Java画心形线
画出心形线,同时在左上角显示步长值和画图所用时间
import java.awt.*; import java.awt.event.*; import java.awt.image.*; import java.util.Random; import java.math.BigDecimal; import static java.lang.Math.*; public class Test{ long start = System.currentTimeMillis(); private Frame f = new Frame("心形线"); //画布大小 private final int SIZE=600; //重写paint() private MyCanvas area = new MyCanvas(); private BufferedImage image = new BufferedImage(SIZE,SIZE,BufferedImage.TYPE_INT_RGB); private Graphics g = image.getGraphics(); //循环步长 private final double STEP = 0.00001; private void init(){ area.setPreferredSize(new Dimension(SIZE,SIZE)); // 画白色背景 g.setColor(Color.white); g.fillRect(0, 0, SIZE, SIZE); // 画两条坐标轴 g.setColor(Color.black); g.drawLine(0,SIZE/2,SIZE,SIZE/2); g.drawLine(SIZE/2,0,SIZE/2,SIZE); //计算坐标 //新坐标 int x1, y1,x2, y2; for (double t = -Math.PI; t < Math.PI; t = t + STEP){ g.setColor(Color.black); x1 = axisSystem(axisX(t)); y1 = axisSystem(axisY(t)); x2 = axisSystem(axisX(t+STEP)); y2 = axisSystem(axisY(t+STEP)); //原曲线是横向的,为求美观调整了输出把它画成纵向,若画其他函数须修改 //g.drawLine(x1, y1, x2, y2); g.drawLine(y1, SIZE-x1, y2, SIZE-x2); } //关闭窗口 f.addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e){ System.exit(0); } }); long end = System.currentTimeMillis(); g.setColor(Color.red); g.setFont(new Font("Times", Font.BOLD,15)); g.drawString("步长值:" + BigDecimal.valueOf(STEP) , 20, 30); g.drawString("画图所用时间:" + (end - start) + "毫秒", 20, 50); area.repaint(); f.add(area); f.pack(); f.setVisible(true); } //根据t算出对应的心形线新坐标X值,若画其他函数须修改 private double axisX(double t){ return 2*cos(t) - cos(2*t); } //根据t算出对应的心形线新坐标Y值,若画其他函数须修改 private double axisY(double t){ return 2*sin(t) - sin(2*t); } //把新坐标换算成系统坐标,若画其他函数须修改 private int axisSystem(double d){ return (int)((0.5+d/8)*SIZE); } private class MyCanvas extends Canvas{ public void paint(Graphics g){ g.drawImage(image, 0, 0, null); } } public static void main(String[] args){ new Test().init(); } }
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