[0], TRUE, a-1, b-1, 2, 2 );
else
vik_viewport_draw_rectangle(vp, vdl->gcs[(gint)floor((elev - vdl->min_elev)/(vdl->max_elev - vdl->min_elev)*(DEM_N_HEIGHT_COLORS-2))+1], TRUE, a-1, b-1, 2, 2 );
}
} /* for y= */
}
} /* for x= */
}
}
