MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:custom="using:Dynaframe3.TransitionTypes"
        mc:Ignorable="d"
        x:Class="Dynaframe3.MainWindow"
        TransparencyLevelHint="Transparent"
        Background="Black"
        Name="mainWindow"
        >
  <Panel Name="mainPanel">
    <custom:CrossFadeTransition Name="CrossFadeImage"/>
      <TextBlock Name="tb" 
                 Text="" 
                 FontSize="30" 
                 HorizontalAlignment="Left" 
                 VerticalAlignment="Bottom" 
                 Foreground="AliceBlue" 
                 Opacity="1" 
                 Margin="0"/>
  </Panel>
</Window>