/* Fourier.java -- a graph drawing program * * Copyright (C) 2009 Erica Asai * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Usage: java CountDown * */ import javax.swing.*; import java.awt.*; public class Fourier extends JPanel { double start=-Math.PI*3.0; double end=Math.PI*3.0; public void paint(Graphics g) { int w=getWidth(); int h=getHeight(); int yOffset=h/20; h-=yOffset*2; double min=0; double max=0; double value=0; for(int i=0;i<w;i++) { value=f(i); if(i==0) { min=value; max=value; } if(value<min) min=value; if(max<value) max=value; } double scaleX=(double)w/(end-start); double step=(end-start)/w; double scaleY=(double)h/(max-min); Point p0=new Point(-1,-1); Point p1=new Point(-1,-1); int y0=(int)(-min*scaleY)+yOffset; for(double i=start;i<end;i+=step) { p1.x=(int)((i-start)*scaleX); p1.y=(int)(-f(i)*scaleY+y0); if(0<p0.x) { g.drawLine(p0.x,p0.y,p1.x,p1.y); } p0.x=p1.x; p0.y=p1.y; } } public double f(double x) { double value=Math.sin(x); for(int i=3;i<700;i+=2) value+=Math.sin(i*x)/i; value*=4.0/Math.PI; return value; } }
/* Fourier.java -- a graph drawing program * * Copyright (C) 2009 Erica Asai * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * */ import javax.swing.*; import java.awt.*; public class FourierFrame extends JFrame { Fourier f=new Fourier(); FourierFrame() { getContentPane().add(f); setTitle("Fourier"); setSize(1000,800); setVisible(true); } public static void main(String args[]) { FourierFrame frame=new FourierFrame(); } }