我有一个功能,当按下一个按钮时(几个按钮代表几种动物类型),该动物类型 SVG 会使用其相应的数据进行更新。我正在尝试复制 this zoom
功能,但在使用我的代码实现它时遇到问题。有几种 SVG 像这样在全局范围内使用(每种动物类型一个):
let x = d3.scaleLinear()
.domain([0, 1000])
.range([ 0, width ]);
var xAxis = d3.axisBottom(x);
svgReptile.append("g")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
const yAxis = d3.scaleLinear()
.domain([0, 220])
.range([ height, 0])
svgReptile.append("g")
.call(d3.axisLeft(yAxis))
按下其中一个动物按钮时调用以下函数。
function update(animal, whatSVG, xAxis, yAxis, color) {
const points = whatSVG
.selectAll("circle")
.data(data);
points.enter()
.append("circle")
.attr("cx", function(d) {
return xAxis(d.state);
})
.attr("cy", function(d) {
return yAxis(d.percentage);
})
.merge(points)
.attr("r", 3)
.attr("cx", function(d) {
return xAxis(d.decade)
})
.attr("cy", function(d) {
return yAxis(d.count)
})
.style("fill", function (d) { return colour(d.animal) } );
points.exit()
.attr('r', 0)
.remove();
}
问题:
我怎样才能像上面链接的那样实现在缩放(或类似的东西)时扩展 x 轴的缩放功能?
最佳答案
我认为您正在寻找问题最后一行的“画笔缩放”。
以下源代码来自 d3 graph gallery 中的示例
十字准线允许您选择要扩展的区域。如果你点击链接,上面有一个标题为“用轴缩放”的图表,但它不会按照你描述的方式放大,它只是移动轴,但不会用它放大图表内容。也许两者都有用!
希望对你有帮助
// set the dimensions and margins of the graph
var margin = {top: 10, right: 20, bottom: 20, left: 20},
width = 500 - margin.left - margin.right,
height = 400 - margin.top - margin.bottom;
// append the svg object to the body of the page
var Svg = d3.select("#brushZoom")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform",
"translate(" + margin.left + "," + margin.top + ")");
//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/iris.csv", function(data) {
// Add X axis
var x = d3.scaleLinear()
.domain([4, 8])
.range([ 0, width ]);
var xAxis = Svg.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
// Add Y axis
var y = d3.scaleLinear()
.domain([0, 9])
.range([ height, 0]);
Svg.append("g")
.call(d3.axisLeft(y));
// Add a clipPath: everything out of this area won't be drawn.
var clip = Svg.append("defs").append("svg:clipPath")
.attr("id", "clip")
.append("svg:rect")
.attr("width", width )
.attr("height", height )
.attr("x", 0)
.attr("y", 0);
// Color scale: give me a specie name, I return a color
var color = d3.scaleOrdinal()
.domain(["setosa", "versicolor", "virginica" ])
.range([ "#440154ff", "#21908dff", "#fde725ff"])
// Add brushing
var brush = d3.brushX() // Add the brush feature using the d3.brush function
.extent( [ [0,0], [width,height] ] ) // initialise the brush area: start at 0,0 and finishes at width,height: it means I select the whole graph area
.on("end", updateChart) // Each time the brush selection changes, trigger the 'updateChart' function
// Create the scatter variable: where both the circles and the brush take place
var scatter = Svg.append('g')
.attr("clip-path", "url(#clip)")
// Add circles
scatter
.selectAll("circle")
.data(data)
.enter()
.append("circle")
.attr("cx", function (d) { return x(d.Sepal_Length); } )
.attr("cy", function (d) { return y(d.Petal_Length); } )
.attr("r", 8)
.style("fill", function (d) { return color(d.Species) } )
.style("opacity", 0.5)
// Add the brushing
scatter
.append("g")
.attr("class", "brush")
.call(brush);
// A function that set idleTimeOut to null
var idleTimeout
function idled() { idleTimeout = null; }
// A function that update the chart for given boundaries
function updateChart() {
extent = d3.event.selection
// If no selection, back to initial coordinate. Otherwise, update X axis domain
if(!extent){
if (!idleTimeout) return idleTimeout = setTimeout(idled, 350); // This allows to wait a little bit
x.domain([ 4,8])
}else{
x.domain([ x.invert(extent[0]), x.invert(extent[1]) ])
scatter.select(".brush").call(brush.move, null) // This remove the grey brush area as soon as the selection has been done
}
// Update axis and circle position
xAxis.transition().duration(1000).call(d3.axisBottom(x))
scatter
.selectAll("circle")
.transition().duration(1000)
.attr("cx", function (d) { return x(d.Sepal_Length); } )
.attr("cy", function (d) { return y(d.Petal_Length); } )
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.13.0/d3.min.js"></script>
<div id="brushZoom"></div>
关于javascript - 在 D3 中创建缩放功能,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56315855/