How to use drawable (or equivalent) as background in an flutter widget

I'm an Android developer and I start studying Flutter. To better understand this framework, I'm trying to convert an existing application. I'm trying to convert the following fragment:

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/home_background"
    android:paddingLeft="@dimen/fragment_horizontal_margin"
    android:paddingTop="@dimen/fragment_vertical_margin"
    android:paddingRight="@dimen/fragment_horizontal_margin"
    android:paddingBottom="@dimen/fragment_vertical_margin"
    tools:context=".ui.login.LoginFragment">

    <EditText
        android:id="@+id/fragment_login_username"
        style="@android:style/Widget.AutoCompleteTextView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="24dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="24dp"
        android:background="@color/white"
        android:hint="@string/prompt_username"
        android:inputType="text"
        android:padding="4dp"
        android:selectAllOnFocus="true"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/baseUrl" />

    <EditText
        android:id="@+id/fragment_login_password"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="24dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="24dp"
        android:background="@color/white"
        android:hint="@string/prompt_password"
        android:imeActionLabel="@string/action_sign_in_short"
        android:imeOptions="actionDone"
        android:inputType="textPassword"
        android:padding="4dp"
        android:selectAllOnFocus="true"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/fragment_login_username" />

    <Button
        android:id="@+id/fragment_login_login"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="start"
        android:layout_marginStart="48dp"
        android:layout_marginEnd="48dp"
        android:layout_marginBottom="64dp"
        android:enabled="false"
        android:text="@string/action_sign_in"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <ProgressBar
        android:id="@+id/fragment_login_loading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginBottom="64dp"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        tools:visibility="visible" />

    <ImageView
        android:id="@+id/imageView4"
        android:layout_width="128dp"
        android:layout_height="128dp"
        android:layout_marginTop="48dp"
        android:src="@drawable/ic_lock_outline_primary_24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:tint="@color/white" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/login_button"
        android:textAppearance="@style/TextAppearance.AppCompat.Display3"
        android:textColor="@color/white"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView4" />

    <TextView
        android:id="@+id/baseUrl"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        tools:text="http://localhost"
        android:textColor="@color/white"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2" />

    <ImageView
        android:id="@+id/login_refresh_backend_url"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:src="@drawable/ic_refresh_24dp"
        app:layout_constraintBottom_toBottomOf="@+id/baseUrl"
        app:layout_constraintStart_toEndOf="@+id/baseUrl"
        app:layout_constraintTop_toBottomOf="@+id/textView2"
        app:tint="@color/white" />

</androidx.constraintlayout.widget.ConstraintLayout>

As you can see, the ConstraintLayout uses a vector image as background.

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="100dp"
    android:height="100dp"
    android:viewportHeight="700"
    android:viewportWidth="700">
    <path
        android:pathData="M0,0L700,0L700,400Q350,550,0,400"
        android:strokeColor="@color/primary_color"
        android:strokeWidth="1"
        android:fillColor="@color/primary_color"/>
</vector>

In Flutter's implementation of my application, I would like to continue to use vector graphics because it's scalable.

Is there a way to use vector graphics as background in Flutter widgets?

Is there a way to automatically convert an existing XML layout into a flutter widget tree?

Thank you in advance.