Gain is the ratio of cursor displacement to device displacement
Aliases: C-D gain · pointer speed · cursor sensitivity
What it is
Control-display gain (C-D gain) is the ratio of screen-cursor displacement to physical device displacement. If one centimetre of mouse movement moves a cursor through more pixels, gain is higher. It describes how input motion is amplified or reduced, not sensor resolution itself.
Why it happens
The system multiplies measured device displacement by a mapping coefficient before accumulating cursor position. Gain changes the display extent covered by the same hand motion: high gain shortens large travel, while low gain makes each unit of hand error produce less screen error. Device, operating system, display setup, and application mapping all contribute.
Studying it
Manipulate gain in target acquisition across distances and widths, recording time, endpoint error, overshoot, and throughput. Hold device, display, pointer settings, and practice constant. A system's labelled speed setting does not itself state the mapping coefficient.
Where it stops holding
Direct touchscreen endpoints usually have no C-D gain; wheels, joysticks, and force devices may instead have velocity mappings. With nonlinear acceleration, gain varies by speed and one ratio is only an approximation. Remote desktops and in-app zoom can add further mappings.
Applying it
- Describe and test gain in actual control-surface and screen travel, rather than only calling it fast or slow.
- Preserve a consistent mapping or a recovery option when an application takes pointer control.
- Validate both short precise selections and cross-screen travel, recording errors and extra corrections.
Related
- Same group: C1.03.2 High gain shortens long travel; low gain improves fine positioning · C1.03.3 Gain couples with display size and pixel density, so it cannot transfer directly across devices · C1.03.4 One fixed gain cannot satisfy both coarse and fine positioning
- Nearby: C1.02 Absolute and relative positioning · C1.04 Mouse acceleration curves
- Search terms:
control-display gain·pointer sensitivity·C-D mapping