App.xaml

<Application x:Class="ScallableApplication.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <Style TargetType="Window" x:Key="FullScreenStyle">
            <Setter Property="Height" Value="768"></Setter>
            <Setter Property="Width" Value="1366"></Setter>
            <Setter Property="WindowStyle" Value="None"></Setter>
            <Setter Property="ResizeMode" Value="NoResize"></Setter>
            <Setter Property="WindowState" Value="Maximized"></Setter>
        </Style>
        <Style TargetType="Window" x:Key="WindowStyle">
            <Setter Property="Height" Value="460.7"></Setter>
            <Setter Property="Width" Value="819.6"></Setter>
        </Style>

        <DrawingBrush x:Key="gridBackgroundBrush" Viewport="0,0,10,10" ViewportUnits="Absolute" TileMode="Tile">
            <DrawingBrush.Drawing>
                <DrawingGroup>
                    <DrawingGroup.Children>
                        <GeometryDrawing Geometry="M0,0 L1,0 1,0.1, 0,0.1Z" Brush="Beige" />
                        <GeometryDrawing Geometry="M0,0 L0,1 0.1,1, 0.1,0Z" Brush="Beige" />
                    </DrawingGroup.Children>
                </DrawingGroup>
            </DrawingBrush.Drawing>
        </DrawingBrush>
    </Application.Resources>
</Application>

App.xaml.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace ScallableApplication
{
    /// <summary>
    /// App.xaml の相互作用ロジック
    /// </summary>
    public partial class App : Application
    {
    }
}

MainWindow.xaml

<Window x:Class="ScallableApplication.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <StackPanel.Resources>
            <Style TargetType="Button">
                <Setter Property="Height" Value="50"></Setter>
            </Style>
        </StackPanel.Resources>
        <Button Click="Button_Click">全画面</Button>
        <Button Click="Button_Click_1">ウィンドウ</Button>
    </StackPanel>
</Window>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace ScallableApplication
{
    /// <summary>
    /// MainWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.PreviewKeyDown += HandleEsc;
        }

        private void HandleEsc(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Escape)
            {
                this.Close();
            }
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            var w = new SubWindow() { Style = this.FindResource("FullScreenStyle") as Style };
            w.Show();
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            var w = new SubWindow() { Style = this.FindResource("WindowStyle") as Style };
            w.Show();
        }
    }
}

SubWindow.xaml

<Window x:Class="ScallableApplication.SubWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="SubWindow">
    <Window.Resources>
        <SolidColorBrush x:Key="MainBorderBrush">
            <SolidColorBrush.Color>Blue</SolidColorBrush.Color>
        </SolidColorBrush>
        <Style x:Key="MainBorder" TargetType="Border">
            <Setter Property="CornerRadius" Value="24.5"/>
            <Setter Property="Height" Value="500"/>
            <Setter Property="Width" Value="1260"/>
            <Setter Property="BorderThickness" Value="10"/>
            <Setter Property="BorderBrush" Value="{StaticResource MainBorderBrush}"/>
        </Style>
    </Window.Resources>
    <Grid Background="{StaticResource gridBackgroundBrush}">
        <Viewbox>
            <Grid>
                <Border Style="{StaticResource MainBorder}"/>
                <Canvas>
                    <Canvas.RenderTransform>
                        <TranslateTransform X="100" Y="100"/>
                    </Canvas.RenderTransform>
                    <Rectangle Width="100" Height="100" Fill="Gray"></Rectangle>
                    <Rectangle 
                        Canvas.Left="150"
                        Width="100" Height="100">
                        <Rectangle.Fill>
                            <SolidColorBrush Opacity="0.5" Color="Gray"/>
                        </Rectangle.Fill>
                    </Rectangle>
                    <Rectangle 
                        Canvas.Left="300"
                        Width="100" Height="100">
                        <Rectangle.Fill>
                            <SolidColorBrush Opacity="0.2" Color="Gray"/>
                        </Rectangle.Fill>
                    </Rectangle>
                    <Rectangle 
                        Canvas.Left="450"
                        Width="100" Height="100">
                        <Rectangle.Fill>
                            <SolidColorBrush Opacity="0.1" Color="Gray"/>
                        </Rectangle.Fill>
                    </Rectangle>
                    <Rectangle 
                        Canvas.Left="600"
                        Width="100" Height="100">
                        <Rectangle.Fill>
                            <SolidColorBrush Opacity="0.05" Color="Gray"/>
                        </Rectangle.Fill>
                    </Rectangle>
                </Canvas>
            </Grid>
        </Viewbox>
    </Grid>
</Window>

SubWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace ScallableApplication
{
    /// <summary>
    /// SubWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class SubWindow : Window
    {
        public SubWindow()
        {
            InitializeComponent();
            this.PreviewKeyDown += HandleEsc;
        }

        private void HandleEsc(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Escape)
            {
                this.Close();
            }
        }
    }
}