////////////////////////////////////////////////////////////////////////////
// Implementatation of CoolHeadLines class
//
// The main applet.
//
// This is a part of the Internet Information Server SDK Samples
// Copyright (C) 1997 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the Software
// Development Kit Reference and related electronic documentation provided.
//
////////////////////////////////////////////////////////////////////////////
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.net.*;
import TextJump;
import DoubleBuffer;
public class CoolHeadLines extends Applet implements Runnable
{
// constants to gather data from <param> tags
private final String PARAM_BackColor = "BackColor";
private final String PARAM_TextColor = "TextColor";
private final String PARAM_HiliteTextColor = "HiliteTextColor";
private final String PARAM_ScrollDelay = "ScrollDelay";
private final String PARAM_MessageDelay = "MessageDelay";
private final String PARAM_NumItems = "NumItems";
private final String PARAM_URLPrefix = "URLPrefix";
// data from <param> tags
private Color m_colBackColor;
private Color m_colTextColor;
private Color m_colHiliteTextColor;
private int m_iScrollDelay = 10;
private int m_iMessageDelay = 4;
private int m_iNumItems;
private String m_strURLPrefix;
private Thread m_CoolHeadLines = null; // worker thread
private Dimension m_dimAppletSize; // size of the containing applet
private Vector m_vectData=null; // vector of TextJump objects
private Font m_font; // font to draw text with
private FontMetrics m_fm; // size of the font
private int m_iFontHeight; // maximum height of font
private DoubleBuffer m_buff=null; // off-screen buffer
private boolean m_fStoppedScrolling = false; // has the image stopped scrolling (when true mouse-clicks are active)
private int m_iCurrentMessage = -1; // what's the current message at the bottom of the screen?
private int m_iMaxMessage=0; // how many messages can the applet display at once?
private int m_iOldMessageSelected = -1; // what was the last message the mouse moved over?
private int m_iOldMessageSelectedYOffset = -1; // what was the last message location on screen?
////////////////////////////////////////////////////////////////////////////
// ctor
public CoolHeadLines()
{
// set some default colors
m_colBackColor = new Color(255,255,128);
m_colTextColor = new Color(0,0,0);
m_colHiliteTextColor = new Color(255,0,0);
}
////////////////////////////////////////////////////////////////////////////
// getAppletInfo
// info about this applet
public String getAppletInfo()
{
return "Name: CoolHeadLines\r\n" +
"Author: Michael Howard (mikehow@microsoft.com)\r\n" +
"Created with Microsoft Visual J++ Version 1.1";
}
////////////////////////////////////////////////////////////////////////////
// getParameterInfo
// <param> info
public String[][] getParameterInfo()
{
String[][] info =
{
{ PARAM_BackColor, "String", "Background Color" },
{ PARAM_TextColor, "String", "Text Color" },
{ PARAM_HiliteTextColor, "String", "Hilited Text Color" },
{ PARAM_ScrollDelay, "int", "msec delay between each scroll" },
{ PARAM_MessageDelay, "int", "sec delay between each message" },
{ PARAM_NumItems, "int", "Number of items" },
{ PARAM_URLPrefix, "String", "Prefix for all .htm or .asp files" },
};
return info;
}
////////////////////////////////////////////////////////////////////////////
// init
// initialize the applet
public void init()
{
String param;
// background color
param = getParameter(PARAM_BackColor);
if (param != null)
m_colBackColor = getColorFromRGB(param);
// text color
param = getParameter(PARAM_TextColor);
if (param != null)
m_colTextColor = getColorFromRGB(param);
// high-lighted text color
param = getParameter(PARAM_HiliteTextColor);
if (param != null)
m_colHiliteTextColor = getColorFromRGB(param);
// scroll delay in msec
param = getParameter(PARAM_ScrollDelay);
if (param != null)
m_iScrollDelay = Integer.parseInt(param);
// pause between messages in seconds
param = getParameter(PARAM_MessageDelay);
if (param != null)
m_iMessageDelay = Integer.parseInt(param);
// number of items to be displayed
param = getParameter(PARAM_NumItems);
if (param != null)
m_iNumItems = Integer.parseInt(param);
// path for .htm and .asp files
param = getParameter(PARAM_URLPrefix);
if (param != null)
m_strURLPrefix = param;
// various vars
m_dimAppletSize = size();
m_font = new Font("Helvetica",Font.PLAIN,12);
m_fm = getFontMetrics(m_font);
m_iFontHeight = m_fm.getMaxDescent() + m_fm.getLeading() + m_fm.getMaxAscent();
Rectangle r = new Rectangle(0,0,m_dimAppletSize.width,m_dimAppletSize.height + m_iFontHeight);
m_buff = new DoubleBuffer(this,r);
// fill in the background of the off-screen buffer and the applet
m_buff.getGraphics().setColor(m_colBackColor);
m_buff.getGraphics().fillRect(r.x, r.y, r.width, r.height);
setBackground(m_colBackColor);
// maximum number of messages
m_iMaxMessage = 1 +( m_dimAppletSize.height / m_iFontHeight);
// get all the headlines from the <param> tags
m_vectData = new Vector();
for (int i=0; i<m_iNumItems; i++)
{
String strText = new String();
strText = getParameter("Text"+i);
String strURL = new String();
strURL = getParameter("URL"+i);
m_vectData.addElement(new TextJump(strURL,strText));
}
}
////////////////////////////////////////////////////////////////////////////
// getColorFromRGB
// converts an RGB triplet (such as "255 255 255") to a Color object
public Color getColorFromRGB(String strRGB)
{
StringTokenizer st = new StringTokenizer(strRGB);
int iRed = Integer.parseInt(st.nextToken());
int iGreen = Integer.parseInt(st.nextToken());
int iBlue = Integer.parseInt(st.nextToken());
return new Color(iRed,iGreen,iBlue);
}
////////////////////////////////////////////////////////////////////////////
// start
public void start()
{
if (m_CoolHeadLines == null)
{
m_CoolHeadLines = new Thread(this);
m_CoolHeadLines.start();
}
else
{
// This is so we get a quick refresh when we move back to the homepage
drawHeadlines();
}
}
////////////////////////////////////////////////////////////////////////////
// stop
public void stop()
{
if (m_CoolHeadLines != null)
{
m_CoolHeadLines.stop();
m_CoolHeadLines = null;
}
}
////////////////////////////////////////////////////////////////////////////
// run
// most of the work is done here, essentially loops until the applet dies
public void run()
{
while (true)
{
try
{
// the applet is about to scroll
m_fStoppedScrolling = false;
// there is no old message because we are about to
// scroll which invalidates the last message
m_iOldMessageSelected=-1;
m_iOldMessageSelectedYOffset=-1;
// re-draw the headlines
drawHeadlines();
// ok, we've stopped scrolling, we can now accept mouse input
m_fStoppedScrolling = true;
// ZZZzzzz...
Thread.sleep(m_iMessageDelay * 1000);
}
catch (InterruptedException e)
{
stop();
}
}
}
////////////////////////////////////////////////////////////////////////////
// drawHeadlines
// draws the headlines on the screen
private void drawHeadlines()
{
// get the next message and loop round to message #0
// if we reach the last message
m_iCurrentMessage++;
m_iCurrentMessage %= m_vectData.size();
// if we are about to display the first message then clear the screen
if (m_iCurrentMessage == 0)
for (int i=0; i<m_iMaxMessage; i++)
scrollOneLine();
// write in the text in the off-screen buffer.
// note the text is drawn BELOW the bottom of the applet so when it
// gets scrolled it appears to rise from nowhere
drawString(m_buff.getGraphics(),
m_iCurrentMessage,
0,
m_buff.getSize().height-m_fm.getDescent(),
m_colTextColor);
// scroll one line
scrollOneLine();
}
////////////////////////////////////////////////////////////////////////////
// drawString
// draw a string at a given location and place a 'dot' at the start
private void drawString(Graphics g,String str, int x, int y, Color col)
{
int iFontWidth = m_fm.charWidth('W');
int iOvalWidth = Math.min(iFontWidth/2,m_iFontHeight/2);
g.setFont(m_font);
g.setColor(col);
g.drawString(str,x + iFontWidth,y);
g.fillOval(x + iOvalWidth/2,y-iOvalWidth-2,iOvalWidth,iOvalWidth);
}
////////////////////////////////////////////////////////////////////////////
// drawString
// draw a string at a given location and place a 'dot' at the start
// this version takes an index into the vector to get the string
private void drawString(Graphics g,int iMsg, int x, int y, Color col)
{
drawString(g,getStringFromVector(iMsg),x,y,col);
}
////////////////////////////////////////////////////////////////////////////
// getStringFromVector
// returns a string from the vector of TextJumps.
private String getStringFromVector(int iIndex)
{
TextJump t = (TextJump)m_vectData.elementAt(iIndex);
return (String)t.getString();
}
////////////////////////////////////////////////////////////////////////////
// scrollOneLine
//
private void scrollOneLine()
{
// smoothly draw the off-screen buffer
for (int j=0; j < m_iFontHeight; j++)
{
getGraphics().drawImage(m_buff.getImage(),0,-j,this);
try { Thread.sleep(m_iScrollDelay);}
catch (InterruptedException e) { }
}
Graphics g = m_buff.getGraphics();
// move image up one-line inside the off-screen buffer
g.drawImage(m_buff.getImage(),0,-m_iFontHeight,this);
// erase old text at bottom of image
g.setColor(m_colBackColor);
g.fillRect(0,
m_dimAppletSize.height,
m_dimAppletSize.width,
m_dimAppletSize.height+m_iFontHeight);
}
////////////////////////////////////////////////////////////////////////////
// getYOffset
// based on a mouse y-location determine which text row we are on
private int getYOffset(int y)
{
int iY = (m_dimAppletSize.height - y) / m_iFontHeight;
return iY;
}
////////////////////////////////////////////////////////////////////////////
// mouseMove
// highlights a row of text as we move over it
public boolean mouseMove(Event evt, int x, int y)
{
// if the image is still scrolling then bail
if (!m_fStoppedScrolling)
return true;
// get the message we must be over
int iYOffset = getYOffset(y);
int iWhichMsg = m_iCurrentMessage - iYOffset;
// if we are still over the same message then don't do anything
if (m_iOldMessageSelected == iWhichMsg)
return true;
// if there was an old message we were over then re-draw it in it's non-highlighted color
if (m_iOldMessageSelected >= 0)
{
drawString(getGraphics(),
m_iOldMessageSelected,
0,
m_dimAppletSize.height - (m_iOldMessageSelectedYOffset * m_iFontHeight) - m_fm.getDescent() + 1,
m_colTextColor);
if (iWhichMsg < 0)
m_iOldMessageSelected=-1;
}
// if we are over a valid message then draw it in a highlighted color
if (iWhichMsg >= 0)
{
// set the old message to be this message
m_iOldMessageSelected = iWhichMsg;
m_iOldMessageSelectedYOffset = iYOffset;
drawString(getGraphics(),
iWhichMsg,
0,
m_dimAppletSize.height - (iYOffset * m_iFontHeight) - m_fm.getDescent() + 1,
m_colHiliteTextColor);
// put the string on the status line
String strStatusMsg = getStringFromVector(iWhichMsg) +
" at " + m_strURLPrefix +
"/" +
(((TextJump)m_vectData.elementAt(iWhichMsg)).getURL());
getAppletContext().showStatus(strStatusMsg);
}
return true;
}
////////////////////////////////////////////////////////////////////////////
// mouseExit
// if we move the mouse out of the applet and there was an old message
// highlighted then redraw it as a non-highlighted message
public boolean mouseExit(Event evt, int x, int y)
{
if (!m_fStoppedScrolling)
return true;
if (m_iOldMessageSelected >= 0)
{
drawString(getGraphics(),
m_iOldMessageSelected,
0,
m_dimAppletSize.height - (m_iOldMessageSelectedYOffset * m_iFontHeight) - m_fm.getDescent() + 1,
m_colTextColor);
m_iOldMessageSelected=-1;
}
return true;
}
////////////////////////////////////////////////////////////////////////////
// mouseDown
// user is interested in a message
public boolean mouseDown(Event evt, int x, int y)
{
// if the image is still scrolling then bail
if (!m_fStoppedScrolling)
return true;
// get the message we must be over
int iYOffset = getYOffset(y);
int iWhichMsg = m_iCurrentMessage - iYOffset;
try
{
m_CoolHeadLines.suspend();
// Build the url for the sample
String strSampleURL = m_strURLPrefix + "/" + (((TextJump)m_vectData.elementAt(iWhichMsg)).getURL());
showStatus(strSampleURL);
getAppletContext().showDocument(new URL(strSampleURL));
} catch(MalformedURLException e) { }
return true;
}
}
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