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Stacked bar chart with (computed) average line in Plotly.js

I've got a (stacked) bar chart and I want an average line plotted on my chart.
Let's take this example:
var trace1 = {
x: ['giraffes', 'orangutans', 'monkeys'],
y: [20, 14, 23],
name: 'SF Zoo',
type: 'bar'
};
var trace2 = {
x: ['giraffes', 'orangutans', 'monkeys'],
y: [12, 18, 29],
name: 'LA Zoo',
type: 'bar'
};
var data = [trace1, trace2];
var layout = {barmode: 'stack'};
Plotly.newPlot('myDiv', data, layout, {showSendToCloud:true});
Result:
Expected output:
I've found a similar question, but in that case it was pretty easy to add a line with a 'fixed' value. In this case I've got a stacked bar chart nicolaskruchten/pivottable, so the user can easily drag and drop columns. That makes computing the average harder.
I can loop through all results and compute the average value, but since Plotly is very powerful and has something like aggregate functions, I feel like there should be a better way.
How can I add a (computed) average line to my (stacked) bar chart?

Plotly.js not provided any direct options for drawing average line.
But you can do this simple way.
//Find average value for Y
function getAverageY() {
allYValues = trace1.y.map(function (num, idx) {
return num + trace2.y[idx];
});
if (allYValues.length) {
sum = allYValues.reduce(function (a, b) {
return a + b;
});
avg = sum / allYValues.length;
}
return avg;
}
//Create average line in shape
var layout = {
barmode: 'stack',
shapes: [{
type: 'line',
xref: 'paper',
x0: 0,
y0: getAverageY(),
x1: 1,
y1: getAverageY(),
line: {
color: 'green',
width: 2,
dash: 'dot'
}
}]
};
Updated:
You need to update your graph after loading this drawing a average
line for any numbers of trace.
//Check graph is loaded
if (document.getElementById('myDiv')) {
//draw average line
drawAvgLine(document.getElementById('myDiv'))
}
function drawAvgLine(graph) {
var graphData = graph.data; //Loaded traces
//making new layout
var newLayout = {
barmode: 'stack',
shapes: [{
type: 'line',
xref: 'paper',
x0: 0,
y0: getAverageY(graphData),
x1: 1,
y1: getAverageY(graphData),
line: {
color: 'green',
width: 2,
dash: 'dot'
}
}]
};
//Update plot pass existing data
Plotly.update('myDiv', graphData, newLayout)
}
//Calculate avg value
function getAverageY(graphData) {
var total = [],
undefined;
for (var i = 0, n = graphData.length; i < n; i++) {
var arg = graphData[i].y
for (var j = 0, n1 = arg.length; j < n1; j++) {
total[j] = (total[j] == undefined ? 0 : total[j]) + arg[j];
}
}
return total.reduce(function (a, b) {
return a + b;
}) / total.length;
}

Adding annotations to Google candlestick chart (Posted solution triggers TypeError)

I am trying to add some annotations to a Google Candlestick chart. I noticed someone had already asked this same question (Adding annotations to Google Candlestick chart). The user Aperçu replied with a detailed solution to extend the chart and add annotations since the chart doesn't have any such feature built in. However, when I try this solution I get an error "TypeError: document.querySelectorAll(...)[0] is undefined"
Here is my code:
chartPoints = [
['Budget', 0, 0, 9999, 9999, 'foo1'],
['Sales', 0, 0, 123, 123, 'foo2'],
['Backlog', 123, 123, 456, 456, 'foo3'],
['Hard Forecast', 456, 456, 789, 789, 'foo4'],
['Sales to Budget', 789, 789, 1000, 1000, 'foo5']
];
var data = google.visualization.arrayToDataTable(chartPoints, true);
data.setColumnProperty(5, 'role', 'annotation');
var options = {
legend: 'none',
bar: { groupWidth: '40%', width: '100%' },
candlestick: {
fallingColor: { strokeWidth: 0, fill: '#a52714' },
risingColor: { strokeWidth: 0, fill: '#0f9d58' }
}
};
var chart = new google.visualization.CandlestickChart(document.getElementById('chart_div'));
chart.draw(data, options);
// attempt to use Aperçu's solution
const bars = document.querySelectorAll('#chart_div svg > g:nth-child(5) > g')[0].lastChild.children // this triggers a TypeError
for (var i = 0 ; i < bars.length ; i++) {
const bar = bars[i]
const { top, left, width } = bar.getBoundingClientRect()
const hint = document.createElement('div')
hint.style.top = top + 'px'
hint.style.left = left + width + 5 + 'px'
hint.classList.add('hint')
hint.innerText = rawData.filter(t => t[1])[i][0]
document.getElementById('chart_div').append(hint)
}
I want the chart to show the last piece of data next to the bars (i.e. "foo1", "foo2", etc)

each candle or bar will be represented by a <rect> element
we can use the rise and fall colors to separate the bars from other <rect> elements in the chart
there will be the same number of bars as rows in the data table
once we find the first bar, we can use rowIndex of zero to pull values from the data
we need to find the value of the rise / fall, to know where to place the annotation
then use chart methods to find the location for the annotation
getChartLayoutInterface() - Returns an object containing information about the onscreen placement of the chart and its elements.
getYLocation(position, optional_axis_index) - Returns the screen y-coordinate of position relative to the chart's container.
see following working snippet
two annotations are added
one for the difference in rise and fall
and the other for the value in the column with annotation role
google.charts.load('current', {
callback: drawChart,
packages: ['corechart']
});
function drawChart() {
var chartPoints = [
['Budget', 0, 0, 9999, 9999, 'foo1'],
['Sales', 0, 0, 123, 123, 'foo2'],
['Backlog', 123, 123, 456, 456, 'foo3'],
['Hard Forecast', 456, 456, 789, 789, 'foo4'],
['Sales to Budget', 789, 789, 1000, 1000, 'foo5']
];
var data = google.visualization.arrayToDataTable(chartPoints, true);
data.setColumnProperty(5, 'role', 'annotation');
var options = {
legend: 'none',
bar: { groupWidth: '40%', width: '100%' },
candlestick: {
fallingColor: { strokeWidth: 0, fill: '#a52714' },
risingColor: { strokeWidth: 0, fill: '#0f9d58' }
}
};
var container = document.getElementById('chart_div');
var chart = new google.visualization.CandlestickChart(container);
google.visualization.events.addListener(chart, 'ready', function () {
var annotation;
var bars;
var chartLayout;
var formatNumber;
var positionY;
var positionX;
var rowBalance;
var rowBottom;
var rowIndex;
var rowTop;
var rowValue;
var rowWidth;
chartLayout = chart.getChartLayoutInterface();
rowIndex = 0;
formatNumber = new google.visualization.NumberFormat({
pattern: '#,##0'
});
bars = container.getElementsByTagName('rect');
for (var i = 0; i < bars.length; i++) {
switch (bars[i].getAttribute('fill')) {
case '#a52714':
case '#0f9d58':
rowWidth = parseFloat(bars[i].getAttribute('width'));
if (rowWidth > 2) {
rowBottom = data.getValue(rowIndex, 1);
rowTop = data.getValue(rowIndex, 3);
rowValue = rowTop - rowBottom;
rowBalance = Math.max(rowBottom, rowTop);
positionY = chartLayout.getYLocation(rowBalance) - 6;
positionX = parseFloat(bars[i].getAttribute('x'));
// row value
annotation = container.getElementsByTagName('svg')[0].appendChild(container.getElementsByTagName('text')[0].cloneNode(true));
annotation.textContent = formatNumber.formatValue(rowValue);
annotation.setAttribute('x', (positionX + (rowWidth / 2)));
annotation.setAttribute('y', positionY);
annotation.setAttribute('font-weight', 'bold');
// annotation column
annotation = container.getElementsByTagName('svg')[0].appendChild(container.getElementsByTagName('text')[0].cloneNode(true));
annotation.textContent = data.getValue(rowIndex, 5);
annotation.setAttribute('x', (positionX + (rowWidth / 2)));
annotation.setAttribute('y', positionY - 18);
annotation.setAttribute('font-weight', 'bold');
rowIndex++;
}
break;
}
}
});
chart.draw(data, options);
}
<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="chart_div"></div>

Google Charts Get maximum scale

I'm trying to make an all positive bubble chart have quadrants by drawing the quadrants using the baseline property like so:
var dataT = google.visualization.arrayToDataTable(.....);
var options = {
hAxis: {title: 'h axis',baseline:100},
vAxis: {title: 'v axis',baseline:20},
...}
var chart = new google.visualization.BubbleChart(...);
chart.draw(dataT,options);
Except the graph will keep changing depending on the query so the baselines will not be the same for all the graphs. I would like to be able to get the max axis value and divide it by 2 to set the baselines right in the middle of each axis.
Example:
var options = {
hAxis: {title: 'h axis',baseline:max_h_axis/2},
vAxis: {title: 'v axis',baseline:max_v_axis/2},
...
Is there any way of knowing the max axis values of the graph before drawing the graph?

the getColumnRange method works for this...
Returns the minimal and maximal values of values in a specified column. The returned object has properties min and max. If the range has no values, min and max will contain null.
you can also use this information to produce your own axis tick marks.
see following working snippet...
google.charts.load('current', {
callback: function () {
var data = google.visualization.arrayToDataTable([
['X', 'Y'],
[8, 120],
[4, 155],
[11, 140],
[4, 205],
[3, 35],
[6, 78]
]);
var ticksX = [];
var ticksY = [];
var numberOfTicks = 10;
var rangeX = data.getColumnRange(0);
var rangeY = data.getColumnRange(1);
var stepX = Math.ceil((rangeX.max - rangeX.min) / numberOfTicks);
for (var i = rangeX.min - stepX; i <= rangeX.max + stepX; i = i + stepX) {
ticksX.push(i);
}
var stepY = Math.ceil((rangeY.max - rangeY.min) / numberOfTicks);
for (var i = rangeY.min - stepY; i <= rangeY.max + stepY; i = i + stepY) {
ticksY.push(i);
}
var baseX = Math.ceil((rangeX.max - rangeX.min) / 2) + rangeX.min;
var baseY = Math.ceil((rangeY.max - rangeY.min) / 2) + rangeY.min;
var options = {
hAxis: {
title: 'h axis',
baseline: baseX,
ticks: ticksX
},
vAxis: {
title: 'v axis',
baseline: baseY,
ticks: ticksY
},
legend: 'none',
height: 600,
width: 600
};
var chart = new google.visualization.ScatterChart(document.getElementById('chart_div'));
chart.draw(data, options);
},
packages: ['corechart']
});
<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="chart_div"></div>

Scrollable x axis with chart.js 2.1.4

I have a line graph with lot of points to plot
I want x axis to be scrollable
I have already looked few solutions but they are providing solution with old versions of chart js.
Is there any option to get scrollable x axis in chart.js version 2?
And
How can i get width of content in y axis in chart.js version 2?
if there is no direct option to get scrollable x axis, I can copy content in Y-axis region and draw image in other canvas.

My answer on a related question will help you. In my example I have made the Y axis scrollable, but this could easily be applied to the X axis too.
https://stackoverflow.com/a/51282003/10060003
JS fiddle - https://jsfiddle.net/EmmaLouise/eb1aqpx8/3/
I am using the animation onComplete and onProgress options to redraw the axis that I want to scroll with the chart. (See https://www.chartjs.org/docs/latest/configuration/animations.html).
$(function () {
var rectangleSet = false;
var canvasTest = $('#chart-Test');
var chartTest = new Chart(canvasTest, {
type: 'bar',
data: chartData,
maintainAspectRatio: false,
responsive: true,
options: {
tooltips: {
titleFontSize: 0,
titleMarginBottom: 0,
bodyFontSize: 12
},
legend: {
display: false
},
scales: {
xAxes: [{
ticks: {
fontSize: 12,
display: false
}
}],
yAxes: [{
ticks: {
fontSize: 12,
beginAtZero: true
}
}]
},
animation: {
onComplete: function () {
if (!rectangleSet) {
var scale = window.devicePixelRatio;
var sourceCanvas = chartTest.chart.canvas;
var copyWidth = chartTest.scales['y-axis-0'].width - 10;
var copyHeight = chartTest.scales['y-axis-0'].height + chartTest.scales['y-axis-0'].top + 10;
var targetCtx = document.getElementById("axis-Test").getContext("2d");
targetCtx.scale(scale, scale);
targetCtx.canvas.width = copyWidth * scale;
targetCtx.canvas.height = copyHeight * scale;
targetCtx.canvas.style.width = `${copyWidth}px`;
targetCtx.canvas.style.height = `${copyHeight}px`;
targetCtx.drawImage(sourceCanvas, 0, 0, copyWidth * scale, copyHeight * scale, 0, 0, copyWidth * scale, copyHeight * scale);
var sourceCtx = sourceCanvas.getContext('2d');
// Normalize coordinate system to use css pixels.
sourceCtx.clearRect(0, 0, copyWidth * scale, copyHeight * scale);
rectangleSet = true;
}
},
onProgress: function () {
if (rectangleSet === true) {
var copyWidth = chartTest.scales['y-axis-0'].width;
var copyHeight = chartTest.scales['y-axis-0'].height + chartTest.scales['y-axis-0'].top + 10;
var sourceCtx = chartTest.chart.canvas.getContext('2d');
sourceCtx.clearRect(0, 0, copyWidth, copyHeight);
}
}
}
}
});

How to display only last point on highcharts and that point should travel with chart line?

I have a area chart which is having a dynamic point that will be added to chart.I got this http://jsfiddle.net/rjpjwve0/
but it looks like the point gets displayed first and then after a delay the chart draws back. Now i want to display the last point which will be a animated point and it should travel with chart without delay in rendering.
Could any one help me to achieve this.

I put together a test, and it seems to work well.
I updated the load event to add a second series, using the same series.data[len -1] values; then in the setInterval portion, we update that new point at each iteration.
That way, by updating the existing marker rather than destroying one marker and creating another, the animation works as desired.
Code:
events: {
load: function () {
var series = this.series[0],
len = series.data.length;
//-------------------------------------
//added this part ->
this.addSeries({
id: 'end point',
type: 'scatter',
marker: {
enabled:true,
symbol:'circle',
radius:5,
fillColor:'white',
lineColor: 'black',
lineWidth:2
},
data: [[
series.data[len - 1].x,
series.data[len - 1].y
]]
});
var series2 = this.get('end point');
//-------------------------------------
setInterval(function () {
var x = (new Date()).getTime(),
y = Math.random();
len = series.data.length;
series.addPoint([x,y], true, true);
//and added this line -->
series2.data[0].update([x,y]);
}, 1000);
}
}
Fiddle:
http://jsfiddle.net/jlbriggs/a6pshutt/

You can try this :
series: [{
name: 'Random data',
marker : {
enabled : false,
lineWidth: 0,
radius: 0
},
data: (function () {
// generate an array of random data
var data = [],
time = (new Date()).getTime(),
i;
for (i = -19; i <= 0; i += 1) {
data.push({
x: time + i * 1000,
y: Math.random()
});
}
return data;
}())
}]
Its works.
Greg.