我有一个可缩放的热力图，但在缩放时看起来非常缓慢。是否有任何方法可以使其更快/更流畅，或者这只是因为点太多而已达到了最佳效果。我想知道是否有一些诀窍可以让浏览器更轻松地处理它，同时保持像工具提示这样的增强功能。或者也许我的处理缩放功能的代码不是很好。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<style>
.axis text {
font: 10px sans-serif;
}
.axis path,
.axis line {
fill: none;
stroke: #000000;
}
.x.axis path {
//display: none;
}
.chart rect {
fill: steelblue;
}
.chart text {
fill: white;
font: 10px sans-serif;
text-anchor: end;
}
#tooltip {
position:absolute;
background-color: #2B292E;
color: white;
font-family: sans-serif;
font-size: 15px;
pointer-events: none; /*dont trigger events on the tooltip*/
padding: 15px 20px 10px 20px;
text-align: center;
opacity: 0;
border-radius: 4px;
}
</style>
<title>Bar Chart</title>
<!-- Reference style.css -->
<!-- <link rel="stylesheet" type="text/css" href="style.css">-->
<!-- Reference minified version of D3 -->
<script src='https://d3js.org/d3.v4.min.js' type='text/javascript'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js'></script>
</head>
<body>
<div id="chart" style="width: 700px; height: 500px"></div>
<script>
var dataset = [];
for (let i = 1; i < 360; i++) {
for (j = 1; j < 75; j++) {
dataset.push({
day: i,
hour: j,
tOutC: Math.random() * 25,
})
}
};
var days = d3.max(dataset, function(d) {
return d.day;
}) -
d3.min(dataset, function(d) {
return d.day;
});
var hours = d3.max(dataset, function(d) {
return d.hour;
}) -
d3.min(dataset, function(d) {
return d.hour;
});
var tMin = d3.min(dataset, function(d) {
return d.tOutC;
}),
tMax = d3.max(dataset, function(d) {
return d.tOutC;
});
var dotWidth = 1,
dotHeight = 3,
dotSpacing = 0.5;
var margin = {
top: 0,
right: 25,
bottom: 40,
left: 25
},
width = (dotWidth * 2 + dotSpacing) * days,
height = (dotHeight * 2 + dotSpacing) * hours;
var colors = ['#2C7BB6', '#00A6CA','#00CCBC','#90EB9D','#FFFF8C','#F9D057','#F29E2E','#E76818','#D7191C'];
var xScale = d3.scaleLinear()
.domain(d3.extent(dataset, function(d){return d.day}))
.range([0, width]);
var yScale = d3.scaleLinear()
.domain(d3.extent(dataset, function(d){return d.hour}))
.range([(dotHeight * 2 + dotSpacing) * hours, dotHeight * 2 + dotSpacing]);
var colorScale = d3.scaleQuantile()
.domain([0, colors.length - 1, d3.max(dataset, function(d) {
return d.tOutC;
})])
.range(colors);
var xAxis = d3.axisBottom().scale(xScale);
// Define Y axis
var yAxis = d3.axisLeft().scale(yScale);
var zoom = d3.zoom()
.scaleExtent([dotWidth, dotHeight])
.translateExtent([
[80, 20],
[width, height]
])
.on("zoom", zoomed);
var tooltip = d3.select("body").append("div")
.attr("id", "tooltip")
.style("opacity", 0);
// SVG canvas
var svg = d3.select("#chart")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.call(zoom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
// Clip path
svg.append("clipPath")
.attr("id", "clip")
.append("rect")
.attr("width", width)
.attr("height", height);
// Heatmap dots
svg.append("g")
.attr("clip-path", "url(#clip)")
.selectAll("ellipse")
.data(dataset)
.enter()
.append("ellipse")
.attr("cx", function(d) {
return xScale(d.day);
})
.attr("cy", function(d) {
return yScale(d.hour);
})
.attr("rx", dotWidth)
.attr("ry", dotHeight)
.attr("fill", function(d) {
return colorScale(d.tOutC);
})
.on("mouseover", function(d){
$("#tooltip").html("X: "+d.day+"<br/>Y:"+d.hour+"<br/>Value:"+Math.round(d.tOutC*100)/100);
var xpos = d3.event.pageX +10;
var ypos = d3.event.pageY +20;
$("#tooltip").css("left",xpos+"px").css("top",ypos+"px").animate().css("opacity",1);
}).on("mouseout", function(){
$("#tooltip").animate({duration: 500}).css("opacity",0);
});
//Create X axis
var renderXAxis = svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + yScale(0) + ")")
.call(xAxis)
//Create Y axis
var renderYAxis = svg.append("g")
.attr("class", "y axis")
.call(yAxis);
function zoomed() {
// update: rescale x axis
renderXAxis.call(xAxis.scale(d3.event.transform.rescaleX(xScale)));
update();
}
function update() {
// update: cache rescaleX value
var rescaleX = d3.event.transform.rescaleX(xScale);
svg.selectAll("ellipse")
.attr('clip-path', 'url(#clip)')
// update: apply rescaleX value
.attr("cx", function(d) {
return rescaleX(d.day);
})
// .attr("cy", function(d) {
// return yScale(d.hour);
// })
// update: apply rescaleX value
.attr("rx", function(d) {
return (dotWidth * d3.event.transform.k);
})
.attr("fill", function(d) {
return colorScale(d.tOutC);
});
}
</script>
</body>
</html>谢谢