第十九章总结：Java绘图

news2024/12/24 3:09:06

19.1：Java绘图类

19.2：绘制图形

package nineteentn;
import java.awt.*;
import javax.swing.*;

public class DrawCircle extends JFrame {
	private final int OVAL_WIDTH = 80; // 圆形的宽
	private final int OVAL_HEIGHT = 80; // 圆形的高

	public DrawCircle() {
		initialize(); // 调用初始化方法
	}

	private void initialize() {// 初始化方法
		setSize(300, 200); // 设置窗体大小
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 设置窗体关闭模式
		setContentPane(new DrawPanel()); // 设置窗体面板为绘图面板对象
		setTitle("绘图实例1"); // 设置窗体标题
	}

	class DrawPanel extends JPanel {// 创建绘图面板
		public void paint(Graphics g) {// 重写绘制方法
			g.drawOval(10, 10, OVAL_WIDTH, OVAL_HEIGHT); // 绘制第1个圆形
			g.drawOval(80, 10, OVAL_WIDTH, OVAL_HEIGHT); // 绘制第2个圆形
			g.drawOval(150, 10, OVAL_WIDTH, OVAL_HEIGHT); // 绘制第3个圆形
			g.drawOval(50, 70, OVAL_WIDTH, OVAL_HEIGHT); // 绘制第4个圆形
			g.drawOval(120, 70, OVAL_WIDTH, OVAL_HEIGHT); // 绘制第5个圆形
		}
	}

	public static void main(String[] args) {
		new DrawCircle().setVisible(true);
	}
}//例题19.1


import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;

public class DrawFrame extends JFrame {
	public DrawFrame() {
		setTitle("绘图实例2"); // 设置窗体标题
		setSize(300, 200); // 设置窗体大小
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 设置窗体关闭模式
		add(new CanvasPanel()); // 设置窗体面板为绘图面板对象

	}

	class CanvasPanel extends JPanel {// 绘图变慢
		public void paint(Graphics g) {
			Graphics2D g2 = (Graphics2D) g;
			Shape[] shapes = new Shape[4]; // 声明图形数组
			shapes[0] = new Ellipse2D.Double(5, 5, 100, 100); // 创建圆形对象
			shapes[1] = new Rectangle2D.Double(110, 5, 100, 100); // 创建矩形对象

			shapes[2] = new Rectangle2D.Double(15, 15, 80, 80); // 创建矩形对象
			shapes[3] = new Ellipse2D.Double(120, 15, 80, 80); // 创建圆形对象
			for (Shape shape : shapes) { // 遍历图形数组
				Rectangle2D bounds = shape.getBounds2D();
				if (bounds.getWidth() == 80)
					g2.fill(shape); // 填充图形
				else
					g2.draw(shape); // 绘制图形
			}
		}
	}

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

//例题19.2

19.3：绘图颜色与画笔属性

19.3.1：绘制颜色

	if (bounds.getWidth() == 80){//小的是实心的，大的是空心的
					Color c = new Color(255,0,0);//设置颜色
					g2.setColor(c);
					g2.fill(shape);//填充变颜色
					g2.fill(shape); // 填充图形
				}else {
					Color c = new Color(0,0,255);//让线条变颜色
					g2.setColor(c);
					g2.draw(shape); // 绘制图形
				
				}