I have a project where I need to recreate a gradient chart. I have found some documentation online on how to recreate a area chart with gradient: Documentation.
The main problem is that I cannot get this code to work. I have changed it to work with my data and the chart won't show up. The axis are being rendered correctly. But the chart itself doesn't show up.
I have replaced the var x = d3.scaleTime().range([0, width]); to var x = d3.scaleBand().range([0, width]); because in the documentation they were working with Date object on the x axis.
There are no console errors but the chart won't simply show up. The code seems very straight forward but I can't seem to get what is wrong with it. I am very new to D3.js and still learning a lot about the library.
<!DOCTYPE html>
<html>
<head>
<title></title>
<script src="https://unpkg.com/vue"></script>
<script src="https://d3js.org/d3.v6.js"></script>
</head>
<body>
<div class="p-3 flex flex-col" id="one">
<div class="w-full flex-1">
<div id="chart"></div>
</div>
</div>
<script>
new Vue({
el: '#one',
data: {
type: Array,
required: true,
},
mounted() {
// set the dimensions and margins of the graph
var margin = { top: 20, right: 20, bottom: 30, left: 50 },
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
// append the svg obgect to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3
.select("#chart")
.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 + ")");
var data = [
{
date: "Jan",
value: 1507
},
{
date: "Feb",
value: 1600
},
{
date: "Mar",
value: 1281
},
{
date: "Apr",
value: 1898
},
{
date: "May",
value: 1749
},
{
date: "June",
value: 1270
},
{
date: "July",
value: 1712
},
{
date: "Aug",
value: 1270
},
{
date: "Sept",
value: 1257
},
{
date: "Oct",
value: 1257
},
{
date: "Nov",
value: 1257
},
{
date: "Dec",
value: 1257
}
];
// set the ranges
var x = d3.scaleBand().range([0, width]);
var y = d3.scaleLinear().rangeRound([height, 0]);
// define the area
var area = d3
.area()
.x(function(d) {
console.log(d.date);
console.log(x.domain());
return x(d.date);
})
.y(function(d) {
console.log(d.value);
console.log(y.domain());
return y(d.value);
});
x.domain(
data.map(function(d) {
return d.date;
})
);
y.domain([
0,
d3.max(data, function(d) {
return d.value;
})
]);
// set the gradient
svg
.append("linearGradient")
.attr("id", "area-gradient")
.attr("gradientUnits", "userSpaceOnUse")
.attr("x1", 0)
.attr("y1", y(0))
.attr("x2", 0)
.attr("y2", y(1000))
.selectAll("stop")
.data([
{ offset: "0%", color: "red" },
{ offset: "30%", color: "red" },
{ offset: "45%", color: "black" },
{ offset: "55%", color: "black" },
{ offset: "60%", color: "lawngreen" },
{ offset: "100%", color: "lawngreen" }
])
.enter()
.append("stop")
.attr("offset", function(d) {
return d.offset;
})
.attr("stop-color", function(d) {
return d.color;
});
// Add the area.
svg
.append("path")
.datum(data)
.attr("class", "area")
.attr("d", area);
// Add the X Axis
svg
.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
// Add the Y Axis
svg.append("g").call(d3.axisLeft(y));
}
});
</script>
</body>
</html>Couple things.
First, you missed the css which sets the path to fill with the gradient:
.area {
fill: url(#area-gradient);
stroke-width: 0px;
}
Second, in order to draw an "area" the d3.area generator requires .y0 and .y1 accessors. It's what says fill from here to there.
var area = d3
.area()
.x(function (d) {
return x(d.date);
})
.y1(function (d) {
return y(d.value);
})
.y0(height);
Running snippet:
<!DOCTYPE html>
<html>
<head>
<title></title>
<script src="https://unpkg.com/vue"></script>
<script src="https://d3js.org/d3.v6.js"></script>
<style>
.area {
fill: url(#area-gradient);
stroke-width: 0px;
}
</style>
</head>
<body>
<div class="p-3 flex flex-col" id="one">
<div class="w-full flex-1">
<div id="chart"></div>
</div>
</div>
<script>
new Vue({
el: '#one',
data: {
type: Array,
required: true,
},
mounted() {
// set the dimensions and margins of the graph
var margin = { top: 20, right: 20, bottom: 30, left: 50 },
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
// append the svg obgect to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3
.select('#chart')
.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 + ')'
);
var data = [
{
date: 'Jan',
value: 1507,
},
{
date: 'Feb',
value: 1600,
},
{
date: 'Mar',
value: 1281,
},
{
date: 'Apr',
value: 1898,
},
{
date: 'May',
value: 1749,
},
{
date: 'June',
value: 1270,
},
{
date: 'July',
value: 1712,
},
{
date: 'Aug',
value: 1270,
},
{
date: 'Sept',
value: 1257,
},
{
date: 'Oct',
value: 1257,
},
{
date: 'Nov',
value: 1257,
},
{
date: 'Dec',
value: 1257,
},
];
// set the ranges
var x = d3.scaleBand().range([0, width]);
var y = d3.scaleLinear().rangeRound([height, 0]);
// define the area
var area = d3
.area()
.x(function (d) {
return x(d.date);
})
.y1(function (d) {
return y(d.value);
})
.y0(height);
x.domain(
data.map(function (d) {
return d.date;
})
);
y.domain([
0,
d3.max(data, function (d) {
return d.value;
}),
]);
// set the gradient
svg
.append('linearGradient')
.attr('id', 'area-gradient')
.attr('gradientUnits', 'userSpaceOnUse')
.attr('x1', 0)
.attr('y1', y(0))
.attr('x2', 0)
.attr('y2', y(1000))
.selectAll('stop')
.data([
{ offset: '0%', color: 'red' },
{ offset: '30%', color: 'red' },
{ offset: '45%', color: 'black' },
{ offset: '55%', color: 'black' },
{ offset: '60%', color: 'lawngreen' },
{ offset: '100%', color: 'lawngreen' },
])
.enter()
.append('stop')
.attr('offset', function (d) {
return d.offset;
})
.attr('stop-color', function (d) {
return d.color;
});
// Add the area.
svg.append('path').datum(data).attr('class', 'area').attr('d', area);
// Add the X Axis
svg
.append('g')
.attr('transform', 'translate(0,' + height + ')')
.call(d3.axisBottom(x));
// Add the Y Axis
svg.append('g').call(d3.axisLeft(y));
},
});
</script>
</body>
</html>