tornadofx使用RichTextFX控件

依赖：
dependencies {
    implementation(kotlin("stdlib-jdk8"))
    compile("org.jetbrains.kotlinx:kotlinx-coroutines-javafx:1.3.0-M1")
    compile("no.tornado:tornadofx:1.7.19")
    compile("org.openjfx:javafx-controls:11.0.2")
    compile("org.openjfx:javafx-graphics:11.0.2")
    compile("org.openjfx:javafx-fxml:11.0.2")
    compile("org.openjfx:javafx-base:11.0.2")
    compile("org.openjfx:javafx-web:11.0.2")
    compile("org.openjfx:javafx-media:11.0.2")
    compile("org.fxmisc.richtext:richtextfx:0.10.1")
}

UI：

class RichTextV : View("view picture") {

    val ca= CodeArea()
    val mBold = MenuItem("加粗")
    val mClear = MenuItem("清除")
    val mColor = MenuItem("变色")
    override val root = scrollpane {
        hbox {
            add(ca)
        }
    }
    fun prepareCA(ca:CodeArea) {
        ca.setParagraphGraphicFactory(LineNumberFactory.get(ca))
        ca.isAutoScrollOnDragDesired=true
        ca.prefWidth=800.0
        ca.prefHeight=600.0

        ca.setStyle("-fx-font-size: 20px;")
        mBold.setOnAction {
            ca.setStyle("-fx-font-weight: bold;-fx-font-size: 20px;")
        }
        mClear.setOnAction {
            ca.replaceText("")
        }
        mColor.setOnAction {
            val colors= mutableListOf("red","purple","green","yellow","blue")
            val color=colors.shuffled().take(1)
            ca.setStyle("-fx-background-color: ${color[0]};-fx-font-size: 20px;")
        }

        ca.contextMenu = ContextMenu(mClear)
        ca.contextMenu.items.addAll(mBold,mColor)
    }
    init {
        prepareCA(ca)
    }
}