Signal-Android/app/src/main/res/layout/camerax_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.cardview.widget.CardView
        android:id="@+id/camerax_camera_parent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:cardCornerRadius="18dp"
        app:cardElevation="0dp"
        app:layout_constraintTop_toTopOf="parent">

        <androidx.camera.view.PreviewView
            android:id="@+id/camerax_camera"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="top"
            app:implementationMode="compatible" />
    </androidx.cardview.widget.CardView>

    <FrameLayout
        android:id="@+id/camerax_controls_container"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="@id/camerax_camera_parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>