HelloWorld.kt

import io.nacular.doodle.application.Application
import io.nacular.doodle.application.application
import io.nacular.doodle.controls.panels.GridPanel
import io.nacular.doodle.controls.text.Label
import io.nacular.doodle.core.*
import io.nacular.doodle.geometry.Size
import io.nacular.doodle.layout.constrain
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import org.kodein.di.instance

class HelloWorld(display: Display) : Application {
    init {
        display += FormView()
    }

    override fun shutdown() {}
}

class FormView() : View() {
    init {
        GlobalScope.launch {
            val outputHeight  = 100.0
            val buttonSpacing =  10.0

            val gridPanel = GridPanel().apply {
                add(Label("x"), 0, 0); add(Label("y"), 0, 1); add(Label("z"), 0, 2); add(Label("1"), 0, 3)
                add(Label("z"), 1, 0); add(Label("3"), 1, 1); add(Label("0"), 1, 2); add(Label("4"), 1, 3)
                add(Label("b"), 2, 0); add(Label("q"), 2, 1); add(Label("t"), 2, 2); add(Label("o"), 2, 3)

                verticalSpacing = { buttonSpacing }
                horizontalSpacing = { buttonSpacing }
            }

            children += listOf(gridPanel)

            // Place output outside grid so the height can be more easily controlled
            val constraints = constrain(gridPanel) { grid ->
                grid.top      = parent.top
                grid.left     = parent.left
                grid.right    = parent.right
                grid.bottom   = parent.bottom
            }

            layout = object: Layout by constraints {
                // Set total height to grid panel's ideal width and height, plus output and spacing
                override fun idealSize(container: PositionableContainer, default: Size?) = gridPanel.idealSize?.let {
                    Size(it.width, it.height + outputHeight + buttonSpacing)
                }
            }

            // Force idealSize when gridPanel is laid out
            gridPanel.sizePreferencesChanged += { _,_,new ->
                idealSize = new.idealSize?.let { Size(it.width, it.height + outputHeight + buttonSpacing) }
            }
        }
    }
}

fun main() {
    application {
        HelloWorld(display = instance())
    }
}