第十九章总结：Java绘图

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elseg2.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}