screentinker/docs/109-android-pip-visibility.md
ScreenTinker 10abb3b35f docs(#109): record web PiP (HTML+JS) verification on emulator
Web PiP type loads its WebView and executes JS (a page stamping JS OK · <time>
rendered over live YouTube). No code change — web PiPs don't use the image path
that had the token bug. Completes the image/web/box content-type verification.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-19 14:38:30 -05:00

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#109 — Android PiP overlay not painting over YouTube

Symptom

POST /api/pip returns sent: 1, the overlay's title text appears in uiautomator dump (so the view IS attached, laid out, and on-screen in the accessibility tree), but nothing paints on the panel. The repro is while YouTube content is playing (R.id.youtubeWebView).

The PiP title and its media are siblings in one box, so "title in the dump but nothing on screen" means the whole box is attached-but-not-painting, not a media-only failure.

The three candidate causes

# Cause What the magenta-box instrumentation shows
1 Surface occlusion — the YouTube WebView's hardware video plane composites above the in-tree overlay magenta box visible over a static image but not over YouTube
2 Orientation transformrootView's rotation/translation pushes the box off-screen box getGlobalVisibleRect() empty / outside the 1920×1080 panel
3 Measure / visibilitypipLayout not laid out, 0-size, or GONE on attach box not shown / 0-size / pipLayout childCount==0

Phase 1 — Instrumentation (shipped, default OFF)

A pipDebug flag (PipOverlay.pipDebug, default false) is toggled over the existing device:command transport — no new transport invented:

device:command { "type": "pip_debug", "payload": { "enabled": true } }

When on, PipOverlay.show():

  • paints the box solid magenta (#CCFF00FF) with an 8px magenta border and renders the media on top, so the box paints even if the media never loads;
  • posts a one-shot Runnable that logs, over device:log tag pip:
    • box width/height, getGlobalVisibleRect(), isShown
    • pipLayout width/height/visibility/childCount + its index in its parent
    • rootView rotation / translationX / translationY / scaleX / isHardwareAccelerated
    • youtubeWebView visibility + getGlobalVisibleRect()
  • loadImageInto also logs on success (bitmap w/h), not just failure.

pipDebug is left present and default-false.

Phase 2 — Reproduce

Enable remote debug logging from the dashboard (so device:log is forwarded), then enable the PiP debug flag, then fire a PiP under each content type and read the pip-tagged lines.

(a) PiP over a static image

  1. Assign a single still image to the device; let it display.
  2. device:command {type:"pip_debug",payload:{enabled:true}}.
  3. POST /api/pip {device_id, type:"image", uri:"https://…/x.png", position:"top-right", duration:30}.
  4. Capture the pip dbg … lines + a screenshot.

(b) PiP over YouTube (the failing repro)

  1. Assign a YouTube item; let it play in R.id.youtubeWebView.
  2. (debug already enabled.)
  3. Same POST /api/pip as above.
  4. Capture the pip dbg … lines + a screenshot.

Decision table (compare a-vs-b):

  • magenta box visible over the image but NOT over YouTube → (1) surface occlusion
  • box globalRect empty / off the 1920×1080 panel → (2) orientation
  • box not shown / 0-size / not laid out → (3) measure/visibility

Note: on-device capture must be done on the real signage hardware (Fire TV / Android TV). The WebView hardware-video-overlay behaviour that drives cause (1) is device- and WebView-version-specific and does not reproduce on a stock emulator, so it cannot be captured from a CI/dev box with no device attached.

Which cause — and the fix

By elimination the symptom points at (1) surface occlusion:

  • It is YouTube-specific (a WebView playing HTML5 video). An orientation (2) or measure (3) fault would fail over images too, but the overlay is only reported broken over YouTube.
  • The repro is landscape (the default orientation → rotation = 0, no translation), so the box cannot be transformed off-screen → not (2).
  • The title shows with real on-screen bounds in uiautomator dump, so the box is laid out at non-zero size and pipLayout is VISIBLE → not (3).

That leaves the video surface compositing above the in-tree overlay.

Fix (cause 1) — file/line

pipLayout previously lived as the last child of rootLayout, i.e. in the same compositing band as R.id.youtubeWebView; the WebView's playing video surface drew over it. The fix moves the PiP layer to a top-level view above the WebView (the task's option 1a):

  • MainActivity.onCreate (android/app/src/main/java/com/remotedisplay/player/MainActivity.kt) reparents R.id.pipLayout out of rootLayout up to the window content (android.R.id.content), as a sibling drawn after rootLayout → it composites above the WebView.
  • MainActivity.mirrorTransformToPip() copies rootView's current size + rotation/translation/scale onto pipLayout after every transform change (applyOrientation / applyWallTransform), so corner positions still track the rotated content — mirroring how the web/Tizen players apply the same transform to #pip as to #stage.
  • PipOverlay.show() (…/player/PipOverlay.kt) raises the layer and forces a layout/redraw on attach (bringToFront() + requestLayout() + invalidate()), which also covers the cause-(3) measure/visibility path.
  • The remote-view screenshot source moved from rootView to captureRoot (the window content) so the reparented PiP is still captured.

Server dispatch logging

POST /api/pip and the clear handler (server/routes/pip.js) now log one concise [pip] … line each (target kind + id + sent/offline counts) so journalctl shows PiP activity.

Emulator validation (landscape + portrait)

The fix was exercised end-to-end on an Android emulator (pixel10, API 34) paired to an isolated local server, with a YouTube item playing in R.id.youtubeWebView:

  • No crash — provisioning → MainActivity → playback ran clean; the reparent
    • mirrorTransformToPip() executed (Applied orientation: landscape … / portrait (rotation=90.0, swap=true)).
  • PiP composites above the playing YouTube video — a POST /api/pip box (magenta via background_color) rendered on top of the live video frame (center and top-right placements both correct, 4% inset honoured).
  • Clear removed the overlay cleanly; the video kept playing.
  • Portrait — the overlay rotated with the rotated stage and stayed inside the frame (not off-screen), confirming the transform mirror.
  • Server [pip] show … 1 sent / [pip] clear (all) … dispatch lines appeared.

Caveat (unchanged): the emulator's WebView composites video inline, so it confirms the reparent renders correctly and doesn't regress, but it does not reproduce the Fire TV / Android TV hardware-overlay punch-through that is the strongest form of cause (1). That still needs the real signage device — use the pipDebug magenta box there to confirm.

Follow-up bug found in emulator testing: image PiPs never painted the image

Verifying an image PiP (a QR PNG) surfaced a separate, pre-existing defect (present on main, unrelated to the occlusion reparent): the image area was always blank — only the box background + title showed. Root cause in PipOverlay.show(): teardown() clears current to null, then loadImageInto captured token = current (null) as its drop-if-replaced guard, but current was only set to the new pip_id after the media was built. The decode finishes on a background thread and posts back after show() returns — so the guard token != current (null ≠ pip_id) was always true and every decoded bitmap was dropped. (Web PiPs and the box/title were unaffected, which masked it.)

Fix: set current = pip_id before building the media (so loadImageInto's token matches). Confirmed on the emulator — the QR now renders in the PiP box over both a static image and live YouTube.

Content types verified on the emulator (over live YouTube)

  • image PiP (a QR PNG) — renders after the token-ordering fix above.
  • web PiP (an HTML page) — loads in the PiP WebView and executes JS (a page that stamps JS OK · <time> into the DOM rendered correctly over the playing video); composites above the main YouTube WebView. No code change needed — web PiPs never went through the broken image path.
  • title + background_color box — paints above the video (the original cause-1 fix).

If the magenta box is STILL hidden over YouTube on the test device

Then it is the stronger form of cause (1): the WebView places its video on a hardware overlay / SurfaceView plane that no in-window view can beat. Escalate (task options 1b/1c), keeping the first that works on the device:

  • host the PiP box in a SurfaceView with setZOrderMediaOverlay(true) / setZOrderOnTop(true), or a small WindowManager panel sub-window; or
  • when YouTube is active, render the PiP via the in-tree image path so no competing WebView video surface is involved.

The pipDebug instrumentation stays in place to make that determination.