it.unibo.tuprolog.ui.gui.GraphvizRenderer.kt Maven / Gradle / Ivy

Go to download
package it.unibo.tuprolog.ui.gui

import guru.nidi.graphviz.engine.Format
import guru.nidi.graphviz.engine.Graphviz
import it.unibo.tuprolog.bdd.BinaryDecisionDiagram
import it.unibo.tuprolog.bdd.toDotString
import java.io.ByteArrayOutputStream
import java.io.OutputStream
import java.lang.Exception
import java.lang.UnsupportedOperationException
import java.util.concurrent.CompletableFuture
import java.util.concurrent.Future

object GraphvizRenderer {
    private var available: Future = CompletableFuture.completedFuture(false)

    @Suppress("TooGenericExceptionCaught", "SwallowedException")
    fun initialize() {
        available =
            CompletableFuture.supplyAsync {
                try {
                    val outputStream = ByteArrayOutputStream()
                    val sampleBDD = BinaryDecisionDiagram.terminalOf(true)
                    Graphviz
                        .fromString(sampleBDD.toDotString())
                        .render(Format.PNG)
                        .toOutputStream(outputStream)
                    true
                } catch (e: Exception) {
                    false
                }
            }
    }

    val isAvailable: Boolean get() = if (available.isDone) available.get() else false

    val isReady: Boolean get() = available.isDone

    fun renderAsPNG(
        graph: String,
        imageOutputStream: OutputStream,
    ) {
        if (!isAvailable) {
            throw UnsupportedOperationException("Graphviz renderer is not available")
        }
        Graphviz
            .fromString(graph)
            .render(Format.PNG)
            .toOutputStream(imageOutputStream)
    }
}