我试图实现一个简单的力布局,其中节点(没有链接)可以动态添加和删除。我成功地在D3版本3中实现了这个概念,但我无法将其转化为版本4。在添加和更新节点后,模拟冻结,并在svg的左上角绘制传入的圆圈。有人知道为什么会这样吗?谢谢你的帮助:)
我的概念是基于这个解决方案:向强制布局添加新节点
JSFiddle:在d3 v3中的工作代码
/* Define class */
class Planet {
constructor(selector) {
this.w = $(selector).innerWidth();
this.h = $(selector).innerHeight();
this.svg = d3.select(selector)
.append('svg')
.attr('width', this.w)
.attr('height', this.h);
this.force = d3.layout.force()
.gravity(0.05)
.charge(-100)
.size([this.w, this.h]);
this.nodes = this.force.nodes();
}
/* Methods (are called on object) */
update() {
/* Join selection to data array -> results in three new selections enter, update and exit */
const circles = this.svg.selectAll('circle')
.data(this.nodes, d => d.id); // arrow function, function(d) { return d.y;}
/* Add missing elements by calling append on enter selection */
circles.enter()
.append('circle')
.attr('r', 10)
.style('fill', 'steelblue')
.call(this.force.drag);
/* Remove surplus elements from exit selection */
circles.exit()
.remove();
this.force.on('tick', () => {
circles.attr('cx', d => d.x)
.attr('cy', d => d.y);
});
/* Restart the force layout */
this.force.start();
}
addThought(content) {
this.nodes.push({ id: content });
this.update();
}
findThoughtIndex(content) {
return this.nodes.findIndex(node => node.id === content);
}
removeThought(content) {
const index = this.findThoughtIndex(content);
if (index !== -1) {
this.nodes.splice(index, 1);
this.update();
}
}
}
/* Instantiate class planet with selector and initial data*/
const planet = new Planet('.planet');
planet.addThought('Hallo');
planet.addThought('Ballo');
planet.addThought('Yallo');
这是我将代码翻译成v4的意图:
/* Define class */
class Planet {
constructor(selector) {
this.w = $(selector).innerWidth();
this.h = $(selector).innerHeight();
this.svg = d3.select(selector)
.append('svg')
.attr('width', this.w)
.attr('height', this.h);
this.simulation = d3.forceSimulation()
.force('charge', d3.forceManyBody())
.force('center', d3.forceCenter(this.w / 2, this.h / 2));
this.nodes = this.simulation.nodes();
}
/* Methods (are called on object) */
update() {
/* Join selection to data array -> results in three new selections enter, update and exit */
let circles = this.svg.selectAll('circle')
.data(this.nodes, d => d.id); // arrow function, function(d) { return d.y;}
/* Add missing elements by calling append on enter selection */
const circlesEnter = circles.enter()
.append('circle')
.attr('r', 10)
.style('fill', 'steelblue');
circles = circlesEnter.merge(circles);
/* Remove surplus elements from exit selection */
circles.exit()
.remove();
this.simulation.on('tick', () => {
circles.attr('cx', d => d.x)
.attr('cy', d => d.y);
});
/* Assign nodes to simulation */
this.simulation.nodes(this.nodes);
/* Restart the force layout */
this.simulation.restart();
}
addThought(content) {
this.nodes.push({ id: content });
this.update();
}
findThoughtIndex(content) {
return this.nodes.findIndex(node => node.id === content);
}
removeThought(content) {
const index = this.findThoughtIndex(content);
if (index !== -1) {
this.nodes.splice(index, 1);
this.update();
}
}
}
请参见plunkr示例
我使用画布,但理论是一样的:
你必须先给你的新的数组的节点和链接到D3的核心功能,然后再添加到原来的数组。
drawData: function(graph){
var countExtent = d3.extent(graph.nodes,function(d){return d.connections}),
radiusScale = d3.scalePow().exponent(2).domain(countExtent).range(this.nodes.sizeRange);
// Let D3 figure out the forces
for(var i=0,ii=graph.nodes.length;i<ii;i++) {
var node = graph.nodes[i];
node.r = radiusScale(node.connections);
node.force = this.forceScale(node);
};
// Concat new and old data
this.graph.nodes = this.graph.nodes.concat(graph.nodes);
this.graph.links = this.graph.links.concat(graph.links);
// Feed to simulation
this.simulation
.nodes(this.graph.nodes);
this.simulation.force("link")
.links(this.graph.links);
this.simulation.alpha(0.3).restart();
}
之后,告诉D3用新数据重启。
当D3调用您的tick()
函数时,它已经知道您需要将什么坐标应用于SVG元素。
ticked: function(){
if(!this.graph) {
return false;
}
this.context.clearRect(0,0,this.width,this.height);
this.context.save();
this.context.translate(this.width / 2, this.height / 2);
this.context.beginPath();
this.graph.links.forEach((d)=>{
this.context.moveTo(d.source.x, d.source.y);
this.context.lineTo(d.target.x, d.target.y);
});
this.context.strokeStyle = this.lines.stroke.color;
this.context.lineWidth = this.lines.stroke.thickness;
this.context.stroke();
this.graph.nodes.forEach((d)=>{
this.context.beginPath();
this.context.moveTo(d.x + d.r, d.y);
this.context.arc(d.x, d.y, d.r, 0, 2 * Math.PI);
this.context.fillStyle = d.colour;
this.context.strokeStyle =this.nodes.stroke.color;
this.context.lineWidth = this.nodes.stroke.thickness;
this.context.fill();
this.context.stroke();
});
this.context.restore();
}
Plunkr示例