CODEWITHSUNDEEP
scalachartsjfreechart
DK_
DK_

Reputation: 2658

How to create a multi-series (line) chart with scala-chart

I came across Scala-chart, a really nice wrapper for using jFreeChart in Scala. It has several utility classes for generating charts with minimal effort.

What is the best way to generate a line chart with multiple series using scala-chart?

Upvotes: 2

Views: 1377

Answers (1)

Urist McDev
Urist McDev

Reputation: 508

In scala-chart there are several different ways to create a multi-series line chart. Which way to use depends on how you create your dataset (including ways to work with legacy JFreeChart code):

  • (for comparison) create a single-series line chart:

    val series = for (x <- 1 to 5) yield (x,x*x)
val chart = XYLineChart(series)

  • build up a multi-series line chart entirely from scala collections (this way I recommend because it is the most idiomatic):

    val names: List[String] = "Series A" :: "Series B" :: Nil

val data = for {
  name <- names
  series = for (x <- 1 to 5) yield (x,util.Random.nextInt(5))
} yield name -> series

val chart = XYLineChart(data)

  • from a collection of XYSeries objects:

    val names: List[String] = "Series A" :: "Series B" :: Nil

def randomSeries(name: String): XYSeries =
  List.tabulate(5)(x => (x,util.Random.nextInt(5))).toXYSeries(name)

val data = for (name <- names) yield randomSeries(name)

val chart = XYLineChart(data)

  • explicitly create an XYSeriesCollection object:

    def data: XYSeriesCollection = ???
val chart = XYLineChart(data)

These are some simple snippets but they should illustrate how data creation is possible and most of the time it boils down to one of these ways.

The current implementation (as of 0.4.0) work in the way that:

  • all chart factories accept an arbitrary data object of type A and
  • in addition accept an implicit -- a type class like ToXYDataset[A] -- which converts this arbitrary data of type A to the respective dataset the factory is based on
  • in the case of xy charts there are default converters for XYSeries, XYSeriesCollection, Coll[XYSeries] (where coll is a scala standard library collection), Coll[(A,B)] and Coll[(A,Coll[(B,C)])]

This way the chart factories are fully extendable and can be used with data instances of your custom types -- you just have to write your own conversion type class instances for your custom types.

Upvotes: 4

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