Fitts Lens Autor: h74611264

Fitts Lens is a temporary pointing-assistance layer for people who benefit from larger effective targets, semantic target stability, dwell activation, or protection against unintended repeated clicks. It activates only on the current tab after the user presses its toolbar action and then explicitly chooses Activate.

The Calibration Lab presents sixteen targets with varied position and size. It measures acquisition time, traveled distance, Fitts index, path efficiency, endpoint error, direction changes, overshoot entries, and high-frequency movement near the target. From those trials it recommends an aperture radius, dwell duration, repeated-click guard interval, and visual smoothing level. Calibration paths remain in the extension page and only the resulting settings profile is stored locally.

On an activated webpage, Fitts Lens samples a small pattern around the current pointer position to locate nearby interactive elements. It recognizes generic links, buttons, fields, roles, and keyboard-focusable controls without reading or retaining their text. The best nearby target receives a visible aperture. A smoothly moving proxy dot communicates the stable selection; it does not claim to move or replace the operating system pointer.

When Enlarged Hit Area is enabled, a trusted physical click landing immediately beside the highlighted target can be redirected to that target. When Dwell Click is enabled, remaining over the same safe target completes a visible progress ring and activates it. Password fields are excluded from assistance.

Controls whose visible action resembles deletion, payment, purchase, submission, publishing, or sending are treated as dangerous. Dwell never activates them. The first physical click is stopped and a confirmation notice appears; the same control must receive another physical click within the confirmation window. The repeated-click guard can separately suppress a rapid second click on the same target.

Escape removes the assistance layer immediately. It also disappears when the page is closed or navigated. Injection is limited to the top-level active page and does not enter subframes.

Included capabilities:
• sixteen-target local calibration sequence;
• Fitts-index, efficiency, tremor, overshoot, and reversal analysis;
• automatically recommended aperture, dwell, smoothing, and click-guard values;
• temporary semantic target highlighting on the active tab;
• optional enlarged click area and dwell activation;
• password-field exclusion;
• physical confirmation for potentially destructive or transactional controls;
• repeated-click suppression;
• visible activation indicator and immediate Escape kill switch;
• no retained webpage interaction history.

Fitts Lens is an interaction aid, not a medical device. Browser security boundaries mean it does not move the operating system pointer and does not operate in inaccessible or cross-origin frames.