1 /*
2 * File: ShowData.java
3 * Author: Nancy McCracken
4 * Converted to Java 1.1: October 30, 1997
5 * Copyright: Northeast Parallel Architectures Center
6 * at Syracuse University 1997
7 *
8 * This Java applet divides the applet area into two parts: an area
9 * with controls such as buttons and checkboxes, called controlPanelNorth,
10 * and an area called dataPanel which is treated as a Canvas to display
11 * a set of data points. The dataPanel is a separate class.
12 *
13 * The data points are read from a file which has the following format:
14 * an integer which is the number of data points
15 * a maximum x value - the horizontal display will cover 0 through this value
16 * a maximum y value - the vertical display will cover 0 through this value
17 * data points x y
18 *
19 * This applet is intended to be a template for displaying a set of static
20 * data from a file. Each point is displayed in a very simple fashion, and
21 * the only two controls provided is a choice box with 5 colors and a checkbox
22 * group of 3 checkboxes controlling the shape of the point icon.
23 *
24 */
25
26 import java.awt.*;
27 import java.awt.event.*;
28 import java.io.*;
29 import java.net.*;
30
31 public class ShowData extends java.applet.Applet
32 implements ItemListener
33 {
34 DataPanel dataPanel; // the display panel, from the class below
35 String inname = null; // name of the data file
36
37 Choice colorChoice; // color control
38 CheckboxGroup shape; // shape controls
39 Checkbox circleBox, squareBox, plusBox;
40
41 public void init()
42 { InputStream instream = null;
43 Panel controlPanelNorth = new Panel();
44
45 setLayout(new BorderLayout());
46
47 // initialize the input stream and data panel
48 try
49 { inname = getParameter("inputfile");
50 instream = new URL(getDocumentBase(), inname).openStream();
51 dataPanel = new DataPanel(instream);
52 }
53 catch (IOException e)
54 { System.err.println
55 ("I/O Exception: probably bad filename or bad connection."
56 + e.getMessage());
57 }
58
59 // make the control panel
60 controlPanelNorth.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));
61
62 colorChoice = new Choice();
63 colorChoice.addItem("green");
64 colorChoice.addItem("cyan");
65 colorChoice.addItem("blue");
66 colorChoice.addItem("purple");
67 colorChoice.addItem("magenta");
68 colorChoice.addItemListener(this);
69
70 shape = new CheckboxGroup();
71 circleBox = new Checkbox("circle", shape, true);
72 squareBox = new Checkbox("square", shape, false);
73 plusBox = new Checkbox("plus", shape, false);
74 circleBox.addItemListener(this);
75 squareBox.addItemListener(this);
76 plusBox.addItemListener(this);
77
78 controlPanelNorth.add(colorChoice);
79 controlPanelNorth.add(circleBox);
80 controlPanelNorth.add(squareBox);
81 controlPanelNorth.add(plusBox);
82
83 // add the two components to the applet area
84 add("North", controlPanelNorth);
85 add("Center", dataPanel);
86 }
87
88 public void update(Graphics g)
89 {
90 dataPanel.repaint();
91 }
92
93 public void paint(Graphics g)
94 {
95 dataPanel.repaint();
96 }
97
98 public void itemStateChanged(ItemEvent e)
99 {
100 /* in response to activation of controls, call methods in the
101 DataPanel class that will change the appearance of the display */
102
103 if (e.getSource() == colorChoice)
104 {
105 dataPanel.setColor(colorChoice.getSelectedIndex());
106 repaint();
107 }
108 else // it was a checkbox
109 {
110 dataPanel.setShape(shape.getSelectedCheckbox().getLabel());
111 repaint();
112 }
113 }
114 }
115
116 class DataPanel extends Panel
117 {
118 // variables to hold the data from the file
119 int numdata;
120 double maxx, maxy;
121 double xdata[], ydata[];
122
123 // variables to scale the data to pixels
124 int maxxoffset, maxyoffset;
125 int xoffset[], yoffset[];
126 int xscale,yscale;
127
128 InputStreamReader isr;
129 // these two variables control the current appearance of the data
130 Color currentColor;
131 String currentshape;
132
133 // the set of allowed colors
134 Color ctable[] = new Color[5];
135
136
137 public DataPanel(InputStream instream)
138 {
139 try
140 {
141 isr = new InputStreamReader(instream);
142 StreamTokenizer intokens = new StreamTokenizer(isr);
143 intokens.parseNumbers(); intokens.slashSlashComments(true);
144
145 /* read the number of data points and allocate data and pixel
146 offset arrays */
147 int tok = intokens.nextToken();
148 numdata = (int) intokens.nval;
149 xdata = new double[numdata]; ydata = new double[numdata];
150 xoffset = new int[numdata]; yoffset = new int[numdata];
151
152 /* read maximum x and y data values and scale data from 0 to maxx
153 to pixels to fit the window, and same for y */
154 tok = intokens.nextToken();
155 maxx = intokens.nval;
156 tok = intokens.nextToken();
157 maxy = intokens.nval;
158 maxxoffset = 600;
159 maxyoffset = 450;
160 xscale = (int) (maxxoffset/maxx);
161 yscale = (int) (maxyoffset/maxy);
162
163 // read x,y data pairs
164 for (int i=0; i<numdata; i++)
165 { tok = intokens.nextToken(); xdata[i] = intokens.nval;
166 tok = intokens.nextToken(); ydata[i] = intokens.nval;
167 }
168 /* for debugging
169 for (int i=0; i<numdata; i++)
170 { System.out.println(xdata[i]);
171 System.out.println(ydata[i]);
172 }
173 */
174 }
175 catch (IOException e)
176 { System.err.println
177 ("I/O Exception: Reading data from file"
178 + e.getMessage());
179 }
180
181 // initialize current control variables and color table
182 currentColor = Color.green;
183 currentshape = "circle";
184 setBackground(Color.black);
185
186 ctable[0] = Color.green;
187 ctable[1] = Color.cyan;
188 ctable[2] = Color.blue;
189 ctable[3] = new Color(127,0,255);
190 ctable[4] = Color.magenta;
191 }
192
193
194 public void setColor(int colorindex)
195 { currentColor = ctable[colorindex];
196 }
197
198
199 public void setShape(String selectedshape)
200 { currentshape = selectedshape;
201 }
202
203
204 public void paint(Graphics g)
205 {
206 g.setColor (currentColor);
207 if (currentshape.equals("circle"))
208 { // draw a circle for each point
209 for (int i=0; i<numdata; i++)
210 { g.fillOval((int)(xdata[i]*xscale),
211 maxyoffset - (int)(ydata[i]*yscale), 12, 12);
212 }
213 }
214 else if (currentshape.equals("square"))
215 { // draw a square for each point
216 for (int i=0; i<numdata; i++)
217 { g.fillRect((int)(xdata[i]*xscale),
218 maxyoffset - (int)(ydata[i]*yscale), 12, 12);
219 }
220 }
221 else if (currentshape.equals("plus"))
222 { //draw a plus for each point
223 g.setFont(new Font("TimesRoman", Font.BOLD, 14));
224 for (int i=0; i<numdata; i++)
225 { g.drawString("+", (int)(xdata[i]*xscale),
226 maxyoffset - (int)(ydata[i]*yscale));
227 }
228 }
229 }
230 }