Custom layout for scanning barcodes

PartialScanningPage.xaml

<?xml version="1.0" encoding="utf-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
                        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                        x:Class="ZXingSample.PartialScreenScanning"
                        xmlns:zxing="clr-namespace:ZXing.Net.Mobile.Forms;assembly=ZXing.Net.Mobile.Forms"
                        Title="Partial screen">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        
        <BoxView Grid.Row="0" BackgroundColor="Chocolate"/>
        <zxing:ZXingScannerView Grid.Row="1" x:Name="_scanView" OnScanResult="Handle_OnScanResult" IsScanning="true"
                                WidthRequest="200" HeightRequest="200" />
        <BoxView Grid.Row="2" BackgroundColor="Blue" />
    </Grid>
</ContentPage>

The red line is part of the ScanningPage, think of it as an example view that is provided for you. The ScanningView allows you to customize that. It will provide you nothing out of the box, you can draw lines or whatever you want yourself though