Kanvas

This project contains a few libraries to make it easy to draw on a JavaFX Canvas using either a Kotlin or Groovy DSL.

Libraries

Diagram produced by Kanvas itself!

kanvas-core

Maven coordinates: com.athaydes.kanvas:kanvas-core:<version>

The basic functionality of Kanvas. It's written in Kotlin and provides the basic API for drawing on a canvas via the com.athaydes.kanvas.Kanvas class.

This library also provides an abstract class, com.athaydes.kanvas.KanvasApp, to make it easy to create a javafx.application.Application implementation that displays a Kanvas and nothing else:

import com.athaydes.kanvas.Kanvas
import com.athaydes.kanvas.KanvasApp
import javafx.application.Application
import javafx.scene.paint.Color

fun main() {
    Application.launch(KanvasDemo::class.java)
}

class KanvasDemo : KanvasApp() {
    override fun draw(): Kanvas {
        return Kanvas(300.0, 250.0).apply {
            // draw your shapes here!
            background(Color.BLACK).fill(Color.BLUE)
            at(50.0, 30.0).circle(radius = 100.0, fill = true)
        }
    }
}

Result:

kanvas-groovy

Maven coordinates: com.athaydes.kanvas:kanvas-groovy:<version>

A Groovy DSL based on kanvas-core.

It provides a base class for Groovy scripts exposing a nice DSL for Kanvas:

import com.athaydes.kanvas.gr.KanvasScript
import groovy.transform.BaseScript
import javafx.scene.paint.Color

@BaseScript KanvasScript baseScript

title 'Groovy Kanvas Demo'
width 300
height 250

background Color.BLACK
fill Color.BLUE
at 50, 30 circle 100, true

This example is equivalent to the Kotlin example shown earlier.

Hot reloading Groovy scripts

This library also provides a JavaFX application class, com.athaydes.kanvas.gr.GroovyKanvasApp, that can launch a Groovy script and hot-reload it as it changes.

All files under the same directory tree as the Groovy script are watched.

For details on how to run Kanvas Groovy scripts, see the Groovy Demo.

Demos

Kotlin Demo

Groovy Demo

Kanvas-Reactive (shown below)

Kanvas-To-Image

Showcase from demo/groovy/src/showcase.groovy:

Development

To install the current version of the library in your local maven cache, use

./gradlew install

since this library uses JavaFX, make sure that you use a jdk with JavaFX, eg.

sdk install java 11.0.8.fx-zulu