D3 V4 如何根据放大折线图移动点?

Question

小问题很难识别。我正在使用示例使用 d3 v4 创建折线图。我使用的是d3.line((而不是d3.area((。还在线峰值点上画圆圈。一切进展顺利。

问题出在绘制的圆圈上。当我缩放图形时，它们没有移动到正确的位置。 以下是完整的代码：

.area {
fill: none;
stroke: #a2dced;
stroke-width: 2;
clip-path: url(#clip);
}
.zoom {
cursor: move;
fill: none;
pointer-events: all;
}
rect.selection
{
	fill:green;
}

<script src="https://d3js.org/d3.v4.min.js"></script>
<svg width="960" height="500"></svg>
<script>
var data = [{date: "10:30:00", price: 36000},
			{date: "11:00:20", price: 40000},
			{date: "12:00:00", price: 38000},
			{date: "14:20:00", price: 50400}];
			
var svg = d3.select("svg"),
margin = {top: 20, right: 20, bottom: 110, left: 40},
margin2 = {top: 430, right: 20, bottom: 30, left: 40},
width = +svg.attr("width") - margin.left - margin.right,
height = +svg.attr("height") - margin.top - margin.bottom,
height2 = +svg.attr("height") - margin2.top - margin2.bottom;
var parseDate = d3.timeParse("%H:%M:%S");//"%b %Y");
var x = d3.scaleTime().range([0, width]),
x2 = d3.scaleTime().range([0, width]),
y = d3.scaleLinear().range([height, 0]),
y2 = d3.scaleLinear().range([height2, 0]);
var xAxis = d3.axisBottom(x),
xAxis2 = d3.axisBottom(x2),
yAxis = d3.axisLeft(y);
var brush = d3.brushX()
.extent([[0, 0], [width, height2]])
.on("brush end", brushed);
var zoom = d3.zoom()
.scaleExtent([1, Infinity])
.translateExtent([[0, 0], [width, height]])
.extent([[0, 0], [width, height]])
.on("zoom", zoomed);
var area = d3.line()
	//.curve(d3.curveMonotoneX)
	.x(function (d) {
		return x(d.date);
	})
	.y(function (d) {
		return y(d.price);
	});
				
var area2 = d3.line()
	.curve(d3.curveMonotoneX)
	.x(function (d) {
		return x2(d.date);
	})
	.y(function (d) {
		return y2(d.price);
	});
	
svg.append("defs").append("clipPath")
.attr("id", "clip")
.append("rect")
.attr("width", width)
.attr("height", height);
var focus = svg.append("g")
.attr("class", "focus")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var context = svg.append("g")
.attr("class", "context")
.attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");
function update(){	
	
	  for(var k in data)
		{
			type(data[k]);
		}	  
	  
	  x.domain(d3.extent(data, function(d) { return d.date; }));
	  y.domain([0, d3.max(data, function(d) { return d.price; })]);
	  x2.domain(x.domain());
	  y2.domain(y.domain());
focus.append("path")
		  .datum(data)
		  .attr("class", "area")
		  .attr("d", area);
	  focus.append("g")
		  .attr("class", "axis axis--x")
		  .attr("transform", "translate(0," + height + ")")
		  .call(xAxis);
	  focus.append("g")
		  .attr("class", "axis axis--y")
		  .call(yAxis);
	  focus.selectAll("circle")                                    
		  .data(data)                                         
		  .enter().append("circle") 
		  .attr("class","circle")	
		  .attr("r", 5)
		  .style("fill", 'orange')
		  .style("stroke", 'red')
		  .style("stroke-width", "2")
		  .attr("cx", function(d) { return x(d.date) })
		  .attr("cy", function(d) { return y(d.price); });
	
	  context.append("path")
		  .datum(data)
		  .attr("class", "area")
		  .attr("d", area2);
	  context.append("g")
		  .attr("class", "axis axis--x")
		  .attr("transform", "translate(0," + height2 + ")")
		  .call(xAxis2);
	
	  context.selectAll("circle")                                    
		  .data(data)                                         
		  .enter().append("circle") 
		  .attr("class","circle")	
		  .attr("r", 1)
		  .style("fill", 'blue')
		  .style("stroke", 'red')
		  .style("stroke-width", "2")
		  .attr("cx", function(d) { return x(d.date) })
		  .attr("cy", function(d) { return y(d.price); });	
	  context.append("g")
		  .attr("class", "brush")
		  .call(brush)
		  .call(brush.move, x.range());
	  svg.append("rect")
		  .attr("class", "zoom")
		  .attr("width", width)
		  .attr("height", height)
		  .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
		  .call(zoom);
}
function brushed() {
if (d3.event.sourceEvent && d3.event.sourceEvent.type === "zoom") return; // ignore brush-by-zoom
var s = d3.event.selection || x2.range();
x.domain(s.map(x2.invert, x2));
focus.select(".area").attr("d", area);

focus.selectAll('.circle').attr("transform", function(d) { 
	return "translate(" + x(d.date) + "," + y(d.price) + ")"; 
});


focus.select(".axis--x").call(xAxis);
svg.select(".zoom").call(zoom.transform, d3.zoomIdentity
.scale(width / (s[1] - s[0]))
.translate(-s[0], 0));
}
function zoomed() {
if (d3.event.sourceEvent && d3.event.sourceEvent.type === "brush") return; // ignore zoom-by-brush
var t = d3.event.transform;
x.domain(t.rescaleX(x2).domain());
focus.select(".area").attr("d", area);

focus.selectAll('.circle').attr("transform", function(d) { 
	return "translate(" + x(d.date) + "," + y(d.price) + ")"; 
});
		
focus.select(".axis--x").call(xAxis);
context.select(".brush").call(brush.move, x.range().map(t.invertX, t));
context.selectAll('.circle').attr("transform", function(d) { 
	return "translate(" + x2(d.date) + "," + y2(d.price) + ")"; 
});
}
function type(d) {
d.date = parseDate(d.date);
d.price = +d.price;
return d;
}
update();
</script>

JSFiddlelink.

Answer 1

我通过将transform属性更改为cx和cy来替换所有属性来更新您的 jsfiddle，例如：

以前

focus.selectAll('.circle').attr("transform", function(d) { 
return "translate(" + x(d.date) + "," + y(d.price) + ")"; 
});

后

focus.selectAll('.circle')
.attr("cx", function(d) { return x(d.date) })
.attr("cy", function(d) { return y(d.price); });

否则，您将使用其他坐标进行翻译，这可能会导致难以找到的问题