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@aurelient
Last active December 11, 2019 23:28
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Manually Sortable D3 Barchart
license: mit
<!DOCTYPE html>
<html lang="en">
<style>
.axis {
font: 10px sans-serif;
}
.axis path,
.axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
</style>
<head>
<script src="https://d3js.org/d3.v5.min.js" charset="utf-8"></script>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div id="vis"></div>
<script>
var height = 300,
width = 500,
padding = { top: 20, left: 20, right: 20, bottom: 20},
xScale = d3.scale.ordinal(),
yScale = d3.scale.linear(),
svg = d3.select("#vis").append("svg").attr("width", width).attr("height", height),
color = d3.scale.category10(),
xAxis = d3.svg.axis(),
data = [
{ category: "A", value: 50 },
{ category: "B", value: 30 },
{ category: "C", value: 20 },
{ category: "D", value: 20 },
],
drag = d3.behavior.drag()
.on("dragstart", function(){
var bar = d3.select(this),
mouseX = d3.mouse(this)[0],
barX = +bar.attr("x");
/* Keep at which x coordinate the bar is drawn when the dragging starts */
bar.property("startX", barX)
/* Since x of the bar starts at the top-left corner of the rect,
Here, calculate how much the x of the current bar is apart from the x of the mouse */
bar.property("xDiff", mouseX - barX);
/* Bring the bar to the front */
bar.node().parentNode.appendChild(bar.node());
})
.on("drag", function(){
var curBar = d3.select(this),
curIdx = data.indexOf(curBar.datum()),
startX = curBar.property("startX"),
mouseX = d3.mouse(this)[0],
newX = mouseX - curBar.property("xDiff"),
xRange = (xScale.range()[1] - xScale.range()[0]) / 2,
backlash = xScale.rangeBand() / 2.5,
nearestBar, nearestIdx, nearestX;
if (newX < xScale.range()[0] - backlash
|| xScale.range()[data.length - 1] + backlash < newX)
return;
curBar.attr("x", newX);
/* Get the index of the nearest bar */
if (curIdx == 0)
nearestIdx = 1;
else if (newX < startX || curIdx == data.length - 1)
nearestIdx = curIdx - 1;
else
nearestIdx = curIdx + 1;
nearestBar = d3.selectAll(".bar").filter(function(d) { return d == data[nearestIdx]; });
nearestX = +nearestBar.attr("x");
/* If the current bar is moved close enough to the nearest bar,
then update the order of the data array. For example, if we are dragging
the first bar and moving to right, the order will be [a, b, c] to [b, a, c] */
if (startX + xRange < newX || newX < startX - xRange) {
var tmp = data[curIdx];
data[curIdx] = data[nearestIdx];
data[nearestIdx] = tmp;
curBar.property("startX", nearestX);
xScale.domain(data.map(function(d){ return d.category; }));
d3.select(".x.axis").transition().duration(200).call(xAxis.scale(xScale));
nearestBar.transition().duration(100).attr("x", xScale(nearestBar.datum().category));
}
})
.on("dragend", function(){
var bar = d3.select(this);
bar.transition().duration(300).attr("x", xScale(bar.datum().category));
});
xScale.domain(data.map(function(d){ return d.category; }))
.rangeRoundBands([ padding.left, width - padding.right], 0.3);
yScale.domain([0, d3.max(data, function(d) { return d.value; })])
.range([height - padding.bottom, padding.top]);
xAxis.scale(xScale).orient("bottom");
svg.selectAll("rect").data(data).enter()
.append("rect").attr("width", xScale.rangeBand())
.attr("height", function(d) { return height - padding.bottom - yScale(d.value)})
.attr("x", function(d) { return xScale(d.category); })
.attr("y", function(d) { return yScale(d.value); })
.attr("fill", function(d,i) { return color(i); })
.attr("class", "bar")
.call(drag);
svg.append("g")
.attr("transform", "translate(" + 0 + "," + (height - padding.bottom) + ")")
.attr("class", "x axis")
.call(xAxis);
</script>
</body>
</html>
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