+ // scalar_t grab_previous_x = grab_start_x, grab_previous_y = grab_start_y;
+
+ {
+ int n = 36;
+ scalar_t xp[n], yp[n];
+ for(int k = 0; k < n; k++) {
+ scalar_t radius = 1/scaling;
+ scalar_t alpha = 2 * M_PI * scalar_t(k) / scalar_t(n);
+ xp[k] = grab_start_x + radius * cos(alpha);
+ yp[k] = grab_start_y + radius * sin(alpha);
+ }
+ grab_trace.set_drawing_color(0.0, 0.0, 0.0);
+ grab_trace.set_line_width(1.0);
+ grab_trace.draw_polygon(1, n, xp, yp);
+ }