- // TODO: make this optional
- plot_signal_amplitude_difference(_analysis_area, cr);
+ if (_pointer_in_area_xpos >= 0) {
+ update_pointer_info (_pointer_in_area_xpos);
+ }
+
+ if (_signal_button->get_active()) {
+ plot_signal_amplitude_difference(_analysis_area, cr);
+ }
+
+ if (_pointer_in_area_xpos >= 0 && _pointer_in_area_freq > 0) {
+ const double dashed[] = {0.0, 2.0};
+ cairo_set_dash (cr, dashed, 2, 0);
+ cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+ cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+ cairo_set_line_width (cr, 1.0);
+ cairo_move_to (cr, _pointer_in_area_freq - .5, -.5);
+ cairo_line_to (cr, _pointer_in_area_freq - .5, _analysis_height - .5);
+ cairo_stroke(cr);
+ }