From 2a826294613e183dd2264a7d69a7a4f862b49b0b Mon Sep 17 00:00:00 2001 From: Ole-Morten Duesund Date: Mon, 11 May 2026 17:06:37 +0200 Subject: [PATCH] Document orientation policy and emulator-testing pitfalls in CLAUDE.md MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Capture two things future sessions need to know up front: (1) the activity is locked to portrait and the camera image stays in the device frame on purpose — eight releases of orientation-tracking attempts (v1.1.6 → v1.1.13) all got reverted, and per-orientation correctness now lives in the EXIF tag rather than the GL pipeline; (2) the Pixel 6 emulator's default virtual scene is too symmetric to verify rotation visually, `emu rotate` decrements rather than increments, and there is a startup window where camera bitmaps look black. Co-Authored-By: Claude Opus 4.7 (1M context) --- CLAUDE.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/CLAUDE.md b/CLAUDE.md index 6e1a655..249fe6a 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -86,6 +86,21 @@ Bitmaps emitted to `StateFlow`s are **never eagerly recycled** immediately after - Error/success dismiss indicators use cancellable `Job` tracking to prevent race conditions - `writeExifToUri()` returns boolean and logs at ERROR level on failure +### Orientation policy (do not change without asking) + +- Activity is `screenOrientation="portrait"` in the manifest. The GL surface and Compose layout therefore never rotate. +- The camera passthrough uses a fixed 90° texcoord rotation (`texCoordsBack`/`texCoordsFront`). There is no `setTargetRotation`/`setDisplayRotation`/`getTransformMatrix`-based rotation tracking — past attempts (v1.1.6 through v1.1.13) all introduced subtle bugs and were reverted. +- The camera image lives in the device's portrait frame and visually follows the phone as it tilts. Per-orientation correctness comes from the EXIF orientation tag written at capture (`OrientationDetector.degreesToExifOrientation(rotationToDegrees(deviceRotation), isFrontCamera)`), not from rotating the bitmap. +- `OrientationEventListener` (`viewModel.currentRotation`) is for EXIF only. It is **not** the same as `Display.rotation`: it fires at the 45° tilt threshold while the activity rotates later, so it must not drive anything that has to stay in sync with the GL surface. +- `SurfaceTexture.getTransformMatrix()` with a custom `SurfaceProvider` does not change on `Preview.targetRotation` updates; rebinding doesn't reliably help either. Don't go down that road again. + +### Local Android testing + +- AVD: `tilfluktsrom` (Pixel 6, API 35, Google APIs) at `~/.android/avd/`. Boot with `emulator -avd tilfluktsrom -no-snapshot-save -gpu swiftshader_indirect -no-audio`. +- `adb -s emulator-5554 emu rotate` cycles `ROTATION_0 → 3 → 2 → 1 → 0` (decrements by 90°), not the other way. +- The default virtual scene is too rotationally symmetric to verify which way is "up". For orientation testing, pass `-virtualscene-poster wall=/path/to/marker.png` and ensure the scene camera faces the wall, or just don't trust emulator screenshots as proof of correct orientation. +- Camera bitmaps captured at startup tend to look black for a few seconds while CameraX rebinds. Wait ≥10 s after `am start` before screenshotting. + ## Permissions | Permission | Purpose | Notes |