Java绘图-第19章
Java绘图-第19章
1.Java绘图类
1.1Graphics类
Graphics类是用于绘制图形的抽象类，它是java.awt包中的一部分。Graphics类提供了各种方法，可以在图形上绘制各种形状、文本和图像。这些方法包括画线、画矩形、画椭圆、画弧、绘制图像等。
1.2Graphics2D类
Graphics2D类是java.awt包中的一个子类，它扩展了Graphics类，提供了更多的绘图功能和灵活性。Graphics2D类支持更高级的绘图操作，包括渐变、缩放、旋转等。它是Java 2D API 的一部分，用于在二维平面上执行各种图形操作。
以下是一些Graphics2D类中常用的方法：
-
设置颜色：
void setColor(Color c) -
设置渐变：
void setPaint(GradientPaint paint) -
设置线条宽度：
void setStroke(Stroke s) -
绘制直线：
void drawLine(int x1, int y1, int x2, int y2) -
绘制形状：
void draw(Shape s) -
填充形状：
void fill(Shape s) -
设置字体：
void setFont(Font font) -
绘制字符串：
void drawString(String str, int x, int y) -
绘制图像：
boolean drawImage(Image img, int x, int y, ImageObserver observer) -
旋转：
void rotate(double theta, double x, double y) -
缩放：
void scale(double sx, double sy) -
平移：
void translate(double tx, double ty)
使用Graphics2D类的示例可以嵌入在paintComponent方法中，例如：
import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JPanel;
public class MyPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
// 设置抗锯齿
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// 绘制直线
g2d.drawLine(10, 10, 100, 100);
// 设置颜色
g2d.setColor(Color.BLUE);
// 绘制矩形
g2d.drawRect(120, 10, 80, 50);
// 设置渐变
GradientPaint gradient = new GradientPaint(200, 10, Color.RED, 300, 60, Color.YELLOW);
g2d.setPaint(gradient);
// 填充椭圆
g2d.fillOval(220, 10, 100, 60);
}
}
在这个示例中，我们创建了一个Graphics2D对象，启用了抗锯齿，并使用了一些Graphics2D的方法来绘制直线、矩形和填充椭圆。这只是Graphics2D类的一小部分功能，你可以根据需要探索更多的方法来满足你的绘图需求。
例题1-7
1.绘制奥运五环
2.绘制实心与空心的集合图形
3.在窗体中显示图片
4.通过滑动条改变图片大小
5.翻转图片
6.让图片围绕左上角点旋转
7.让照片变成向左倾斜的平行四边形形状
8.绘制文字钟表
1-7例题代码汇总
package nineteen;
import javax.swing.*;
import java.awt.*;
import java.awt.Graphics;
public class DrawCircle extends JFrame {
private final int OVAL_WIDTH=80;
private final int OVAL_HEIGHT=80;
public DrawCircle(){
initialize();
}
private void initialize(){
setSize(300,200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setContentPane(new DrawPanel());
setTitle("绘图实例1");
}
class DrawPanel extends JPanel{
public void paint(Graphics g){
g.drawOval(10,10,OVAL_WIDTH,OVAL_HEIGHT);
g.drawOval(80,10,OVAL_WIDTH,OVAL_HEIGHT);
g.drawOval(150,10,OVAL_WIDTH,OVAL_HEIGHT);
g.drawOval(50,70,OVAL_WIDTH,OVAL_HEIGHT);
g.drawOval(120,70,OVAL_WIDTH,OVAL_HEIGHT);
}
}
public static void main(String[] args){
new DrawCircle().setVisible(true);
}
}
package nineteen;
import javax.swing.*;
import java.awt.*;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
public class DrawFrame extends JFrame {
public DrawFrame(){
setTitle("绘图实例2");
setSize(300,200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(new CanvasPanel());
}
class CanvasPanel extends JPanel{
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D) g;
Shape[] shapes = new Shape[4];
shapes[0] = new Ellipse2D.Double(5,5,100,100);
shapes[1] = new Rectangle2D.Double(110,5,100,100);
shapes[2] = new Rectangle2D.Double(15,15,80,80);
shapes[3] = new Ellipse2D.Double(120,15,80,80);
for(Shape shape:shapes){
Rectangle2D bounds = shape.getBounds2D();
if(bounds.getWidth()==80) {
g2.fill(shape);
g.setColor(Color.BLUE);
}else g2.draw(shape);
}
}
}
public static void main(String[] args){
new DrawFrame().setVisible(true);
}
}
package nineteen;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.io.File;
import java.io.IOException;
public class DrawImage extends JFrame{
Image img;
public DrawImage(){
try{
img= ImageIO.read(new File("src/20220909223037.png"));
}catch(IOException e){
e.printStackTrace();
}
setSize(440,300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(new CanvasPanel());
setTitle("繪製圖片");
}
class CanvasPanel extends JPanel{
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D) g;
g2.drawImage(img,0,0,this);
}
}
public static void main(String[] args){
new DrawImage().setVisible(true);
}
}
package nineteen;
import java.awt.*;
import java.io.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;
public class ImageZoom extends JFrame {
Image img;
private int imgWidth,imgHeight;
private JSlider jSlider;
public ImageZoom() {
try {
img=ImageIO.read(new File("src/20220909223037.png"));//读取图片文件
}catch (IOException e) {
e.printStackTrace();
}
CanvasPanel canvas =new CanvasPanel();
jSlider = new JSlider();
jSlider.setMaximum(1000);
jSlider.setValue(100);
jSlider.setMaximum(1);
jSlider.addChangeListener(new ChangeListener(){
public void stateChanged(ChangeEvent e) {
canvas.repaint();
}
});
JPanel center =new JPanel();
center.setLayout(new BorderLayout());
center.add(jSlider,BorderLayout.SOUTH);
center.add(canvas,BorderLayout.CENTER);
setContentPane(center);
setBounds(100,100,800,600);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("绘制图片");
}
class CanvasPanel extends JPanel{
public void paint(Graphics g) {
int newW=0,newH =0;
imgWidth =img.getWidth(this);
imgHeight =img.getHeight(this);
float value =jSlider.getValue();
newW =(int)(imgWidth*value/10);
newH =(int)(imgHeight*value/10);
g.drawImage(img, 0, 0, newW, newH, this );
} }
public static void main(String[] args) {
new ImageZoom().setVisible(true);
}}
package nineteen;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import javax.imageio.*;
public class PartImage extends JFrame {
private Image img;
private int dx1,dy1,dx2,dy2;
private int sx1,sy1,sx2,sy2;
private int width=1920,height =1080;
private JButton vBtn=null;
private JButton hBtn=null;
private CanvasPanel canvasPanel =null;
public PartImage() {
try {
img=ImageIO.read(new File("src/20220909223037.png"));//读取图片文件
}catch (IOException e) {
e.printStackTrace();
}
dx2 =sx2 =width;
dy2 =sy2= height;
vBtn =new JButton("垂直");
hBtn =new JButton("水平");
JPanel bottom=new JPanel();
bottom.add(hBtn);
bottom.add(vBtn);
Container c=getContentPane();
c.add(bottom,BorderLayout.SOUTH);
canvasPanel =new CanvasPanel();
c.add(canvasPanel,BorderLayout.CENTER);
addListener();
setBounds(400,400,600,560);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("图片翻转");
}
private void addListener() {
vBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sy1=Math.abs(sy1-height);
sy2=Math.abs(sy2-height);
canvasPanel.repaint();
}
});
hBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sx1=Math.abs(sx1-width);
sx2=Math.abs(sx2-width);
canvasPanel.repaint();
}
});
}
class CanvasPanel extends JPanel{
public void paint(Graphics g) {
g.drawImage(img, dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, this);//绘制指定大小
}}
public static void main(String[] args) {
new PartImage().setVisible(true);
}}
package nineteen;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.io.File;
import java.io.IOException;
public class RotateImage extends JFrame {
private Image img;
public RotateImage(){
try{
img = ImageIO.read(new File("src/20220909223037.png"));
}catch (IOException e){
e.printStackTrace();
}
setBounds(100,100,400,350);
add(new CanvasPanel());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("图片旋转");
}
class CanvasPanel extends JPanel{
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D) g;
g2.rotate(Math.toRadians(5));
g2.drawImage(img,70,10,300,200,this);
g2.rotate(Math.toRadians(5));
g2.drawImage(img,70,10,300,200,this);
g2.rotate(Math.toRadians(5));
g2.drawImage(img,70,10,300,200,this);
}
}
public static void main(String[] args){
new RotateImage().setVisible(true);
}
}
package nineteen;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.io.File;
import java.io.IOException;
public class TiltImage extends JFrame {
private Image img;
public TiltImage(){
try{
img = ImageIO.read(new File("src/20220909223037.png"));
}catch(IOException e){
e.printStackTrace();
}
setBounds(100,100,400,300);
add(new CanvasPanel());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("图片倾斜");
}
class CanvasPanel extends JPanel{
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D)g;
g2.shear(0.3,0);
g2.drawImage(img,0,0,300,200,this);
}
}
public static void main(String[] args){
new TiltImage().setVisible(true);
}
}
package nineteen;
import javax.swing.*;
import java.awt.*;
import java.awt.geom.Rectangle2D;
import java.util.Date;
public class DrawString extends JFrame {
public DrawString(){
setSize(230,140);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(new CanvasPanel());
setTitle("绘图文本");
}
class CanvasPanel extends JPanel{
public void paint(Graphics g){
Graphics2D g2=(Graphics2D) g;
Rectangle2D rect = new Rectangle2D.Double(10,10,200,80);
Font font= new Font("宋体",Font.BOLD,16);
Date date = new Date();
g2.setColor(Color.CYAN);
g2.fill(rect);
g2.setColor(Color.BLUE);
g2.setFont(font);
g2.drawString(String.format("%tr",date),50,60);
}
}
public static void main(String[] args){
new DrawString().setVisible(true);
}
}