javafx框架tornadofx畫個心形

import javafx.animation.AnimationTimer
import javafx.application.Application
import javafx.application.Platform
import javafx.geometry.Pos
import javafx.scene.canvas.GraphicsContext
import javafx.scene.control.RadioButton
import javafx.scene.paint.Color
import tornadofx.*
import java.util.*
import kotlin.math.PI
import kotlin.math.cos
import kotlin.math.sin

fun main(args: Array<String>) {
    Application.launch(TestApp::class.java, *args)
}

class TestApp : App(TestView::class)
class TestView : View("逐個顯示圖形") {
    val isRun = booleanProperty()
    val pNums = intProperty()
    val aniMate = AniTimer()
    var t = -PI
    var renderedList: MutableList<Point> = LinkedList<Point>()

val step= doubleProperty(0.01)
    lateinit var context: GraphicsContext
    override val root = borderpane {

        top = hbox(10) {
            style {
                alignment = Pos.CENTER
            }
            label("點密度")
            togglegroup {
                listOf(0.01, 0.03, 0.05, 0.07, 0.1).map { v ->
                    radiobutton(v.toString(), this, v) { if (v === 0.01) isSelected = true }
                }
                selectedToggleProperty().addListener { _, _, newValue ->
//                    step.value = (selectedToggle as RadioButton).text.toDouble()
                    step.value = (newValue as RadioButton).text.toDouble()
                }
            }
            button("start") {
                isRun.addListener { _,_,isrun->
                    if (isrun)
                        this.text = "Pause"
                    else
                        this.text = "Start"
                }
                action {
                    if (isRun.value) {
                        aniMate.stop()
                        this.text = "Start"
                        isRun.value = false
                    } else {
                        t = -PI
                        renderedList.clear()
                        pNums.value=0
                        aniMate.start()
                        this.text = "Pause"
                        isRun.value = true
                    }
                }
            }
            label(pNums.stringBinding { "當前點數：$it" })
        }

        center = canvas(800.0, 600.0) {
            style {
                alignment = Pos.CENTER
            }
            context = this.graphicsContext2D
            paddingAll = 30
        }
    }

    inner class AniTimer : AnimationTimer() {
        var lastTime = 0L
        val r = 10.0
        var syncLock = Any()
        override fun handle(now: Long) {
            if ((now - lastTime) > 10000000) {
                lastTime = now
            } else {
                return
            }
            Platform.runLater {
                val y = 200 + (2 * cos(t) - cos(2 * t)) * -80
                val x = 400 + (2 * sin(t) - sin(2 * t)) * 100
                val p = Point(x, y)
                // 鎖住，防止其餘線程修改
                synchronized(syncLock) {
                    // 添加歷史記錄
                    renderedList.add(p)
                    // 清屏
                    context.fill = Color.WHITE
                    context.clearRect(0.0, 0.0, 800.0, 600.0)
                    context.fill =  Color.RED
                    // 渲染點
                    for (point in renderedList) {
                        context.fillOval(point.x, point.y, r, r)

                    }
                    pNums.value += 1
                    t += step.value
                    // 控制點的數量
                    if (t > PI) {
                        aniMate.stop()
                        isRun.value=false
                    }
                }
            }
        }
    }
}

class Point(val x: Double, val y: Double)