利用 Mike Bostocks 美国各县区 block :https://bl.ocks.org/mbostock/4122298 。
目标是创建一个鼠标移动函数，在事件期间鼠标移动将突出显示所有选定的县。当前示例仅突出显示使用 :hover 并且不保留选择。
<!DOCTYPE html>
<style>
.counties :hover {
fill: red;
}
.county-borders {
fill: none;
stroke: #fff;
stroke-width: 0.5px;
stroke-linejoin: round;
stroke-linecap: round;
pointer-events: none;
}
</style>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<script>
var svg = d3.select("svg");
var path = d3.geoPath();
d3.json("https://d3js.org/us-10m.v1.json", function(error, us) {
if (error) throw error;
svg.append("g")
.attr("class", "counties")
.selectAll("path")
.data(topojson.feature(us, us.objects.counties).features)
.enter().append("path")
.attr("d", path);
svg.append("path")
.attr("class", "county-borders")
.attr("d", path(topojson.mesh(us, us.objects.counties, function(a, b) { return a !== b; })));
});
</script>
最佳答案
请参阅我的片段 - 这就是我的理解。您需要使用 JavaScript 事件和类，因为 CSS 无法更改状态。
var svg = d3.select("svg");
var path = d3.geoPath();
d3.json("https://d3js.org/us-10m.v1.json", function(error, us) {
if (error) throw error;
svg.append("g")
.attr("class", "counties")
.selectAll("path")
.data(topojson.feature(us, us.objects.counties).features)
.enter()
.append("path")
.attr("d", path);
// the following block is new, adding JS events
let hoverEnabled = false;
svg.on('mousedown', x => hoverEnabled = true)
.on('mouseup', x => hoverEnabled = false)
svg.selectAll('.counties path').on('mouseover', function() {
if (hoverEnabled) {
this.classList.add('hovered');
}
});
svg.append("path")
.attr("class", "county-borders")
.attr("d", path(topojson.mesh(us, us.objects.counties, function(a, b) { return a !== b; })));
});/* paths with class "hovered" need to be selected here, too */
.counties .hovered, .counties :hover {
fill: red;
}
.county-borders {
fill: none;
stroke: #fff;
stroke-width: 0.5px;
stroke-linejoin: round;
stroke-linecap: round;
pointer-events: none;
}<!DOCTYPE html>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>关于javascript - d3.js topojson 县/州 map 上的鼠标移动功能 - 按住单击可选择多个县，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/42955816/