Added configuration setting for chart edge line colour

README.md

@@ -206,7 +206,8 @@ The following settings can be included in a `StarCharter` configuration file:
 * `axis_ticks_value_only` - If 1, axis labels will appear as simply "5h" or "30 deg". If 0, these labels will be preceded by alpha= or delta=
 * `az_central` - The local azimuth of the centre of the plot; degrees. This setting is only used if `coords=alt_az`.
 * `cardinals` - Boolean (0 or 1) indicating whether to write the cardinal points around the edge of alt/az star charts
-* `chart_edge_line_width` - Line width to use when marking the edge of the chart. Default 2.5.
+- `chart_edge_line_col` - Colour to use when marking the edge of the chart. Default `0,0,0`.
+- `chart_edge_line_width` - Line width to use when marking the edge of the chart. Default 2.5.
 * `constellation_boundaries` - Boolean (0 or 1) indicating whether we draw constellation boundaries
 * `constellation_boundary_col` - Colour to use when drawing constellation boundaries
 * `constellation_highlight` - Optionally, highlight the boundary of one particular constellation, identified by a three-letter abbreviation.

src/settings/chart_config.c

@@ -216,6 +216,7 @@ void default_config(chart_config *i) {
     i->constellations_label_shadow = 1;
     i->constellation_sticks_line_width = 1.4;
     i->chart_edge_line_width = 2.5;
+    i->chart_edge_line_col = (colour) {0, 0, 0};
 
     // Boolean flags indicating which settings have been manually overridden
     i->mag_min_is_set = 0;

src/settings/chart_config.h

@@ -612,6 +612,9 @@ typedef struct chart_config {
     //! Line width to use for the edge of the star chart
     double chart_edge_line_width;
 
+    //! Colour to use for the edge of the star chart
+    colour chart_edge_line_col;
+
     //! Boolean flags indicating which settings have been manually overridden
     //! (so that automatic scaling does not overwrite them).
     int mag_min_is_set;

src/settings/read_config.c

@@ -1135,6 +1135,10 @@ int process_configuration_file_line(char *line, const char *filename, const int
         CHECK_VALUE_NUMERIC("chart_edge_line_width")
         x->chart_edge_line_width = key_val_num;
         return 0;
+    } else if (strcmp(key, "chart_edge_line_col") == 0) {
+        //! chart_edge_line_col - Colour to use when marking the edge of the chart.
+        x->chart_edge_line_col = colour_from_string(key_val);
+        return 0;
     } else {
         snprintf(temp_err_string, FNAME_LENGTH, "Bad input file. Unrecognised setting '%s'.", key);
         stch_error(temp_err_string);

src/vectorGraphics/cairo_page.c

@@ -287,7 +287,7 @@ void draw_chart_edging(cairo_page *p, chart_config *s) {
     cairo_show_text(s->cairo_draw, s->title);
 
     // Draw outline of chart
-    cairo_set_source_rgb(s->cairo_draw, 0, 0, 0);
+    cairo_set_source_rgb(s->cairo_draw, s->chart_edge_line_col.red, s->chart_edge_line_col.grn, s->chart_edge_line_col.blu);
     cairo_set_line_width(s->cairo_draw, s->chart_edge_line_width * s->line_width_base);
     cairo_new_path(s->cairo_draw);
     if ((s->projection == SW_PROJECTION_SPHERICAL) || (s->projection == SW_PROJECTION_ALTAZ)) {