Ruler Control

Learn creating an on-screen Ruler using Windows App SDK with this Tutorial

Ruler Control shows how to create an on-screen Ruler for Metric or Imperial using Windows App SDK.

Step 1

Follow Setup and Start on how to get Setup and Install what you need for Visual Studio 2022 and Windows App SDK.

In Windows 11 choose Start and then find or search for Visual Studio 2022 and then select it.
Visual Studio 2022
Once Visual Studio 2022 has started select Create a new project.
Create a new project
Then choose the Blank App, Packages (WinUI in Desktop) and then select Next.
Blank App, Packages (WinUI in Desktop)
After that in Configure your new project type in the Project name as RulerControl, then select a Location and then select Create to start a new Solution.
Configure project

Step 2

Then in Visual Studio within Solution Explorer for the Solution, right click on the Project shown below the Solution and then select Add then New Item…

Add New Item

Step 3

Then in Add New Item from the C# Items list, select Code and then select Code File from the list next to this, then type in the name of Ruler.cs and then Click on Add.

Add New Code File

Step 4

Then from Solution Explorer for the Solution double-click on Ruler.cs to see the Code for the User Control.
Solution Explorer Ruler.cs

Step 5

You will now be in the View for the Code of Ruler.cs, within this type the following Code:

using Microsoft.UI;
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Media;
using Microsoft.UI.Xaml.Shapes;
using Windows.Foundation;

namespace RulerControl;

public enum Units

public class Ruler : Canvas
    private const double default_height = 40.0;

    private double _originalHeight;

    // Static Methods

    // Dependency Properties & Properties

    // Layout Method

    // Constructor & Measure Override Event Handler


There are using statements for the User Control, a namespace for RulerControl with an enum for the Units along with a class of Ruler that will represent the User Control for the Ruler.

Step 6

Then in the namespace of RulerControl in the class of Ruler after the Comment of // Static Methods type the following Static Methods:

private static double CmToDip(double cm) => 
    cm * 96.0 / 2.54;

private static double InchToDip(double inch) => 
    inch * 96.0;

private static Path GetLine(Brush stroke, double thickness, 
    Point start, Point finish) => new()
    Stroke = stroke,
    StrokeThickness = thickness,
    Data = new LineGeometry()
        StartPoint = start,
        EndPoint = finish

These Static Methods include CmToDip and InchToDip which will perform the conversions for the measurements to be displayed on the Ruler to device independent pixels. There is also GetLine which will return the Path used to display the lines on the Ruler.

Step 7

While still in the namespace of RulerControl in the class of Ruler after the Comment of // Dependency Properties & Properties type the following Dependency Properties and Properties

public static readonly DependencyProperty ForegroundProperty =
DependencyProperty.Register(nameof(Foreground), typeof(Brush),
typeof(Ruler), new PropertyMetadata(new SolidColorBrush(Colors.Black)));

public static readonly DependencyProperty LengthProperty =
DependencyProperty.Register(nameof(Length), typeof(double),
typeof(Ruler), new PropertyMetadata(10.0));

public static readonly DependencyProperty SegmentProperty =
DependencyProperty.Register(nameof(Segment), typeof(double),
typeof(Ruler), new PropertyMetadata(20.0));

public static readonly DependencyProperty UnitProperty =
DependencyProperty.Register(nameof(Unit), typeof(double),
typeof(Ruler), new PropertyMetadata(Units.Cm));

public Brush Foreground
    get { return (Brush)GetValue(ForegroundProperty); }
    set { SetValue(ForegroundProperty, value); }

public double Length
    get { return (double)GetValue(LengthProperty); }
    set { SetValue(LengthProperty, value); }

public double Segment
    get { return (double)GetValue(SegmentProperty); }
    set { SetValue(SegmentProperty, value); }

public Units Unit
    get { return (Units)GetValue(UnitProperty); }
    set { SetValue(UnitProperty, value); }

The Dependency Properties or Properties for the User Control can be customised for the Ruler.

Step 8

While still in the namespace of RulerControl in the class of Ruler after the Comment of // Layout Method type the following Method:

private void Layout()
    for (double value = 0.0; value <= Length; value++)
        double dip;
        if (Unit == Units.Cm)
            dip = CmToDip(value);
            if (value < Length)
                for (int i = 1; i <= 9; i++)
                    if (i != 5)
                        var mm = CmToDip(value + 0.1 * i);
                        Children.Add(GetLine(Foreground, 0.5, new Point(mm, Height),
                        new Point(mm, Height - Segment / 3.0)));
                var middle = CmToDip(value + 0.5);
                Children.Add(GetLine(Foreground, 1.0, new Point(middle, Height),
                new Point(middle, Height - Segment * 2.0 / 3.0)));
            dip = InchToDip(value);
            if (value < Length)
                var quarter = InchToDip(value + 0.25);
                Children.Add(GetLine(Foreground, 0.5, new Point(quarter, Height),
                new Point(quarter, Height - Segment / 3.0)));
                var middle = InchToDip(value + 0.5);
                Children.Add(GetLine(Foreground, 1.0, new Point(middle, Height),
                new Point(middle, Height - 0.5 * Segment * 2.0 / 3.0)));
                var division = InchToDip(value + 0.75);
                Children.Add(GetLine(Foreground, 0.5, new Point(division, Height),
                new Point(division, Height - 0.25 * Segment / 3.0)));
        Children.Add(GetLine(Foreground, 1.0, new Point(dip, Height),
        new Point(dip, Height - Segment)));

This Method creates the look-and-feel for the User Control for either Metric or Imperial units to be displayed accordingly for the Ruler.

Step 9

While still in the namespace of RulerControl in the class of Ruler after the Comment of // Constructor & Measure Override Event Handler type the following Constructor and Event Handler:

public Ruler() => 
    Loaded += (object sender, RoutedEventArgs e) => Layout();

protected override Size MeasureOverride(Size availableSize)
    Height = !double.IsNaN(Height) ? Height : default_height;
    var desiredSize = (Unit == Units.Cm) ? 
        new Size(CmToDip(Length), Height) : 
        new Size(InchToDip(Length), Height);
    if(Height != _originalHeight)
        _originalHeight = Height;
    return desiredSize;

The Constructor will call the Method of Layout when the User Control has been Loaded and the Event Handler of MeasureOverride will manage the resizing of the Ruler.

Step 10

Within Solution Explorer for the Solution double-click on MainWindow.xaml to see the XAML for the Main Window.
Solution Explorer MainWindow.xaml

Step 11

In the XAML for MainWindow.xaml there will be some XAML for a StackPanel, this should be Removed:

<StackPanel Orientation="Horizontal" 
HorizontalAlignment="Center" VerticalAlignment="Center">
    <Button x:Name="myButton" Click="myButton_Click">Click Me</Button>

Step 12

While still in the XAML for MainWindow.xaml above </Window>, type in the following XAML:

<Viewbox Margin="50">
    <local:Ruler Length="15.0" Unit="Cm"
    Background="{ThemeResource SystemControlHighlightAccentBrush}"
    Foreground="{ThemeResource SystemControlBackgroundAltHighBrush}"/>

This XAML contains a ViewBox and the User Control of Ruler with the Length and Unit set.

Step 13

Within Solution Explorer for the Solution select the arrow next to MainWindow.xaml then double-click on MainWindow.xaml.cs to see the Code for the Main Window.
Solution Explorer MainWindow.xaml.cs

Step 14

In the Code for MainWindow.xaml.cs there be a Method of myButton_Click(...) this should be Removed by removing the following:

private void myButton_Click(object sender, RoutedEventArgs e)
    myButton.Content = "Clicked";

Step 15

That completes the Windows App SDK application. In Visual Studio 2022 from the Toolbar select RulerControl (Package) to Start the application.
RulerControl (Package)

Step 16

Once running you will see the Ruler Control displayed with the given Length and Unit.

Ruler Control Running and Output

Step 17

To Exit the Windows App SDK application, select the Close button from the top right of the application as that concludes this Tutorial for Windows App SDK from!
Close application