function handle(delta) {
        if (delta < 0)
		zoomImageDown(imageViewer, undefined);
        else
		zoomImageUp(imageViewer, undefined);
}

 
function wheel(event){
        var delta = 0;
        if (!event) /* For IE. */
                event = window.event;
        if (event.wheelDelta) { /* IE/Opera. */
                delta = event.wheelDelta/120;
     if (window.opera)
                        delta = -delta;
        } else if (event.detail) { /** Mozilla case. */
 delta = -event.detail/3;
        }
 
        if (delta)
                handle(delta);
  if (event.preventDefault)
                event.preventDefault();
	event.returnValue = false;
}


if (window.addEventListener)
 window.addEventListener('DOMMouseScroll', wheel, false);
window.onmousewheel = document.onmousewheel = wheel;


function cancelEvent(e) {
       if (document.all) {
                e.returnValue = false;
                e.cancelBubble = true;
        } else
                e.preventDefault();  
}; 

function getEvent(event)
{
    if(event == undefined) {
        return window.event;
    }
    
    return event;
}


 



function prepareViewer(imageViewer, tileDir, tileSize,maxzoom,pnts)
{

    for(var child = imageViewer.firstChild; child; child = child.nextSibling) {
        if(child.className == 'surface') {
            imageViewer.activeSurface = child;
            child.imageViewer = imageViewer;
        
        } else if(child.className == 'well') {
            imageViewer.tileWell = child;
            child.imageViewer = imageViewer;
        
        } else if(child.className == 'status') {
            imageViewer.status = child;
            child.imageViewer = imageViewer;
        
        }else if(child.className == 'overlay') {
            imageViewer.overlay = child;
            child.imageViewer = imageViewer;
        
        }
		
		
    }

   imageViewer.maxzoom=maxzoom;
   imageViewer.pnts=pnts;
   
    var width = imageViewer.offsetWidth;
    var height = imageViewer.offsetHeight;
    var zoomLevel = -1; // guaranteed at least one increment below, so start at less-than-zero
    var fullSize = tileSize * Math.pow(2, zoomLevel); // full pixel size of the image at this zoom level
    do {
        zoomLevel += 1;
        fullSize *= 2;
    } while((fullSize < Math.max(width, height)));

    var center = {'x': ((fullSize - width) / -2), 'y': ((fullSize - height) / -2)}; // top-left pixel of viewer, if it were to be centered in the view window

    imageViewer.style.width = width+'px';
    imageViewer.style.height = height+'px';
    
    var top = 0;
    var left = 0;
    for(var node = imageViewer; node; node = node.offsetParent) {
        top += node.offsetTop;
        left += node.offsetLeft;
    }

    imageViewer.dimensions = {

         // width and height of the viewer in pixels
         'width': width, 'height': height,

         // position of the viewer in the document, from the upper-left corner
         'top': top, 'left': left,

         // location and height of each tile; they're always square
         'tileDir': tileDir, 'tileSize': tileSize,

         // zero or higher; big number == big image, lots of tiles
         'zoomLevel': zoomLevel,

         // initial viewer position
         // defined as window-relative x,y coordinate of upper-left hand corner of complete image
         // usually negative. constant until zoomLevel changes
         'x': center.x, 'y': center.y

         };

    imageViewer.start = {'x': 0, 'y': 0}; // this is reset each time that the mouse is pressed anew
    imageViewer.pressed = false;

    if(document.body.imageViewers == undefined) {
        document.body.imageViewers = [imageViewer];
        imageViewer.onmouseup = releaseViewer;
 imageViewer.onmouseout = releaseViewer;
  imageViewer.onselectstart = function(){return false;};
    } else {
        document.body.imageViewers.push(imageViewer);
    
    }

    prepareTiles(imageViewer);
}


function prepareTiles(imageViewer)
{
    var activeSurface = imageViewer.activeSurface;
    var tileWell = imageViewer.tileWell;
    var dim = imageViewer.dimensions;

    imageViewer.tiles = [];
    
    var rows = Math.ceil(dim.height / dim.tileSize) + 1;
    var cols = Math.ceil(dim.width / dim.tileSize) + 1;
    
    
    
    for(var c = 0; c < cols; c += 1) {
        var tileCol = [];
    
        for(var r = 0; r < rows; r += 1) {

            var tile = {'c': c, 'r': r, 'img': document.createElement('img'), 'imageViewer': imageViewer};
            tile.img.className = 'tile';
            tile.img.style.width = dim.tileSize+'px';
            tile.img.style.height = dim.tileSize+'px';
			 tile.img.src = 'kartes/x.gif';
            setTileImage(tile, true);
            
            tileWell.appendChild(tile.img);
            tileCol.push(tile);
        }
        
        imageViewer.tiles.push(tileCol);
    }
    
    activeSurface.onmousedown = pressViewer;
    positionTiles(imageViewer, {'x': 0, 'y': 0}); // x, y should match imageViewer.start x, y
}

function positionTiles(imageViewer, mouse)
{
    var tiles = imageViewer.tiles;
    var dim = imageViewer.dimensions;
    var start = imageViewer.start;
	
 
maxsize=dim.tileSize*imageViewer.maxzoom*imageViewer.maxzoom;
divider=maxsize/(Math.pow(2, dim.zoomLevel) * dim.tileSize);
 
//imageViewer.pnts
for(c=0;c<imageViewer.pnts.length;c++){
var tim=imageViewer.pnts[c][0];
if(tim===null){
aa=document.createElement('a');
aa.href=imageViewer.pnts[c][5];

tim=document.createElement('img');
tim.src="kartes/p.gif";
tim.style.position="absolute";
tim.style.border="none";
tim.style.zIndex=700;

aa.appendChild(tim);
imageViewer.overlay.appendChild(aa);
 
imageViewer.pnts[c][0]=tim;

}

tim.style.width=((imageViewer.pnts[c][3]-imageViewer.pnts[c][1])/divider)+"px";
tim.style.height=( (imageViewer.pnts[c][4]-imageViewer.pnts[c][2]) /divider)+"px";

tim.style.left=(dim.x +(mouse.x - start.x))+(imageViewer.pnts[c][1]/divider)+"px";
tim.style.top=(dim.y +(mouse.y - start.y))+(imageViewer.pnts[c][2]/divider)+"px";
}


 
    for(var c = 0; c < tiles.length; c += 1) {
        for(var r = 0; r < tiles[c].length; r += 1) {

            var tile = tiles[c][r];
        var wrappedAround = false;
            tile.x = (tile.c * dim.tileSize) + dim.x + (mouse.x - start.x);
            tile.y = (tile.r * dim.tileSize) + dim.y + (mouse.y - start.y);
            
            if(tile.x > dim.width) {
            do {
                    tile.c -= tiles.length;
                    tile.x = (tile.c * dim.tileSize) + dim.x + (mouse.x - start.x);
                    wrappedAround = true;

                } while(tile.x > dim.width);

            } else {
           while(tile.x < (-1 * dim.tileSize)) {
                    tile.c += tiles.length;
                    tile.x = (tile.c * dim.tileSize) + dim.x + (mouse.x - start.x);
                    wrappedAround = true;

                }
            }
            
            if(tile.y > dim.height) {
            do {
                    tile.r -= tiles[c].length;
                    tile.y = (tile.r * dim.tileSize) + dim.y + (mouse.y - start.y);
                    wrappedAround = true;

                } while(tile.y > dim.height);

            } else {
             while(tile.y < (-1 * dim.tileSize)) {
                    tile.r += tiles[c].length;
                    tile.y = (tile.r * dim.tileSize) + dim.y + (mouse.y - start.y);
                    wrappedAround = true;

                }
            }
 setTileImage(tile, wrappedAround);
           
 tile.img.style.top = tile.y+'px';
 tile.img.style.left = tile.x+'px';
        }
    }
    
 
}

function setTileImage(tile, nullOverride) {
    var dim = tile.imageViewer.dimensions;
  var src = dim.tileDir+'tile-'+dim.zoomLevel+'-'+tile.c+'-'+tile.r+'.jpg';
  var left = tile.c < 0;
    var high = tile.r < 0;
    var right = tile.c >= Math.pow(2, tile.imageViewer.dimensions.zoomLevel);
    var low = tile.r >= Math.pow(2, tile.imageViewer.dimensions.zoomLevel);
    var outside = high || left || low || right;
if(outside) { src = dim.tileDir+'x.gif';          }
 if(tile.img.src!=src){
 tile.img.src = src;
 }
}

function moveViewer(event)
{
    var imageViewer = this.imageViewer;
    var ev = getEvent(event);
    var mouse = localizeCoordinates(imageViewer, {'x': ev.clientX, 'y': ev.clientY});
 positionTiles(imageViewer, {'x': mouse.x, 'y': mouse.y});
 }

function localizeCoordinates(imageViewer, client)
{
    var local = {'x': client.x, 'y': client.y};

    for(var node = imageViewer; node; node = node.offsetParent) {
        local.x -= node.offsetLeft;
        local.y -= node.offsetTop;
    }
    
    return local;
}

function pressViewer(event)
{
    var imageViewer = this.imageViewer;
    var dim = imageViewer.dimensions;
    var ev = getEvent(event);
    var mouse = localizeCoordinates(imageViewer, {'x': ev.clientX, 'y': ev.clientY});

    imageViewer.pressed = true;
    imageViewer.tileWell.style.cursor = imageViewer.activeSurface.style.cursor = 'move';
    
    imageViewer.start = {'x': mouse.x, 'y': mouse.y};
    this.onmousemove = moveViewer;
   
}

function releaseViewer(event)
{
    var ev = getEvent(event);
    
    for(var i = 0; i < document.body.imageViewers.length; i += 1) {
        var imageViewer = document.body.imageViewers[i];
        var mouse = localizeCoordinates(imageViewer, {'x': ev.clientX, 'y': ev.clientY});
        var dim = imageViewer.dimensions;

        if(imageViewer.pressed) {
            imageViewer.activeSurface.onmousemove = null;
            imageViewer.tileWell.style.cursor = imageViewer.activeSurface.style.cursor = 'default';
            imageViewer.pressed = false;
          dim.x += (mouse.x - imageViewer.start.x);
            dim.y += (mouse.y - imageViewer.start.y);
        }

        
    }
	cancelEvent(ev);
}
 
 

function zoomImage(imageViewer, mouse, direction)
{
    var dim = imageViewer.dimensions;
    
    if(mouse == undefined) {
        var mouse = {'x': dim.width / 2, 'y': dim.height / 2};
    }

    var pos = {'before': {'x': 0, 'y': 0}};
 
    pos.before.x = (mouse.x - pos.before.x) - dim.x;
    pos.before.y = (mouse.y - pos.before.y) - dim.y;
    pos.before.width = pos.before.height = Math.pow(2, dim.zoomLevel) * dim.tileSize;
    
 

    if(dim.zoomLevel + direction >= 0) {
        pos.after = {'width': (pos.before.width * Math.pow(2, direction)), 'height': (pos.before.height * Math.pow(2, direction))};
        
        pos.after.x = pos.before.x * Math.pow(2, direction);
        pos.after.y = pos.before.y * Math.pow(2, direction);
        
        pos.after.left = mouse.x - pos.after.x;
        pos.after.top = mouse.y - pos.after.y;
        
        dim.x = pos.after.left;
        dim.y = pos.after.top;
        dim.zoomLevel += direction;
        
        imageViewer.start = mouse;
        positionTiles(imageViewer, mouse);
    }
 
}

function zoomImageUp(imageViewer, mouse)
{
if(imageViewer.maxzoom>imageViewer.dimensions.zoomLevel)
    zoomImage(imageViewer, mouse, 1);
}

function zoomImageDown(imageViewer, mouse)
{
    zoomImage(imageViewer, mouse, -1);
}