a while ago i had promised to create a better patch. so here is a, well, at least slightly better one. it changes the following:
- the old version just draws fixed-size boxes in any zoom. in high zoom modes, this results in sparse boxes all over the screen. the new version scales these boxes so they fill the area completely. this works for both absolute and height gradient - change of DEM source path from /srtm/version2_1/SRTM3/OLD/ to /srtm/version2_1/SRTM3/. again, yes. that's because the first is not working but the second is. - some cleanup i guess. it's been a while since i wrote all of this, i just forgot about it. i hope you like it, and sorry i didn't push it earlier. david -- Umlaut Zebra über alles!
--- git-src/src/vikdemlayer.c 2010-02-07 16:44:19.000000000 +0000
+++ my-src/src/vikdemlayer.c 2010-02-07 16:51:16.000000000 +0000
@@ -63,7 +63,7 @@
#define SRTM_CACHE_TEMPLATE "%ssrtm3-%s%s%c%02d%c%03d.hgt.zip"
#define SRTM_HTTP_SITE "dds.cr.usgs.gov"
-#define SRTM_HTTP_URI "/srtm/version2_1/SRTM3/OLD/"
+#define SRTM_HTTP_URI "/srtm/version2_1/SRTM3/"
#ifdef VIK_CONFIG_DEM24K
#define DEM24K_DOWNLOAD_SCRIPT "dem24k.pl"
@@ -352,14 +352,21 @@
}
+static inline guint16 get_height_difference(gint16 elev, gint16 new_elev)
+{
+ if(new_elev == VIK_DEM_INVALID_ELEVATION)
+ return 0;
+ else
+ return abs(new_elev - elev);
+}
+
static void vik_dem_layer_draw_dem ( VikDEMLayer *vdl, VikViewport *vp, VikDEM
*dem )
{
- VikDEMColumn *column;
- VikDEMColumn *nextcolumn;
+ VikDEMColumn *column, *prevcolumn, *nextcolumn;
struct LatLon dem_northeast, dem_southwest;
- gdouble max_lat, max_lon, min_lat, min_lon;
+ gdouble max_lat, max_lon, min_lat, min_lon;
/**** Check if viewport and DEM data overlap ****/
@@ -436,7 +443,7 @@
gint16 elev;
- guint skip_factor = ceil ( vik_viewport_get_xmpp(vp) / 40 ); /* todo:
smarter calculation. */
+ 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);
@@ -457,96 +464,120 @@
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;
counter.lon += escale_deg * skip_factor, x += skip_factor ) {
- if ( x > 0 && x < dem->n_columns ) {
+ 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 >= 0 && x < dem->n_columns ) {
column = g_ptr_array_index ( dem->columns, x );
- if(x+1 == dem->n_columns) {
- nextcolumn = g_ptr_array_index ( dem->columns, x-1);
- } else {
- nextcolumn = g_ptr_array_index ( dem->columns, x+1);
- }
+ // 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];
- if(vdl->type == DEM_TYPE_HEIGHT) {
- 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;
- }
+ // 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?
+
+ if(vdl->type == DEM_TYPE_HEIGHT) {
+ 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;
+ if(box_width < 0 || box_height < 0) // FIXME: why does this happen?
+ continue;
- vik_coord_load_from_latlon(&tmp, vik_viewport_get_coord_mode(vp),
&counter);
- vik_viewport_coord_to_screen(vp, &tmp, &a, &b);
- if(vdl->type == DEM_TYPE_GRADIENT) {
- if( elev == VIK_DEM_INVALID_ELEVATION ) {
- /* don't draw it */
- } else {
- // calculate gradient, but only in two orthogonal
directions.
- gint16 change = 0;
- gint16 newelev;
-
- // down
- if(y+1 == column->n_points)
- newelev = column->points[y-1];
- else
- newelev = column->points[y+1];
- if(newelev != VIK_DEM_INVALID_ELEVATION)
- change += abs(newelev - elev);
-
- // down + right
- if(y+1 == nextcolumn->n_points)
- newelev = nextcolumn->points[y-1];
- else
- newelev = nextcolumn->points[y+1];
- if(newelev != VIK_DEM_INVALID_ELEVATION)
- change += abs(newelev - elev);
-
- // right
- newelev = nextcolumn->points[y];
- if(newelev != VIK_DEM_INVALID_ELEVATION)
- change += abs(newelev - elev);
-
- // up + right
- if(y <= 1)
- newelev = nextcolumn->points[y+1];
- else
- newelev = nextcolumn->points[y-1];
- if(newelev != VIK_DEM_INVALID_ELEVATION)
- change += abs(newelev - elev);
-
- change = log(change) * log(change) * log(change);
-
- if(change < vdl->min_elev)
- change = 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, a-2, b-2, 4, 4 );
- }
+ 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)
+ change = 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 )
- vik_viewport_draw_rectangle(vp, vdl->gcs[0],
TRUE, a-2, b-2, 4, 4 );
- 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-2, b-2, 4, 4 );
- }
- }
-
+ if(vdl->type == DEM_TYPE_HEIGHT) {
+ if ( elev == VIK_DEM_INVALID_ELEVATION )
+ ; /* don't draw it */
+ else if ( elev <= 0 )
+ 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= */
}
@@ -628,9 +659,9 @@
if ( elev == VIK_DEM_INVALID_ELEVATION )
; /* don't draw it */
else if ( elev <= 0 )
- vik_viewport_draw_rectangle(vp, vdl->gcs[0], TRUE, a-2, b-2, 4,
4 );
+ 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-2, b-2, 4, 4 );
+ 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= */
}
@@ -782,8 +813,8 @@
(intlon >= 0) ? 'E' : 'W',
ABS(intlon) );
- static DownloadOptions options = { 0, NULL, 0, a_check_map_file };
- a_http_download_get_url ( SRTM_HTTP_SITE, src_fn, p->dest, &options, NULL );
+ static DownloadOptions options = { NULL, 0, a_check_map_file };
+ a_http_download_get_url ( SRTM_HTTP_SITE, src_fn, p->dest, &options );
g_free ( src_fn );
}
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