我在使用 d3 创建多个力布局图并从 json 文件中读取数据时遇到问题。我使用 for 循环遍历图形，为每个图形创建一个包含 svg 的单独 div。问题是，强制布局只应用于最后一个创建的布局，所以基本上其他布局只在左上角显示一个点。我可以通过在每次迭代结束时放置一个 for 循环来部分解决它，但我仍然失去了单独图形的交互能力。
找到下面的代码，在此先感谢。
干杯，迈克尔
var color = d3.scale.category20();
var force = new Array();
var div = new Array();
var svg = new Array();
var graph = new Array();
var link;
var node;
var width = 360;
var height = 360;
var brush = new Array();
var shiftKey;
var count = 0;
//loop through the different subsystems in the json-file
for(name_subsystem in graphs) {
//add a div for each subsystem
div[count] = document.createElement("div");
div[count].style.width = "360px";
div[count].style.height = "360px";
div[count].style.cssFloat="left";
div[count].id = name_subsystem;
document.body.appendChild(div[count]);
//force is called. all attributes with default values are noted. see API reference on github.
force[count] = d3.layout.force()
.size([width, height])
.linkDistance(20)
.linkStrength(1)
.friction(0.9)
.charge(-30)
.theta(0.8)
.gravity(0.1);
div[count].appendChild(document.createTextNode(name_subsystem));
//create the svg rectangle in which other elements can be visualised
svg[count] = d3.select("#"+name_subsystem)
.on("keydown.brush", keydown)
.on("keyup.brush", keyup)
.append("svg")
.attr("width", width)
.attr("height", height)
.attr("id",name_subsystem);
brush[count] = svg[count].append("g")
.datum(function() { return {selected: false, previouslySelected: false}; })
.attr("class", "brush");
//force is started
force[count]
.nodes(graphs[name_subsystem].nodes)
.links(graphs[name_subsystem].links)
.start();
//link elements are called, joined with the data, and links are created for each link object in links
link = svg[count].selectAll(".link")
.data(graphs[name_subsystem].links)
.enter().append("line")
.attr("class", "link")
.style("stroke-width", function(d) { return Math.sqrt(d.thickness); })
.style("stroke", function(d){
if (d.linktype === 'reactant'){
return "black";
} else {
return "red";
}
});
//node elements are called, joined with the data, and circles are created for each node object in nodes
node = svg[count].selectAll(".node")
.data(graphs[name_subsystem].nodes)
.enter().append("circle")
.attr("class", "node")
//radius
.attr("r", 5)
//fill
.attr("fill", function(d) {
if (d.type === 'metabolite') {
return "blue";
} else {
return "red";
}
})
.on("mousedown", function(d) {
if (!d.selected) { // Don't deselect on shift-drag.
if (!shiftKey) node.classed("selected", function(p) { return p.selected = d === p; });
else d3.select(this).classed("selected", d.selected = true);
}
})
.on("mouseup", function(d) {
if (d.selected && shiftKey) d3.select(this).classed("selected", d.selected = false);
})
.call(force[count].drag()
.on("dragstart",function dragstart(d){
d.fixed=true;
d3.select(this).classed("fixed",true);
})
);
//gives titles to nodes. i do not know why this is separated from the first node calling.
node.append("title")
.text(function(d) { return d.name; });
//enable brushing of the network
brush[count].call(d3.svg.brush()
.x(d3.scale.identity().domain([0, width]))
.y(d3.scale.identity().domain([0, height]))
.on("brushstart", function(d) {
node.each(function(d) { d.previouslySelected = shiftKey && d.selected; });
})
.on("brush", function() {
var extent = d3.event.target.extent();
node.classed("selected", function(d) {
return d.selected = d.previouslySelected ^
(extent[0][0] <= d.x && d.x < extent[1][0]
&& extent[0][1] <= d.y && d.y < extent[1][1]);
});
})
.on("brushend", function() {
d3.event.target.clear();
d3.select(this).call(d3.event.target);
})
);
//applies force per step or 'tick'.
force[count].on("tick", function() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; });
});
//with this it works partly
//for (var i = 0; i < 5000; ++i)force[count].tick();
count++;
};
function keydown() {
if (!d3.event.metaKey) switch (d3.event.keyCode) {
case 38: nudge( 0, -1); break; // UP
case 40: nudge( 0, +1); break; // DOWN
case 37: nudge(-1, 0); break; // LEFT
case 39: nudge(+1, 0); break; // RIGHT
}
shiftKey = d3.event.shiftKey || d3.event.metaKey;
}
function keyup() {
shiftKey = d3.event.shiftKey || d3.event.metaKey;
}
编辑：评论后更新了代码，仍然是同样的问题。