Floating ball & OSD

Two overlays with different jobs: the ball controls recording, the OSD shows live numbers.

Floating ball

Gesture	Behaviour
Tap	Start / stop recording the foreground app
Long-press	Open the control panel (live SoC power and FPS on top)
Drag	Move it; it stays where you release it (enable "snap to edge" for the old behaviour)
Idle 7 s	Fades to 55% opacity

The ball is FLAG_NOT_FOCUSABLE — tapping it never steals focus, so the recording target is always the app you were using, not WattScope itself.

Recording linkage

Once a ball-started recording is running, leaving the target app stops it. Two details matter:

• "Start recording" and "still in foreground?" use the same data source (root dumpsys), so the two checks cannot disagree and stop a recording one second in
• A 5-second grace period after start suppresses the "left app" check, covering the window where a freshly focused app has not settled in system state yet

Sizes

Mini 40 / standard 48 / large 56 dp, standard by default, applied instantly. The ball is dark glass: top inner highlight, gradient rim, and an outer glow ring while recording.

OSD overlay

Display only — never written to recordings. Its job is glancing at power while gaming, not replacing recording.

Metrics

Any of 11, opt-in:

Group	Metrics
Power	SOC, CPU-L, CPU-M, GPU, wall power
Performance	GPU frequency, GPU busy, FPS
Thermal	CPU, GPU, DDR

Layout and interaction

• Two-column HUD: labels left, values right-aligned in fixed-width cells, so digits do not jitter while you read
• Title row carries a REC / LIVE dot so you can tell recording from preview at a glance
• Draggable anywhere
• Tap to cycle three opacity levels
• Slow sensors (thermals) hold their last valid value instead of flashing --

Why neither overlay uses live blur

Per-frame Gaussian blur keeps the GPU busy — which is exactly what pollutes the power you are measuring. Both overlays therefore use a static liquid-glass layer (translucency + 1 dp rim + inner highlight). Only the in-app nav bar uses Backdrop's live blur, because at that moment you are not measuring.

The same reasoning drives "reduce nav bar effects while recording", on by default.