試圖繪製函數

Question

我想畫在C＃中的圖形，像

到目前爲止，我已經能夠得出使用DrawLine簡單的線條，但是這是非常限制了自己的，因爲，不僅我被迫提供起點和終點，我也被限制爲直線。

正如你所看到的

我在表達的最後trech（一倒拋物線）的曲線

關於如何將BMP圖中執行此任何提示？

我一直在使用以下

using (Graphics g = Graphics.FromImage(bmp)) 
      { //g.DrawLine and others 
} 

Answer 1

您可以使用從Graphics類DrawCurve類似的功能繪圖。它將一系列點作爲參數，然後通過它們進行繪製。根據您想要曲線的準確度，您可以獲取起點，終點和轉折點。

https://msdn.microsoft.com/en-us/library/7ak09y3z%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396

Answer 2

第一步，繪製函數將對其進行評估，並將其保存到一個點陣列：

 //Create a Point array to store the function's values 
     Point[] functionValues = new Point[100]; 

     //Calculate the function for every Point in the Point array 
     for (int x = 0; x < functionValues.Length; x++) 
     { 
      //Set the every point's X value to the current iteration of the loop. That means that we are evaluating the function in steps of 1 
      functionValues[x].X = x; 
      //Calculate the Y value of every point. In this exemple I am using the function x^2 
      functionValues[x].Y = x * x; 
     } 

然後，當你畫出來的函數，繪製它就像這樣：

 //Iterate through every point in the array 
     for (int i = 1; i < functionValues.Length; i++) 
     { 
      //Draw a line between every point and the one before it 
      //Note that 'g' is your graphics object 
      g.DrawLine(Pens.Black, functionValues[i-1], functionValues[i]); 
     } 

當你是畫，做在窗體的Paint事件，並確保該形式是雙緩衝：

Point[] functionValues; 

    public Form1() 
    { 
     InitializeComponent(); 
     this.DoubleBuffered = true; 
     this.Paint += Form1_Paint; //Subscribe to the Paint Event 

     //Create a Point array to store the function's values 
     functionValues = new Point[100]; 

     //Calculate the function for every Point in the Point array 
     for (int x = 0; x < functionValues.Length; x++) 
     { 
      //Set the every point's X value to the current iteration of the loop. That means that we are evaluating the function in steps of 1 
      functionValues[x].X = x; 
      //Calculate the Y value of every point. In this exemple I am using the function x^2 
      functionValues[x].Y = x * x; 
     } 
    } 

    void Form1_Paint(object sender, PaintEventArgs e) 
    { 
     Graphics g = e.Graphics; 
     //Draw using 'g' or 'e.Graphics'. 
     //For exemple: 

     //Iterate through every point in the array 
     for (int i = 1; i < functionValues.Length; i++) 
     { 
      //Draw a line between every point and the one before it 
      g.DrawLine(Pens.Black, functionValues[i - 1], functionValues[i]); 
     } 

    } 

而且lastley，使形式更新和重新繪製自己，請致電形式的Invalidate方法：

this.Invalidate();