2026-01-30

Scrutinizer v1.5: Mobile Emulation & Academic Tooling

Most web content is consumed on phones. Most usability testing tools assume desktops. v1.5 bridges that gap with device-accurate mobile emulation (viewport locking, DPI simulation, user-agent switching), so peripheral vision simulation runs on the layouts users see on their phones. The release also introduces tools for academic reproducibility: citation-embedded screenshots and a declarative mode registry.

Highlights

Mobile Emulation Mode: Device profiles (iPhone 14 Pro, Pixel 7 Pro, iPad Air, Galaxy S23 Ultra) with viewport locking, high-DPI scale factors, and UA override. Sites load their actual mobile layouts.
Touch Simulation (Alpha): Hold Option+Click to synthesize touch events in mobile mode. Unblocks testing of touch-only interactions under foveated rendering.
Citation-Ready Exports: Golden capture PNGs embed metadata (version, mode, foveal radius, degradation strength) in PNG tEXt chunks, plus a full pipeline config JSON for exact reproducibility. Extract with exiftool.
Declarative Mode Registry: Aesthetic modes defined in shared/modes.json. Researchers can add custom simulation parameters without modifying the codebase.
Auto-Updates: Checks GitHub releases on startup and notifies when a new version is available (first shipped in v1.4.0).

Why mobile matters for peripheral vision

On a phone held at arm's length, the entire screen subtends roughly 15–20° of visual angle. Most content is parafoveal. The simulation parameters that produce dramatic effects on a 27″ monitor need recalibration for a 6.1″ screen because the viewing geometry changes. This also makes Mobile First (Wroblewski 2009) a perceptual argument as well as a screen-size argument. The entire mobile viewport maps to parafoveal vision, where resolution degradation is moderate but measurable, so every design decision lands in a single visual processing regime. The same geometry means peripheral color holds up better on phones than on desktops, because the parafoveal zone retains most chrominance.

Update (2026-10-01): The parafovea extends about 5° from fixation (Rayner 1998). A screen 15–20° across reaches 7.5–10° from a central fixation and farther from an off-center one, so a phone viewport spans both parafoveal and near-peripheral vision.

For more on mobile-specific usability constraints, see NNg’s mobile UX research. The viewport geometry findings here complement their interaction-level observations.

Techmeme in Scrutinizer desktop view with three-column layout and foveated peripheral blur — Desktop: three-column layout, wide peripheral field. Most content falls in parafoveal and far-peripheral zones.

Techmeme in Scrutinizer iPhone 14 emulation with single-column layout — iPhone 14 emulation: single column, narrower visual angle. The same foveated model at phone-appropriate geometry.

Links: GitHub · Full changelog · v1.5.0 release · Wroblewski, “Mobile First” (2009)