Gain couples with display size and pixel density, so it cannot transfer directly across devices

What it is

Display-dependent C-D gain means the same pointer setting need not feel or perform the same on different displays. Physical size, resolution, pixel density, scaling, and multi-display layout alter the visible distance and selectable pixels associated with a device movement.

Why it happens

The gain chain includes device units, system coordinates, logical pixels, and physical display extent. The same pixel shift can be shorter on a high-DPI display, while scaling changes content's visual size; a wider desktop expands the range a cursor may need to cover. A setting suitable for a laptop panel can therefore become too slow or too fast on a high-resolution external or dual display.

Studying it

Report display size, resolution, scaling factor, physical pixel density, device settings, and task travel range; permit renewed practice in each configuration. A labelled pointer-speed notch is not reproducible. In multi-display work, record whether mappings differ at screen crossings.

Where it stops holding

Visual scale is not the sole factor: posture, viewing distance, device friction, and in-app zoom also matter. Operating systems may normalise logical coordinates across displays, so density effects are not simply linear in physical pixels. Screen specifications alone cannot determine an optimal setting.

Applying it

• When display configuration changes, offer discoverable sensitivity adjustment and preview rather than silently retaining old parameters.
• Test cross-screen movement and tiny-target stopping in multi-display workflows, especially at density boundaries.
• Log physical display conditions and mapping parameters as part of reproducible performance and usability reports.

Related

• Same group: C1.03.1 Gain is the ratio of cursor displacement to device displacement · C1.03.2 High gain shortens long travel; low gain improves fine positioning · 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: C-D gain · pixel density · multi-display pointing