MapsJavascript_javascript技巧








//常数
var viewportWidth=800;
var viewportHeight=600;
var tileSize=100;
var zoom=0;
var zoomSizes=[["2000px","1400px"],["1500px","1050px"]];
//用来控制地图div的移动
var dragging=false;
var top;
var left;
var dragStartTop;
var dragStartLeft;

function init(){
//让inner div足够大，以正确显示出地图
setInnerDivSize(zoomSizes[zoom][0],zoomSizes[zoom][1]);
//为拖曳操作绑定鼠标监听器
var outerDiv=document.getElementById("outerDiv");
outerDiv.onmousedown=startMove;
outerDiv.onmousemove=processMove;
outerDiv.onmouseup=stopMove;
//在IE中支持拖曳所必须
outerDiv.ondragstart=function()
{ return false;}
//解决在IE中触发器div的透明度问题
new OpacityObject('toggleZoomDiv','resource/images/zoom').setBackground();
new OpacityObject('togglePushPinDiv','resource/images/pushpin').setBackground();
checkTiles();
}

function startMove(event){
//针对IE必需
if(!event)event=window.event;
dragStartLeft=event.clientX;
dragStartTop=event.clientY;
var innerDiv=document.getElementById("innerDiv");
innerDiv.style.cursor="-moz-grab";

top=stripPx(innerDiv.style.top);
left=stripPx(innerDiv.style.left);

dragging=true;
return false;
}

function processMove(event){
if(!event)event=window.event; //for IE
var innerDiv=document.getElementById("innerDiv");
if(dragging){
innerDiv.style.top=parseFloat(top)+(event.clientY-dragStartTop);
innerDiv.style.left=parseFloat(left)+(event.clientX-dragStartLeft);
}
checkTiles();
}

function checkTiles(){
//检查在inner div中将显示哪个标题
var visibleTiles=getVisibleTiles();
//当把每个小地图快添加到inner div中时，要先检查其是否已经添加
var innerDiv=document.getElementById("innerDiv");
var visibleTilesMap={};
for (i=0;i {
var tileArray=visibleTiles[i];
var tileName="x"+tileArray[0]+"y"+tileArray[1]+"z"+zoom;
visibleTilesMap[tileName]=true;
var img=document.getElementById(tileName);
if(!img){
img=document.createElement("img");
img.src="resource/tiles/"+tileName+".jpg";
img.style.position="absolute";
img.style.left=(tileArray[0]*tileSize)+"px";
img.style.top=(tileArray[1]*tileSize)+"px";
img.style.zIndex=0;
img.setAttribute("id",tileName);
innerDiv.appendChild(img);
}
}
var imgs=innerDiv.getElementByTagName("img");
for(i=0;i var id=imgs[i].getAttribute("id");
if(!visibleTilesMap[id]){
innerDiv.removeChild(imgs[i]);
i--;//compensate for live nodeslist
}
}
}

function getVisibleTiles(){
var innerDiv=document.getElementById("innerDiv");
var mapX=stripPx(innerDiv.style.left);
var mapY=stripPx(innerDiv.style.top);
var startX=Math.abs(Math.floor(mapX/tileSize))-1;
var startY=Math.abs(Math.floor(mapY/tileSize))-1;
var tilesX=Math.ceil(viewportWidth/tileSize)+1;
var tilesY=Math.ceil(viewportHeight/tileSize)+1;
var visibleTileArray=[];
var counter=0;
for(x=startX;x<(tilesX+startX);x++){
for(y=startY;y<(tilesY+startY);y++){
visibleTileArray[counter++]=[x,y];
}
}
return visibleTileArray;
}

function stopMove(){
var innerDiv=document.getElementById("innerDiv");
innerDiv.style.cursor="";
dragging=false;
}

function stripPx(value){
if(value=="")return 0;
return parseFloat(value.substring(0,value.length-2));
}

function setInnerDivSize(width,height){
var innerDiv=document.getElementById("innerDiv");
innerDiv.style.width=width;
innerDiv.style.height=height;
}

function toggleZoom(){
zoom=(zoom==0)?1:0;
var innerDiv=document.getElementById("innerDiv");
var imgs=innerDiv.getElementsByTagName("img");
while(imgs.length>0)innerDiv.removeChild(imgs[0]);
setInnerDivSize(zoomSizes[zoom][0],zoomSizes[zoom][1]);
if(document.getElementById("pushPin"))togglePushPin();
checkTiles();
}

function togglePushPin(){
var pinImage=document.getElementById("pushPin");
if(pinImage){
pinImage.parentNode.removeChild(pinImage);
var dialog=document.getElementById("pinDialog");
dialog.parentNode.removeChild(dialog);
return;
}

var innerDiv=document.getElementById("innerDiv");
pinImage=document.createElement("div");
pinImage.style.position="absolute";
pinImage.style.left=(zoom==0)?"850px":"630px";
pinImage.style.top=(zoom==0)?"570px":"420px";
pinImage.style.width="37px";
pinImage.style.height="34px";
pinImage.zIndex=1;
pinImage.setAttribute("id","pushPin");
innerDiv.appendChild(pinImage);

new OpacityObject("pubshPin","resource/images/pin").setBackground();
var dialog=document.createElement("div");
dialog.style.position="absolute";
dialog.style.left=(stripPx(pinImage.style.left)-90)+"px";
dialog.style.top=(stripPx(pinImage.style.top)-210)+"px";
dialog.style.width="309px";
dialog.style.height="229px";
dialog.style.zIndex=2;
dialog.setAttribute("id","pinDialog");
dialog.innerHTML="

"+"

The capital of Spain

";
innerDiv.appendChild(dialog);
new OpacityObject('pinDialog','resource/images/dialog').setBackground();
}

Ajaxian Maps

The rain in Spain falls mainly in the plains.