Placing the nodes in the center of screen in d3 force layout

Question

How can i place the nodes in the center of the force layout in d3.js. Here i'm getting the JSON data, which is like this

"nodes": [{
    "cName": "User",
    "cImage_url": "/final/images/component_icons/user_image.png",
    "x": 49.99999999999999,
    "y": 150,
    "fixed": true
}, {
    "cType": "Oracle WebLogic",
    "cName": "weblogic177:7001",
    "cImage_url": "/final/images/Light/component_icons/APPLICATION_SERVERS.png",
    "x": 167,
    "y": 150,
    "fixed": true,
    "AlarmPopup": "WebLogic_server:weblogic177:7001",
    "cStateImage_url": "/final/images/Light/state20_INTERMEDIATE.png",
    "linktoLayermodel": "/final/monitor/EgDispLayers.jsp?site=egurkha.physical.topology&qctr=0&host=weblogic177:7001&comptype=Oracle WebLogic&comeFrom=topology&To=layerMode&isFromZone=null&iszoneName=&parentZone=null&tab=LayerModel&toDashBoardLayer=true"
}, {
    "cType": "Group",
    "cName": "hari11",
    "cImage_url": "/final/images/component_icons/group.png",
    "x": 283.99999999999994,
    "y": 49.99999999999999,
    "fixed": true,
    "AlarmPopup": "Group:hari11:NULL",
    "cStateImage_url": "/final/images/Light/state20_LOW.png",
    "linktoLayermodel": "/final/monitor/EgDisplayGroups.jsp?ptype=group&showsitesegments=false&group=hari11&serverType=Group&site=egurkha.physical.topology&segmentName=sample&fromHomepage=true"
}..

so the nodes always starting from left corner of the screen but i need to start it from center.

so how can i manipulate the existing x, y in the JSON data?

Answer 1

Exactly what Lars said.

force.on("tick", function() {
    nodes[0].x = w / 2;
    nodes[0].y = h / 2;}

this puts the first node in the middle of the screen (nodes[0] means first node) and if you want all the nodes to move to the right do something like this :

var movement = 200;

    node.attr("transform", function(d)
    { 
    return "translate(" + movement + "," + 0 + ")"; }); //Here you move the nodes
        ;

This basically goes through the nodes and moves every one to the right 200px. I did the same for the links :

link.attr("transform", function(d)
        { 
        return "translate(" + movement + "," + 0 + ")"; }); //Here you move the links
            ;

Updated JSFiddle : http://jsfiddle.net/aVhd8/159/