
double xc = 0.5; double yc = 0.5; double radius = 0.4; double angle1 = 45.0 * (M_PI/180.0); /* angles are specified */ double angle2 = 180.0 * (M_PI/180.0); /* in radians */ cairo_arc_negative (cr, xc, yc, radius, angle1, angle2); cairo_stroke (cr); /* draw helping lines */ cairo_set_rgb_color (cr, 1,0.2,0.2); cairo_set_alpha (cr, 0.6); cairo_arc (cr, xc, yc, 0.05, 0, 2*M_PI); cairo_fill (cr); cairo_set_line_width (cr, 0.03); cairo_arc (cr, xc, yc, radius, angle1, angle1); cairo_line_to (cr, xc, yc); cairo_arc (cr, xc, yc, radius, angle2, angle2); cairo_line_to (cr, xc, yc); cairo_stroke (cr);