dgclock.java

一个用JAVA编写的数字时钟源码

import java.applet.*;
import java.awt.*;
import java.awt.image.*;
import java.util.Hashtable;
import java.util.*;

//////////////////////////////////////////////////////////
// Description: a simple digital clock in Java (1.0.2 applet)
// Author: Muhammad A Muquit
// email:  [e-mail]
// URL:    http://www.fccc.edu/users/muquit/Dgclock.html
//
// 12/05/1995           lets play with Java
// 01/29/96             some clean up
// 02/13/96             added ornamental frame
//                      added 24 hr time format (TimeFormat)
// 02/15/96             GMT+-hhmm to display time of any place (TZ)
//                      date (ShowDate)
// 03/13/96             using MediaTrcaker to stop incremental display
//                      Suggested by Jim Graham
// 03/16/96             display clock without frame.
//                      shows version info while mouse is moved on the appl.
//                      stop clock by clicking mouse
// 10/29/1996           jdk 1.1 on DEC OSF1 found a syntax error
// 11/02/1996           Version 2.2
// 11/02/1996           uses an image strip instead of individual digit images
//                      loads much faster.
// 11/05/1996           Version 2.3
//                      change fg & bg color on the fly
//
// Copyright:
// This program is in the public domain. Do anything you like with it.
// It would be nice if you give me credit for it tho.
//////////////////////////////////////////////////////////

/*

Example of calling convention:

The default 24 hr format:

<applet code="Dgclock.class" width=100 height=30></applet>

To display time in 12 hr format:

<applet code="Dgclock.class" width=100 height=30>
<param name="TimeFormat" value="%I">
</applet>

To display NewYork time:

<applet code="Dgclock.class" width=100 height=30>
<param name="TZ" value="GMT-0500">
</applet>

12 or 24 hr format
<param name="TimeFormat" value="%H">    (24 hr format - default)
<param name="TimeFormat" value="%I">    (12 hr format)

the format for value is GMT+-hhmm, for example

<param name="TZ" value="GMT+0600">    (6 hours west of Greenwich meridian)
<param name="TZ" value="GMT+0430">    (4 hours, 30 minutes
                                      west of Greenwich meridian)
<param name="TZ" value="GMT+0000">    (Greenwich)
<param name="TZ" value="GMT-0500">    (5 hours east of Greenwich meridian)

<param name="ShowDate" value="yes">   (show date with time)
<param name="ShowDate" value="no">   (don't show date - default)

<applet code="Dgclock.class" width=89 height=20>
<param name="ShowFrame" value="no">   (do not wrap clock with frame)

<param name="ShowVersion" value="no"> (do not show version info when the
                                       mouse cursor is moved on the applet)

<param name="fg" value="color">       (change foreground color, color can be
                                       any of red,green,blue,cyan,magenta,
                                       yellow,orange,pink,black,white or 
                                       a 6 digit hex number like ff0000)

<param name="bg" value="color">       (change background color)

*/

public class Dgclock extends Applet implements Runnable
{
    MediaTracker
        tracker;

    Thread
        timer=null;

    boolean
        suspended=false;

    Image
        big_image,
        buf_image;

    int
        bdigit_width=15;
    int
        bdigit_height=20;
    int
        sdigit_width=7;
    int
        sdigit_height=9;

    int
        base_width=100;

    int
        base_height=30;

    int
        offset=4;

    String
        TimeFormat="%H";

    long
        TimeDiff=0L;

    boolean
        ShowDate=false;
    boolean
        ShowStatus=true;

    boolean
        use_frame=true;

    Color
        bg_color=Color.black;

        /**
         * Cache of colors indexed by name or color-spec.
         */
        static Hashtable colorCache = new Hashtable();
        
        /**
         * Initialize the color hash table.
         */
        static
        {
            colorCache.put("red", Color.red);
            colorCache.put("green", Color.green);
            colorCache.put("blue", Color.blue);
            colorCache.put("cyan", Color.cyan);
            colorCache.put("magenta", Color.magenta);
            colorCache.put("yellow", Color.yellow);
            colorCache.put("orange", Color.orange);
            colorCache.put("pink", Color.pink);
            colorCache.put("white", Color.white);
            colorCache.put("black", Color.black);
        }
             

    int checkTZ(String TZ)
    {
       int
          d;

       int
            hr,
            min;
                 
       int   
            counter=0;

       int diff=0; 
     
       hr=0;
       min=0;
       if (TZ != null)
       { 
            int length=TZ.length();
            if (length == 8)
            {
                //Print("Length= " + length);
                int c=TZ.charAt(3);
                if ((c == '-') || (c == '+'))
                {
                    String tzval=TZ.substring(4,8);
                    //Print("TZ value= " + tzval);
             
                    for (int i=0; i < tzval.length(); i++)
                    {
                        d=tzval.charAt(i);
         
                        if ( (d >= '0') && d <= '9')
                        {
                            if (counter < 2)  
                                hr=hr*10+(d-'0');
                            else  
                                min=min*10+(d-'0');
                            counter++;
                        }
                    }
                    //Print("Hour: " + hr + " Min: " + min);
                    diff=(hr*60)+min;
                    if (c == '-')
                        diff=(-diff);
                }
            }
       }

       return diff;
    }  

    public void init()
    {
        int
            x,
            y;

        Image
            rgb_image=null;

        String
            fg,
            bg;

        fg=bg=null;
        // check if TimeFormat is supplied
        TimeFormat=getParameter("TimeFormat");
        if (TimeFormat != null)
        {
            if  ((!TimeFormat.equals("%I")) && (!TimeFormat.equals("%H")))
                TimeFormat="%H";
        }
        else
            TimeFormat="%H";

        String gp=getParameter("ShowDate");
        if (gp != null)
        {
            if (gp.equals("yes"))
                ShowDate=true;
        }

        gp=getParameter("ShowVersion");
        if (gp != null)
        {
            if (gp.equals("no"))
                ShowStatus=false;
        }

        // check if frame need to be displayed
        gp=getParameter("ShowFrame");
        if (gp != null)
        {
            if (gp.equals("no"))
            {
                use_frame=false;
                /*
                offset=0;
                base_width=89;
                base_height=20;
                */
            }
        }     

        // check if fg and bg parameters are supplied
        fg=getParameter("fg");
        bg=getParameter("bg");

        //Print("TImeForamt= " + TimeFormat);

        tracker=new MediaTracker(this);
        try
        {
        // load the big image
            if ((fg == null) && (bg == null))
            {
                //Print("fg and bg null");
                big_image=getImage(getCodeBase(),"./dgstrip.gif");
                tracker.addImage(big_image,0);
            }
            else
            {
                rgb_image=getImage(getCodeBase(),"./dgstrip.gif");
                tracker.addImage(rgb_image,0);
            }
        } catch (Exception e) {;}

        if ((fg != null) || (bg != null))
        {
            //Print ("fg or bg is not null");
            Color
                fgc,
                bgc;

            if (fg != null)
                fgc=lookupColor(true,fg);
            else
                fgc=Color.cyan;

            if (bg != null)
                bgc=lookupColor(false,bg);
            else
                bgc=Color.black;

            bg_color=bgc;
            ImageFilter f=new ColorFilter(fgc,bgc);
            ImageProducer producer=new FilteredImageSource(
                rgb_image.getSource(),f);
            big_image=this.createImage(producer);
        }

        // check for TZ
        int
            diff=0;
        String timezone=getParameter("TZ");
        if (timezone != null)
        {
            if (timezone.equals("LOCAL"))
                TimeDiff=0L;
            else
            {
                Date date=new Date();
                diff=checkTZ(timezone);
                TimeDiff=((long) date.getTimezoneOffset())*60000+diff*60000;
            }

        }

        try
        {
            buf_image=createImage(base_width,base_height);
        } catch (Exception e) {;}   //jdk 1.1 on osf found a problem
    }
    
    /**
     * taken from AlphaBullet applet by Jim Graham
     */
    private synchronized Color lookupColor(boolean bb,String colorname)
    {
        /**
         * boolean bb is true when looking color for foreground
         * we need this flag, so if color lookup fails, we can choose
         * contrasting colors for fg and bg
         */

        String lowername=colorname.toLowerCase();
        Color newcolor=(Color) colorCache.get(lowername);
        if (newcolor != null)
            return newcolor;

        int colorval;
       
        try
        {
            colorval=Integer.parseInt(lowername,16);
        } catch (NumberFormatException e)
          {
            if (bb == true)
                return (Color.cyan);
            else
                return (Color.black);