in_rect = function(rect, x,y)
	-- return true if x,y in viewport coordinates lie with rect on the surface
	if x < vx(rect.x) then return end
	if y < vy(rect.y) then return end
	if x > vx(rect.x+rect.w) then return end
	if y > vy(rect.y+rect.h) then return end
	return true
end