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Created May 8, 2018 03:36
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Brushable Horizontal Bar Chart - I
Raw
.block
height: 540
Raw
README.md

EDIT: I've now created a much more intuitive version of this chart. View version IV for a non-updating x axis and version V for a updating x axis. So you can basically ignore this one :)

For a bit more background, you can read my mini-blog about it Brushable & interactive bar chart in d3.js

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

This brushable horizontal bar chart gives you the option to browse through a large dataset without the separate bars becoming too small.

You have the option to adjust how many bars you're seeing at the same time by adjusting the size of the little box on the right mini chart.

You can also move the box and see the bars that you've selected appear in a bigger form on the left. Moving can be done either by grabbing and moving the box or scrolling

I have another version that uses a slightly different way to transition can be found here: Brushable Horizontal Bar Chart - II

The reason why the code is divided up into the overarching functions is to prepare it a bit already for the charting framework that I work with at my day job (and yes, I know the global variables are not-done, but I'm not known for writing beautiful or short code :) )

Why the rainbow? Just because it made it more fun to look at during the development :) (Please don't use a rainbow for a serious case though)

Some options to think about: You can update the x axis domain to update when you select a new set of bars, so that the largest bar always fills the space. This way you can see the smaller bars with more detail. Just wondering if that is confusing for a viewer... which I finally did in Brushable Horizontal Bar Chart - III

Although I found tidbits to get to this point all over the web, the initial help to set up an ordinal brush came from this example

Tested in (new versions of) Chrome, Firefox and Safari

Built with blockbuilder.org

forked from nbremer's block: Brushable Horizontal Bar Chart - I

Raw
index.html
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<!-- Google fonts -->
<link href='https://fonts.googleapis.com/css?family=Open+Sans:300,400' rel='stylesheet' type='text/css'>
<script src="//d3js.org/d3.v3.min.js"></script>
<style>
body {
font-size: 10px;
font-family: 'Open Sans', sans-serif;
font-weight: 400;
text-align: center;
}
#title {
font-size: 20px;
padding-bottom: 10px;
padding-top: 20px;
font-weight: 300;
}
#explanation {
font-size: 12px;
max-width: 620px;
margin: 0 auto;
padding-top: 10px;
color: #ababab;
font-weight: 300;
}
.axis path,
.axis line {
fill: none;
}
.y.axis path {
display: none;
}
.brush .extent {
fill-opacity: .125;
shape-rendering: crispEdges;
}
.resize {
display: inline !important; /* show when empty */
fill: #7A7A7A;
fill-opacity: 1;
stroke: #7A7A7A;
stroke-width: 2px;
}
.bar {
/*shape-rendering: crispEdges;*/
}
</style>
</head>
<body>
<div id="title">Brushable horizontal bar chart</div>
<div id="chart"></div>
<div id="explanation">You can see more or less of the total bar chart on the left by either dragging the box in the mini chart on the right or by scrolling your mouse. You can also click anywhere in the mini chart to center the box on that region. And you can increase and decrease the size of the box by dragging the top or bottom handle up or down.</div>
<script>
var data = [],
svg,
defs,
gBrush,
brush,
main_xScale,
mini_xScale,
main_yScale,
mini_yScale,
main_yAxis,
mini_width,
brushTotalStart,
brushTotalEnd,
updatedData,
mousewheelTimer,
scrolling = false,
scrollEnd = false;
init();
function init() {
//Create the random data
for (var i = 0; i < 40; i++) {
var my_object = {};
my_object.key = i;
my_object.country = makeWord();
my_object.value = Math.floor(Math.random() * 600);
data.push(my_object);
}//for i
data.sort(function(a,b) { return b.value - a.value; });
/////////////////////////////////////////////////////////////
///////////////// Set-up SVG and wrappers ///////////////////
/////////////////////////////////////////////////////////////
//Added only for the mouse wheel
var zoomer = d3.behavior.zoom()
.on("zoom", null);
var main_margin = {top: 10, right: 10, bottom: 10, left: 100},
main_width = 500 - main_margin.left - main_margin.right,
main_height = 400 - main_margin.top - main_margin.bottom;
var mini_margin = {top: 10, right: 10, bottom: 10, left: 10},
mini_height = 400 - mini_margin.top - mini_margin.bottom;
mini_width = 100 - mini_margin.left - mini_margin.right;
svg = d3.select("#chart").append("svg")
.attr("class", "svgWrapper")
.attr("width", main_width + main_margin.left + main_margin.right + mini_width + mini_margin.left + mini_margin.right)
.attr("height", main_height + main_margin.top + main_margin.bottom)
.call(zoomer)
.on("wheel.zoom", scroll)
//.on("mousewheel.zoom", scroll)
//.on("DOMMouseScroll.zoom", scroll)
//.on("MozMousePixelScroll.zoom", scroll)
//Is this needed?
.on("mousedown.zoom", null)
.on("touchstart.zoom", null)
.on("touchmove.zoom", null)
.on("touchend.zoom", null);
var mainGroup = svg.append("g")
.attr("class","mainGroup")
.attr("transform","translate(" + main_margin.left + "," + main_margin.top + ")");
var miniGroup = svg.append("g")
.attr("class","miniGroup")
.attr("transform","translate(" + (main_margin.left + main_width + main_margin.right + mini_margin.left) + "," + mini_margin.top + ")");
var brushGroup = svg.append("g")
.attr("class","brushGroup")
.attr("transform","translate(" + (main_margin.left + main_width + main_margin.right + mini_margin.left) + "," + mini_margin.top + ")");
/////////////////////////////////////////////////////////////
////////////////////// Initiate scales //////////////////////
/////////////////////////////////////////////////////////////
main_xScale = d3.scale.linear().range([0, main_width]);
mini_xScale = d3.scale.linear().range([0, mini_width]);
main_yScale = d3.scale.ordinal().rangeRoundBands([0, main_height], 0.4, 0);
mini_yScale = d3.scale.ordinal().rangeBands([0, mini_height], 0.4, 0);
//Create y axis object
main_yAxis = d3.svg.axis()
.scale(main_yScale)
.orient("left")
.tickSize(0)
.outerTickSize(0);
//Add group for the y axis
mainGroup.append("g")
.attr("class", "y axis")
.attr("transform", "translate(-5,0)");
/////////////////////////////////////////////////////////////
/////////////////////// Update scales ///////////////////////
/////////////////////////////////////////////////////////////
//Update the scales
main_xScale.domain([0, d3.max(data, function(d) { return d.value; })]);
mini_xScale.domain([0, d3.max(data, function(d) { return d.value; })]);
main_yScale.domain(data.map(function(d) { return d.country; }));
mini_yScale.domain(data.map(function(d) { return d.country; }));
//Create the visual part of the y axis
d3.select(".mainGroup").select(".y.axis").call(main_yAxis);
brushTotalStart = mini_yScale.domain()[0];
brushTotalEnd = mini_yScale.domain()[1];
/////////////////////////////////////////////////////////////
///////////////////////// Create brush //////////////////////
/////////////////////////////////////////////////////////////
//What should the first extent of the brush become - a bit arbitrary this
var brushExtent = Math.max( 1, Math.min( 20, Math.round(data.length*0.2) ) );
brush = d3.svg.brush()
.y(mini_yScale)
.extent([mini_yScale(data[0].country), mini_yScale(data[brushExtent].country)])
.on("brush", brushmove)
.on("brushend", brushend);
//Set up the visual part of the brush
gBrush = d3.select(".brushGroup").append("g")
.attr("class", "brush")
.call(brush);
gBrush.selectAll(".resize")
.append("line")
.attr("x2", mini_width);
gBrush.selectAll(".resize")
.append("path")
.attr("d", d3.svg.symbol().type("triangle-up").size(20))
.attr("transform", function(d,i) {
return i ? "translate(" + (mini_width/2) + "," + 4 + ") rotate(180)" : "translate(" + (mini_width/2) + "," + -4 + ") rotate(0)";
});
gBrush.selectAll("rect")
.attr("width", mini_width);
gBrush.select(".background")
.on("mousedown.brush", brushcenter)
.on("touchstart.brush", brushcenter);
///////////////////////////////////////////////////////////////////////////
/////////////////// Create a rainbow gradient - for fun ///////////////////
///////////////////////////////////////////////////////////////////////////
defs = svg.append("defs")
//Create two separate gradients for the main and mini bar - just because it looks fun
createGradient("gradient-rainbow-main", "60%");
createGradient("gradient-rainbow-mini", "13%");
/////////////////////////////////////////////////////////////
//////////////// Set-up the main bar chart //////////////////
/////////////////////////////////////////////////////////////
//DATA JOIN
var bar = d3.select(".mainGroup").selectAll(".bar")
.data(data, function(d) { return d.key; });
//UPDATE
bar
.attr("width", function(d) { return main_xScale(d.value); })
.attr("y", function(d,i) { return main_yScale(d.country); })
.attr("height", main_yScale.rangeBand());
//ENTER
bar.enter().append("rect")
.attr("class", "bar")
.attr("x", 0)
.attr("width", function(d) { return main_xScale(d.value); })
.attr("y", function(d,i) { return main_yScale(d.country); })
.attr("height", main_yScale.rangeBand())
.style("fill", "url(#gradient-rainbow-main)");
//.style("fill", "#3B8C3D");
//EXIT
bar.exit()
.remove();
/////////////////////////////////////////////////////////////
/////////////// Set-up the mini bar chart ///////////////////
/////////////////////////////////////////////////////////////
//The mini brushable bar
//DATA JOIN
var mini_bar = d3.select(".miniGroup").selectAll(".bar")
.data(data, function(d) { return d.key; });
//UDPATE
mini_bar
.attr("width", function(d) { return mini_xScale(d.value); })
.attr("y", function(d,i) { return mini_yScale(d.country); })
.attr("height", mini_yScale.rangeBand());
//ENTER
mini_bar.enter().append("rect")
.attr("class", "bar")
.attr("x", 0)
.attr("width", function(d) { return mini_xScale(d.value); })
.attr("y", function(d,i) { return mini_yScale(d.country); })
.attr("height", mini_yScale.rangeBand())
.style("fill", "url(#gradient-rainbow-mini)");
//.style("fill", "#3B8C3D");
//EXIT
mini_bar.exit()
.remove();
//Start the brush
gBrush.call(brush.event);
}//init
//Function runs on a brush move - to update the big bar chart
function update(data) {
//The transition (& delay) time of the bars and the axis
var transTime = 400;
var delayTime = scrollEnd ? 0 : transTime;
/////////////////////////////////////////////////////////////
///////////////////// Update the axis ///////////////////////
/////////////////////////////////////////////////////////////
//Update the domain of the y scale of the big bar chart
main_yScale.domain(data.map(function(d) { return d.country; }));
//Update the y axis of the big chart
d3.select(".mainGroup")
.select(".y.axis")
.transition()
.duration(transTime).delay(delayTime)
.call(main_yAxis);
/////////////////////////////////////////////////////////////
////////// Update the bars of the main bar chart ////////////
/////////////////////////////////////////////////////////////
//DATA JOIN
var bar = d3.select(".mainGroup").selectAll(".bar")
.data(data, function(d) { return d.key; });
//UPDATE
bar
.transition().duration(transTime).delay(delayTime)
.attr("x", 0)
.attr("width", function(d) { return main_xScale(d.value); })
.attr("y", function(d,i) { return main_yScale(d.country); })
.attr("height", main_yScale.rangeBand());
//ENTER
bar.enter().append("rect")
.attr("class", "bar")
.attr("x", 0)
.attr("width", 0)
.attr("y", function(d,i) { return main_yScale(d.country); })
.attr("height", main_yScale.rangeBand())
.style("fill", "url(#gradient-rainbow-main)")
.transition().duration(transTime).delay(delayTime*2)
.attr("width", function(d) { return main_xScale(d.value); });
//EXIT
bar.exit()
.transition().duration(transTime)
.attr("width", 0)
.remove();
}//update
/////////////////////////////////////////////////////////////
////////////////////// Brush functions //////////////////////
/////////////////////////////////////////////////////////////
//First function that runs on a brush move
function brushmove() {
//What is the extent of the brush
var extent = brush.extent();
//Adjust the extent of the brush so that is snaps to the bars
if (d3.event.mode === "move" || scrollEnd === true) {
//If dragging, preserve the width of the extent
//Does the top edge lie closer to the upper or lower bar
var topExtent = extent[0];
//Using ES5 - http://stackoverflow.com/questions/8584902/get-closest-number-out-of-array
var closestTop = mini_yScale.range().reduce(function (prev, curr) {
return (Math.abs(curr - topExtent) < Math.abs(prev - topExtent) ? curr : prev);
});
//Pixel location of the bottom bar
var maxBar = d3.max(mini_yScale.range());
//Does the top edge lie closer to the upper or lower bar
var bottomExtent = extent[1];
//Using ES5 - http://stackoverflow.com/questions/8584902/get-closest-number-out-of-array
var closestBottom = mini_yScale.range().reduce(function (prev, curr) {
return (Math.abs(curr - bottomExtent) < Math.abs(prev - bottomExtent) ? curr : prev);
});
//Don't let it go over the last bar in the design
if(maxBar === closestBottom) {
//The new extent that snaps to the bars
extent = [closestBottom+mini_yScale.rangeBand()-(extent[1] - extent[0]),closestBottom+mini_yScale.rangeBand()];
} else {
//The new extent that snaps to the bars
extent = [closestTop,closestTop+(extent[1] - extent[0])];
}//else
} else if (!scrolling) {
//If changing size, snap to the nearest rect
//Find the pixel values of the bars that lie within the selected brush
var pixelRanges = mini_yScale.range()
.filter(function(d) { return (d >= extent[0]-mini_yScale.rangeBand()/2) && (d <= extent[1]); });
//The new extent that snaps to the bars within the selection
extent = [d3.min(pixelRanges),d3.max(pixelRanges)+mini_yScale.rangeBand()];
}//else if
//else do nothing - then it comes from the scrolling and the extent has already been determined
//Snap to rect edge - the new extent
d3.select("g.brush")
.call(brush.extent(extent));
//What bars are captured in the brush
//During scrolling take a wider range and don't snap
if( scrolling ) {
var selected = mini_yScale.domain()
.filter(function(d) { return (extent[0]-1e-3-mini_yScale.rangeBand() <= mini_yScale(d)) && (mini_yScale(d) <= extent[1]+1e-3+mini_yScale.rangeBand() ); });
} else {
var selected = mini_yScale.domain()
.filter(function(d) { return (extent[0]-1e-3 <= mini_yScale(d)) && (mini_yScale(d) <= extent[1]+1e-3); });
}
//Take a subset of the selected data from the original dataset
updatedData = data.filter(function(d) { return selected.indexOf(d.country) > -1; });
//Update the colors of the mini chart - Make everything outside the brush grey
d3.select(".miniGroup").selectAll(".bar")
.style("fill", function(d, i) { return selected.indexOf(d.country) > -1 ? "url(#gradient-rainbow-mini)" : "#e0e0e0"; });
////Update the main chart
////If you want to see update during a brush moving uncomment this
////But that doesn't work very well with the transitions of the bars in the update function & scrolling
//update(updatedData);
}//brushmove
//Finally update the data
function brushend() {
if(!scrolling) update(updatedData);
}
//Based on http://bl.ocks.org/mbostock/6498000
//What to do when the user clicks on another location along the brushable bar chart
function brushcenter() {
var target = d3.event.target,
extent = brush.extent(),
size = extent[1] - extent[0],
range = mini_yScale.range(),
y0 = d3.min(range) + size / 2,
y1 = d3.max(range) + mini_yScale.rangeBand() - size / 2,
center = Math.max( y0, Math.min( y1, d3.mouse(target)[1] ) );
d3.event.stopPropagation();
gBrush
.call(brush.extent([center - size / 2, center + size / 2]))
.call(brush.event);
}//brushcenter
/////////////////////////////////////////////////////////////
///////////////////// Scroll functions //////////////////////
/////////////////////////////////////////////////////////////
//Function to calculate what should happen on a mouse scroll
function scroll() {
if (mousewheelTimer) clearTimeout(mousewheelTimer);
var extent = brush.extent(),
size = extent[1] - extent[0],
range = mini_yScale.range(),
y0 = d3.min(range),
y1 = d3.max(range),
dy = d3.event.deltaY,
topSection;
scrolling = true;
if( extent[0] - dy < y0 ) {
topSection = y0;
} else if ( extent[1] - dy > y1 ) {
topSection = y1 - size;
} else {
topSection = extent[0] - dy;
}//else
//Once the person stops scrolling, run the update data function
mousewheelTimer = setTimeout(function() {
mousewheelTimer = null;
scrolling = false;
scrollEnd = true;
//Finally snap the brush and update the data
gBrush
.call(brush.event);
scrollEnd = false;
}, 200);
d3.event.stopPropagation();
d3.event.preventDefault();
//Update the brush position during the scrolling
if(scrolling) {
gBrush
.call(brush.extent([ topSection, topSection + size ]))
.call(brush.event);
}//if
}//scroll
/////////////////////////////////////////////////////////////
///////////////////// Helper functions //////////////////////
/////////////////////////////////////////////////////////////
//Create a gradient
function createGradient(idName, endPerc) {
var coloursRainbow = ["#EFB605", "#E9A501", "#E48405", "#E34914", "#DE0D2B", "#CF003E", "#B90050", "#A30F65", "#8E297E", "#724097", "#4F54A8", "#296DA4", "#0C8B8C", "#0DA471", "#39B15E", "#7EB852"];
defs.append("linearGradient")
.attr("id", idName)
.attr("gradientUnits", "userSpaceOnUse")
.attr("x1", "0%").attr("y1", "0%")
.attr("x2", endPerc).attr("y2", "0%")
.selectAll("stop")
.data(coloursRainbow)
.enter().append("stop")
.attr("offset", function(d,i) { return i/(coloursRainbow.length-1); })
.attr("stop-color", function(d) { return d; });
}//createGradient
//Function to generate random strings of 5 letters - for the demo only
function makeWord() {
var possible_UC = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var text = possible_UC.charAt(Math.floor(Math.random() * possible_UC.length));
var possible_LC = "abcdefghijklmnopqrstuvwxyz";
for( var i=0; i < 5; i++ )
text += possible_LC.charAt(Math.floor(Math.random() * possible_LC.length));
return text;
}//makeWord
</script>
</body>
</html>
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