javascript-D3.js画笔行为触发两个“结束”事件
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了javascript-D3.js画笔行为触发两个“结束”事件，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含4509字，纯文字阅读大概需要7分钟。
内容图文
因此,实现受M Bostock example启发的画笔行为时,我遇到了一些我不太了解的东西.
如果为画笔的“ end”事件设置了回调,则当您直接与画笔进行交互时,将按预期方式调用该回调.
但是,每当我重新整理画笔时,似乎结束事件都会触发两次.
为什么会这样？还是我在这里做错了什么？
<!DOCTYPE html>
<style>
.selected {
fill: red;
stroke: brown;
}
</style>
<svg width="960" height="150"></svg>
<div>Event fired <span id="test"></span></div>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var fired=0;
var randomX = d3.randomUniform(0, 10),
randomY = d3.randomNormal(0.5, 0.12),
data = d3.range(800).map(function() { return [randomX(), randomY()]; });
var svg = d3.select("svg"),
margin = {top: 10, right: 50, bottom: 30, left: 50},
width = +svg.attr("width") - margin.left - margin.right,
height = +svg.attr("height") - margin.top - margin.bottom,
g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var x = d3.scaleLinear()
.domain([0, 10])
.range([0, width]);
var y = d3.scaleLinear()
.range([height, 0]);
var brush = d3.brushX()
.extent([[0, 0], [width, height]])
.on("start brush", brushed)
.on("end", brushend);
var dot = g.append("g")
.attr("fill-opacity", 0.2)
.selectAll("circle")
.data(data)
.enter().append("circle")
.attr("transform", function(d) { return "translate(" + x(d[0]) + "," + y(d[1]) + ")"; })
.attr("r", 3.5);
g.append("g")
.call(brush)
.call(brush.move, [3, 5].map(x))
.selectAll(".overlay")
.each(function(d) { d.type = "selection"; }) // Treat overlay interaction as move.
.on("mousedown touchstart", brushcentered); // Recenter before brushing.
g.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
function brushcentered() {
var dx = x(1) - x(0), // Use a fixed width when recentering.
cx = d3.mouse(this)[0],
x0 = cx - dx / 2,
x1 = cx + dx / 2;
d3.select(this.parentNode).call(brush.move, x1 > width ? [width - dx, width] : x0 < 0 ? [0, dx] : [x0, x1]);
}
function brushed() {
var extent = d3.event.selection.map(x.invert, x);
dot.classed("selected", function(d) { return extent[0] <= d[0] && d[0] <= extent[1]; });
}
function brushend() {
document.getElementById('test').innerHTML = ++fired;
// console.log('end fired - ' + (++fired));
}
</script>解决方法:
每当您希望停止某个事件触发多层操作时,都可以使用：
d3.event.stopPropagation();
在此处,您可以将其包括在brushcentered函数的末尾：
function brushcentered() {
var dx = x(1) - x(0), // Use a fixed width when recentering.
cx = d3.mouse(this)[0],
x0 = cx - dx / 2,
x1 = cx + dx / 2;
d3.select(this.parentNode).call(brush.move, x1 > width ? [width - dx, width] : x0 < 0 ? [0, dx] : [x0, x1]);
d3.event.stopPropagation();
}
和演示：
<style>
.selected {
fill: red;
stroke: brown;
}
</style>
<svg width="960" height="150"></svg>
<div>Event fired <span id="test"></span></div>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var fired=0;
var randomX = d3.randomUniform(0, 10),
randomY = d3.randomNormal(0.5, 0.12),
data = d3.range(800).map(function() { return [randomX(), randomY()]; });
var svg = d3.select("svg"),
margin = {top: 10, right: 50, bottom: 30, left: 50},
width = +svg.attr("width") - margin.left - margin.right,
height = +svg.attr("height") - margin.top - margin.bottom,
g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var x = d3.scaleLinear()
.domain([0, 10])
.range([0, width]);
var y = d3.scaleLinear()
.range([height, 0]);
var brush = d3.brushX()
.extent([[0, 0], [width, height]])
.on("start brush", brushed)
.on("end", brushend);
var dot = g.append("g")
.attr("fill-opacity", 0.2)
.selectAll("circle")
.data(data)
.enter().append("circle")
.attr("transform", function(d) { return "translate(" + x(d[0]) + "," + y(d[1]) + ")"; })
.attr("r", 3.5);
g.append("g")
.call(brush)
.call(brush.move, [3, 5].map(x))
.selectAll(".overlay")
.each(function(d) { d.type = "selection"; }) // Treat overlay interaction as move.
.on("mousedown touchstart", brushcentered); // Recenter before brushing.
g.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
function brushcentered() {
var dx = x(1) - x(0), // Use a fixed width when recentering.
cx = d3.mouse(this)[0],
x0 = cx - dx / 2,
x1 = cx + dx / 2;
d3.select(this.parentNode).call(brush.move, x1 > width ? [width - dx, width] : x0 < 0 ? [0, dx] : [x0, x1]);
d3.event.stopPropagation();
}
function brushed() {
var extent = d3.event.selection.map(x.invert, x);
dot.classed("selected", function(d) { return extent[0] <= d[0] && d[0] <= extent[1]; });
}
function brushend() {
document.getElementById('test').innerHTML = ++fired;
}
</script>内容总结
以上是互联网集市为您收集整理的javascript-D3.js画笔行为触发两个“结束”事件全部内容，希望文章能够帮你解决javascript-D3.js画笔行为触发两个“结束”事件所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。
来源：【匿名】