所有其他示例都帶有svg.append()的鼠標事件....我不知道在哪裏「輸入」以獲取畫布渲染器中的弧,並在v4樣式中添加.on('click', function(){})
。我想點擊以獲得d
的值。在這個例子中,我在哪裏添加處理程序?我理解這個例子下面的老方法。如何添加鼠標事件以強制使用d3畫布渲染器的有向圖?
可能是這樣的工作? d3.select(canvas).call(d3.mouse()).on("click", ...)
var links = d3.range(nodes.length - 1).map(function(i) {
return {
source: Math.floor(Math.sqrt(i)),
target: i + 1
};
});
var simulation = d3.forceSimulation(nodes)
.force("charge", d3.forceManyBody())
.force("link", d3.forceLink(links).distance(20).strength(1))
.force("x", d3.forceX())
.force("y", d3.forceY())
.on("tick", ticked);
var canvas = document.querySelector("canvas"),
context = canvas.getContext("2d"),
width = canvas.width,
height = canvas.height;
d3.select(canvas)
.call(d3.drag()
.container(canvas)
.subject(dragsubject)
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended));
function ticked() {
context.clearRect(0, 0, width, height);
context.save();
context.translate(width/2, height/2);
context.beginPath();
links.forEach(drawLink);
context.strokeStyle = "#aaa";
context.stroke();
context.beginPath();
nodes.forEach(drawNode);
context.fill();
context.strokeStyle = "#fff";
context.stroke();
context.restore();
}
function dragsubject() {
return simulation.find(d3.event.x - width/2, d3.event.y - height/2);
}
function dragstarted() {
if (!d3.event.active) simulation.alphaTarget(0.3).restart();
d3.event.subject.fx = d3.event.subject.x;
d3.event.subject.fy = d3.event.subject.y;
}
function dragged() {
d3.event.subject.fx = d3.event.x;
d3.event.subject.fy = d3.event.y;
}
function dragended() {
if (!d3.event.active) simulation.alphaTarget(0);
d3.event.subject.fx = null;
d3.event.subject.fy = null;
}
function drawLink(d) {
context.moveTo(d.source.x, d.source.y);
context.lineTo(d.target.x, d.target.y);
}
function drawNode(d) {
context.moveTo(d.x + 3, d.y);
context.arc(d.x, d.y, 3, 0, 2 * Math.PI);
}
老辦法
var node = svg.append("g")
.attr("class", "nodes")
.selectAll("circle")
.data(graph.nodes)
.enter().append("circle")
.attr("r", 8)
.attr("fill", function(d) { return color(d.group); })
.on("click", togglenode)
.call(d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended));
肯定有帆布正確的方式做d3.mouse()或東西嗎?我最終使用了從畫布上的d3.drag()模塊開始拖動。我會想象它只是將全局鼠標座標轉換爲畫布的座標空間。 – FlavorScape