LOUP Engineering: E-Paper UI & Controls · advanced
Volume Feedback Can Be a Small Partial-Refresh Overlay
A physical button needs visible confirmation without forcing a page transition.
The important detail in Volume Feedback Can Be a Small Partial-Refresh Overlay was not the component name but the contract around it. LOUP volume up/down events can update a bounded region of the active-call or idle screen instead of rebuilding the page.
The overlay should represent the actual gain state after limits and mapping, not just the raw button count. After a short timeout it can clear or return to the underlying state with minimal refresh work.
The acceptance test was written around observable behaviour rather than whether a task, container or peripheral merely reported that it had started. Evidence marker: volume-overlay.
Good feedback confirms the system state produced by an input, not merely that the button event was received. That gives the team a concrete acceptance condition and a rollback point rather than a subjective sense that the build is probably better.
Project evidence
LOUP engineering marker: volume-overlay. This note records the design or debugging lesson without publishing device credentials, private keys, customer data or manufacturing secrets.