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一、概述

java繪圖的主要核心類
1、Graphics類，此類可以畫圖形，線條等，但是設定到變形等就不行了，由此衍生出更強大的類，Graphics2D
2、Graphics2D，更加強大的繪圖類

1、繪製基本圖形

繪圖方法

package com.test;

import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;

public class Test extends JFrame{
	public Test() {
		setBounds(500,300, 800, 500);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
		MyCanvas myCanvas = new MyCanvas();
		add(myCanvas);
	}
	public static void main(String[] args) {
		new Test();
	}
	private class MyCanvas extends Canvas{ //Canvas類，是畫布，我們沒有紙，只有筆，也沒辦法畫
		@Override
		public void paint(Graphics g) {
			// TODO Auto-generated method stub
			Graphics2D g2d = (Graphics2D)g;
			g2d.drawOval(5, 5, 100, 100);//畫圓
			g2d.drawRect(15,15,80,80);//畫矩形
			g2d.fillRect(45, 45,80,80);//填充矩形
			g2d.drawArc(320,25,100,50,270,200);//弧線
			g2d.drawLine(5,120,100,120);//直線
			g2d.drawRoundRect(102, 120, 100, 50, 10, 10);//圓角矩形
			
			//畫多邊形，第一個引數是橫座標陣列，第二個是縱座標陣列，第三個是有幾個點
			int x[]= {250,300,250,300};
			int y[]= {130,130,200,200};
			
//			g2d.drawPolygon(x, y, 4);
			
			//畫多邊線(測試多邊線需要註釋上面的程式碼，因為用的引數一樣重合了)
			
			g2d.drawPolyline(x, y, 4);
			//上面都是Graphics的方法，下面介紹2d是如何運作的
			
			Shape shape = new Rectangle2D.Double(110,5,100,100);
			
			g2d.draw(shape);
			g2d.fill(shape);
		}
	}
}

2、設定畫筆顏色

package com.test;

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;

public class Test extends JFrame{
	public Test() {
		setBounds(500,300, 800, 500);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
		MyCanvas myCanvas = new MyCanvas();
		add(myCanvas);
	}
	public static void main(String[] args) {
		new Test();
	}
	private class MyCanvas extends Canvas{
		@Override
		public void paint(Graphics g) {
			// TODO Auto-generated method stub
			Graphics2D g2d = (Graphics2D)g;
			g2d.fillRect(5,120,100,120);//直線
			Color blue =Color.BLUE;
			g2d.setColor(blue);
			g2d.fillRect(125,125,103,125);
		}
	}
}

3、設定畫筆（粗細）

package com.test;

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;

public class Test extends JFrame{
	public Test() {
		setBounds(500,300, 800, 500);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
		MyCanvas myCanvas = new MyCanvas();
		add(myCanvas);
	}
	public static void main(String[] args) {
		new Test();
	}
	private class MyCanvas extends Canvas{
		@Override
		public void paint(Graphics g) {
			// TODO Auto-generated method stub
			Graphics2D g2d = (Graphics2D)g;
			g2d.drawLine(5, 120, 100, 120);
			Stroke stroke = new BasicStroke(10);//1、建立畫筆物件
			g2d.setStroke(stroke);//2、設定畫筆
			g2d.drawLine(5, 150, 100, 150);//畫
		}
	}
}

4、畫一個房子

package com.test;

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.Rectangle2D;
import java.util.Random;

import javax.swing.JFrame;

public class Test extends JFrame{
	public Test() {
		setBounds(500,300, 800, 500);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		getContentPane().setBackground(new Color(78, 194, 207));
		setVisible(true);
		MyCanvas myCanvas = new MyCanvas();
		add(myCanvas);
	}
	public static void main(String[] args) {
		new Test();
	}
	private class MyCanvas extends Canvas{
		@Override
		public void paint(Graphics g) {
			// TODO Auto-generated method stub
			Graphics2D g2d = (Graphics2D)g;
			//雲
			g2d.setColor(Color.WHITE);
			g2d.fillOval(550, 2, 100, 50);
			g2d.fillOval(520, -3, 80, 50);
			g2d.fillOval(580, -5, 80, 50);
			//煙囪
			g2d.setColor(Color.BLACK);
			g2d.fillRect(250, 20, 30, 80);
			g2d.fillRect(650, 20, 30, 80);
			//房頂
			int x[] = {100,200,300};
			int y[] = {100,10,100};
			g2d.setColor(new Color(124,86,39));
			g2d.fillPolygon(x, y, 3);
			int x1[] = {500,600,700};
			int y1[] = {100,10,100};
			g2d.fillPolygon(x1, y1, 3);
			//屋子
			g2d.setColor(new Color(109,134,128));
			g2d.fillRect(120,100,160,100);
			g2d.fillRect(520,100,160,100);
			//窗戶和門
			g2d.setColor(Color.WHITE);
			g2d.fillRect(130,120,50,50);
			g2d.fillRect(220,120,50,80);
			g2d.fillRect(530,120,50,50);
			g2d.fillRect(620,120,50,80);
			//太陽
			g2d.setColor(Color.YELLOW);
			g2d.fillOval(740, -20, 50, 50);
			
			//路
			g2d.setColor(new Color(124,86,39));
			g2d.fillRect(0, 200, 800, 300);
			
			//石子
			g2d.setColor(Color.BLACK);
			g2d.fillOval(0, 205, 10, 20);
			Random r = new Random();
			int moveX = 0;
			int moveY = 0;
			for(int i = 0;i<=100;i++) {
				moveX = r.nextInt(800);
				moveY = r.nextInt(300)+200;
				g2d.fillOval(moveX, moveY, r.nextInt(10)+5,r.nextInt(15)+5);
			}
		}
	}
}