GDI繪圖

什麼是GDI+
GDI+ (Graphics Device Interface) 是一種繪圖裝置接口, 可將應用程序和繪圖硬件分隔, 讓咱們可以編寫與裝置無關的應用程序。它能夠讓咱們不需注意特定顯示裝置的詳細數據, 即可在屏幕或打印機顯示信息。咱們能夠呼叫 GDI+ 類別所提供的方法, 而後這些方法會適當地呼叫特定的裝置驅動程序, 而完成繪圖。並且與.NET進行了更好的融合。
GDI (Graphics Device Interface), 是屬於繪圖方面的 API (Application Programming Interface)。
由於應用程序不能直接控制硬件, 因此當咱們要進行繪圖的動做時, 必須透過 GDI 才能完成。

 

 

 

 

 

 

 

 

肯定座標系：1.肯定原點 2.肯定x，y軸和方向

Graphics提供了很是多的繪圖的方法能夠讓咱們進行繪製。
繪圖方法
Graphics 類別的經常使用繪圖方法有：
DrawLine(直線)、
DrawRectangle (矩形)、
DrawEllipse (橢圓)、
DrawCurve (曲線)、
DarwArc (弧線)、
DrawPie (扇形)、
DrawLines (多邊形)、
DrawPolygon (封閉多邊形)、
DrawBezier (貝茲曲線)等。

 

 

使用GDI繪製簡單的圖形

 

//繪製一條直線
        private void button1_Click(object sender, EventArgs e) { //建立GDI對象
            Graphics g = this.CreateGraphics();// new Graphics(); //建立畫筆對象
            Pen pen = new Pen(Brushes.Red); //建立兩個點
            Point p1 = new Point(30, 50); Point p2 = new Point(250, 250); g.DrawLine(pen, p1, p2); } //繪製一個矩形
        private void button2_Click(object sender, EventArgs e) { Graphics g = this.CreateGraphics(); Pen pen=new Pen(Brushes.Yellow); Size size=new System.Drawing.Size(80,80); Rectangle rec=new Rectangle(new Point(50,50),size); g.DrawRectangle(pen,rec); } //繪製一個扇形
        private void button3_Click(object sender, EventArgs e) { Graphics g = this.CreateGraphics(); Pen pen=new Pen(Brushes.Blue); Size size=new System.Drawing.Size(180,180); Rectangle rec=new Rectangle(new Point(150,150),size); g.DrawPie(pen, rec, 60, 60); } //繪製一個文本
        private void button4_Click(object sender, EventArgs e) { Graphics g = this.CreateGraphics(); g.DrawString("老趙是最帥的", new Font("宋體", 20, FontStyle.Underline), Brushes.Black, new Point(300, 300)); }

//實心畫圓

private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
        {
            Graphics g=e.Graphics;
            //定義實心填充畫筆
            SolidBrush myBrush=new SolidBrush(Color.Yellow);
            g.FillEllipse(myBrush,50,50,300,200);
            myBrush.Dispose();
            g.Dispose();
        }

 

生成驗證碼圖片實例

1.經過Random生成隨機數或字符及驗證碼
2.經過驗證碼內容長度生成指定大小的圖片
3.獲取生成圖片的Graphics對象
4.定義驗證碼字體格式
5.經過指定字體將驗證碼繪製到圖片
6.向圖片上添加背景噪音線
7.添加前景噪音點

 

Random r = new Random(); /// <summary>
        /// 點擊更換驗證碼 /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void pictureBox1_Click(object sender, EventArgs e) { //建立一張圖片對象
            Bitmap bmp = new Bitmap(120, 20); //存儲的就是驗證碼
            string str = string.Empty; for (int i = 0; i < 5; i++) { str += r.Next(0, 10); } //建立GDI+對象
            Graphics g = Graphics.FromImage(bmp); string[] fonts = { "微軟雅黑", "隸書", "宋體", "黑體", "仿宋" }; Color[] colors = { Color.Black, Color.Yellow, Color.Red, Color.Green, Color.Gold }; //開始繪製驗證碼
            for (int i = 0; i < str.Length; i++) { Point p = new Point(i * 20, 0); g.DrawString(str[i].ToString(), new Font(fonts[r.Next(0, 5)], 15, FontStyle.Bold), new SolidBrush(colors[r.Next(0, 5)]), p); } //給驗證碼圖片中繪製一些直線
            for (int i = 0; i < 20; i++) { Point p1 = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height)); Point p2 = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height)); g.DrawLine(new Pen(Brushes.Pink), p1, p2); } //給驗證碼添加像素顆粒
            for (int i = 0; i < 100; i++) { bmp.SetPixel(r.Next(0, bmp.Width), r.Next(0, bmp.Height), Color.Black); } //把建立的位圖對象放在pictureBox上
            pictureBox1.Image = bmp; }

 

神奇的參數

/// <summary>
        /// 
        /// </summary>
        /// <param name="sender">觸發這個事件的對象</param>
        /// <param name="e">關於事件的一些數據</param>
        private void Form1_MouseMove(object sender, MouseEventArgs e) { label1.Text = e.X + "," + e.Y; } private void Form1_KeyDown(object sender, KeyEventArgs e) { // e.KeyCode 獲取用戶按下了哪一個鍵 if (e.KeyCode == Keys.W || e.KeyCode == Keys.Up) { MessageBox.Show("前進！！！"); } else if (e.KeyCode == Keys.S || e.KeyCode == Keys.Down) { MessageBox.Show("後退"); } else if (e.KeyCode == Keys.A || e.KeyCode == Keys.Left) { MessageBox.Show("向左"); } else if (e.KeyCode == Keys.D || e.KeyCode == Keys.Right) { MessageBox.Show("向右"); } }

 

小坦克移動案例

 

using System; using System.Collections.Generic; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; using 小坦克移動.Properties; namespace 小坦克移動 { enum Direction { Up, Down, Left, Right } class Tank { //存儲圖片
        private Image[] imgs = { Resources.p1tankU, Resources.p1tankD, Resources.p1tankL, Resources.p1tankR }; //小坦克的X、Y座標
        public int X { get; set; } public int Y { get; set; } //定義4個方向
        public Direction Dir { get; set; } //定義坦克移動的速度
        public int Speed { get; set; } //定義坦克的構造函數
        public Tank(int x, int y, int speed, Direction dir) { this.X = x; this.Y = y; this.Speed = speed; this.Dir = dir; } //小坦克移動的行爲
        public void Move() { //根據方向 來判斷小坦克要改變的座標
            switch (this.Dir) { case Direction.Up: this.Y -= this.Speed; break; case Direction.Down: this.Y += this.Speed; break; case Direction.Left: this.X -= this.Speed; break; case Direction.Right: this.X += this.Speed; break; } //移動完成後 判斷小坦克是否超過了窗體
            if (this.X <= 0) { this.X = 0; } if (this.Y <= 0) { this.Y = 0; } if (this.X >= 700-80) { this.X = 620; } if (this.Y >= 600-100) { this.Y = 500; } } public void DrawTank(Graphics g) { switch (this.Dir) { case Direction.Up: g.DrawImage(imgs[0], this.X, this.Y); break; case Direction.Down: g.DrawImage(imgs[1], this.X, this.Y); break; case Direction.Left: g.DrawImage(imgs[2], this.X, this.Y); break; case Direction.Right: g.DrawImage(imgs[3], this.X, this.Y); break; } } public void TankKeyDown(KeyEventArgs e) { if (e.KeyCode == Keys.W || e.KeyCode == Keys.Up) { this.Dir = Direction.Up; } else if (e.KeyCode == Keys.S || e.KeyCode == Keys.Down) { this.Dir = Direction.Down; } else if (e.KeyCode == Keys.A || e.KeyCode == Keys.Left) { this.Dir = Direction.Left; } else if (e.KeyCode == Keys.D || e.KeyCode == Keys.Right) { this.Dir = Direction.Right; } this.Move();//讓坦克移動
 } } }

Tank Class

public partial class Form1 : Form { public Form1() { InitializeComponent(); } Tank tank; private void Form1_Load(object sender, EventArgs e) { //建立小坦克對象
            tank = new Tank(200, 200, 10, Direction.Up); //設置雙緩衝 減小屏幕閃爍
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.ResizeRedraw | ControlStyles.Selectable | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.SupportsTransparentBackColor, true); } private void Form1_Paint(object sender, PaintEventArgs e) { //在繪製窗體的時候 將坦克也繪製出來
 tank.DrawTank(e.Graphics); } private void Form1_KeyDown(object sender, KeyEventArgs e) { //獲取用戶按下了哪一個鍵盤
 tank.TankKeyDown(e); } private void timer1_Tick(object sender, EventArgs e) { //不停的執行Paint事件
            this.Invalidate(); } }

Form1