Lets-Plot Kotlin API

A Grammar of Graphics for Kotlin.

Lets-Plot Kotlin API is a Kotlin API for Lets-Plot Multiplatform plotting library,
which is built on the principles of layered graphics first described in the
Leland Wilkinson work The Grammar of Graphics.

Lets-Plot Kotlin API is largely based on the API provided by ggplot2 package well-known to data scientists who use R. To learn more about the Grammar of Graphics, we recommend an excellent book called “ggplot2: Elegant Graphics for Data Analysis”. This will be a good prerequisite for further exploration of the Lets-Plot library.

Quickstart

Inside Kotlin Notebook, Datalore or Jupyter with Kotlin Kernel:

%use lets-plot

val rand = java.util.Random()
val data = mapOf(
    "rating" to List(200) { rand.nextGaussian() } + List(200) { rand.nextGaussian() * 1.5 + 1.5 },
    "cond" to List(200) { "A" } + List(200) { "B" }
)

var p = letsPlot(data)
p += geomDensity(color = "dark_green", alpha = .3) { x = "rating"; fill = "cond" }
p + ggsize(700, 350)

See the "Quickstart" notebook in Datalore or Jupyter nbviewer.

Table of Contents

• Usage
  • Notebooks
  • Compose Multiplatform
  • JVM and Kotlin/JS
• Documentation
• What is new in 4.7.0
• Recent Updates in the Gallery
• Change Log
• Code of Conduct
• License

Usage

Notebooks

With the help of Lets-Plot Kotlin API you can easily create plots in Kotlin Notebook, Datalore, Jupyter with Kotlin Kernel
or any other notebook that supports Kotlin Kernel.

"Line Magics"

%use lets-plot

This "line magic" will apply Lets-Plot library descriptor which adds to your notebook all the boilerplate code necessary to create plots.

By default, library descriptor is bundled with the Kotlin Jupyter Kernel installed in your environment.
However, you can override the default settings using:

%useLatestDescriptors

In this case the latest library descriptor will be pulled from the Kotlin Jupyter Libraries repository.

Library Descriptor Parameters

%use lets-plot(api=4.7.2, lib=4.3.2, js=4.3.2, isolatedFrame=false)

• api - version of the Lets-Plot Kotlin API.
• lib - version of the Lets-Plot Multiplatform (JARs).
• js - version of the Lets-PLot Multiplatform JavaScript bundle.
• isolatedFrame - If false: load JS just once per notebook (default in Jupyter). If true: include Lets-Plot JS in each output (default in Datalore notebooks).

Compose Multiplatform

To learn how to embed Lets-Plot charts in Compose Multiplatform applications, please check out the Lets-Plot Skia Frontend project.

JVM and Kotlin/JS

To learn more about creating plots in JVM or Kotlin/JS environment please read USAGE_SWING_JFX_JS.md.

Examples

Examples of using of the Lets-Plot Kotlin API in JVM and Kotlin/JS applications are available in the Lets-Plot Kotlin Mini Apps (Demos) GitHub repository.

Documentation

• A quick introduction to the Grammar of Graphics and Lets-Plot Kotlin API: Lets-Plot Usage Guide

• Lets-Plot Kotlin API docs: docs/README.md

• Lets-Plot Kotlin API reference: https://lets-plot.org/kotlin

• The "Example Notebooks" reference: examples.md

• Example notebooks in the Binder: mybinder.org

What is new in 4.7.0

• coordPolar()

  The polar coordinate system is most commonly used for pie charts, but it can also be used for constructing Spider or Radar charts using the flat option.

  
  

  See: example notebook.

• In the theme():

  • panelInset parameter - primarily used for plots with polar coordinates. See: example notebook.

  • panelBorderOntop parameter - enables the drawing of panel border on top of the plot geoms.

  • panelGridOntop, panelGridOntopX, panelGridOntopY parameters - enable the drawing of grid lines on top of the plot geoms.

• geomCurve()

  
  

  See: example notebook.

• [UNIQUE] Visualizing Graph-like Data with geomSegment() and geomCurve()

  • Aesthetics sizeStart, sizeEnd, strokeStart and strokeEnd enable better alignment of segments/curves with nodes of the graph by considering the size of the nodes.

  • The spacer parameter allows for additional manual fine-tuning.

    
    

  See: example notebook.

• The alphaStroke Parameter in geomLabel()

  Use the alphaStroke parameter to apply alpha to entire label. By default, alpha is only applied to the label background.

  See: example notebook.

Recent Updates in the Gallery

Change Log

See CHANGELOG.md.

Code of Conduct

This project and the corresponding community are governed by the JetBrains Open Source and Community Code of Conduct. Please make sure you read it.

License

Code and documentation released under the MIT license. Copyright © 2019-2024, JetBrains s.r.o.