Draw Your Own Contour Function
import java.awt.*;
import java.applet.*;
import graph.*;
/*
**************************************************************************
**
** Applet parse2d
**
**************************************************************************
** Copyright (C) 1995, 1996 Leigh Brookshaw
**
** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
**************************************************************************
*
* This applet uses the ParseFunction class to parse an input string
* and plot the result.
*
*************************************************************************/
public class parse2d extends Applet {
Contour graph = new Contour(); // Graph class to do the plotting
Axis xaxis;
Axis yaxis;
DataSet data;
TextField cinput = new TextField(4); // Number of contours
TextField xinput = new TextField(4); // X grid dimension
TextField yinput = new TextField(4); // Y grid dimension
TextField xmininput = new TextField(10); // Minimum x value input
TextField xmaxinput = new TextField(10); // Maximum x value input
TextField ymininput = new TextField(10); // Minimum y value input
TextField ymaxinput = new TextField(10); // Maximum y value input
TextField finput = new TextField(40); // Input for the function to plot
Button plot = new Button("Plot It!"); // Button to plot it.
public void init() {
Label title = new Label(
"Function Parsing & Contouring",Label.CENTER);
Panel panel = new Panel();
GridBagLayout gridbag = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
Font font = new Font("TimesRoman",Font.PLAIN,15);
title.setFont(new Font("TimesRoman",Font.PLAIN,25));
setLayout(new BorderLayout() );
add("North",title);
add("Center",panel);
finput.setText("x*y*(sin(x)/x+sin(y)/y)");
cinput.setText("20");
xinput.setText("50");
yinput.setText("50");
xmininput.setText("-10");
xmaxinput.setText("10");
ymininput.setText("-10");
ymaxinput.setText("10");
panel.setLayout(gridbag);
/*
** create labels for all the text input fields
*/
Label clabel = new Label("Number of Contours");
Label xlabel = new Label("X grid dimension");
Label ylabel = new Label("Y grid dimension");
Label xminlabel = new Label("Minimum x Value");
Label xmaxlabel = new Label("Maximum x Value");
Label yminlabel = new Label("Minimum y Value");
Label ymaxlabel = new Label("Maximum y Value");
Label flabel = new Label("Function");
/*
** Set the fonts and colors to use
*/
clabel.setFont(font);
xlabel.setFont(font);
ylabel.setFont(font);
flabel.setFont(font);
xminlabel.setFont(font);
xmaxlabel.setFont(font);
yminlabel.setFont(font);
ymaxlabel.setFont(font);
cinput.setFont(font);
cinput.setBackground(Color.lightGray);
xinput.setFont(font);
xinput.setBackground(Color.lightGray);
yinput.setFont(font);
yinput.setBackground(Color.lightGray);
finput.setFont(font);
finput.setBackground(Color.lightGray);
xmininput.setFont(font);
xmininput.setBackground(Color.lightGray);
xmaxinput.setFont(font);
xmaxinput.setBackground(Color.lightGray);
ymininput.setFont(font);
ymininput.setBackground(Color.lightGray);
ymaxinput.setFont(font);
ymaxinput.setBackground(Color.lightGray);
plot.setFont(font);
plot.setBackground(Color.green);
/*
** First row of the GridBag contains the plot
*/
c.weightx = 1.0;
c.weighty = 1.0;
c.gridwidth = 4;
c.gridwidth=GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.BOTH;
gridbag.setConstraints(graph,c);
/*
** Second row of the gridBag contains the function input and the
** plotit button
*/
c.fill = GridBagConstraints.NONE;
c.weightx=0.0;
c.weighty=0.0;
c.gridheight=1;
c.gridwidth=1;
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(flabel,c);
c.anchor = GridBagConstraints.CENTER;
c.gridwidth=GridBagConstraints.RELATIVE;
c.fill = GridBagConstraints.HORIZONTAL;
gridbag.setConstraints(finput,c);
c.fill = GridBagConstraints.NONE;
c.gridwidth=GridBagConstraints.REMAINDER;
gridbag.setConstraints(plot,c);
/*
** Third row contains only the Number of contours
*/
c.gridwidth=2;
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(clabel,c);
c.anchor = GridBagConstraints.WEST;
c.gridwidth=GridBagConstraints.REMAINDER;
gridbag.setConstraints(cinput,c);
/*
** Fourth row contains the grid dimensions
*/
c.gridwidth=1;
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(xlabel,c);
c.anchor = GridBagConstraints.WEST;
gridbag.setConstraints(xinput,c);
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(ylabel,c);
c.anchor = GridBagConstraints.WEST;
c.gridwidth=GridBagConstraints.REMAINDER;
gridbag.setConstraints(yinput,c);
/*
** Fifth row contains the x range of the grid
*/
c.gridwidth=1;
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(xminlabel,c);
c.anchor = GridBagConstraints.WEST;
gridbag.setConstraints(xmininput,c);
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(xmaxlabel,c);
c.anchor = GridBagConstraints.WEST;
c.gridwidth=GridBagConstraints.REMAINDER;
gridbag.setConstraints(xmaxinput,c);
/*
** Sixth row contains the y range of the grid
*/
c.gridwidth=1;
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(yminlabel,c);
c.anchor = GridBagConstraints.WEST;
gridbag.setConstraints(ymininput,c);
c.anchor = GridBagConstraints.EAST;
gridbag.setConstraints(ymaxlabel,c);
c.anchor = GridBagConstraints.WEST;
c.gridwidth=GridBagConstraints.REMAINDER;
gridbag.setConstraints(ymaxinput,c);
panel.add(graph);
panel.add(flabel);
panel.add(finput);
panel.add(plot);
panel.add(clabel);
panel.add(cinput);
panel.add(xlabel);
panel.add(xinput);
panel.add(ylabel);
panel.add(yinput);
panel.add(xminlabel);
panel.add(xmininput);
panel.add(xmaxlabel);
panel.add(xmaxinput);
panel.add(yminlabel);
panel.add(ymininput);
panel.add(ymaxlabel);
panel.add(ymaxinput);
xaxis = graph.createXAxis();
xaxis.setTitleText("X_axis");
yaxis = graph.createYAxis();
yaxis.setTitleText("Y_axis");
graph.setDataBackground(new Color(255,200,175));
graph.setBackground(new Color(200,150,100));
graph.setContourColor(Color.green);
graph.setLabelledContourColor(Color.red);
graph.setLabelLevels(3);
graph.setDrawLabels(false);
graph.square = true;
plot();
}
void plot() {
int levels;
int nx;
int ny;
double xmax;
double xmin;
double ymax;
double ymin;
double x, y;
int count = 0;
boolean error = false;
try {
graph.setNLevels( Integer.parseInt(cinput.getText()) );
} catch(Exception e) {
// this.showStatus("Error with number of contour levels!");
System.out.println(
"Number of contour levels error "+e.getMessage());
return;
}
try {
nx = Integer.parseInt(xinput.getText());
ny = Integer.parseInt(yinput.getText());
} catch(Exception e) {
// this.showStatus("Error parsing grid dimensions!");
System.out.println(
"Error parsing grid dimensions! "+e.getMessage());
return;
}
try {
xmax = Double.valueOf(xmaxinput.getText()).doubleValue();
xmin = Double.valueOf(xmininput.getText()).doubleValue();
} catch(Exception e) {
// this.showStatus("Error with X range!");
System.out.println("X range error "+e.getMessage());
return;
}
try {
ymax = Double.valueOf(ymaxinput.getText()).doubleValue();
ymin = Double.valueOf(ymininput.getText()).doubleValue();
} catch(Exception e) {
// this.showStatus("Error with Y range!");
System.out.println("Y range error "+e.getMessage());
return;
}
if(xmin>=xmax || ymin>= ymax ) {
// this.showStatus("Error with Grid range!");
System.out.println("grid range error! ");
return;
}
if( nx < 2 || ny < 2 ) {
// this.showStatus("Error with Grid dimensions!");
System.out.println("grid dimension error!");
return;
}
graph.setRange(xmin,xmax,ymin,ymax);
// this.showStatus("Parsing Function!");
ParseFunction function = new ParseFunction(finput.getText());
if(!function.parse()) {
this.showStatus("Failed to parse function!");
System.out.println("Failed to parse function!");
return;
}
double d[] = new double[nx*ny];
// this.showStatus("Calculating Grid Values!");
count = 0;
for(int j=0; j<ny; j++) {
y = ymin + j*(ymax-ymin)/(ny-1);
for(int i=0; i<nx; i++) {
x = xmin + i*(xmax-xmin)/(nx-1);
try {
d[count++] = function.getResult(x,y);
} catch(Exception e) {
d[count++] = 0.0;
error = true; }
}
}
if( error ) {
// this.showStatus("Error while Calculating points!");
System.out.println("Error while calculating points!");
}
graph.setGrid(d,nx,ny);
// this.showStatus("Calculating Contours!");
graph.repaint();
}
public boolean action(Event e, Object a) {
if(e.target instanceof Button) {
if( plot.equals(e.target) ) {
plot();
return true;
}
}
return false;
}
public static void main(String[] a){
javax.swing.JFrame f = new javax.swing.JFrame();
Applet app = new parse2d();
app.init();
f.getContentPane().add (app);
f.pack();
f.setSize (new Dimension (500, 500));
f.setVisible(true);
}
}
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