我正在尝试更改空间树中的默认方向，但不知道在哪里添加：
st.switchPosition("top", "animate", {
onComplete: function() {
alert('completed!');
}
});
这样树将从顶部开始，而不是默认的右侧。
在我看到的示例中，switchPosition 仅与事件处理程序一起使用，我不打算拥有它。
因此，在示例中（取自 infovis 站点：Infovis - spacetree），我应该在哪里添加代码（或任何代码）以更改默认方向？
var labelType，useGradients，nativeTextSupport，动画；
(function() {
var ua = navigator.userAgent,
iStuff = ua.match(/iPhone/i) || ua.match(/iPad/i),
typeOfCanvas = typeof HTMLCanvasElement,
nativeCanvasSupport = (typeOfCanvas == 'object' || typeOfCanvas == 'function'),
textSupport = nativeCanvasSupport
&& (typeof document.createElement('canvas').getContext('2d').fillText == 'function');
//I'm setting this based on the fact that ExCanvas provides text support for IE
//and that as of today iPhone/iPad current text support is lame
labelType = (!nativeCanvasSupport || (textSupport && !iStuff))? 'Native' : 'HTML';
nativeTextSupport = labelType == 'Native';
useGradients = nativeCanvasSupport;
animate = !(iStuff || !nativeCanvasSupport);
})();
var Log = {
elem: false,
write: function(text){
if (!this.elem)
this.elem = document.getElementById('log');
this.elem.innerHTML = text;
this.elem.style.left = (500 - this.elem.offsetWidth / 2) + 'px';
}
};
function init(){
//init data
var json = {....removed due to space here in the group....}
//end
//A client-side tree generator
var getTree = (function() {
var i = 0;
return function(nodeId, level) {
var subtree = eval('(' + json.replace(/id:\"([a-zA-Z0-9]+)\"/g,
function(all, match) {
return "id:\"" + match + "_" + i + "\""
}) + ')');
$jit.json.prune(subtree, level); i++;
return {
'id': nodeId,
'children': subtree.children
};
};
})();
//Implement a node rendering function called 'nodeline' that plots a straight line
//when contracting or expanding a subtree.
$jit.ST.Plot.NodeTypes.implement({
'nodeline': {
'render': function(node, canvas, animating) {
if(animating === 'expand' || animating === 'contract') {
var pos = node.pos.getc(true), nconfig = this.node, data = node.data;
var width = nconfig.width, height = nconfig.height;
var algnPos = this.getAlignedPos(pos, width, height);
var ctx = canvas.getCtx(), ort = this.config.orientation;
ctx.beginPath();
if(ort == 'left' || ort == 'right') {
ctx.moveTo(algnPos.x, algnPos.y + height / 2);
ctx.lineTo(algnPos.x + width, algnPos.y + height / 2);
} else {
ctx.moveTo(algnPos.x + width / 2, algnPos.y);
ctx.lineTo(algnPos.x + width / 2, algnPos.y + height);
}
ctx.stroke();
}
}
}
});
//init Spacetree
//Create a new ST instance
var st = new $jit.ST({
'injectInto': 'infovis',
//set duration for the animation
duration: 800,
//set animation transition type
transition: $jit.Trans.Quart.easeInOut,
//set distance between node and its children
levelDistance: 50,
//set max levels to show. Useful when used with
//the request method for requesting trees of specific depth
levelsToShow: 2,
//set node and edge styles
//set overridable=true for styling individual
//nodes or edges
Node: {
height: 20,
width: 40,
//use a custom
//node rendering function
type: 'nodeline',
color:'#23A4FF',
lineWidth: 2,
align:"center",
overridable: true
},
Edge: {
type: 'bezier',
lineWidth: 2,
color:'#23A4FF',
overridable: true
},
//Add a request method for requesting on-demand json trees.
//This method gets called when a node
//is clicked and its subtree has a smaller depth
//than the one specified by the levelsToShow parameter.
//In that case a subtree is requested and is added to the dataset.
//This method is asynchronous, so you can make an Ajax request for that
//subtree and then handle it to the onComplete callback.
//Here we just use a client-side tree generator (the getTree function).
request: function(nodeId, level, onComplete) {
var ans = getTree(nodeId, level);
onComplete.onComplete(nodeId, ans);
},
onBeforeCompute: function(node){
Log.write("loading " + node.name);
},
onAfterCompute: function(){
Log.write("done");
},
//This method is called on DOM label creation.
//Use this method to add event handlers and styles to
//your node.
onCreateLabel: function(label, node){
label.id = node.id;
label.innerHTML = node.name;
label.onclick = function(){
st.onClick(node.id);
};
//set label styles
var style = label.style;
style.width = 40 + 'px';
style.height = 17 + 'px';
style.cursor = 'pointer';
style.color = '#fff';
//style.backgroundColor = '#1a1a1a';
style.fontSize = '0.8em';
style.textAlign= 'center';
style.textDecoration = 'underline';
style.paddingTop = '3px';
},
//This method is called right before plotting
//a node. It's useful for changing an individual node
//style properties before plotting it.
//The data properties prefixed with a dollar
//sign will override the global node style properties.
onBeforePlotNode: function(node){
//add some color to the nodes in the path between the
//root node and the selected node.
if (node.selected) {
node.data.$color = "#ff7";
}
else {
delete node.data.$color;
}
},
//This method is called right before plotting
//an edge. It's useful for changing an individual edge
//style properties before plotting it.
//Edge data proprties prefixed with a dollar sign will
//override the Edge global style properties.
onBeforePlotLine: function(adj){
if (adj.nodeFrom.selected && adj.nodeTo.selected) {
adj.data.$color = "#eed";
adj.data.$lineWidth = 3;
}
else {
delete adj.data.$color;
delete adj.data.$lineWidth;
}
}
});
//load json data
st.loadJSON(eval( '(' + json + ')' ));
//compute node positions and layout
st.compute();
//emulate a click on the root node.
st.onClick(st.root);
//end
//Add event handlers to switch spacetree orientation. - Which i do not want...
// function get(id) {
// return document.getElementById(id);
// };
// var top = get('r-top'),
// left = get('r-left'),
// bottom = get('r-bottom'),
// right = get('r-right');
// function changeHandler() {
// if(this.checked) {
// top.disabled = bottom.disabled = right.disabled = left.disabled = true;
// st.switchPosition(this.value, "animate", {
// onComplete: function(){
// top.disabled = bottom.disabled = right.disabled = left.disabled = false;
// }
// });
// }
// };
// top.onchange = left.onchange = bottom.onchange = right.onchange = changeHandler;
//end
}