Java繪圖類

1.Graphics類
提供了繪圖常用的方法，利用這些方法可以實(shí)現(xiàn)直線，矩形，多邊形等文本，圖片的繪制其操作主要包括顏色，字體，畫筆，文本，圖像等

2.Graphics2D類
使用Graphics2D類可以實(shí)現(xiàn)更強(qiáng)的圖像繪制功能

3.將Graphics強(qiáng)制轉(zhuǎn)換成Graphics2D類：

public static void paint(Graphics g){Graphics2D g2 = (Graphics2D)g; }

繪制圖形

Graphics 類常用圖形繪制方法

方法說明

draw(int x,int y,int height,int startAngle,int arcAngle)	弧形
drawLine(int x1,int y1,int x2,int y2)	直線
drawOval(int x,int y,int width,int height)	橢圓
drawPolygon(int[] xPoints,int[] yPoints,int nPoints)	多邊形
drawPolyline(int[] xPoints,int[] yPoints,int nPoints)	多邊線
drawRect(int x,int y,int width,int height)	矩形
drawRoundRect(int x,int y,int width,int height,int arcWidth,int arcAngle)	圓角矩形
fillArc(int x,int y,int width,int height,int startAngle,int arcAngle)	實(shí)心弧形
fillOval(int x,int y,int width,int height)	實(shí)心橢圓
fillPolygon(int[] xPoints,int[] yPoints,int nPoints)	實(shí)心多邊形
fillRect(int x,int y,int width,int height)	實(shí)心矩形
fillRoundRect(int x,int y,int width,int height,int arcWidth,int arcHeight)	實(shí)心圓角矩形

當(dāng)我們要繪制圖形時(shí)，我們必須要進(jìn)行創(chuàng)建并初始化圖形類對(duì)象。這些圖形必須時(shí)Shape接口的實(shí)現(xiàn)類，然后使用Graphics2D類的draw方法進(jìn)行繪制，或者fill方法進(jìn)行填充。

語法：

draw(Shape form) fill(Shape form)

常用圖形類：
主函數(shù)：

public static void main(String[] args) {new G_1().setVisible(true);}

• Arc2D類：弧

Graphics2D g2d =(Graphics2D)g;Shape[] shapes = new Shape[3];shapes[0] = new Arc2D.Double(50,50,185,160,10,90,Arc2D.OPEN);//坐標(biāo)位置(50，50)，寬85，高60，起始角是5度，終止角是90度shapes[1] = new Arc2D.Double(150,150,185,160,10,90,Arc2D.CHORD);shapes[2] = new Arc2D.Double(200,300,185,160,10,90,Arc2D.PIE);for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.draw(shape);//繪制圖形} //Arc2D.OPEN、Arc2D.CHORD、Arc2D.PIE分別表示圓弧是開弧、弓弧和餅弧。

• CubicCurve2D類：立方曲線

class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;Shape[] shapes = new Shape[1];shapes[0] =new CubicCurve2D.Double(100,100,50,75,15,15,260,300);//參數(shù)分別表示坐標(biāo)起點(diǎn)，控制點(diǎn)1，控制點(diǎn)2，終點(diǎn)的坐標(biāo)for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.draw(shape);//繪制圖形}}}

• Ellipse2D類：橢圓

class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;Shape[] shapes = new Shape[1];shapes[0] = new Ellipse2D.Double(150,150,200,100);//參數(shù)表示起點(diǎn)，寬，高for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.draw(shape);//繪制圖形}}}

class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;Shape[] shapes = new Shape[1];shapes[0] = new Ellipse2D.Double(150,150,200,100);//參數(shù)表示起點(diǎn)，寬，高for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.draw(shape);//繪制圖形}}}

• Line2D類：線

class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;Shape[] shapes = new Shape[1];shapes[0] = new Line2D.Double(10,150,250,150);//參數(shù)表示起點(diǎn)和終點(diǎn)for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.draw(shape);//繪制圖形}}}

• Point2D類：點(diǎn)

• QuadCurve2D類：二次曲線

class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;Shape[] shapes = new Shape[1];shapes[0] = new QuadCurve2D.Double(100,100,10,150,250,300);//參數(shù)表示起點(diǎn),控制點(diǎn)，終點(diǎn)for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.draw(shape);//繪制圖形}}}

• Rectangle2D類：矩形
• RoundRectangle2D類：圓角矩形
  例子：

import javax.swing.*; import java.awt.*; import java.awt.geom.Ellipse2D; import java.awt.geom.Rectangle2D;public class G_1 extends JFrame {public G_1(){setTitle("繪圖實(shí)例");setSize(500,500);//設(shè)置窗體大小setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//設(shè)置窗體的關(guān)閉模式add(new CanvasPanel());//設(shè)置窗體畫板為繪圖畫板對(duì)象}class CanvasPanel extends JPanel{ //繪圖畫板public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;Shape[] shapes = new Shape[4];//聲明圖形數(shù)組shapes[0] = new Ellipse2D.Double(5,5,100,100);//創(chuàng)建圓形對(duì)象shapes[1] = new Rectangle2D.Double(110,5,160,40);//矩形shapes[2] = new Ellipse2D.Double(120,15,80,80);shapes[3] = new Rectangle2D.Double(35,15,80,80);for (Shape shape:shapes){//遍歷圖形數(shù)組Rectangle2D bounds = shape.getBounds2D();if (bounds.getWidth()==80){g2d.fill(shape);//填充}else {g2d.draw(shape);//繪制圖形}}}}public static void main(String[] args) {new G_1().setVisible(true);} }

程序展示：

繪圖顏色和畫筆屬性

1.設(shè)置顏色
語法：

Color col = new Color(int r,ing g,int b);//參數(shù)表示三原色 Color col = new Color(int rgb);//參數(shù)表示顏色值，是三原色的總和

在繪圖類中使用setColor方法快速設(shè)置顏色

g.setColor(Color.color)//注意是有.的

例子：

import javax.swing.*; import java.awt.*; import java.awt.geom.*;public class G_2 extends JFrame {public G_2(){setTitle("Graphics2D繪制測試");setSize(500,500);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new drawplace());}class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;g2d.setColor(Color.green);Shape[] shapes = new Shape[1];shapes[0] = new Ellipse2D.Double(150,150,200,200);for (Shape shape:shapes){//遍歷圖形數(shù)組g2d.fill(shape);g2d.draw(shape);//繪制圖形}}}public static void main(String[] args) {new G_2().setVisible(true);} }

程序展示：

設(shè)置畫筆
語法：

Stroke st = new BasicStroke(4); g2d.setStroke(st);

例子：

import javax.swing.*; import java.awt.*; import java.awt.geom.*;public class G_2 extends JFrame {public G_2(){setTitle("Graphics2D繪制測試");setSize(500,500);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new drawplace());}class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d =(Graphics2D)g;g2d.setColor(Color.green);Stroke st = new BasicStroke(15);g2d.setStroke(st);Shape[] shapes = new Shape[1];shapes[0] = new Ellipse2D.Double(150,150,200,200);for (Shape shape:shapes){//遍歷圖形數(shù)組//g2d.fill(shape);g2d.draw(shape);//繪制圖形}}}public static void main(String[] args) {new G_2().setVisible(true);} }

程序展示：

常用構(gòu)造方法：

• BasicStroke()
• BasicStroke(float width)
• BasicStroke(float width,int cap,int join)
• BasicStroke(float width,int cap,int join,float miterlimit)
• BasicStroke(float width,int cap,int join,float miterlimit,float[] dash,float dash_phase)

BasicStroke類構(gòu)造方法的參數(shù)說明

參數(shù)說明

width	畫筆寬度默認(rèn)為1px
cap	線端點(diǎn)裝飾
join	應(yīng)用在路徑線段交匯處的裝飾
miterlimit	斜接處的剪裁限制，參數(shù)必須大于等于1.0f
dash	表示虛線模式的數(shù)組
dash_phase	開始虛線模式的偏移量

cap參數(shù)的三個(gè)常量：

CAP_BUTT：末端圓滑

CAP_ROUND：末端平整

CAP_SQUARE：末端設(shè)置以線段寬度為邊長的方形

join參數(shù)的三個(gè)常量：

JOIN_BEVEL：平角

JOIN_MITER：尖角

JOIN_ROUND：圓角

繪制文本

1.設(shè)置字體
可以設(shè)置名稱，樣式，字體大小
語法：

Font f = new Font("方正舒體",Font.BOLD,25); g2d.setFont(f);

Font類的常量：

PLAIN：普通

BOLD：加粗

ITALIC：斜體

ITALIC|BOLD：斜體加粗

例子：

import javax.swing.*; import java.awt.*;public class G_3 extends JFrame {public G_3(){setTitle("font_test");setSize(400,400);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new drawplace());}class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;Font f = new Font("方正舒體",Font.BOLD,25);g2d.setFont(f);g2d.drawString("文字：方正舒體",100,100);}}public static void main(String[] args) {new G_3().setVisible(true);} }

程序展示：

例子：

import javax.swing.*; import java.awt.*; import java.util.Date;public class G_3 extends JFrame {public G_3(){setTitle("font_test");setSize(400,400);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new drawplace());}class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;Date time = new Date();Font f = new Font("方正舒體",Font.BOLD,25);g2d.setColor(Color.RED);g2d.setFont(f);g2d.drawString("現(xiàn)在是：",50,100);g2d.drawString(String.format("%tr",time),100,200);}}public static void main(String[] args) {new G_3().setVisible(true);} }

程序展示：

顯示圖片

使用drawImage方法將圖片顯示到繪圖中
語法：

drawImage(Image img,int x,int y,ImageObserver observer)

參數(shù)表示要顯示的圖片對(duì)象，坐標(biāo)，要通知的圖像觀察者
例子:

import javax.imageio.ImageIO; import javax.swing.*; import java.awt.*; import java.io.File; import java.io.IOException;public class show_photos extends JFrame {Image img;public show_photos(){try{img = ImageIO.read(new File("D:\\work\\累.png"));}catch(IOException e){e.printStackTrace();}setTitle("show_photos");setSize(916,525);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new drawplace());}class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;g2d.drawImage(img,0,0,this);}}public static void main(String[] args) {new show_photos().setVisible(true);} }

程序展示：

圖像處理

1.放大和縮小
依然使用drawImage方法語法：

drawImage(Image img,int x,int y,int width,int height,ImageObserver observer)

例子：

import javax.imageio.ImageIO; import javax.swing.*; import java.awt.*; import java.io.File; import java.io.IOException;public class show_photos extends JFrame {Image img;public show_photos(){try{img = ImageIO.read(new File("D:\\work\\累.png"));}catch(IOException e){e.printStackTrace();}setTitle("show_photos");setSize(916,525);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new drawplace());}class drawplace extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;g2d.drawImage(img,0,0,300,200,this);}}public static void main(String[] args) {new show_photos().setVisible(true);} }

程序展示：

例子（用劃片改變大小）：

import javax.imageio.ImageIO; import javax.swing.*; import javax.swing.event.ChangeEvent; import javax.swing.event.ChangeListener; import java.awt.*; import java.io.File; import java.io.IOException;public class show_p_change extends JFrame {Image img;int imgwidth,imgheight;private JSlider js;public show_p_change(){try{img = ImageIO.read(new File("D:\\work\\累.png"));}catch(IOException e){e.printStackTrace();}showplace sp = new showplace();js = new JSlider();js.setMaximum(1500);js.setValue(50);js.setMinimum(10);js.addChangeListener(new ChangeListener() {@Overridepublic void stateChanged(ChangeEvent e) {sp.repaint();}});JPanel center = new JPanel();center.setLayout(new BorderLayout());center.add(js,BorderLayout.SOUTH);center.add(sp,BorderLayout.CENTER);setContentPane(center);setTitle("change_p_show");setBounds(100,100,800,600);//設(shè)置窗體大小和位置setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}class showplace extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;int n_w = 0,n_h = 0;imgwidth = img.getWidth(this);imgheight = img.getHeight(this);float value = js.getValue();n_w = (int)(imgwidth*value/100);n_h = (int)(imgheight*value/100);g2d.drawImage(img,0,0,n_w,n_h,this);}}public static void main(String[] args) {new show_p_change().setVisible(true);} }

程序展示：


圖像翻轉(zhuǎn)
語法：

drawImage(image img,int x1,int y1,int x2,int y2,int x3,int y3,int x4,int y4,ImageObserver observer)

參數(shù)說明：

參數(shù)說明

img	要繪制的對(duì)象
x1	目標(biāo)矩陣第一個(gè)坐標(biāo)的x位置
y1	目標(biāo)矩陣第一個(gè)坐標(biāo)的y位置
x2	目標(biāo)矩陣第二個(gè)坐標(biāo)的x位置
y2	目標(biāo)矩陣第二個(gè)坐標(biāo)的y位置
x3	源矩陣第一個(gè)坐標(biāo)的x位置
y3	源矩陣第一個(gè)坐標(biāo)的y位置
x4	源矩陣第二個(gè)坐標(biāo)的x位置
y4	源矩陣第二個(gè)坐標(biāo)的y位置
observer	要通知的圖像觀察者

例子：

import javax.imageio.ImageIO; import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import java.io.IOException;public class G_flip extends JFrame {Image img;int dx1,dy1,dx2,dy2;int sx1,sx2,sy1,sy2;int imgw= 800,imgh=500;//照片的寬高JButton vbtn = null;//垂直翻轉(zhuǎn)JButton hbtn = null;//水平翻轉(zhuǎn)Cpanel canvas = null;public G_flip(){try{img = ImageIO.read(new File("D:\\work\\累.png"));}catch(IOException e){e.printStackTrace();}dx2 = sx2 =imgw;dy2 = sy2 = imgh;vbtn = new JButton("垂直翻轉(zhuǎn)");hbtn = new JButton("水平翻轉(zhuǎn)");JPanel bottom = new JPanel();bottom.add(vbtn);bottom.add(hbtn);Container c = getContentPane();c.add(bottom,BorderLayout.SOUTH);canvas = new Cpanel();c.add(canvas,BorderLayout.CENTER);addL();setBounds(100,100,800,700);setTitle("圖像翻轉(zhuǎn)");setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}void addL(){vbtn.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {sy1 = Math.abs(sy1-imgh); //縱坐標(biāo)交換sy2 = Math.abs(sy2-imgh);canvas.repaint();}});hbtn.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {sx1 = Math.abs(sx1-imgw); //橫坐標(biāo)交換sx2 = Math.abs(sx2-imgw);canvas.repaint();}});}class Cpanel extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;g2d.drawImage(img,dx1,dy1,dx2,dy2,sx1,sy1,sx2,sy2,this);}}public static void main(String[] args) {new G_flip().setVisible(true);} }

程序展示：

圖像旋轉(zhuǎn)
使用Graphics2D中的rotate方法根據(jù)弧度旋轉(zhuǎn)圖像語法：

rotate(double 旋轉(zhuǎn)弧度)

我們可以使用Math類中的toRadians方法把旋轉(zhuǎn)角度轉(zhuǎn)化為弧度
例子：

import javax.imageio.ImageIO; import javax.swing.*; import java.awt.*; import java.io.File; import java.io.IOException;public class G_route extends JFrame {Image img;public G_route(){try{img = ImageIO.read(new File("D:\\work\\累.png"));}catch(IOException e){e.printStackTrace();}setBounds(100,100,800,800);setTitle("圖像旋轉(zhuǎn)");setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);add(new Cp());}class Cp extends JPanel{public void paint(Graphics g){Graphics2D g2d = (Graphics2D)g;g2d.rotate(Math.toRadians(10));g2d.drawImage(img,100,100,300,300,this);g2d.rotate(Math.toRadians(60));g2d.drawImage(img,300,-300,300,300,this);}}public static void main(String[] args) {new G_route().setVisible(true);} }

程序展示：

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