Touch coverage and trace continuity
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Touchscreen Test
Use the touch grid to check touch-point count, trace continuity, edge coverage, and possible dead zones on a touchscreen.
Settings
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Current conditions
Draw on the grid with one or more fingers.
Visited grid coverage—Draw on the grid with one or more fingers.
- Maximum simultaneous touch points
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- Edge coverage
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- Trace and event diagnostics
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This page records browser Pointer Events with pointerType=touch. It can reveal coverage and event continuity, but cannot certify the digitizer, driver, or panel hardware.
Touch coverage and trace continuity
Learn more
Use and interpret
Use a finger rather than a mouse or stylus and draw across the full grid, including the outer cells. Repeat with multiple fingers if supported; review maximum touch points, trace continuity, edge coverage, pressure, and lost events.
Method and validation
The page accepts Pointer Events only when pointerType=touch. pointerdown, pointermove, pointerup, and pointercancel update the visited cells and traces; pointer capture keeps a stroke attached to the grid. Long gaps during movement and cancellations are recorded as possible lost events.
Mouse and pen events are ignored. A mark counts only when a touch event reaches the canvas; browser event coalescing, OS gestures, palm rejection, or leaving the target can create gaps.
Scope and limitations
Browser events do not expose every sensor sample or prove the digitizer's physical coverage. The grid is a screen-space check, and edge coverage, pressure, simultaneous contacts, and event continuity depend on browser, OS, hardware, and the gesture.
How does the tool identify a touch?
It accepts Pointer Events whose pointerType is touch; mouse and pen input are not counted as touch contacts.
What do coverage and lost events mean?
Coverage is the proportion of grid cells reached by interpolated touch points. Lost events are possible gaps or cancellations in the recorded pointer trace, not a direct hardware-fault diagnosis.
Can this prove a touchscreen hardware fault?
No. It can show an area or event-path symptom in this browser, but a digitizer or panel fault needs device diagnostics or suitable equipment.
Privacy and implementation
This tool runs in the browser. It does not upload input, call a remote API, or write to local storage.
The page uses standalone HTML, CSS, and JavaScript without a third-party runtime library.