MainPage.xaml

<Page
    x:Class="ImageCropperTest.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:ImageCropperTest"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" xmlns:controls="using:Microsoft.Toolkit.Uwp.UI.Controls"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    <Grid x:Name="mainGrid">
        <Grid.RowDefinitions>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="70"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"></ColumnDefinition>
            <ColumnDefinition Width="600"></ColumnDefinition>
            <ColumnDefinition Width="*"></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <controls:ImageCropper x:Name="imgCropper" Grid.Row="1" Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Height="{Binding Path=CROPPER_MAX_HEIGHT, ElementName=mainGrid}"></controls:ImageCropper>
        <Grid Grid.Row="2" Grid.ColumnSpan="3" Margin="10">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"></ColumnDefinition>
                <ColumnDefinition Width=".8*"></ColumnDefinition>
                <ColumnDefinition Width=".8*"></ColumnDefinition>
                <ColumnDefinition Width="*"></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <Button x:Name="Cancel" Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="10" Content="Cancel"></Button>
            <Button x:Name="Done" Grid.Column="2" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="10" Content="Done"></Button>
        </Grid>
    </Grid>
</Page>