In one embodiment, a computing device displays a graphical parameter-control element in a graphical user interface indicating a range and a position value of a controllable parameter of an application of the computing device. The computing device may detect a touch event on a touchpad of the computing device. The computing device may determine that the touch event is a scrolling event, and scroll the position value along the range based on a direction of the scrolling event, and adjust the position value by a relative amount within the range mapping to a relative distance of the scrolling event along the touchpad.