double x=25.6, y=128.0;
double x1=102.4, y1=230.4,
x2=153.6, y2=25.6,
x3=230.4, y3=128.0;
cairo_move_to (cr, x, y);
cairo_curve_to (cr, x1, y1, x2, y2, x3, y3);
cairo_set_line_width (cr, 10.0);
cairo_stroke (cr);
cairo_set_source_rgba (cr, 1, 0.2, 0.2, 0.6);
cairo_set_line_width (cr, 6.0);
cairo_move_to (cr,x,y); cairo_line_to (cr,x1,y1);
cairo_move_to (cr,x2,y2); cairo_line_to (cr,x3,y3);
cairo_stroke (cr);