ReaderRotation = InputContainer:new{
	key_events = {
		-- these will all generate the same event, just with different arguments
		RotateLeft = { {"J"}, doc = "rotate left by 90 degrees", event = "Rotate", args = -90 },
		RotateRight = { {"K"}, doc = "rotate right by 90 degrees", event = "Rotate", args = 90 },
	},
	current_rotation = 0
}

-- TODO: reset rotation on new document, maybe on new page?

function ReaderRotation:onRotate(rotate_by)
	self.current_rotation = (self.current_rotation + rotate_by) % 360
	self.ui:handleEvent(Event:new("RotationUpdate", self.current_rotation))
	return true
end