Displaywhere

Displaywhere is a term used in discussions of multi-display user interfaces to denote the mechanism by which a program decides on which physical display or virtual workspace a given content element should appear. It is not a single, standardized API, but a concept that underpins window placement, content routing, and rendering decisions across screens with different resolutions and scales.

At its core, displaywhere involves algorithms and data structures that map coordinates, windows, and input events to displays. Common approaches include proximity-based placement (placing content on the display nearest to the cursor or an anchor element), focus-based placement (aligning with the active window), and user- or policy-driven rules (preferences for a primary display or task-specific layouts).

Implementation can be part of graphical toolkits, window managers, or remote-desktop software, affecting when a new window is created and when it is moved or resized. The concept also requires handling coordinate normalization across displays with different DPI scales and offsets, typically through a unified coordinate space or per-display transforms.

Applications range from desktop environments and game engines to web-based interfaces that adapt to multiple screens. For developers, key concerns include latency and animation smoothness during display reassignment, accessibility and focus behavior, and robustness during monitor reconfiguration or hot-plug events.

Future directions for displaywhere emphasize dynamic, context-aware policies, improved support for virtual and mixed-reality displays, and standardized APIs to enable cross-platform implementation.