Crisp showing of barcodes

GenerateBarcodes.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.GenerateBarcodePage"
             xmlns:zxing="clr-namespace:ZXing.Net.Mobile.Forms;assembly=ZXing.Net.Mobile.Forms"
             xmlns:zxcm="clr-namespace:ZXing.Common;assembly=zxing.portable"
             Title="Generate">
    <ScrollView>
        <StackLayout HorizontalOptions="Center" VerticalOptions="Center">
            <zxing:ZXingBarcodeImageView WidthRequest="300" HeightRequest="100" BarcodeValue="1337" BarcodeFormat="CODE_39">
                <zxing:ZXingBarcodeImageView.BarcodeOptions>
                    <zxcm:EncodingOptions Width="300" Height="100" />
                </zxing:ZXingBarcodeImageView.BarcodeOptions>
            </zxing:ZXingBarcodeImageView>
            <zxing:ZXingBarcodeImageView WidthRequest="300" HeightRequest="300" BarcodeValue="1337" BarcodeFormat="QR_CODE">
                <zxing:ZXingBarcodeImageView.BarcodeOptions>
                    <zxcm:EncodingOptions Width="300" Height="300" />
                </zxing:ZXingBarcodeImageView.BarcodeOptions>
            </zxing:ZXingBarcodeImageView>
            <zxing:ZXingBarcodeImageView WidthRequest="300" HeightRequest="100" BarcodeValue="1337133713378" BarcodeFormat="EAN_13">
                <zxing:ZXingBarcodeImageView.BarcodeOptions>
                    <zxcm:EncodingOptions Width="300" Height="100" />
                </zxing:ZXingBarcodeImageView.BarcodeOptions>
            </zxing:ZXingBarcodeImageView>
        </StackLayout>
    </ScrollView>
</ContentPage>