/* 
------------------------------------------------ 
 Original: Stefano Occhetti 
 E-mail: starnuto_di_topo@hotmil.com 
 Web Site: http://www.geocities.com/starnuto_di_topo_2001 

*/ 


var ns = (document.layers)?1:0; 

/* 
Button: 
 this code is to show a "button" to switch 
 the fly ON/OFF. 
 It is always shown on the frame's 
 bottom-right corner. 
------------------------------------------------ 
*/ 
var imgwidth=40; // Image width 
var imgheight=40; // Image height 

var button = Array(); // to pre-cache images 
button[0]=new Image(); 
button[0].src="images/Mosca_OFF.gif"; 
button[1]=new Image(); 
button[1].src="imgmages/Mosca_ON.gif"; 

var text="<table width=10 bgcolor=#ffffff><td><a href='javascript:showhideAnimation()'><center><img name='Button' src='"+button[0].src+"' width='"+imgwidth+"' height='"+imgheight+"' border='0'></center></a></font></td></table>" // A bit of HTML code to display the button 


//Initialize some variables to make the button always to appear on the frame's bottom-right corner 
if (ns) { 
 document.write("<LAYER NAME='FlyOnOff' LEFT=0 TOP=0>"+text+"</LAYER>"); 
 horz=".left"; 
 vert=".top"; 
 docStyle="document."; 
 styleDoc=""; 
 innerW="window.innerWidth"; 
 innerH="window.innerHeight"; 
 offsetX="window.pageXOffset"; 
 offsetY="window.pageYOffset"; 
}else { 
 document.write("<div id='FlyOnOff' style='position:absolute; visibility:show; left:235px; top:-50px; z-index:2'>"+text+"</div>"); 
 horz=".pixelLeft"; 
 vert=".pixelTop"; 
 docStyle=""; 
 styleDoc=".style"; 
 innerW="document.body.clientWidth"; 
 innerH="document.body.clientHeight"; 
 offsetX="document.body.scrollLeft"; 
 offsetY="document.body.scrollTop"; 
} 


// Moves the button in the right position 
function checkLocation() { 
 objectXY="FlyOnOff"; 
 var availableX=eval(innerW); 
 var availableY=eval(innerH); 
 var currentX=eval(offsetX); 
 var currentY=eval(offsetY); 
 x=availableX-(imgwidth+30)+currentX; 
 y=availableY-(imgheight+20)+currentY; 
 eval(docStyle + objectXY + styleDoc + horz + "=" + x); 
 eval(docStyle + objectXY + styleDoc + vert + "=" + y); 
} 

setInterval('checkLocation()', 10); 

/* 
end of Button management 
------------------------------------------------ 
*/ 




/* 
Fly: 
 this code provides some facilities 
 to show a fly moving on the screen. 

 The fly does not actually follow the 
 mouse, but a "Dot" (not shown!). 
------------------------------------------------ 
*/ 


(document.layers)?window.captureEvents(Event.MOUSEMOVE):0; 
(document.layers)?window.onMouseMove=getMousePosition:document.onmousemove=getMousePosition; 


var Dot_Ro=60; //Dot's distance from the mouse pointer 
var Dot_Theta=0; //Dot's initial angle 
var Dot_Speed; //Dot's absolute Angular speed 
var Dot_Direction=1; //Dot's direction (1=clockwise) 
var Dot_x=0; //Dot's original position 
var Dot_y=0; 

var alpha; //Angle from the fly to the mouse 
var mult; //Ausiliary variable to define the angle 

var picX = 20; //Fly's coords. 
var picY = 100; 
var mouseX = 0; //Mouse coords. 
var mouseY = 0; 
var step = 10; //Pixels 
var speed = 100;//u-seconds 


// Dir specifies the right picture; 
// img pre-caches images. 
var dir = Array(); 
dir[-4]="Mosca_3.gif"; 
dir[-1]="Mosca_6.gif"; 
dir[-2]="Mosca_5.gif"; 
dir[-3]="Mosca_4.gif"; 
dir[3]="Mosca_8.gif"; 
dir[4]="Mosca_7.gif"; 
dir[1]="Mosca_2.gif"; 
dir[2]="Mosca_1.gif"; 
dir[0]=""; 

var img = Array(); 
for (var i=-4; i<5; i++){ 
 img[i]=new Image(); 
 img[i].src="images/"+dir[i]; 
} 

// Some HTML code to show the fly. 
if (ns) { 
 document.write("<LAYER NAME='FlyDiv' LEFT=0 TOP=0><img src="+img[1].src+" name='pic'></LAYER>"); 
}else { 
 document.write("<div id='FlyDiv' style='position:absolute'>"); 
 document.write("<img name='pic' src=" + img[1].src + "></div>"); 
} 

// Shows the proper image for the fly. 
function display(direction) { //direction must be from -4 to 4, but not 0. 
 if (ns) { 

document.pic.src = img[direction].src; 
 }else{ 

pic.src = img[direction].src; 
 } 
} 


function getMousePosition(e) { 
 mouseY=(ns)?e.pageY:window.event.y + document.body.scrollTop; 
 mouseX=(ns)?e.pageX:window.event.x + document.body.scrollLeft; 
} 

//Calculate new position 
function calcNewPos() { 
 /* 

All this calculations make the Dot 

to come near the mouse-pointer, 

and the fly to follow the dot. 
 */ 
 var dist=Math.sqrt(Math.pow(mouseY-picY,2) + Math.pow(mouseX-picX,2)); 
 Dot_Speed=Math.PI/15; 
 Dot_Theta+=Dot_Direction*Dot_Speed; 
 Dot_x=mouseX+Dot_Ro*Math.cos(Dot_Theta); 
 Dot_y=mouseY+Dot_Ro*Math.sin(Dot_Theta); 
 var arg = (Dot_y-picY) / (Dot_x-picX); 
 mult = (Dot_x - picX < 0)? mult = -1:1; 
 alpha = Math.atan(arg); 
 var dx = mult * step * Math.cos(alpha); 
 var dy = mult * step * Math.sin(alpha); 
 picX += dx; 
 picY += dy; 
} 

//Shows or hides the fly when the "button" is pressed 
function showhideAnimation() { 
 if (ns) { 

document.layers['FlyDiv'].visibility=document.layers['FlyDiv'].visibility=="hide"?"show":"hide"; 

document.Button.src = document.layers['FlyDiv'].visibility=="hide"?button[1].src:button[0].src; 
 }else { 

FlyDiv.style.visibility=="hidden"?FlyDiv.style.visibility = "visible":FlyDiv.style.visibility = "hidden"; 

Button.src = FlyDiv.style.visibility=="hidden"?button[1].src:button[0].src; 
 } 
} 


// Moves the fly around the screen 
function moveFly() { 
 // moves the fly in a new position... 
 calcNewPos(); 
 if (ns) { 

document.layers['FlyDiv'].left = picX; 

document.layers['FlyDiv'].top = picY; 
 }else{ 

FlyDiv.style.left = picX - pic.width / 2; 

FlyDiv.style.top = picY - pic.height / 2; 
 } 

 // ... and changes the image. 
 alpha=-180*alpha/Math.PI; 
 alpha+=22.5; 
 var OK=0; 
 for(var i=0; (i<4)&& !OK; i++){ 

if (alpha<-Math.PI+45*i){ 
   display(mult*(i+1)); 
   OK=1; 

} 
 } 
} 

// Changes Dot's turning direction 
function ChangeDotDirection() { 
 Dot_Direction=-Dot_Direction; 
 Dot_Theta+=Math.PI; 
} 

//Go! 
setInterval('moveFly()', speed); 
setInterval('ChangeDotDirection()', speed*50); 

/* 
The end. 
------------------------------------------------ 
*/