C#WPF how to draw a Geometry diagram tutorial drawing a sin curve sine-drawn 2D coordinate system there's a diagram with the code

C#WPF How do I draw geometry? How to draw a coordinate system?

This is inseparable from the path (System.Windows.Shapes) and StreamGeometry (System.Windows.Media) classes.

I. Building a WPF Project

Second, add code

Code in MainWindow.xaml

<Window x:Class="WPFDrawingTraning.MainWindow"
        xmlns="<a target=_blank href="http://schemas.microsoft.com/winfx/2006/xaml/presentation">http://schemas.microsoft.com/winfx/2006/xaml/presentation</a>"
        xmlns:x="<a target=_blank href="http://schemas.microsoft.com/winfx/2006/xaml">http://schemas.microsoft.com/winfx/2006/xaml</a>"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Canvas Name="mainPanel" HorizontalAlignment="Left" Height="320" VerticalAlignment="Top" Width="517"/>
    </Grid>
</Window>

Code in 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 WPFDrawingTraning
{
    /// <summary>
    /// Interaction logic of MainWindow.xaml
    /// </summary>
    Public partial class MainWindow : System.Windows.Window
    {
        //Canvas mainPanel = new Canvas();
        Public MainWindow()
        {
            InitializeComponent();

            Drawsin();//Draw 2D coordinate system and sin curve
    
            Drawpentagon();

        }
        /// <summary>
        /// draw a set of line segments
        /// </summary>
        Protected void Drawing()
        {
            PathFigure myPathFigure = new PathFigure();
            myPathFigure.StartPoint = new Point(10, 50);

            LineSegment myLineSegment = new LineSegment();
            myLineSegment.Point = new Point(200, 70);

            PathSegmentCollection myPathSegmentCollection = new PathSegmentCollection();
            myPathSegmentCollection.Add(myLineSegment);

            myPathFigure.Segments = myPathSegmentCollection;

            PathFigureCollection myPathFigureCollection = new PathFigureCollection();
            myPathFigureCollection.Add(myPathFigure);

            PathGeometry myPathGeometry = new PathGeometry();
            myPathGeometry.Figures = myPathFigureCollection;
            

            Path myPath = new Path();
            myPath.Stroke = Brushes.Black;
            myPath.StrokeThickness = 1;
            myPath.Data = myPathGeometry;

            // Add path shape to the UI.
            StackPanel mainPanel = new StackPanel();
            mainPanel.Children.Add(myPath);
            this.Content = mainPanel;

        }
        /// <summary>
        /// draw a line segment
        /// </summary>
        Protected void DrawingLine(Point startPt,Point endPt)
        {
            LineGeometry myLineGeometry = new LineGeometry();
            myLineGeometry.StartPoint = startPt;
            myLineGeometry.EndPoint = endPt;

            Path myPath = new Path();
            myPath.Stroke = Brushes.Black;
            myPath.StrokeThickness = 1;
            myPath.Data = myLineGeometry;

            mainPanel.Children.Add(myPath);
            
        }
        /// <summary>
        /// draw a star line
        /// </summary>
        Protected void DrawingAstroid(Point center,double r)
        {

            Double h1 = r * Math.Sin(18 * Math.PI / 180);
            Double h2 = r * Math.Cos(18*Math.PI/180);
            Double h3 = r * Math.Sin(36 * Math.PI / 180);
            Double h4 = r * Math.Cos(36 * Math.PI / 180); ;
            Point p1 = new Point(r, 0);
            Point p2 = new Point(r - h2, r - h1);
            Point p3 = new Point(r - h3, r + h4);
            Point p4 = new Point(r + h3, p3.Y);
            Point p5 = new Point(r + h2, p2.Y);
            Point[] values = new Point[] { p1, p2, p3, p4, p5 };
            PathFigureCollection myPathFigureCollection = new PathFigureCollection();
            PathGeometry myPathGeometry = new PathGeometry();
            
            For (int i = 0; i < values.Length; i++)
            {
                //DrawingLine(center, values[i]);
                PathFigure myPathFigure = new PathFigure();
                myPathFigure.StartPoint = center;

                LineSegment myLineSegment = new LineSegment();
                myLineSegment.Point = values[i];

                PathSegmentCollection myPathSegmentCollection = new PathSegmentCollection();
                myPathSegmentCollection.Add(myLineSegment);

                myPathFigure.Segments = myPathSegmentCollection;

                myPathFigureCollection.Add(myPathFigure);
            }
            myPathGeometry.Figures = myPathFigureCollection;
            Path myPath = new Path();
            myPath.Stroke = Brushes.Black;
            myPath.StrokeThickness = 1;
            myPath.Data = myPathGeometry;
            
            mainPanel.Children.Add(myPath);
        }

        /// <summary>
        /// Draw a five-pointed star
        /// </summary>
        Private void Drawpentagon()
        {
            Point center = new Point(50, 50);
            Double r = 50;
            DrawingAstroid(center, r);

            Double h1 = r * Math.Sin(18 * Math.PI / 180);
            Double h2 = r * Math.Cos(18 * Math.PI / 180);
            Double h3 = r * Math.Sin(36 * Math.PI / 180);
            Double h4 = r * Math.Cos(36 * Math.PI / 180); ;
            Point p1 = new Point(r, 0);
            Point p2 = new Point(r - h2, r - h1);
            Point p3 = new Point(r - h3, r + h4);
            Point p4 = new Point(r + h3, p3.Y);
            Point p5 = new Point(r + h2, p2.Y);
            Point[] values = new Point[] { p1, p3, p5, p2, p4 };
            // Create a path to draw a geometry with.

Path myPath = new Path();
            myPath.Stroke = Brushes.Black;
            myPath.StrokeThickness = 1;
            StreamGeometry theGeometry = BuildRegularPolygon(values, true, false);
            // Create a StreamGeometry to use to specify myPath.
            theGeometry.FillRule = FillRule.EvenOdd;

            // Freeze the geometry (make it unmodifiable)
            // for additional performance benefits.
            theGeometry.Freeze();

            // Use the StreamGeometry returned by the BuildRegularPolygon to
            // specify the shape of the path.
            myPath.Data = theGeometry;

            // Add path shape to the UI.
            mainPanel.Children.Add(myPath);

        }

        /// <summary>
        /// draw continuous segments
        /// </summary>
        /// <param name="values"></param>
        /// <returns></returns>
        Private StreamGeometry BuildRegularPolygon(Point[] values, bool isClosed, bool isfilled)
        {
            // c is the center, r is the radius,
            // numSides the number of sides, offsetDegree the offset in Degrees.
            // Do not add the last point.

            StreamGeometry geometry = new StreamGeometry();

            Using (StreamGeometryContext ctx = geometry.Open())
            {
                ctx.BeginFigure(values[0], isfilled /* is filled */, isClosed /* is closed */);
                
                For (int i = 1; i < values.Length; i++)
                {
                    ctx.LineTo(values[i], true /* is stroked */, false /* is smooth join */);
                }
            }
            
            Return geometry;

        }

        /// <summary>
        /// Draw a five-pointed star
        /// </summary>
        Private void Drawsin()
        {
            Point point = new Point(this.mainPanel.Width, this.mainPanel.Height);
            Point xypoint = new Point(point.X / 2, point.Y / 2); / / new coordinate origin

            //x axis coordinate starting point
            Point xstartpoint = new Point(0, point.Y / 2);
            //x-axis coordinate end point
            Point xendpoint = new Point(point.X, point.Y / 2);

            //y axis coordinate starting point
            Point ystartpoint = new Point(point.X / 2, point.Y);
            //y axis coordinate end point
            Point yendpoint = new Point(point.X / 2, 0);

            Line xline = new Line();
            xline.Stroke = System.Windows.Media.Brushes.LightSteelBlue;

            xline.X1 = 0;
            xline.Y1 = this.mainPanel.Height / 2;

            xline.X2 = this.mainPanel.Width;
            xline.Y2 = this.mainPanel.Height / 2;

            this.mainPanel.Children.Add(xline);


            Line yline = new Line();
            yline.Stroke = System.Windows.Media.Brushes.LightSteelBlue;

            yline.X1 = this.mainPanel.Width / 2;
            yline.Y1 = this.mainPanel.Height;

            yline.X2 = this.mainPanel.Width / 2;
            yline.Y2 = 0;

            this.mainPanel.Children.Add(yline);
            Point[] points=new Point[1000];

            / / Draw sin curve, starting from the origin (0,0)
              Point zpoint = new Point(0, 0);
            Zpoint = XYTransf(zpoint, xypoint);
            Points[0] = zpoint;//the starting point of the sin curve

         
              For (int i = 1; i < 1000; i++)
            {
                / / Calculate sin (x, y)
                point.X =10 * i;//x
              point.Y =10 * Math.Sin(i);//y
  
                / / coordinate conversion
                Point = XYTransf(point, xypoint);
                Points[i] = point;

            }

            Path myPath = new Path();
            myPath.Stroke = Brushes.Black;
            myPath.StrokeThickness = 1;
            StreamGeometry theGeometry = BuildRegularPolygon(points, true, false);
            // Create a StreamGeometry to use to specify myPath.
            theGeometry.FillRule = FillRule.EvenOdd;

            // Freeze the geometry (make it unmodifiable)
            // for additional performance benefits.
            theGeometry.Freeze();

            // Use the StreamGeometry returned by the BuildRegularPolygon to
            // specify the shape of the path.
            myPath.Data = theGeometry;

            // Add path shape to the UI.
            mainPanel.Children.Add(myPath);

        }

        / / The coordinates in the constructed XY coordinate system are converted to the interface coordinate system
        Public Point XYTransf(Point point, Point xypoint)
        {
            point.X += xypoint.X;
            point.Y = xypoint.Y - point.Y;

            Return point; / / display the position of the screen coordinate system
        }
    }
}  

Third, the page effect

C#WPF how to draw a Geometry diagram tutorial drawing a sin curve sine-drawn 2D coordinate system there's a diagram with the code