C#WPF 如何繪製幾何圖形？ 怎麼繪製座標系？繪製sin曲線（正弦曲線）？

這離不開Path（System.Windows.Shapes）和StreamGeometry（System.Windows.Media）類。

完成該工程，我們首先要建立並繪製一個座標系，然後在該座標系中繪製sin曲線的點（x，y），最後，把曲線的點轉換為螢幕座標並連線；這樣座標系和sin曲線就繪製完成了。

如果有幫助，別忘了給評價！

一、建立WPF工程  

二、新增程式碼

MainWindow.xaml 中程式碼

<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>

 
 

MainWindow.xaml.cs中程式碼

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>
    /// MainWindow.xaml 的互動邏輯
    /// </summary>
    public partial class MainWindow : System.Windows.Window
    {
        //Canvas mainPanel = new Canvas();
        public MainWindow()
        {
            InitializeComponent();

            Drawsin();//繪製2D座標系和sin曲線
    
            Drawpentagon();

        }
        /// <summary>
        /// 繪製一組線段
        /// </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>
        /// 繪製線段
        /// </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>
        /// 繪製星狀線
        /// </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>
        /// 繪製座標系和sin曲線
        /// </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>
        /// 繪製連續的線段
        /// </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>
        /// 繪製五角星
        /// </summary>
        private void Drawsin()
        {
            Point point = new Point(this.mainPanel.Width, this.mainPanel.Height);
            Point xypoint = new Point(point.X / 2, point.Y / 2);//新座標原點

            //x軸座標起點
            Point xstartpoint = new Point(0, point.Y / 2);
            //x軸座標終點
            Point xendpoint = new Point(point.X, point.Y / 2);

            //y軸座標起點
            Point ystartpoint = new Point(point.X / 2, point.Y);
            //y軸座標終點
            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];

            //繪製sin曲線,從原點（0,0）開始
              Point zpoint = new Point(0, 0);
            zpoint = XYTransf(zpoint, xypoint);
            points[0] = zpoint;//sin曲線的起點

         
              for (int i = 1; i < 1000; i++)
            {
                //計算sin（x，y）
                point.X =10 * i;//x
              point.Y =10 * Math.Sin(i);//y
  
                //座標轉換
                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);

        }

        //構建的XY座標系中的座標轉換為介面座標系
        public Point XYTransf(Point point, Point xypoint)
 

        {
            point.X += xypoint.X;
            point.Y = xypoint.Y - point.Y;

            return point;//顯示螢幕座標系的位置
        }
    }
}

三、頁面效果

四、介紹

private void Drawsin()  函式中完成：座標系繪製，sin曲線繪製；

point是繪圖座標系中的點，xypoint（maincanvas.Width/2,maincanvas.Height/2）是繪圖螢幕座標的幾何中心點（ 圖 座標點轉換，中x軸和y軸原點）的座標。

public Point XYTransf(Point point, Point xypoint）函式返回值是在螢幕座標繪製點的座標。

        //轉換為介面座標系
        public Point XYTransf(Point point, Point xypoint）

        {
            point.X += xypoint.X;
            point.Y = xypoint.Y - point.Y;

            return point;//顯示螢幕座標系的位置
        }

1.mainPanel  是一個Canvas面板，我們在該面板繪製圖形。

2.繪製座標系，以mainPanel 的圖形中心為座標原點；

                                                                                           圖 座標點轉換

 3.計算sin（x，y）並轉換為螢幕座標點，取1000個座標點，並存在points陣列中

            for (int i = 1; i < 1000; i++)
            {
                //計算sin（x，y）
                point.X =10 * i;//sin x
              point.Y =10 * Math.Sin(i);//sin y
  
                //座標轉換
                point = XYTransf(point, xypoint);
              points[i] = point;

            }

4.連線1000個sin（x，y）的螢幕座標點，並顯示在Canvas中

StreamGeometry theGeometry = BuildRegularPolygon(points, true, false);   通過該函式連線points中所有的點；

            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);

5.執行顯示效果

點選“啟動”或按鍵盤“F5”執行工程，顯示介面。