import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
/** Synthetic button, not using Native toolkit. This is slightly fancier
* than the XButton* classes, but still does not do everything you
* might want in a button. It does both support actionListeners AND
* have a TARGET URL that it jumps to (after notifying the actionListeners).
*
* @author Copyright 1995, 1997 Ian F. Darwin,
* <A HREF="mailto:ian@darwinsys.com">ian@darwinsys.com</A>,
* <A HREF="http:www.darwinsys.com/">http://www.darwinsys.com</A>.
* @version $Id: LinkButton.java,v 1.1.1.1 1998/12/27 20:20:32 ian Exp $
*/
public class LinkButton extends Applet implements MouseListener {
/** The label that is to appear in the button */
protected String label = null;
/** The name of the image */
protected String imName = null;
/** The Image to display in the button */
protected Image im;
/** The width and height, based on the Image */
protected int width, height;
/** The list of ActionListeners. Usually short, so a Vector is fine.
* TODO use new AwtMulticastBroadcaster */
protected Vector l;
/** Padding around the text for getMinimumSize() */
protected final int MIN_PAD = 5;
/** Padding around the text for getPreferredSize() */
protected final int PREF_PAD = 10;
/** State: at first CALM; AWAKE when the mouse enters, ARMED if
* the mouse has been clicked but not yet released
* in our window; FIRED if activated,
*/
protected int state;
public final static int CALM=0, AWAKE=1, ARMED=2, FIRED=3;
/** The string form of the URL to jump to */
String target;
/** The URL to jump to when the button is pushed. */
URL targetURL;
/** Called from the browser to set up. We want to throw various
* kinds of exceptions but the API predefines that we don't, so we
* limit ourselves to the ubiquitous IllegalArgumentException.
*/
public void init() {
String s;
System.out.println("In LinkButton::init");
try {
if ((target = getParameter("target")) == null)
throw new IllegalArgumentException("TARGET parameter REQUIRED");
targetURL = new URL(target);
if ((imName = getParameter("image")) != null)
setImage(getImage(new URL(imName)));
} catch (MalformedURLException rsi) {
throw new IllegalArgumentException("MalformedURLException " +
rsi.getMessage());
}
label = getParameter("label");
// last-minute checking: must be an Image or text
if (imName == null && label == null)
throw new IllegalArgumentException("LABEL or IMAGE is REQUIRED");
// Now handle font stuff.
fontName = getParameter("fontname");
if ((s = getParameter("fontsize")) != null)
fontSize = Integer.parseInt(s);
if (fontName != null || fontSize != 0) {
System.out.println("Name " + fontName + ", size " + fontSize);
textFont = new Font(fontName, Font.BOLD, fontSize);
}
// Applets don't do this; application components may:
// setSize(getPreferredSize());
// N.B. Must say we want to handle *mouse* events!
addMouseListener(this);
// set up the list of action handlers
l = new Vector();
}
public void start() {
System.out.println("In LinkButton::start");
}
/** Give Parameter info the the AppletViewer, just for those
* writing HTML without hardcopy documentation :-)
*/
public String[][] getParameterInfo() {
String info[][] = {
{ "label", "string", "Text to display" },
{ "fontname", "name", "Font to display it in" },
{ "fontsize", "10-30?", "Size to display it at" },
{ "image", "img file", "Alternate image" },
{ "target", "URL", "Where do you want to go tomorrow?" },
};
return info;
}
// Font Stuff
/** The font name */
protected String fontName = null;
/** The font size */
protected int fontSize = 0;
/** The font itself */
protected Font textFont;
/** Set the Image to appear. You must have done the appropriate
* (applet or applicatoin) form of getImage before this call.
*/
public void setImage(Image i) {
im = i;
MediaTracker mt = new MediaTracker(this);
mt.addImage(im, 0);
try {
mt.waitForID(0);
} catch(InterruptedException e) {
System.err.println("Wonkey! INTR in waitForID!");
return;
}
if (mt.isErrorID(0)) {
throw new IllegalArgumentException("Couldn't load image");
}
width = im.getWidth(this);
height = im.getHeight(this);
setSize(width, height);
}
/** Compute the size of a String */
protected Dimension getStrSize(String l) {
if (textFont == null)
throw new IllegalArgumentException("No Font!");
FontMetrics fm = getFontMetrics(textFont);
return new Dimension(fm.stringWidth(l), fm.getAscent());
}
/** Paint -- draw the text */
public void paint(Graphics g) {
Dimension bd = getSize();
// System.out.println("In paint, im=" + im + "; label=" + label);
if (im != null) {
g.drawImage(im, 0, 0, bd.width, bd.height, this);
g.draw3DRect(0, 0, bd.width-2, bd.height-2, true);
return;
}
switch(state) {
case CALM:
g.setColor(Color.black);
break;
case AWAKE:
g.setColor(Color.blue);
break;
case ARMED:
g.setColor(Color.red);
break;
case FIRED:
g.setColor(Color.green);
break;
default:
showStatus("LinkButton BUG: state=" + state);
}
// draw the box
g.draw3DRect(0, 0, bd.width-2, bd.height-2, true);
if (label == null)
return;
// Compute where to draw the text.
g.setFont(textFont);
Dimension td = getStrSize(label);
int x = (bd.width-td.width)/2;
if (x<0) // what if text is too wide? Cram at left margin.
x=0;
int y = ((bd.height-td.height)/2)+td.height;
// System.out.println("drawString("+label+", "+x+", "+y+");");
// Now draw it.
g.drawString(label, x, y);
return;
}
/** Add an ActionListener to our list of listeners. */
public void addActionListener(ActionListener listener) {
l.addElement(listener);
}
/** Remove an ActionListener; we'll no longer bother it. */
public void removeActionListener(ActionListener listener) {
l.removeElement(listener);
}
/** The mouse was clicked, so notify all our ActionListeners. */
protected void fireButton() {
repaint();
for (int i=0; i<l.size(); i++)
((ActionListener)(l.elementAt(i))).actionPerformed(
new ActionEvent(this,
ActionEvent.ACTION_PERFORMED,
label == null? "A LinkButton" : label));
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// nothing to do!
}
if (targetURL != null) {
showStatus("Going to " + target);
getAppletContext().showDocument(targetURL);
}
}
public void mousePressed(MouseEvent e) {
state = ARMED;
repaint();
}
/** The mouse was released in our window. If also pressed there,
* consider it a "click", and fire the event. */
public void mouseReleased(MouseEvent e) {
// System.out.println("MouseUp");
if (state==ARMED) {
state = FIRED;
fireButton();
}
state = CALM;
repaint();
}
/** Called by AWT when the mouse walks into our den. */
public void mouseEntered(MouseEvent e) {
// System.out.println("mouseEntered");
state = AWAKE;
repaint();
showStatus(target);
}
/** Called by AWT when the mouse escapes from our den. */
public void mouseExited(MouseEvent e) {
// System.out.println("mouseExited");
state = CALM;
repaint();
showStatus("");
}
/** mouseClicked is defined by MouseListener, but not used here */
public void mouseClicked(MouseEvent e) {
}
}
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