GDI+編程10個基本技巧

2010-08-28 10:49:44來源:西部e網(wǎng)作者:

創(chuàng)建繪圖表面


創(chuàng)建繪圖表面有兩種常用的方法。下面設法得到PictureBox的繪圖表面。


private void Form1_Load(object sender, System.EventArgs e)

{

//得到pictureBox1的繪圖表面

Graphics g = this.pictureBox1.CreateGraphics();

}


private void pictureBox1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)

{

//得到pictureBox1的繪圖表面

Graphics g = e.Graphics;

}


可以利用Graphics對象繪制出各種圖形圖案。控件的Paint事件和OnPaint方法都可以繪圖都是好時機。在OnPaint方法里繪制圖案一定從參數(shù)e里面得到Graphics屬性。下面是兩個例子。


protected override void OnPaint(PaintEventArgs e)

{

e.Graphics.Clear(Color.White);


float x, y, w, h;

x = this.Left+2;

y = this.Top+2;

w = this.Width-4;

h = this.Height-4;

Pen pen = new Pen(Color.Red, 2);

e.Graphics.DrawRectangle(pen, x, y, w, h);


base.OnPaint (e);

}


private void PictureBoxII_Resize(object sender, EventArgs e)

{

this.Invalidate();

}


private void button1_Click(object sender, System.EventArgs e)

{

this.pictureBoxII1.CreateGraphics().FillEllipse(

Brushes.Blue, 10, 20, 50, 100);

}


和文本有關的三個類:


FontFamily——定義有著相似的基本設計但在形式上有某些差異的一組字樣。無法繼承此類。

Font——定義特定的文本格式,包括字體、字號和字形屬性。無法繼承此類。

StringFormat——封裝文本布局信息(如對齊方式和行距),顯示操作(如省略號插入和國家標準 (National) 數(shù)字位替換)和 OpenType 功能。無法繼承此類。


下面的程序顯示了一段文字。


private void button2_Click(object sender, System.EventArgs e)

{

Graphics g = this.pictureBoxII1.CreateGraphics();

g.FillRectangle(Brushes.White, this.pictureBoxII1.ClientRectangle);


string s = "aaaaaaaaaaaaaaaaaaaaaaaaaa";

FontFamily fm = new FontFamily("ËÎÌå");

Font f = new Font(fm, 20, FontStyle.Bold, GraphicsUnit.Point);

RectangleF rectF = new RectangleF(30, 20, 180, 205);

StringFormat sf = new StringFormat();

SolidBrush sbrush = new SolidBrush(Color.FromArgb(255, 0, 0, 255));

sf.LineAlignment = StringAlignment.Center;

sf.FormatFlags = StringFormatFlags.DirectionVertical;

g.DrawString(s, f, sbrush, rectF, sf);

}


GDI+的路徑——GraphicsPath


GraphicsPath類提供了一系列屬性和方法,利用它可以獲取路徑上的關鍵點,可以添加直線段、圓等幾何元素?梢垣@得包圍矩形,進行拾取測試。這些功能都怎么用,要仔細看一下。


private void button3_Click(object sender, System.EventArgs e)

{

//繪圖表面

Graphics g = this.pictureBoxII1.CreateGraphics();

//填充成白色

g.FillRectangle(Brushes.White, this.ClientRectangle);


//弄一個繪圖路徑

GraphicsPath gp = new GraphicsPath();

//添加一些集合圖形

gp.AddEllipse(20, 20, 300, 200);

gp.AddPie(50, 100, 300, 100, 45, 200);

gp.AddRectangle(new Rectangle(100, 30, 100, 80));


//在繪圖表面上繪制繪圖路徑

g.DrawPath(Pens.Blue, gp);

//平移

g.TranslateTransform(200, 20);

//填充繪圖路徑

g.FillPath(Brushes.GreenYellow, gp);


gp.Dispose();

}


區(qū)域——Region


從已有的矩形和路徑可以創(chuàng)建Region。使用Graphics.FillRegion方法繪制Region。該類指示由矩形和由路徑構成的圖形形狀的內部。無法繼承此類。


漸變色填充


需要使用兩個刷子:

線性梯度刷子(LinearGradientBrush)

路徑梯度刷子(PathGuadientBrush)


private void button4_Click(object sender, System.EventArgs e)

{

//繪圖表面

Graphics g = this.pictureBoxII1.CreateGraphics();

g.FillRectangle(Brushes.White, this.pictureBoxII1.ClientRectangle);

//定義一個線性梯度刷子

LinearGradientBrush lgbrush =

new LinearGradientBrush(

new Point(0, 10),

new Point(150, 10),

Color.FromArgb(255, 0, 0),

Color.FromArgb(0, 255, 0));

Pen pen = new Pen(lgbrush);


//用線性筆刷梯度效果的筆繪制一條直線段并填充一個矩形

g.DrawLine(pen, 10, 130, 500, 130);

g.FillRectangle(lgbrush, 10, 150, 370, 30);


//定義路徑并添加一個橢圓

GraphicsPath gp = new GraphicsPath();

gp.AddEllipse(10, 10, 200, 100);

//用該路徑定義路徑梯度刷子

PathGradientBrush brush =

new PathGradientBrush(gp);

//顏色數(shù)組

Color[] colors = {

Color.FromArgb(255, 0, 0),

Color.FromArgb(100, 100, 100),

Color.FromArgb(0, 255, 0),

Color.FromArgb(0, 0, 255)};

//定義顏色漸變比率

float[] r = {0.0f, 0.3f, 0.6f, 1.0f};

ColorBlend blend = new ColorBlend();

blend.Colors = colors;

blend.Positions = r;

brush.InterpolationColors = blend;

//在橢圓外填充一個矩形

g.FillRectangle(brush, 0, 0, 210, 110);


//用添加了橢圓的路徑定義第二個路徑梯度刷子

GraphicsPath gp2 = new GraphicsPath();

gp2.AddEllipse(300, 0, 200, 100);

PathGradientBrush brush2 = new PathGradientBrush(gp2);

//設置中心點位置和顏色

brush2.CenterPoint = new PointF(450, 50);

brush2.CenterColor = Color.FromArgb(0, 255, 0);

//設置邊界顏色

Color[] color2 = {Color.FromArgb(255, 0, 0)};

brush2.SurroundColors = color2;

//用第二個梯度刷填充橢圓

g.FillEllipse(brush2, 300, 0, 200, 100);

}


GDI+的坐標系統(tǒng)


通用坐標系——用戶自定義坐標系。

頁面坐標系——虛擬坐標系。


設備坐標系——屏幕坐標系。


當頁面坐標系和設備坐標系的單位都是象素時,它們相同。


private void button10_Click(object sender, System.EventArgs e)

{

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

this.Draw(g);

}

private void Draw(Graphics g)

{

g.DrawLine(Pens.Black, 10, 10, 100, 100);

g.DrawEllipse(Pens.Black, 50, 50, 200, 100);

g.DrawArc(Pens.Black, 100, 10, 100, 100, 20, 160);

g.DrawRectangle(Pens.Green, 50, 200, 150, 100);

}


private void button5_Click(object sender, System.EventArgs e)

{

//左移

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.TranslateTransform(-50, 0);

this.Draw(g);

}


private void button6_Click(object sender, System.EventArgs e)

{

//右移

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.TranslateTransform(50, 0);

this.Draw(g);

}


private void button7_Click(object sender, System.EventArgs e)

{

//旋轉

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.RotateTransform(-30);

this.Draw(g);

}


private void button8_Click(object sender, System.EventArgs e)

{

//放大

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.ScaleTransform(1.2f, 1.2f);

this.Draw(g);

}


private void button9_Click(object sender, System.EventArgs e)

{

//縮小

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.ScaleTransform(0.8f, 0.8f);

this.Draw(g);

}


全局坐標——變換對于繪圖表面上的每個圖元都會產生影響。通常用于設定通用坐標系。


一下程序將原定移動到控件中心,并且Y軸正向朝上。


//先畫一個圓

Graphics g = e.Graphics;

g.FillRectangle(Brushes.White, this.ClientRectangle);

g.DrawEllipse(Pens.Black, -100, -100, 200, 200);


//使y軸正向朝上,必須做相對于x軸鏡像

//變換矩陣為[1,0,0,-1,0,0]

Matrix mat = new Matrix(1, 0, 0, -1, 0, 0);

g.Transform = mat;

Rectangle rect = this.ClientRectangle;

int w = rect.Width;

int h = rect.Height;

g.TranslateTransform(w/2, -h/2);


//以原點為中心,做一個半徑為100的圓

g.DrawEllipse(Pens.Red, -100, -100, 200, 200);


g.TranslateTransform(100, 100);

g.DrawEllipse(Pens.Green, -100, -100, 200, 200);

g.ScaleTransform(2, 2);

g.DrawEllipse(Pens.Blue, -100, -100, 200, 200);



局部坐標系——只對某些圖形進行變換,而其它圖形元素不變。


protected override void OnPaint(PaintEventArgs e)

{

Graphics g = e.Graphics;

//客戶區(qū)設置為白色

g.FillRectangle(Brushes.White, this.ClientRectangle);

//y軸朝上

Matrix mat = new Matrix(1, 0, 0, -1, 0, 0);

g.Transform = mat;

//移動坐標原點到窗體中心

Rectangle rect = this.ClientRectangle;

int w = rect.Width;

int h = rect.Height;

g.TranslateTransform(w/2, -h/2);

//在全局坐標下繪制橢圓

g.DrawEllipse(Pens.Red, -100, -100, 200, 200);

g.FillRectangle(Brushes.Black, -108, 0, 8, 8);

g.FillRectangle(Brushes.Black, 100, 0, 8, 8);

g.FillRectangle(Brushes.Black, 0, 100, 8, 8);

g.FillRectangle(Brushes.Black, 0, -108, 8, 8);


//創(chuàng)建一個橢圓然后在局部坐標系中進行變換

GraphicsPath gp = new GraphicsPath();

gp.AddEllipse(-100, -100, 200, 200);

Matrix mat2 = new Matrix();

//平移

mat2.Translate(150, 150);

//旋轉

mat2.Rotate(30);

gp.Transform(mat2);

g.DrawPath(Pens.Blue, gp);


PointF[] p = gp.PathPoints;

g.FillRectangle(Brushes.Black, p[0].X-2, p[0].Y+2, 4, 4);

g.FillRectangle(Brushes.Black, p[3].X-2, p[3].Y+2, 4, 4);

g.FillRectangle(Brushes.Black, p[6].X-4, p[6].Y-4, 4, 4);

g.FillRectangle(Brushes.Black, p[9].X-4, p[9].Y-4, 4, 4);


gp.Dispose();


//base.OnPaint (e);

}


Alpha混合


Color.FromArgb()A就是Alpha。Alpha的取值范圍從02550表示完全透明,255完全不透明。


當前色=前景色×alpha/255+背景色×255alpha/255


protected override void OnPaint(PaintEventArgs e)

{

Graphics g = e.Graphics;

//創(chuàng)建一個填充矩形

SolidBrush brush = new SolidBrush(Color.BlueViolet);

g.FillRectangle(brush, 180, 70, 200, 150);

//創(chuàng)建一個位圖,其中兩個位圖之間有透明效果

Bitmap bm1 = new Bitmap(200, 100);

Graphics bg1 = Graphics.FromImage(bm1);

SolidBrush redBrush =

new SolidBrush(Color.FromArgb(210, 255, 0, 0));

SolidBrush greenBrush =

new SolidBrush(Color.FromArgb(210, 0, 255, 0));

bg1.FillRectangle(redBrush, 0, 0, 150, 70);

bg1.FillRectangle(greenBrush, 30, 30, 150, 70);

g.DrawImage(bm1, 100, 100);

//創(chuàng)建一個位圖,其中兩個位圖之間沒有透明效果

Bitmap bm2 = new Bitmap(200, 100);

Graphics bg2 = Graphics.FromImage(bm2);

bg2.CompositingMode = CompositingMode.SourceCopy;

bg2.FillRectangle(redBrush, 0, 0, 150, 170);

bg2.FillRectangle(greenBrush, 30, 30, 150, 70);

g.CompositingQuality = CompositingQuality.GammaCorrected;

g.DrawImage(bm2, 300, 200);


//base.OnPaint (e);

}




反走樣


protected override void OnPaint(PaintEventArgs e)

{

Graphics g = e.Graphics;

//放大8

g.ScaleTransform(8, 8);

//沒有反走樣的圖形和文字

Draw(g);


//設置反走樣

g.SmoothingMode = SmoothingMode.AntiAlias;


//右移40

g.TranslateTransform(40, 0);

//再繪制就是反走樣之后的了

Draw(g);


//base.OnPaint (e);

}


private void Draw(Graphics g)

{

//繪制圖形和文字

g.DrawLine(Pens.Gray, 10, 10, 40, 20);

g.DrawEllipse(Pens.Gray, 20, 20, 30, 10);

string s = "反走樣測試";

Font font = new Font("宋體", 5);

SolidBrush brush = new SolidBrush(Color.Gray);


g.DrawString(s, font, brush, 10, 40);

}

完了。暫時先總結那么多。以后發(fā)現(xiàn)必要的可以再補充。

GDI+編程10個基本技巧


創(chuàng)建繪圖表面


創(chuàng)建繪圖表面有兩種常用的方法。下面設法得到PictureBox的繪圖表面。


private void Form1_Load(object sender, System.EventArgs e)

{

//得到pictureBox1的繪圖表面

Graphics g = this.pictureBox1.CreateGraphics();

}


private void pictureBox1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)

{

//得到pictureBox1的繪圖表面

Graphics g = e.Graphics;

}


可以利用Graphics對象繪制出各種圖形圖案?丶Paint事件和OnPaint方法都可以繪圖都是好時機。在OnPaint方法里繪制圖案一定從參數(shù)e里面得到Graphics屬性。下面是兩個例子。


protected override void OnPaint(PaintEventArgs e)

{

e.Graphics.Clear(Color.White);


float x, y, w, h;

x = this.Left+2;

y = this.Top+2;

w = this.Width-4;

h = this.Height-4;

Pen pen = new Pen(Color.Red, 2);

e.Graphics.DrawRectangle(pen, x, y, w, h);


base.OnPaint (e);

}


private void PictureBoxII_Resize(object sender, EventArgs e)

{

this.Invalidate();

}


private void button1_Click(object sender, System.EventArgs e)

{

this.pictureBoxII1.CreateGraphics().FillEllipse(

Brushes.Blue, 10, 20, 50, 100);

}


和文本有關的三個類:


FontFamily——定義有著相似的基本設計但在形式上有某些差異的一組字樣。無法繼承此類。

Font——定義特定的文本格式,包括字體、字號和字形屬性。無法繼承此類。

StringFormat——封裝文本布局信息(如對齊方式和行距),顯示操作(如省略號插入和國家標準 (National) 數(shù)字位替換)和 OpenType 功能。無法繼承此類。


下面的程序顯示了一段文字。


private void button2_Click(object sender, System.EventArgs e)

{

Graphics g = this.pictureBoxII1.CreateGraphics();

g.FillRectangle(Brushes.White, this.pictureBoxII1.ClientRectangle);


string s = "aaaaaaaaaaaaaaaaaaaaaaaaaa";

FontFamily fm = new FontFamily("ËÎÌå");

Font f = new Font(fm, 20, FontStyle.Bold, GraphicsUnit.Point);

RectangleF rectF = new RectangleF(30, 20, 180, 205);

StringFormat sf = new StringFormat();

SolidBrush sbrush = new SolidBrush(Color.FromArgb(255, 0, 0, 255));

sf.LineAlignment = StringAlignment.Center;

sf.FormatFlags = StringFormatFlags.DirectionVertical;

g.DrawString(s, f, sbrush, rectF, sf);

}


GDI+的路徑——GraphicsPath


GraphicsPath類提供了一系列屬性和方法,利用它可以獲取路徑上的關鍵點,可以添加直線段、圓等幾何元素。可以獲得包圍矩形,進行拾取測試。這些功能都怎么用,要仔細看一下。


private void button3_Click(object sender, System.EventArgs e)

{

//繪圖表面

Graphics g = this.pictureBoxII1.CreateGraphics();

//填充成白色

g.FillRectangle(Brushes.White, this.ClientRectangle);


//弄一個繪圖路徑

GraphicsPath gp = new GraphicsPath();

//添加一些集合圖形

gp.AddEllipse(20, 20, 300, 200);

gp.AddPie(50, 100, 300, 100, 45, 200);

gp.AddRectangle(new Rectangle(100, 30, 100, 80));


//在繪圖表面上繪制繪圖路徑

g.DrawPath(Pens.Blue, gp);

//平移

g.TranslateTransform(200, 20);

//填充繪圖路徑

g.FillPath(Brushes.GreenYellow, gp);


gp.Dispose();

}


區(qū)域——Region


從已有的矩形和路徑可以創(chuàng)建Region。使用Graphics.FillRegion方法繪制Region。該類指示由矩形和由路徑構成的圖形形狀的內部。無法繼承此類。


漸變色填充


需要使用兩個刷子:

線性梯度刷子(LinearGradientBrush)

路徑梯度刷子(PathGuadientBrush)


private void button4_Click(object sender, System.EventArgs e)

{

//繪圖表面

Graphics g = this.pictureBoxII1.CreateGraphics();

g.FillRectangle(Brushes.White, this.pictureBoxII1.ClientRectangle);

//定義一個線性梯度刷子

LinearGradientBrush lgbrush =

new LinearGradientBrush(

new Point(0, 10),

new Point(150, 10),

Color.FromArgb(255, 0, 0),

Color.FromArgb(0, 255, 0));

Pen pen = new Pen(lgbrush);


//用線性筆刷梯度效果的筆繪制一條直線段并填充一個矩形

g.DrawLine(pen, 10, 130, 500, 130);

g.FillRectangle(lgbrush, 10, 150, 370, 30);


//定義路徑并添加一個橢圓

GraphicsPath gp = new GraphicsPath();

gp.AddEllipse(10, 10, 200, 100);

//用該路徑定義路徑梯度刷子

PathGradientBrush brush =

new PathGradientBrush(gp);

//顏色數(shù)組

Color[] colors = {

Color.FromArgb(255, 0, 0),

Color.FromArgb(100, 100, 100),

Color.FromArgb(0, 255, 0),

Color.FromArgb(0, 0, 255)};

//定義顏色漸變比率

float[] r = {0.0f, 0.3f, 0.6f, 1.0f};

ColorBlend blend = new ColorBlend();

blend.Colors = colors;

blend.Positions = r;

brush.InterpolationColors = blend;

//在橢圓外填充一個矩形

g.FillRectangle(brush, 0, 0, 210, 110);


//用添加了橢圓的路徑定義第二個路徑梯度刷子

GraphicsPath gp2 = new GraphicsPath();

gp2.AddEllipse(300, 0, 200, 100);

PathGradientBrush brush2 = new PathGradientBrush(gp2);

//設置中心點位置和顏色

brush2.CenterPoint = new PointF(450, 50);

brush2.CenterColor = Color.FromArgb(0, 255, 0);

//設置邊界顏色

Color[] color2 = {Color.FromArgb(255, 0, 0)};

brush2.SurroundColors = color2;

//用第二個梯度刷填充橢圓

g.FillEllipse(brush2, 300, 0, 200, 100);

}


GDI+的坐標系統(tǒng)


通用坐標系——用戶自定義坐標系。

頁面坐標系——虛擬坐標系。


設備坐標系——屏幕坐標系。


當頁面坐標系和設備坐標系的單位都是象素時,它們相同。


private void button10_Click(object sender, System.EventArgs e)

{

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

this.Draw(g);

}

private void Draw(Graphics g)

{

g.DrawLine(Pens.Black, 10, 10, 100, 100);

g.DrawEllipse(Pens.Black, 50, 50, 200, 100);

g.DrawArc(Pens.Black, 100, 10, 100, 100, 20, 160);

g.DrawRectangle(Pens.Green, 50, 200, 150, 100);

}


private void button5_Click(object sender, System.EventArgs e)

{

//左移

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.TranslateTransform(-50, 0);

this.Draw(g);

}


private void button6_Click(object sender, System.EventArgs e)

{

//右移

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.TranslateTransform(50, 0);

this.Draw(g);

}


private void button7_Click(object sender, System.EventArgs e)

{

//旋轉

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.RotateTransform(-30);

this.Draw(g);

}


private void button8_Click(object sender, System.EventArgs e)

{

//放大

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.ScaleTransform(1.2f, 1.2f);

this.Draw(g);

}


private void button9_Click(object sender, System.EventArgs e)

{

//縮小

Graphics g = this.pictureBoxII1.CreateGraphics();

g.Clear(Color.White);

g.ScaleTransform(0.8f, 0.8f);

this.Draw(g);

}


全局坐標——變換對于繪圖表面上的每個圖元都會產生影響。通常用于設定通用坐標系。


一下程序將原定移動到控件中心,并且Y軸正向朝上。


//先畫一個圓

Graphics g = e.Graphics;

g.FillRectangle(Brushes.White, this.ClientRectangle);

g.DrawEllipse(Pens.Black, -100, -100, 200, 200);


//使y軸正向朝上,必須做相對于x軸鏡像

//變換矩陣為[1,0,0,-1,0,0]

Matrix mat = new Matrix(1, 0, 0, -1, 0, 0);

g.Transform = mat;

Rectangle rect = this.ClientRectangle;

int w = rect.Width;

int h = rect.Height;

g.TranslateTransform(w/2, -h/2);


//以原點為中心,做一個半徑為100的圓

g.DrawEllipse(Pens.Red, -100, -100, 200, 200);


g.TranslateTransform(100, 100);

g.DrawEllipse(Pens.Green, -100, -100, 200, 200);

g.ScaleTransform(2, 2);

g.DrawEllipse(Pens.Blue, -100, -100, 200, 200);



局部坐標系——只對某些圖形進行變換,而其它圖形元素不變。


protected override void OnPaint(PaintEventArgs e)

{

Graphics g = e.Graphics;

//客戶區(qū)設置為白色

g.FillRectangle(Brushes.White, this.ClientRectangle);

//y軸朝上

Matrix mat = new Matrix(1, 0, 0, -1, 0, 0);

g.Transform = mat;

//移動坐標原點到窗體中心

Rectangle rect = this.ClientRectangle;

int w = rect.Width;

int h = rect.Height;

g.TranslateTransform(w/2, -h/2);

//在全局坐標下繪制橢圓

g.DrawEllipse(Pens.Red, -100, -100, 200, 200);

g.FillRectangle(Brushes.Black, -108, 0, 8, 8);

g.FillRectangle(Brushes.Black, 100, 0, 8, 8);

g.FillRectangle(Brushes.Black, 0, 100, 8, 8);

g.FillRectangle(Brushes.Black, 0, -108, 8, 8);


//創(chuàng)建一個橢圓然后在局部坐標系中進行變換

GraphicsPath gp = new GraphicsPath();

gp.AddEllipse(-100, -100, 200, 200);

Matrix mat2 = new Matrix();

//平移

mat2.Translate(150, 150);

//旋轉

mat2.Rotate(30);

gp.Transform(mat2);

g.DrawPath(Pens.Blue, gp);


PointF[] p = gp.PathPoints;

g.FillRectangle(Brushes.Black, p[0].X-2, p[0].Y+2, 4, 4);

g.FillRectangle(Brushes.Black, p[3].X-2, p[3].Y+2, 4, 4);

g.FillRectangle(Brushes.Black, p[6].X-4, p[6].Y-4, 4, 4);

g.FillRectangle(Brushes.Black, p[9].X-4, p[9].Y-4, 4, 4);


gp.Dispose();


//base.OnPaint (e);

}


Alpha混合


Color.FromArgb()A就是Alpha。Alpha的取值范圍從02550表示完全透明,255完全不透明。


當前色=前景色×alpha/255+背景色×255alpha/255


protected override void OnPaint(PaintEventArgs e)

{

Graphics g = e.Graphics;

//創(chuàng)建一個填充矩形

SolidBrush brush = new SolidBrush(Color.BlueViolet);

g.FillRectangle(brush, 180, 70, 200, 150);

//創(chuàng)建一個位圖,其中兩個位圖之間有透明效果

Bitmap bm1 = new Bitmap(200, 100);

Graphics bg1 = Graphics.FromImage(bm1);

SolidBrush redBrush =

new SolidBrush(Color.FromArgb(210, 255, 0, 0));

SolidBrush greenBrush =

new SolidBrush(Color.FromArgb(210, 0, 255, 0));

bg1.FillRectangle(redBrush, 0, 0, 150, 70);

bg1.FillRectangle(greenBrush, 30, 30, 150, 70);

g.DrawImage(bm1, 100, 100);

//創(chuàng)建一個位圖,其中兩個位圖之間沒有透明效果

Bitmap bm2 = new Bitmap(200, 100);

Graphics bg2 = Graphics.FromImage(bm2);

bg2.CompositingMode = CompositingMode.SourceCopy;

bg2.FillRectangle(redBrush, 0, 0, 150, 170);

bg2.FillRectangle(greenBrush, 30, 30, 150, 70);

g.CompositingQuality = CompositingQuality.GammaCorrected;

g.DrawImage(bm2, 300, 200);


//base.OnPaint (e);

}

反走樣


protected override void OnPaint(PaintEventArgs e)

{

Graphics g = e.Graphics;

//放大8

g.ScaleTransform(8, 8);

//沒有反走樣的圖形和文字

Draw(g);


//設置反走樣

g.SmoothingMode = SmoothingMode.AntiAlias;


//右移40

g.TranslateTransform(40, 0);

//再繪制就是反走樣之后的了

Draw(g);


//base.OnPaint (e);

}


private void Draw(Graphics g)

{

//繪制圖形和文字

g.DrawLine(Pens.Gray, 10, 10, 40, 20);

g.DrawEllipse(Pens.Gray, 20, 20, 30, 10);

string s = "反走樣測試";

Font font = new Font("宋體", 5);

SolidBrush brush = new SolidBrush(Color.Gray);


g.DrawString(s, font, brush, 10, 40);

}

完了。暫時先總結那么多。

關鍵詞:C#

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