C# Graphics.DrawLine函數實例講解

Graphics.DrawLine()方法用于繪制連接由坐標對指定的兩個點的線。此方法的重載列表中有4種方法,如下所示:

• DrawLine(Pen, PointF, PointF) Method
• DrawLine(Pen, Int32, Int32, Int32, Int32) Method
• DrawLine(Pen, Single, Single, Single, Single) Method
• DrawLine(Pen, Point, Point) Method

首先,在Set-1中已經討論了兩種方法。在這里,我們將討論最后兩種方法。

DrawLine(Pen, Single, Single, Single, Single) Method

此方法用于繪制線形式的一組指定坐標,這些坐標以離散形式x1,y1,x2,y2給出。

用法:

public void DrawLine (System.Drawing.Pen pen, float x1, float y1, float x2, float y2);

參數:

• pen:Pen確定線條的顏色,寬度和樣式。
• x1:第一點的橫坐標。
• y1:第一點的縱坐標。
• x2:第二點的橫坐標。
• y2:第二點的縱坐標。

異常:如果pen為null,則此方法將提供ArgumentNullException。

例:

// C# program to illustrate the use of? using System; using System.Drawing; using System.Drawing.Printing; using System.Windows.Forms; ??namespace GFG { ??class PrintableForm:Form { ??????// Main Method ????public static void Main() ????{ ????????Application.Run(new PrintableForm()); ????} ??????public PrintableForm() ????{ ????????ResizeRedraw = true; ????} ??????protected override void OnPaint(PaintEventArgs pea) ????{ ????????// Defines the Pen ????????Pen pen = new Pen(ForeColor); ??????????// x1 = 30 ????????// y1 = 30 ????????// x2 = 200 ????????// y2 = 300 ??????????????????// using the Method ????????pea.Graphics.DrawLine(pen, 30.0F, 30.0F, 200.0f, 300.0f); ????} } }

輸出:

DrawLine(Pen, Point, Point)

此方法用于從指定的點集到指定的點集畫一條線。它需要一個Point變量,該變量由(x,y)點組成。

用法:

public void DrawLine (System.Drawing.Pen pen, System.Drawing.PointF pt1, System.Drawing.PointF pt2);

參數:

• pen:Pen確定線條的顏色,寬度和樣式。
• pt1:將(x,y)坐標定義為初始點的Point變量。
• pt2:將(x,y)坐標定義為最終點的Point變量。

異常:如果pen為null,則此方法將提供ArgumentNullException。

例:

// C# program to demonstrate the use of // DrawLine(Pen, Point, Point) Method using System; using System.Drawing; using System.Drawing.Printing; using System.Windows.Forms; ??namespace GFG { ??class PrintableForm:Form { ??????// Main Method ????public static void Main() ????{ ????????Application.Run(new PrintableForm()); ????} ??????public PrintableForm() ????{ ????????ResizeRedraw = true; ????} ??????protected override void OnPaint(PaintEventArgs pea) ????{ ????????// Defines pen ????????Pen pen = new Pen(ForeColor); ??????????// Defines the both points to connect ????????// pt1 is (30, 30) which represents (x1, y1) ????????Point pt1 = new Point(30, 30); ??????????// pt1 is (200, 300) which represents (x2, y2) ????????Point pt2 = new Point(200, 300); ??????????// Draws the line ????????pea.Graphics.DrawLine(pen, pt1, pt2); ????} } }

輸出: