Continuous Input

Continuous input is any interaction technique in which the user varies a parameter smoothly along a range rather than selecting from a set of discrete options — adjusting a slider, dragging a brush, turning a dial, holding a gesture, or modulating vocal loudness. Continuous input is essential for tasks like drawing, fine cursor positioning, pan-and-zoom navigation, and expressive music or video control, and it is especially challenging to provide non-manually to users with motor impairments. Accessibility research has explored a range of approaches including eye tracking, head tracking, breath control, tongue-operated joysticks, and continuous non-speech vocal properties such as pitch or vowel quality, each with different trade-offs in precision, fatigue, and learning curve.