图形图像编程

1.1 GDI+概述

1.1.1 Graphics类

Graphics类包含在System.Drawing名称空间下。要进行图形处理，必须首先创建Graphics对象，然后才能利用它进行各种图画操作。创建Graphics对象的形式有：

1．在窗体或控件的Paint事件中直接引用Graphics对象。

Private void Form_Paint(object sender,System.Windows.Forms.PaintEventArgs e)

{

Grahpics g=e.Graphics;

}

2．从当前窗体获取对Graphics对象的引用。

Graphics g=this.CreateGraphics();

3．从继承自图像的任何对象创建Graphics对象。

Bitmap bitmap=new Bitmap(@”C:\test\a1.bmp”);

Graphics g=Graphics.FromImage(bitmap);

1.1.2 颜色

1．使用FromArgh制定任意颜色。

这个方法有两种常用的形式，第一种形式是指定3种颜色，方法原型为：

Public static Color FromArgb(int red,int green,int blue)

第二种形式使用4格参数，格式为：

public static Color FromArgb(int alpha,int red,int green,int blue)

2．使用系统预定义颜色。

实际上，在Color结构中已经定义了141中颜色，可以直接使用。

Color myColor;

myColor=Color.Red;

1.1.3 笔和画刷

1．笔（Pen）

Pen myPen = new Pen(Color.Black);//创建一支黑色笔，宽度默认为1个像素

Pen myPen = new Pen(Color.Black, 5);//创建一支宽度为5个像素的黑色笔

SolidBrush myBrush = new SolidBrush(Color.Red);//实心画刷，默认宽度为1个像素

Pen myPen = new Pen(myBrush);//从现有画刷创建红色笔

Pen myPen = new Pen(myBrush, 5);//从现有画刷创建宽度为5个像素的红色笔

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen pen = new Pen(Color.Blue, 10.5f);//构造一支宽度为10.5个像素的红色笔

g.DrawString("蓝色，宽度为10.5", this.Font, new SolidBrush(Color.Black), 5,5);

g.DrawLine(pen, new Point(110, 10), new Point(380, 10));

pen.Width = 2;

pen.Color = Color.Red;

g.DrawString("红色，宽度为2", this.Font, new SolidBrush(Color.Black), 5, 25);

g.DrawLine(pen, new Point(110, 30), new Point(380, 30));

pen.StartCap = LineCap.Flat;

pen.EndCap = LineCap.ArrowAnchor;

pen.Width = 9;

g.DrawString("红色箭头线", this.Font, new SolidBrush(Color.Black), 5, 45);

g.DrawLine(pen, new Point(110, 50), new Point(380, 50));

pen.DashStyle = DashStyle.Custom;

pen.DashPattern = new float[] { 4, 4 };

pen.Width = 2;

pen.EndCap = LineCap.NoAnchor;

g.DrawString("自定义虚线", this.Font, new SolidBrush(Color.Black), 5, 65);

g.DrawLine(pen, new Point(110, 70), new Point(380, 70));

pen.DashStyle = DashStyle.Dot;

g.DrawString("点划线", this.Font, new SolidBrush(Color.Black), 5, 85);

g.DrawLine(pen, new Point(110, 90), new Point(380, 90));

}

2．画刷（Brush）

Brush类	说明
SolidBrush	画刷的简单形式，用纯色进行填充。
HatchBrush	类似于SilidBrush，但是可以利用该类从大量与设计的图案中选择绘制时要使用的图案，而不是纯色。
TexttureBrush	使用纹理（如图像）进行绘制。
LinearGradientBrush	使用混合渐变的两种颜色进行填充。
PathGradientBrush	基于编程者定义的唯一路径，使用复杂的混合渐变进行填充。

1．单色画刷演示：

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

SolidBrush myBrush = new SolidBrush(Color.Red);

g.FillEllipse(myBrush, this.ClientRectangle);

}

2．填充简单图案演示

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

HatchBrush aHatchBrush = new HatchBrush(HatchStyle.Percent90, Color.Yellow, Color.Green);

g.FillEllipse(aHatchBrush, this.ClientRectangle);

}

3．创建TextureBrush掩饰

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

//根据文件名创建原始大小的bitmap对象

Bitmap bitmap = new Bitmap(@"\mm.jpg");

//将其缩放到当前窗体大小

bitmap = new Bitmap(bitmap, this.ClientRectangle.Size);

TextureBrush myBrush = new TextureBrush(bitmap);

g.FillEllipse(myBrush, this.ClientRectangle);

}

4．使用LinearGradientBrush演示

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

LinearGradientBrush myBrush = new LinearGradientBrush(this.ClientRectangle, Color.White, Color.Blue, LinearGradientMode.Vertical);

g.FillRectangle(myBrush, this.ClientRectangle);

}

5．使用PathGradientBrush演示路径和路径画刷的使用

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Point centerPoint = new Point(150, 100);

int R = 60;

GraphicsPath path = new GraphicsPath();

path.AddEllipse(centerPoint.X - R, centerPoint.Y - R, 2 * R, 2 * R);

PathGradientBrush brush = new PathGradientBrush(path);

//指定路径中心点

brush.CenterPoint = centerPoint;

//指定路径中心的颜色

brush.CenterColor = Color.Red;

//Color类型的数组指定与路径上每个顶点的颜色

brush.SurroundColors = new Color[] { Color.Plum };

g.FillEllipse(brush, centerPoint.X - R, centerPoint.Y - R, 2 * R, 2 * R);

centerPoint = new Point(350, 100);

R = 20;

path = new GraphicsPath();

path.AddEllipse(centerPoint.X - R, centerPoint.Y - R, 2 * R, 2 * R);

path.AddEllipse(centerPoint.X - 2*R, centerPoint.Y - 2*R, 4 * R, 4 * R);

path.AddEllipse(centerPoint.X - 3*R, centerPoint.Y - 3*R, 6 * R, 6 * R);

brush = new PathGradientBrush(path);

brush.CenterPoint = centerPoint;

brush.CenterColor = Color.Red;

brush.SurroundColors = new Color[] { Color.Black, Color.Blue, Color.Green };

g.FillPath(brush, path);

}

1.1.4 平移、旋转和缩放

1． public void TranslateTransform(float dx,float dy)

dx表示平移的x分量，dy表示平移y分量

2． public void RotateTransform(float angle)

angle表示旋转的角度

3． public void ScaleTransform(ffoat sx,float sy)

sx表示x方向的缩放比例，sy表示y方向的缩放比例

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

//椭圆透明度为80%

g.FillEllipse(new SolidBrush(Color.FromArgb(80, Color.Red)), 120, 30, 200, 100);

//顺时针旋转30度

g.RotateTransform(30.0f);

g.FillEllipse(new SolidBrush(Color.FromArgb(80, Color.Blue)), 120, 30, 200, 100);

//水平方向向右平移200个像素，垂直方向向上平移100个像素

g.TranslateTransform(200.0f, -100.0f);

g.FillEllipse(new SolidBrush(Color.FromArgb(50, Color.Green)), 120, 30, 200, 100);

//缩小到一半

g.ScaleTransform(0.5f, 0.5f);

g.FillEllipse(new SolidBrush(Color.FromArgb(100, Color.Red)), 120, 30, 200, 100);

}

1.2 绘制图形

1.2.1 直线

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen blackPen = new Pen(Color.Black, 3);

Point point1 = new Point(100, 100);

Point point2 = new Point(200, 100);

g.DrawLine(blackPen, point1, point2);

}

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen pen = new Pen(Color.Black, 3);

Point[] points =

{

new Point(10,10),

new Point(10,100),

new Point(200,50),

new Point(250,120)

};

g.DrawLines(pen, points);

}

1.2.2 矩形

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen pen = new Pen(Color.Black, 3);

Rectangle rect = new Rectangle(30, 30, 200, 100);

g.DrawRectangle(pen, rect);

}

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen pen = new Pen(Color.Red, 3);

Rectangle[] rects =

{

new Rectangle(0,0,100,200),

new Rectangle(100,200,250,50),

new Rectangle(300,0,50,100)

};

g.DrawRectangles(pen, rects);

}

1.2.3 多边形

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen pen = new Pen(Color.Red);

Point[] points =

{

new Point(50,50),

new Point(100,100),

new Point(75,150),

new Point(25,150),

new Point(0,100)

};

g.DrawPolygon(pen, points);

points = new Point[]

{

new Point(250,50),

new Point(300,100),

new Point(275,150),

new Point(225,150),

new Point(200,100)

};

g.FillPolygon(new SolidBrush(Color.Yellow), points);

}

1.2.4 曲线

private void Form1_Paint(object sender, PaintEventArgs e)

{

Pen redPen = new Pen(Color.Red, 3);

Pen greenPen = new Pen(Color.Green, 3);

Point[] curvePoints =

{

new Point(50,250),

new Point(100,25),

new Point(200,250),

new Point(250,50),

new Point(300,75),

new Point(350,200),

new Point(400,150)

};

e.Graphics.DrawLines(redPen, curvePoints);

e.Graphics.DrawCurve(greenPen, curvePoints);

}

private void Form1_Paint(object sender, PaintEventArgs e)

{

Pen redPen = new Pen(Color.Red, 3);

Pen greenPen = new Pen(Color.Green, 3);

Point[] curvePoints =

{

new Point(50,250),

new Point(100,25),

new Point(200,250),

new Point(250,50),

new Point(300,75),

new Point(350,200),

new Point(400,150)

};

e.Graphics.DrawLines(redPen, curvePoints);

e.Graphics.DrawClosedCurve(greenPen, curvePoints);

}

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

Pen redPen = new Pen(Color.Red, 3);

Pen greenPen=new Pen(Color.Green,3);

Point[] bezierPoints =

{

new Point(50,250),

new Point(100,25),

new Point(200,250),

new Point(250,50),

new Point(300,75),

new Point(350,200),

new Point(400,150)

};

g.DrawLines(greenPen, bezierPoints);

g.DrawBeziers(redPen, bezierPoints);

}

1.2.5 椭圆

private void Form1_Paint(object sender, PaintEventArgs e)

{

Pen redPen = new Pen(Color.Red, 3);

e.Graphics.DrawEllipse(redPen, 20, 20, 200, 200);

}

1.3 图像的显示与保存

1.3.1 显示图像

1．创建Bitmap对象

public Bitmap(string filename)

2． DrawInage方法

public void DrawImage(Image image,int x,int y,int width,int height)

private void button1_Click(object sender, EventArgs e)

{

OpenFileDialog file = new OpenFileDialog();

file.Filter = "*.jpg;*.bmp|*.jpg;*.bmp";

if (file.ShowDialog() == DialogResult.OK)

{

Bitmap bitmap = new Bitmap(file.FileName);

Graphics g = this.CreateGraphics();

g.DrawImage(bitmap, 3, 10, 200, 200);

g.DrawImage(bitmap, 250, 10, 50, 50);

g.DrawImage(bitmap, 350, 10, bitmap.Width / 2, bitmap.Height / 2);

//使用此类对象时，不要忘记及时释放占用的资源，否则将会严重影响系统的行能

bitmap.Dispose();

g.Dispose();

}

1.3.2 保存图像

private void button1_Click(object sender, EventArgs e)

{

Graphics g = this.CreateGraphics();

DrawMyImage(g);

g.Dispose();

}

private void button2_Click(object sender, EventArgs e)

{

//构造一个指定区域的空图像

Bitmap image = new Bitmap(this.Width, this.Height - 100);

//根据指定区域得到Graphics类

Graphics g = Graphics.FromImage(image);

//设置图像的背景色

g.Clear(this.BackColor);

//将图像画到Graphics对象中

DrawMyImage(g);

try

{

//保存画面到Graphics对象中的图形

image.Save(@"tu1.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);

g = this.CreateGraphics();

Rectangle rect = new Rectangle(0, 0, this.Width, this.Height - 100);

g.FillRectangle(new SolidBrush(this.BackColor), rect);

MessageBox.Show("保存成功！", "恭喜");

}

catch (Exception Err)

{

MessageBox.Show(Err.Message);

}

image.Dispose();

g.Dispose();

}

private void button3_Click(object sender, EventArgs e)

{

Rectangle rect = new Rectangle(0, 0, this.Width, this.Height - 100);

Graphics g = this.CreateGraphics();

Image image = Image.FromFile(@"tu1.jpg");

//将图像缩放为指定的大小显示

g.DrawImage(image, rect);

image.Dispose();

g.Dispose();

}

private void DrawMyImage(Graphics g)

{

Rectangle rect1 = new Rectangle(0, 0, this.Width / 4, this.Height - 100);

HatchBrush hatchBrush = new HatchBrush(HatchStyle.Shingle, Color.White, Color.Black);

g.FillEllipse(hatchBrush, rect1);

Rectangle rect2 = new Rectangle(this.Width / 4 + 50, 0, this.Width / 4, this.Height - 100);

hatchBrush = new HatchBrush(HatchStyle.WideUpwardDiagonal, Color.White, Color.Red);

g.FillRectangle(hatchBrush, rect2);

int x = this.Width - 50 - this.Width / 4;

Point[] points = new Point[]

{

new Point(x,10),

new Point(x+50,60),

new Point(x+150,10),

new Point(x+200,160),

new Point(x+150,260),

new Point(x+50,260),

new Point(x,160)

};

hatchBrush = new HatchBrush(HatchStyle.SmallConfetti, Color.White, Color.Red);

TextureBrush myBrush = new TextureBrush(new Bitmap(@"m23.jpg"));

g.FillClosedCurve(myBrush, points);

}

1.5 WEB应用程序中的图形图像操作

1.5.1 绘制图形

Default.aspx

</head>

 <br />

<asp:Button ID="Button1" runat="server" Text="贝塞尔曲线" OnClick="Button1_Click" />

</form>

</body>

</html>

protected void Button1_Click(object sender, EventArgs e)

{

this.IFRAME1.Attributes["src"] = "Default2.aspx";

}

Default2.aspx.cs

protected void Page_Load(object sender, EventArgs e)

{

if (!this.IsPostBack)

{

Pen blackPen = new Pen(Color.Red, 3);

Point[] bezierPoints =

{

new Point(50,100),

new Point(100,10),

new Point(150,290),

new Point(200,100),

new Point(250,10),

new Point(300,290),

new Point(350,100)

};

int width = 400;

int height = 300;

Bitmap bitmap = new Bitmap(width, height);

Graphics g = Graphics.FromImage(bitmap);

g.Clear(Color.White);

g.DrawBeziers(blackPen, bezierPoints);

Response.ContentType = "image/gif";

bitmap.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif);

}

1.5.2 Web图片浏览器

Default.aspx

</head>

<body>

<asp:Label ID="Label1" runat="server" Text="图片浏览器"></asp:Label><br />

<br />

<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="上一个" />

<asp:Button ID="ButtonPosition" runat="server" Text="ButtonPosition" />

<asp:Button ID="Button3" runat="server" OnClick="Button3_Click" Text="下一个" /></div>

</form>

</body>

</html>

protected void Page_Load(object sender, EventArgs e)

{

if (!this.IsPostBack)

{

Session["index"] = 1;

this.ButtonPosition.Text = "1 of 8";

Session["filename"] = Server.MapPath(".") + "\\t1.jpg";

this.IFRAME1.Attributes["src"] = "Default2.aspx";

}

protected void Button1_Click(object sender, EventArgs e)

{

int index = (int)Session["index"];

if (index > 1)

{

index--;

this.ButtonPosition.Text = index.ToString() + " of 8";

Session["index"] = index;

Session["filename"] = Server.MapPath(".") + @"\t" + index.ToString() + ".jpg";

this.IFRAME1.Attributes["src"] = "Default2.aspx";

}

protected void Button3_Click(object sender, EventArgs e)

{

int index = (int)Session["index"];

if (index < 8)

{

index++;

this.ButtonPosition.Text = index.ToString() + " of 8";

Session["index"] = index;

Session["filename"] = Server.MapPath(".") + @"\t" + index.ToString() + ".jpg";

this.IFRAME1.Attributes["src"] = "Default2.aspx";

}

Default2.aspx.cs

protected void Page_Load(object sender, EventArgs e)

{

if (!this.IsPostBack)

{

string filename = (string)Session["filename"];

Bitmap bitmap = new Bitmap(filename);

bitmap = new Bitmap(bitmap, 250, 200);

TextureBrush myBrush = new TextureBrush(bitmap);

bitmap = new Bitmap(250, 200);

Graphics g = Graphics.FromImage(bitmap);

g.Clear(Color.White);

g.FillEllipse(myBrush, 0, 0, 250, 200);

Response.ContentType = "image/gif";

bitmap.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif);

}

1.5.3 当窗体大小改变时如何使图形自动重画

private void Form1_Paint(object sender, PaintEventArgs e)

{

LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle, Color.Red, Color.Green, LinearGradientMode.Vertical);

e.Graphics.FillRectangle(brush, this.ClientRectangle);

}

private void Form1_Resize(object sender, EventArgs e)

{

this.Invalidate();

}

1.5.4 特殊效果文字

private void Form1_Paint(object sender, PaintEventArgs e)

{

Graphics g = e.Graphics;

string str = "旋转的文字";

for (int i = 0; i <= 360; i+=10)

{

g.TranslateTransform(150, 150);

g.RotateTransform(i);

g.DrawString(str, this.Font, new SolidBrush(Color.Red), 50, 0);

g.ResetTransform();

}

str = "阴影效果的文字";

g.DrawString(str, new Font("隶书", 35), Brushes.Blue, 250, 30);

g.DrawString(str, new Font("隶书", 35), new SolidBrush(Color.FromArgb(60, Color.Blue)), 255, 35);

str = "彩色效果的文字";

HatchBrush b = new HatchBrush(HatchStyle.Plaid, Color.Blue, Color.Red);

g.DrawString(str, new Font("黑体", 35), b, 255, 185);

}

posted @ 2006-10-19 11:49 '.Elvis.' 阅读(1289) 评论(0) 编辑收藏举报

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图形图像编程

公告

┏=想获得小成功,必须掌握足够的技巧.
=想获得大成功,必须掌握扎实的基础.
=想获得更高成就,实现更高理想,在前两者基础上,加上善于思考. ┓