绘制正弦和余弦函数

我目前在做作业方面遇到了一些问题。

这是练习：

（绘制正弦和余弦函数）编写一个程序，用红色绘制正弦函数，用蓝色绘制余弦函数。

提示： Pi的Unicode是\ u03c0 。 要显示-2Pi，请使用g.drawString（“ – 2 \ u03c0”，x，y）。 对于像sin（x）这样的三角函数，x是弧度。 使用以下循环将点添加到多边形p

for (int x = -170; x <= 170; x++) { p.addPoint(x + 200, 100 - (int)(50 * Math.sin((x / 100.0) * 2 * Math.PI))); 

-2Pi为（ 100,100 ），轴的中心为（200,100），2Pi为（300,100）使用Graphics类中的drawPolyline方法连接点。

好吧，所以我所拥有的sin函数与练习中的函数略有不同，但是它起作用所以它应该不是问题。 另一方面，余弦函数，我很难找到它的代码所以我没有在我的程序中。

我还需要做的是将-Pi和Pi放在他们可敬的地方的图表上。

所以，这是代码。

 import java.awt.BorderLayout; import java.awt.Graphics; import java.awt.Polygon; import javax.swing.JFrame; import javax.swing.JPanel; public class Exercise13_12 extends JFrame { public Exercise13_12() { setLayout(new BorderLayout()); add(new DrawSine(), BorderLayout.CENTER); } public static void main(String[] args) { Exercise13_12 frame = new Exercise13_12(); frame.setSize(400, 300); frame.setTitle("Exercise13_12"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocationRelativeTo(null); frame.setVisible(true); } class DrawSine extends JPanel { double f(double x) { return Math.sin(x); } double g(double y) { return Math.cos(y); } protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawLine(10, 100, 380, 100); g.drawLine(200, 30, 200, 190); g.drawLine(380, 100, 370, 90); g.drawLine(380, 100, 370, 110); g.drawLine(200, 30, 190, 40); g.drawLine(200, 30, 210, 40); g.drawString("X", 360, 80); g.drawString("Y", 220, 40); Polygon p = new Polygon(); for (int x = -170; x <= 170; x++) { p.addPoint(x + 200, 100 - (int) (50 * f((x / 100.0) * 2 * Math.PI))); } g.drawPolyline(p.xpoints, p.ypoints, p.npoints); g.drawString("-2\u03c0", 95, 115); g.drawString("2\u03c0", 305, 115); g.drawString("0", 200, 115); } } } 

如果有人有时间帮助我，我将非常感激。

Answer 1

尝试这个：

 import java.awt.BorderLayout; import java.awt.Graphics; import java.awt.Polygon; import java.awt.Color; import javax.swing.JFrame; import javax.swing.JPanel; public class Exercise13_12 extends JFrame { public Exercise13_12() { setLayout(new BorderLayout()); add(new DrawSine(), BorderLayout.CENTER); } public static void main(String[] args) { Exercise13_12 frame = new Exercise13_12(); frame.setSize(400, 300); frame.setTitle("Exercise13_12"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocationRelativeTo(null); frame.setVisible(true); } class DrawSine extends JPanel { double f(double x) { return Math.sin(x); } double gCos(double y) { return Math.cos(y); } protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawLine(10, 100, 380, 100); g.drawLine(200, 30, 200, 190); g.drawLine(380, 100, 370, 90); g.drawLine(380, 100, 370, 110); g.drawLine(200, 30, 190, 40); g.drawLine(200, 30, 210, 40); g.drawString("X", 360, 80); g.drawString("Y", 220, 40); Polygon p = new Polygon(); Polygon p2 = new Polygon(); for (int x = -170; x <= 170; x++) { p.addPoint(x + 200, 100 - (int) (50 * f((x / 100.0) * 2 * Math.PI))); } for (int x = -170; x <= 170; x++) { p2.addPoint(x + 200, 100 - (int) (50 * gCos((x / 100.0) * 2 * Math.PI))); } g.setColor(Color.red); g.drawPolyline(p.xpoints, p.ypoints, p.npoints); g.drawString("-2\u03c0", 95, 115); g.drawString("2\u03c0", 305, 115); g.drawString("0", 200, 115); g.setColor(Color.blue); g.drawPolyline(p2.xpoints, p2.ypoints, p2.npoints); } } } 

基本上它是相同的代码，但你需要一个新的多边形来绘制它。 然后我使用Graphics的setColor（）函数设置颜色。

Answer 2

您可以将它添加到paintComponent方法：

  //Draw pi and -pi g.drawString("-\u03c0", 147, 100); g.drawString("\u03c0", 253, 100); //Create a new polygon Polygon p2 = new Polygon(); //Add the points of the cosine for (int x = -170; x <= 170; x++) { p2.addPoint(x + 200, 100 - (int) (50 * g((x / 100.0) * 2 * Math.PI))); } //Draw the function g.drawPolyline(p2.xpoints, p2.ypoints, p2.npoints); 

有了它，您可以获得所需的结果。

Answer 3

好的，既然程序已经完成，我最终得到了这个 。

 import java.awt.BorderLayout; import java.awt.Graphics; import java.awt.Polygon; import java.awt.Color; import javax.swing.JFrame; import javax.swing.JPanel; public class Exercise13_12 extends JFrame { public Exercise13_12() { setLayout(new BorderLayout()); add(new DrawSine(), BorderLayout.CENTER); } public static void main(String[] args) { Exercise13_12 frame = new Exercise13_12(); frame.setSize(400, 300); frame.setTitle("Exercise13_12"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocationRelativeTo(null); frame.setVisible(true); } class DrawSine extends JPanel { double f(double x) { return Math.sin(x); } double gCos(double y) { return Math.cos(y); } protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawLine(10, 100, 380, 100); g.drawLine(200, 30, 200, 190); g.drawLine(380, 100, 370, 90); g.drawLine(380, 100, 370, 110); g.drawLine(200, 30, 190, 40); g.drawLine(200, 30, 210, 40); g.drawString("X", 360, 80); g.drawString("Y", 220, 40); Polygon p = new Polygon(); Polygon p2 = new Polygon(); for (int x = -170; x <= 170; x++) { p.addPoint(x + 200, 100 - (int) (50 * f((x / 100.0) * 2 * Math.PI))); } for (int x = -170; x <= 170; x++) { p2.addPoint(x + 200, 100 - (int) (50 * gCos((x / 100.0) * 2 * Math.PI))); } g.setColor(Color.red); g.drawPolyline(p.xpoints, p.ypoints, p.npoints); g.drawString("-2\u03c0", 95, 115); g.drawString("-\u03c0", 147, 115); g.drawString("\u03c0", 253, 115); g.drawString("2\u03c0", 305, 115); g.drawString("0", 200, 115); g.setColor(Color.blue); g.drawPolyline(p2.xpoints, p2.ypoints, p2.npoints); } } } 

对于任何可能在以后遇到同样问题的人。

并感谢各位帮助我的人，永远感激不尽。

Answer 4

看看这个 …..

 public class GuiBasicstest { /** * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic herei guiBasics gb = new guiBasics(); JFrame jf = new JFrame(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.setSize(500,500); jf.add(gb); jf.setVisible(true); } } ................................................................................ package guibasics; import java.awt.Graphics; import javax.swing.JPanel; /** * * @author ALI */ public class guiBasics extends JPanel{ //Graphics g = null; public void paintComponent(Graphics g){ //super.paintComponent(g); for(double i = 0; i<200;i++){ double y= Math.sin(i); draw(i,y,g); } } private void draw(double x , double y,Graphics g ){ double x1, y1; x+=10; y+=10; x*=10; y*=30; x1=x+1; y1=y+1; Double d = new Double(x); int a = d.intValue(); int b = (new Double(y)).intValue(); int c = (new Double(x1)).intValue(); int e = (new Double(y1)).intValue(); g.drawLine(a, b, c, e); } }