Camera page kept the session running while the host app was
backgrounded — wastes battery, holds the hardware, and blocks
other apps from grabbing the camera. Add per-platform observers
that pause/resume the session on app foreground/background, with
a uniform `pauseForBackground` / `resumeForForeground` pair on the
shared CameraInstance.
Behaviour:
- On background: any in-flight recording is hard-cancelled
(matches every messaging app — the take ends with the app
switch). The session stops so the OS can release the camera.
- On foreground: session restarts iff it had been running.
Emits `sessionInterrupted` (`reason: appBackgrounded`) and
`sessionResumed` events so the Dart side can surface UX
affordances if needed.
iOS — `ios/Classes/Camera/CameraInstance+iOS.swift`:
Subscribes to UIApplication.{willResignActive, didBecomeActive}
notifications. Work hops onto sessionQueue so AV mutations stay
serialised. Storage uses the shared
`CameraInstance.lifecycleCleanup` closure slot — extension
doesn't need to add stored properties.
Android — added `androidx.lifecycle:lifecycle-process:2.7.0`,
observes `ProcessLifecycleOwner.get().lifecycle`. ON_STOP →
`pauseForBackground` (cancels recording + drops
CustomLifecycleOwner to CREATED → CameraX releases camera).
ON_START → `resumeForForeground`. Observer add/remove on main
thread per `ProcessLifecycleOwner` contract.
macOS — `macos/Classes/Camera/CameraInstance+macOS.swift`:
Intentional no-op. macOS desktop background semantics are
softer; the chat composer's Card dialog typically stays
foregrounded. Slot is wired so the shared
`observeLifecycle()` call still compiles.
Verified: all four platforms (iOS / Android / macOS / app tests)
build clean. Pod install picks up the new iOS extension file
once Pods/ is fresh — `flutter clean` if mid-iteration.
macOS preview was stretching (aspect wrong) and macOS photo capture
was rotating the landscape sensor 90° because the shared
PhotoOutput / CameraInstance code was setting
`AVCaptureConnection.videoOrientation` from the orientation snapshot
unconditionally. iOS needs that to rotate sample buffers to portrait;
macOS desktop cams are physically landscape and any rotation just
skews the result.
Moved the rotation call behind a per-platform extension on
`AVCaptureConnection`:
- `ios/Classes/Camera/AVCaptureConnection+iOS.swift` applies the
snapshot orientation (current behavior).
- `macos/Classes/Camera/AVCaptureConnection+macOS.swift` is a
no-op. macOS-flavoured photos / preview frames now flow at
native landscape orientation.
`CaptureDevice` reports sensorOrientation=0 on macOS (was hardcoded
90 for iOS); on macOS the page's `normalizeCameraCapture` math then
collapses to identity and the saved JPEG stays the landscape the
sensor produced. iOS keeps sensorOrientation=90 (matches
camera_avfoundation's reported value and the existing capture-
transform math).
Photo and video paths now both produce upright content on macOS
(video already worked because VideoRecorder's transform table maps
the always-portraitUp macOS snapshot to `.identity`).
Reuse the AVFoundation Swift files between iOS and macOS without
sprinkling `#if canImport(UIKit)` through them. The split is:
darwin/Camera/ platform-shared (AVFoundation only)
CameraPlugin channel + instance map
CameraInstance session + outputs + texture
CameraSession AVCaptureSession + runtime-error obs
CaptureDevice front/back discovery
PhotoOutput AVCapturePhotoOutput
PreviewSink CVPixelBuffer → FlutterTexture
VideoRecorder AVAssetWriter
DeviceOrientation wire-string enum
ios/Classes/Camera/ iOS-only impls + extensions
AudioSession AVAudioSession.upgradeForRecording
DeviceOrientationBridge UIDevice.orientation listener
CameraSession+iOS AVCaptureSessionWasInterrupted obs
+ InterruptionReason decode + the
application-audio-session flags
(all iOS-only on AVCaptureSession)
CameraSettings UIApplication.openSettingsURLString
FlutterRegistrar+iOS method-form of textures/messenger
macos/Classes/Camera/ macOS no-op stubs (same surface)
AudioSession no-op (no AVAudioSession on macOS)
DeviceOrientationBridge no-op (desktops don't rotate)
CameraSession+macOS no-op setupPlatform()
CameraSettings NSWorkspace → System Settings'
Privacy_Camera pane
FlutterRegistrar+macOS property-form of textures/messenger
`CameraSession.init` now calls `setupPlatform()` which each platform
provides via an extension — keeps the iOS-only interruption observer
and the `automaticallyConfiguresApplicationAudioSession` /
`usesApplicationAudioSession` flags (both iOS-only on AVCaptureSession)
out of the shared file. Flash-mode in PhotoOutput uses
`if #available(macOS 11/13, *)` rather than `#if`, since those are
plain version gates not platform splits.
The shared files compile into the iOS pod from `ios/Classes/Camera-shared/`
and into the macOS pod from `macos/Classes/Camera-shared/`, each a
mirror populated by a `prepare_command` in the podspec:
rm -rf Classes/Camera-shared && cp -R ../darwin/Camera Classes/Camera-shared
Symlinks and `../` source globs both fail — Pathname.glob bails on
symlinks, and CocoaPods silently drops paths that escape the pod
directory. The mirror destinations are .gitignore'd.
macOS UxPlugin now registers CameraPlugin alongside the others.
Black-screen + extra-90°-rotation on Android both came from
AVFoundation vs CameraX behaving differently at the preview output:
- AVFoundation: data-output connection's `videoOrientation`
pre-rotates sample buffers. The Flutter Texture displays them
upright; `device.activeFormat` reports the sensor-native size
synchronously.
- CameraX: the SurfaceProvider hands back a Surface; CameraX
writes raw sensor frames into it. Rotation is a *transform hint*
via Preview.setTargetRotation that consumers must apply
themselves. And the final negotiated resolution isn't known
until the first SurfaceRequest fires — which happens AFTER
bindToLifecycle, AFTER lifecycle.start, async on the camera
executor. So `create` was returning Size(0,0).
Surface extension to bridge the gap:
- UxCameraValue.previewRotationQuarterTurns (int 0/1/2/3).
iOS native always emits 0; Android native emits
`(sensorRotationDegrees / 90) % 4` for the active camera.
[UxCameraPreview] wraps the Texture in a RotatedBox by that many
quarter-turns (applied *before* the front-cam mirror so the
flip lives in screen space, not sensor space).
- UxCameraPreviewSizeChanged event. Android emits this from
PreviewSink.onResize whenever a SurfaceRequest carries a new
resolution; the controller copies it into value.previewSize.
First emission is what unblocks the camera_thumb's SizedBox
from its initial 0x0 = "render nothing" state.
- UxCameraBackend.setDescription's return changed from `Size` to
`({Size previewSize, int previewRotationQuarterTurns})` so
a lens swap can both update the rotation and signal that a new
previewSizeChanged event is incoming.
iOS continues to send previewSize in the create result (the active
format is known synchronously); no previewSizeChanged emission is
needed there. The new field is set to 0 in both create and
setDescription results on iOS.
Drop isVideoMirrored on the AVCaptureVideoDataOutput connection — the
data output feeds both the preview texture AND the recorder, so any
mirror set there ended up baked into the recorded MP4. Recorded video
+ captured JPEG now carry the raw sensor feed ("as others see you"),
matching telegram-iOS and the stock iOS Camera app default.
The selfie preview is mirrored inside UxCameraPreview itself
(Transform.flip(flipX: true) around the Texture when
description.lens == front) — the analog of telegram's
CameraPreviewView.mirroring CALayer transform. Consumers
(CameraThumb, etc.) don't need to know which lens is active.
Two leak paths surfaced after a flip-then-record-then-pop session
left the front camera claim stranded:
1. setDescription swapped instance.device without telling the plugin —
devicesInUse still held the original cameraId. After dispose,
releaseClaim only removed the *current* id, leaving the original
stuck. Next push of the page hit device_busy on the original cam.
Fix: setDescription handler now does a contention check, inserts
the new id and drops the old (or rolls back on swap failure).
2. create's catch path called releaseClaim(for: instance), but if
configureSession threw before instance.device was set,
instance.currentCameraId is nil — and the cameraId we inserted on
line above leaked. Fix: drop the known cameraId + audio claim
explicitly in the catch.
