Different Colors for Bars in Barchart Depend on Value

Different colors for bars in BarChart depend on value

In ios-charts, the colors of the bars are set in an array. If your dataset is called barChartDataset, for example, you would set the colors like this

barChartDataset.colors = [UIColor.red,UIColor.orange,UIColor.green,UIColor.black,UIColor.blue]

The bars will have these colors in this order and will repeat. So if you have 10 bars, you would have 2 red bars etc.

In your case, you just have to write a function to return the right color value, and attach it to the array. Reference the code below.

func setColor(value: Double) -> UIColor{

    if(value < 30){
        return UIColor.red
    }
    else if(value <= 70 && value >= 30){
        return UIColor.orange
    }
    else if(value > 70){
        return UIColor.green
    }

    else { //In case anything goes wrong
    return UIColor.black
    }
}

And then wherever you are setting the chart use

 barChartDataset.colors = [setColor(barOneValue),setColor(barTwoValue),setColor(barThreeValue),setColor(barFourValue),setColor(barFiveValue)]

Hope this helps!

Can the colors of bars in a bar chart be varied based on their value?

As far as I know there is no configuration or callback for each individual point being drawn. The best way I can think of to do this would be to create a function that would modify your chart config/data object. This isn't the most elegant way to deal with the problem, but it would work.

The Fix

Pass your chart config/data object to a function that will add the background color.

Main Point of the example is function AddBackgroundColors(chartConfig)

Example:

function AddBackgroundColors(chartConfig) {  var min = 1; // Min value  var max = 100; // Max value  var datasets;  var dataset;  var value;  var range = (max - min);  var percentage;  var backgroundColor;
  // Make sure the data exists  if (chartConfig &&    chartConfig.data &&    chartConfig.data.datasets) {    // Loop through all the datasets    datasets = chartConfig.data.datasets;    for (var i = 0; i < datasets.length; i++) {      // Get the values percentage for the value range      dataset = datasets[i];      value = dataset.data[0];      percentage = value / range * 100;
      // Change the background color for this dataset based on its percentage      if (percentage > 100) {        // > 100%        backgroundColor = '#0000ff';      } else if (percentage >= 50) {        // 50% - 100%        backgroundColor = '#00ff00';      } else {        // < 50%        backgroundColor = '#ff0000';      }      dataset.backgroundColor = backgroundColor;    }  }
  // Return the chart config object with the new background colors  return chartConfig;}
var chartConfig = {  type: 'bar',  data: {    labels: ["percentage"],    datasets: [{      label: '100%',      data: [100]    }, {      label: '50%',      data: [50]    }, {      label: '49%',      data: [49]    }, {      label: '5%',      data: [5]    }]  },  options: {    scales: {      yAxes: [{        ticks: {          beginAtZero: true        }      }]    }  }};
window.onload = function() {  var ctx = document.getElementById("canvas").getContext("2d");  chartConfig = AddBackgroundColors(chartConfig);  var myChart = new Chart(ctx, chartConfig);};

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.1.2/Chart.bundle.min.js"></script><canvas id="canvas" width="400" height="200"></canvas>

How to custom color Syncfusion BarChart column depending on value in Flutter?

To customize the bar chart for each bar to have a different color there is the need to implement the BarSeries.onCreateRenderer. Take a look at the example below:

Here is a minimal-reproducible-example of this app:

import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_charts/charts.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
      debugShowCheckedModeBanner: false,
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      body: BarHorizontal(),
    );
  }
}

/// Renders customized Column chart
class BarHorizontal extends StatefulWidget {
  /// Creates customized Column chart
  const BarHorizontal({Key? key}) : super(key: key);

  @override
  State<BarHorizontal> createState() => _BarHorizontalState();
}

class _BarHorizontalState extends State<BarHorizontal> {
  _BarHorizontalState();

  @override
  Widget build(BuildContext context) {
    return SfCartesianChart(
      title: ChartTitle(text: 'PC vendor shipments - 2015 Q1'),
      primaryXAxis: CategoryAxis(
        majorGridLines: const MajorGridLines(width: 0),
      ),
      primaryYAxis: NumericAxis(
          labelFormat: '{value}M',
          title: AxisTitle(text: 'Shipments in million'),
          majorGridLines: const MajorGridLines(width: 0),
          majorTickLines: const MajorTickLines(size: 0)),
      series: <ChartSeries<ChartSampleData, String>>[
        BarSeries<ChartSampleData, String>(
          onCreateRenderer: (ChartSeries<ChartSampleData, String> series) =>
              _CustomColumnSeriesRenderer(),
          dataLabelSettings: const DataLabelSettings(
              isVisible: true, labelAlignment: ChartDataLabelAlignment.middle),
          dataSource: <ChartSampleData>[
            ChartSampleData(x: 'HP Inc', y: 12.54),
            ChartSampleData(x: 'Lenovo', y: 13.46),
            ChartSampleData(x: 'Dell', y: 9.18),
            ChartSampleData(x: 'Apple', y: 4.56),
            ChartSampleData(x: 'Asus', y: 5.29),
          ],
          width: 0.8,
          xValueMapper: (ChartSampleData sales, _) => sales.x as String,
          yValueMapper: (ChartSampleData sales, _) => sales.y,
        )
      ],
    );
  }
}

class _CustomColumnSeriesRenderer extends BarSeriesRenderer {
  _CustomColumnSeriesRenderer();

  @override
  BarSegment createSegment() {
    return _ColumnCustomPainter();
  }
}

class _ColumnCustomPainter extends BarSegment {
  final colorList = [
    const Color.fromRGBO(53, 92, 125, 1),
    const Color.fromRGBO(192, 108, 132, 1),
    const Color.fromRGBO(246, 114, 128, 1),
    const Color.fromRGBO(248, 177, 149, 1),
    const Color.fromRGBO(116, 180, 155, 1)
  ];

  @override
  Paint getFillPaint() {
    final Paint customerFillPaint = Paint();
    customerFillPaint.isAntiAlias = false;
    customerFillPaint.color = colorList[currentSegmentIndex!];
    customerFillPaint.style = PaintingStyle.fill;
    return customerFillPaint;
  }
}

class ChartSampleData {
  ChartSampleData({this.x, this.y});

  final dynamic x;
  final num? y;
}

Different color for each bar in a bar chart; ChartJS

After looking into the Chart.Bar.js file I've managed to find the solution.
I've used this function to generate a random color:

function getRandomColor() {
    var letters = '0123456789ABCDEF'.split('');
    var color = '#';
    for (var i = 0; i < 6; i++ ) {
        color += letters[Math.floor(Math.random() * 16)];
    }
    return color;
}

I've added it to the end of the file and i called this function right inside the "fillColor:" under

helpers.each(dataset.data,function(dataPoint,index){
                    //Add a new point for each piece of data, passing any required data to draw.

so now it looks like this:

helpers.each(dataset.data,function(dataPoint,index){
                    //Add a new point for each piece of data, passing any required data to draw.

                    datasetObject.bars.push(new this.BarClass({
                        value : dataPoint,
                        label : data.labels[index],
                        datasetLabel: dataset.label,
                        strokeColor : dataset.strokeColor,
                        fillColor : getRandomColor(),
                        highlightFill : dataset.highlightFill || dataset.fillColor,
                        highlightStroke : dataset.highlightStroke || dataset.strokeColor
                    }));
                },this);

and it works I get different color for each bar.

Plotting different colors on bar chart values If the number falls below 0

plt.bar accepts a parameter color= which either can be a single color, or a list with one color for each of the bars. The list can be constructed via list comprehension, giving a color depending on a constraint.

A bar plot normally only generates one entry in the legend (via plt.bar(..., label='my barplot'). To get more than one label, and also to have it circular instead of rectangular, custom legend elements can be created.

Here is some example code to get you started:

import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.lines import Line2D
import matplotlib

df = pd.DataFrame({'Years': ['2015', '2016', '2017', '2018'],
                   'Value': [-495982.0, 405549.0, -351541.0, 283790.0]})
values = df["Value"]
values = values / 1e3
asOfDates = df['Years']

Value = df['Value'] / 100

fig, ax = plt.subplots()
ax.set_title('Plotting Financials')
ax.set_xlabel('Years')
ax.set_ylabel('value')
plt.bar(asOfDates, values, color=['r' if v < 0 else 'g' for v in values])
ax.get_yaxis().set_major_formatter(matplotlib.ticker.FuncFormatter(lambda x, p: format(int(x), ',')))

legend_handles = [Line2D([0], [0], linewidth=0, marker='o', markerfacecolor=color, markersize=12, markeredgecolor='none')
                  for color in ['g', 'r']]
ax.legend(legend_handles, ['positive', 'negative'])

plt.show()

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