const EventMouse& event(*reinterpret_cast<const EventMouse*>(&x));
if(event.button==BUTTON_LEFT)
{
Color color(canvas_view->get_canvas()->get_context().get_color(event.pos));
const EventMouse& event(*reinterpret_cast<const EventMouse*>(&x));
if(event.button==BUTTON_LEFT)
{
Color color(canvas_view->get_canvas()->get_context().get_color(event.pos));