state works again i think

src/main/kotlin/com/neptuneclient/voidui/widgets/Element.kt

@@ -17,11 +17,6 @@ import com.neptuneclient.voidui.themes.styles.PanelStyleSheet
  */
 sealed class Element<S : StyleSheet> : Widget() {
 
-    /**
-     * Holds the screen in which the element is rendered.
-     */
-    private lateinit var screen: Screen
-
     /**
      * The style sheet for this element.
      */
@@ -35,6 +30,7 @@ sealed class Element<S : StyleSheet> : Widget() {
      */
     override fun init(screen: Screen, parent: Widget?) {
         this.screen = screen
+        this.parent = parent
         this.styles = screen.void.theme.getStyleSheet(this::class, Styles.Type.NORMAL)
 
         val size = sizeSelf(screen, parent)

src/main/kotlin/com/neptuneclient/voidui/widgets/Screen.kt

@@ -3,6 +3,7 @@ package com.neptuneclient.voidui.widgets
 import com.neptuneclient.voidui.VoidUI
 import com.neptuneclient.voidui.rendering.ElementStack
 import kotlin.math.round
+import kotlin.properties.Delegates
 
 /**
  * The base class for screens. A screen is the base node of a widget tree, which can be rendered to the screen.
@@ -49,6 +50,15 @@ constructor(val void: VoidUI) {
         elementStack.render()
     }
 
+    /**
+     * Lets you declare a property which will trigger the screen to be rebuilt once it's value changes.
+     *
+     * @param initialValue The initial value of the property.
+     */
+    protected fun <T> state(initialValue: T) = Delegates.observable(initialValue) { _, _, _ ->
+        init()
+    }
+
     /**
      * A dsl feature which adds the view-width unit from HTML to screens.
      */

src/main/kotlin/com/neptuneclient/voidui/widgets/Widget.kt

@@ -2,6 +2,7 @@ package com.neptuneclient.voidui.widgets
 
 import java.awt.Rectangle
 import kotlin.math.round
+import kotlin.properties.Delegates
 
 /**
  * The base for every node in the widget tree.
@@ -14,12 +15,25 @@ abstract class Widget {
     var height: Int = 0
 
     /**
-     * Called by [Screen.init] and initializes the widget. This includes setting position and size as well as initlializing the child widget.
+     * Holds the screen in which this widget lives.
+     */
+    protected lateinit var screen: Screen
+
+    /**
+     * The parent widget. If this is the first widget in the tree, the parent widget is null.
+     */
+    protected var parent: Widget? = null
+
+    /**
+     * Called by [Screen.init] and initializes the widget. This includes setting position and size as well as initializing the child widget.
      *
      * @param screen The screen in which this widget lives.
      * @param parent The parent widget. If this is the first widget in the tree, the parent widget is null.
      */
     internal open fun init(screen: Screen, parent: Widget?) {
+        this.screen = screen
+        this.parent = parent
+
         val size = sizeSelf(screen, parent)
         x = size.x
         y = size.y
@@ -43,6 +57,17 @@ abstract class Widget {
      * @return The child node in the widget tree.
      */
     abstract fun build(): Widget
+
+    /**
+     * Lets you declare a property which will trigger the widget to be rebuilt once it's value changes.
+     *
+     * @param initialValue The initial value of the property.
+     *
+     * For now this just rebuilds the entire screen.
+     */
+    protected fun <T> state(initialValue: T) = Delegates.observable(initialValue) { _, _, _ ->
+        screen.init()
+    }
 
     /**
      * A dsl feature which adds the view-width unit from HTML to components.

src/main/kotlin/com/neptuneclient/voidui/widgets/widgets.kt

@@ -8,6 +8,9 @@ package com.neptuneclient.voidui.widgets
 internal class Group(protected val children: Array<Widget>) : Widget() {
 
     override fun init(screen: Screen, parent: Widget?) {
+        this.screen = screen
+        this.parent = parent
+
         val size = sizeSelf(screen, parent)
         x = size.x
         y = size.y