QuickLook/QuickLook/MainWindowTransparent.xaml

<controls:MainWindowBase
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:fa="http://schemas.fontawesome.io/icons/"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:busyDecorator="clr-namespace:QuickLook.Controls.BusyDecorator"
    xmlns:glassLayer="clr-namespace:QuickLook.Controls.GlassLayer"
    xmlns:converters="clr-namespace:QuickLook.Converters"
    xmlns:controls="clr-namespace:QuickLook.Controls"
    mc:Ignorable="d" x:Class="QuickLook.MainWindowTransparent" x:Name="mainWindow"
    UseLayoutRounding="True"
    d:DesignWidth="624" d:DesignHeight="700"
    MinWidth="275" MinHeight="150"
    WindowStartupLocation="CenterScreen"
    Focusable="False" WindowStyle="None"
    AllowsTransparency="True"
    Background="Transparent"
    ShowActivated="False" ShowInTaskbar="False">
    <controls:MainWindowBase.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Styles/MainWindowStyles.xaml" />
            </ResourceDictionary.MergedDictionaries>
            <converters:BooleanToResizeModeConverter x:Key="BooleanToResizeModeConverter" />
            <converters:BooleanToKeyTimeConverter x:Key="BooleanToKeyTimeConverter" />
            <converters:WindowStateToThicknessConverter x:Key="WindowStateToThicknessConverter" />
            <converters:BooleanToResizeBorderThicknessConverter x:Key="BooleanToResizeBorderThicknessConverter" />
            <converters:BooleanToVisibilityCollapsedConverter x:Key="BooleanToVisibilityCollapsedConverter" />
            <converters:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
            <converters:ScaledValueConverter x:Key="ScaledValueConverter" />
        </ResourceDictionary>
    </controls:MainWindowBase.Resources>
    <controls:MainWindowBase.Style>
        <Style TargetType="controls:MainWindowBase">
            <Setter Property="Foreground" Value="{DynamicResource MainWindowForeground}" />
            <Setter Property="ResizeMode"
                    Value="{Binding ContextObject.CanResize, ElementName=mainWindow, Converter={StaticResource BooleanToResizeModeConverter}}" />
            <Setter Property="WindowChrome.WindowChrome">
                <Setter.Value>
                    <WindowChrome CaptionHeight="0"
                                  ResizeBorderThickness="{Binding ContextObject.CanResize, Converter={StaticResource BooleanToResizeBorderThicknessConverter}, ElementName=mainWindow}"
                                  UseAeroCaptionButtons="False" />
                </Setter.Value>
            </Setter>
            <Style.Triggers>
                <Trigger Property="WindowState" Value="Maximized">
                    <Setter Property="WindowChrome.WindowChrome">
                        <Setter.Value>
                            <WindowChrome CaptionHeight="0" ResizeBorderThickness="0" UseAeroCaptionButtons="False" />
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
    </controls:MainWindowBase.Style>
    <Border>
        <Border.Effect>
            <DropShadowEffect BlurRadius="{StaticResource MainWindowShadowBlurRadius}" ShadowDepth="0" Opacity="0.6"
                              Color="{DynamicResource MainWindowShadowColor}" />
        </Border.Effect>
        <Grid x:Name="windowFrameContainer" Background="{DynamicResource MainWindowBackground}"
              Margin="{Binding WindowState, ElementName=mainWindow, Converter={StaticResource WindowStateToThicknessConverter}, ConverterParameter={StaticResource MainWindowShadowPaddingThinkness}}">
            <Grid.Resources>
                <Storyboard x:Key="ShowCaptionStoryboard">
                    <DoubleAnimation  
                        Storyboard.Target="{Binding Source={x:Reference windowCaptionContainer}}"
                        Storyboard.TargetProperty="Opacity" To="1" Duration="0:0:0.05">
                    </DoubleAnimation>
                </Storyboard>
                <Storyboard x:Key="ShowAndHideTitlebarStoryboard">
                    <DoubleAnimationUsingKeyFrames
                        Storyboard.Target="{Binding Source={x:Reference windowCaptionContainer}}"
                        Storyboard.TargetProperty="Opacity">
                        <DoubleAnimationUsingKeyFrames.KeyFrames>
                            <LinearDoubleKeyFrame Value="1" KeyTime="0:0:0.05" />
                            <LinearDoubleKeyFrame Value="1" KeyTime="0:0:3" />
                            <LinearDoubleKeyFrame Value="0" KeyTime="0:0:3.05" />
                        </DoubleAnimationUsingKeyFrames.KeyFrames>
                    </DoubleAnimationUsingKeyFrames>
                </Storyboard>
            </Grid.Resources>
            <Grid x:Name="viewerRootContainer" ZIndex="190">
                <Grid x:Name="windowCaptionContainer" Height="{StaticResource MainWindowCaptionHeight}"
                      VerticalAlignment="Top"
                      ZIndex="100">
                    <glassLayer:GlassLayer OverlayColor="{DynamicResource CaptionBackground}" BlurredElement="{Binding ElementName=containerPanel}" />
                    <DockPanel>
                        <Button x:Name="buttonCloseWindow" Style="{StaticResource CaptionCloseButtonStyle}"
                                DockPanel.Dock="Right">
                            <fa:ImageAwesome Icon="TimesCircle"
                                             Foreground="{DynamicResource CaptionButtonIconForeground}" />
                        </Button>
                        <Button x:Name="buttonWindowStatus" Style="{StaticResource CaptionButtonStyle}"
                                Visibility="{Binding ContextObject.CanResize, ElementName=mainWindow, Converter={StaticResource BooleanToVisibilityConverter}}"
                                DockPanel.Dock="Right">
                            <fa:ImageAwesome Foreground="{DynamicResource CaptionButtonIconForeground}">
                                <fa:ImageAwesome.Style>
                                    <Style TargetType="{x:Type fa:ImageAwesome}">
                                        <Setter Property="Icon" Value="WindowMaximize" />
                                        <Style.Triggers>
                                            <DataTrigger Binding="{Binding WindowState, ElementName=mainWindow}"
                                                         Value="Maximized">
                                                <Setter Property="Icon" Value="WindowRestore" />
                                            </DataTrigger>
                                            <DataTrigger Binding="{Binding WindowState, ElementName=mainWindow}"
                                                         Value="Normal">
                                                <Setter Property="Icon" Value="WindowMaximize" />
                                            </DataTrigger>
                                        </Style.Triggers>
                                    </Style>
                                </fa:ImageAwesome.Style>
                            </fa:ImageAwesome>
                        </Button>
                        <Button x:Name="buttonOpenWith" DockPanel.Dock="Right"
                                Style="{StaticResource CaptionTextButtonStyle}">
                            <Button.Content>
                                <TextBlock x:Name="buttonOpenWithText" VerticalAlignment="Center">
                                    Open with <Bold>AppName</Bold>
                                </TextBlock>
                            </Button.Content>
                        </Button>
                        <Button DockPanel.Dock="Left" x:Name="buttonPin" Style="{StaticResource CaptionButtonStyle}">
                            <fa:ImageAwesome Icon="ThumbTack" Foreground="{DynamicResource CaptionButtonIconForeground}" />
                        </Button>
                        <Button x:Name="buttonShare" Style="{StaticResource CaptionButtonStyle}" DockPanel.Dock="Left">
                            <fa:ImageAwesome Icon="ShareAlt" Foreground="{DynamicResource CaptionButtonIconForeground}" />
                        </Button>
                        <Grid x:Name="titleArea" Background="Transparent">
                            <TextBlock Text="{Binding ContextObject.Title, ElementName=mainWindow}" FontSize="12"
                                       HorizontalAlignment="Left" TextTrimming="CharacterEllipsis"
                                       VerticalAlignment="Center" Margin="5,0" />
                        </Grid>
                    </DockPanel>
                </Grid>
                <DockPanel x:Name="containerPanel" Background="{DynamicResource MainWindowBackground}" ZIndex="80">
                    <Grid DockPanel.Dock="Top" Height="{StaticResource MainWindowCaptionHeight}"
                          Visibility="{Binding ContextObject.TitlebarOverlap, ElementName=mainWindow, Converter={StaticResource BooleanToVisibilityCollapsedConverter}}" />
                    <ContentControl x:Name="container"
                                    Foreground="{DynamicResource CaptionButtonIconForeground}"
                                    Content="{Binding ContextObject.ViewerContent, ElementName=mainWindow}" />
                    <DockPanel.Style>
                        <Style TargetType="{x:Type DockPanel}">
                            <Setter Property="Visibility" Value="Visible" />
                            <Style.Triggers>
                                <DataTrigger
                                    Binding="{Binding ContextObject.IsBusy, ElementName=mainWindow}"
                                    Value="True">
                                    <Setter Property="Visibility" Value="Hidden" />
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </DockPanel.Style>
                </DockPanel>
            </Grid>
            <Grid x:Name="busyIndicatorLayer" Background="{DynamicResource MainWindowBackground}" ZIndex="200">
                <Grid.Style>
                    <Style TargetType="{x:Type Grid}">
                        <Setter Property="Visibility" Value="Collapsed" />
                        <Style.Triggers>
                            <DataTrigger
                                Binding="{Binding ContextObject.IsBusy, ElementName=mainWindow}"
                                Value="True">
                                <Setter Property="Visibility" Value="Visible" />
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </Grid.Style>
                <busyDecorator:BusyDecorator x:Name="busyDecorator"
                                             IsBusyIndicatorShowing="True"
                                             VerticalAlignment="Center"
                                             HorizontalAlignment="Center" />
            </Grid>
        </Grid>
    </Border>
</controls:MainWindowBase>