classwavetext.java

java程序

//这个类实现文字的动态滚动效果
import java.awt.*;
import java.applet.*;
import java.util.*;
public class ClassWaveText 
{
char theChars[];
int xLeftTop,yLeftTop;
int mx,my;
int signFlag;
String showText;
Font font;
int fontWidth;

public ClassWaveText(int mx,int my,String str)
{
this.mx=mx;
this.my=my;
showText=str;
//文字运动方向符号，1：向右运动，-1: 向左运动
signFlag=1;	
xLeftTop=2;
yLeftTop=100;
font=new Font("TimesRoman",Font.BOLD,40);
theChars =new char[showText.length()];
showText.getChars(0,str.length(),theChars,0);
}

public void update(Graphics offScreenG)
{
int i;
int x, y;
offScreenG.setColor(Color.red);
//随机设置字型大小
font=new Font("TimesRoman",Font.BOLD,
			   30+(int)(Math.random()*15));
offScreenG.setFont(font);
fontWidth=offScreenG.getFontMetrics().charWidth(showText.charAt(1));
xLeftTop+=15*signFlag;
if(xLeftTop<0)
{
    //下一次应往右移动
	    signFlag=1;
    xLeftTop=0;
}
if(xLeftTop>mx-showText.length()*fontWidth)
{	
    //下一次应往左移动
	    signFlag=-1;
   	xLeftTop=mx-showText.length()*fontWidth;
}
//显示文字
for(i=0;i<showText.length();i++)
{
	    x=xLeftTop+fontWidth*i;
	    y=yLeftTop;;
	    offScreenG.drawChars(theChars,i,1,x,y);
}	
}
}