From 1c19df7cf330c60f2d4ba0b406127af3efbcf508 Mon Sep 17 00:00:00 2001
From: Fingercomp <fingercomp@fomalhaut.me>
Date: Thu, 14 Aug 2025 19:13:56 +0300
Subject: [PATCH 1/3] Implement event capturing

---
 .../ocelot/desktop/inventory/Inventory.scala  |  4 +--
 .../scala/ocelot/desktop/ui/UiHandler.scala   | 30 ++++++++++++-------
 .../desktop/ui/event/CapturingEvent.scala     |  3 ++
 .../desktop/ui/event/Dispatchable.scala       | 28 +++++++++++++++++
 .../scala/ocelot/desktop/ui/event/Event.scala | 11 -------
 .../ocelot/desktop/ui/event/EventAware.scala  |  2 +-
 .../ocelot/desktop/ui/event/KeyEvent.scala    |  2 +-
 .../ocelot/desktop/ui/event/MouseEvent.scala  |  2 +-
 .../ocelot/desktop/ui/event/ScrollEvent.scala |  2 +-
 .../desktop/ui/widget/EventHandlers.scala     | 12 ++++----
 .../ocelot/desktop/ui/widget/Widget.scala     |  4 +++
 11 files changed, 67 insertions(+), 33 deletions(-)
 create mode 100644 src/main/scala/ocelot/desktop/ui/event/CapturingEvent.scala
 create mode 100644 src/main/scala/ocelot/desktop/ui/event/Dispatchable.scala
 delete mode 100644 src/main/scala/ocelot/desktop/ui/event/Event.scala

diff --git a/src/main/scala/ocelot/desktop/inventory/Inventory.scala b/src/main/scala/ocelot/desktop/inventory/Inventory.scala
index 374b563..babcf1b 100644
--- a/src/main/scala/ocelot/desktop/inventory/Inventory.scala
+++ b/src/main/scala/ocelot/desktop/inventory/Inventory.scala
@@ -1,7 +1,7 @@
 package ocelot.desktop.inventory
 
 import ocelot.desktop.inventory.Inventory.SlotObserver
-import ocelot.desktop.ui.event.{BrainEvent, Event, EventAware}
+import ocelot.desktop.ui.event.{BrainEvent, Dispatchable, EventAware}
 import ocelot.desktop.util.Disposable
 import totoro.ocelot.brain.event.NodeEvent
 
@@ -78,7 +78,7 @@ trait Inventory extends EventAware with Disposable {
     super.shouldReceiveEventsFor(address) ||
       inventoryIterator.flatMap(_.get).exists(_.shouldReceiveEventsFor(address))
 
-  override def handleEvent(event: Event): Unit = {
+  override def handleEvent(event: Dispatchable): Unit = {
     super.handleEvent(event)
 
     for (slot <- inventoryIterator; item <- slot.get) {
diff --git a/src/main/scala/ocelot/desktop/ui/UiHandler.scala b/src/main/scala/ocelot/desktop/ui/UiHandler.scala
index 31a3918..df9d718 100644
--- a/src/main/scala/ocelot/desktop/ui/UiHandler.scala
+++ b/src/main/scala/ocelot/desktop/ui/UiHandler.scala
@@ -6,7 +6,7 @@ import ocelot.desktop.geometry.{Rect2D, Size2D, Vector2D}
 import ocelot.desktop.graphics.Graphics
 import ocelot.desktop.ui.event.handlers.HoverHandler
 import ocelot.desktop.ui.event.sources.{BrainEvents, KeyEvents, MouseEvents, ScrollEvents}
-import ocelot.desktop.ui.event.{Event, MouseEvent}
+import ocelot.desktop.ui.event.{Capturing, CapturingEvent, Dispatchable, MouseEvent}
 import ocelot.desktop.ui.widget.window.Window
 import ocelot.desktop.ui.widget.{RootWidget, Widget}
 import ocelot.desktop.util._
@@ -427,16 +427,18 @@ object UiHandler extends Logging {
     Audio.destroy()
   }
 
-  private def dispatchEvent(iter: => IterableOnce[Widget] = hierarchy.reverseIterator)(event: Event): Unit = {
-    for (widget <- iter) {
-      if (event.consumed) {
-        return
-      }
-
+  private def dispatchEvent(iter: => IterableOnce[Widget] = hierarchy.reverseIterator)(event: Dispatchable): Unit = {
+    for (widget <- iter if !event.consumed) {
       widget.handleEvent(event)
     }
   }
 
+  private def dispatchCapturing(target: Widget)(event: CapturingEvent): Unit = {
+    val ancestors = target.ancestors.toSeq
+    dispatchEvent(ancestors.reverseIterator ++ Some(target))(Capturing(event))
+    dispatchEvent(Some(target))(event)
+  }
+
   private def dispatchBrainEvents(): Unit = {
     import totoro.ocelot.brain
 
@@ -476,7 +478,10 @@ object UiHandler extends Logging {
     }
 
     // TODO: dispatch to the focused widget instead of broadcasting to the entire hierarchy.
-    KeyEvents.events.foreach(dispatchEvent())
+    for (event <- KeyEvents.events) {
+      dispatchEvent(hierarchy)(Capturing(event))
+      dispatchEvent()(event)
+    }
 
     MouseEvents.events
       .foreach(dispatchEvent(hierarchy.reverseIterator.filter(w => w.enabled && w.receiveAllMouseEvents)))
@@ -487,17 +492,22 @@ object UiHandler extends Logging {
     val mouseTarget = hierarchy.reverseIterator
       .find(w => w.enabled && w.receiveMouseEvents && w.clippedBounds.contains(mousePos))
 
-    ScrollEvents.events.foreach(dispatchEvent(scrollTarget))
+    for (scrollTarget <- scrollTarget) {
+      ScrollEvents.events.foreach(dispatchCapturing(scrollTarget))
+    }
 
     for (event <- MouseEvents.events) {
       if (event.state == MouseEvent.State.Pressed) {
-        dispatchEvent(mouseTarget)(event)
+        for (mouseTarget <- mouseTarget) {
+          dispatchCapturing(mouseTarget)(event)
+        }
 
         // TODO: this should be done in the event capturing phase in [[Window]] itself.
         for (mouseTarget <- mouseTarget if !mouseTarget.isInstanceOf[Window]) {
           focusParentWindow(mouseTarget.parent)
         }
       } else {
+        dispatchEvent(hierarchy)(Capturing(event))
         dispatchEvent(hierarchy.reverseIterator)(event)
       }
     }
diff --git a/src/main/scala/ocelot/desktop/ui/event/CapturingEvent.scala b/src/main/scala/ocelot/desktop/ui/event/CapturingEvent.scala
new file mode 100644
index 0000000..448d6bd
--- /dev/null
+++ b/src/main/scala/ocelot/desktop/ui/event/CapturingEvent.scala
@@ -0,0 +1,3 @@
+package ocelot.desktop.ui.event
+
+trait CapturingEvent extends Event
diff --git a/src/main/scala/ocelot/desktop/ui/event/Dispatchable.scala b/src/main/scala/ocelot/desktop/ui/event/Dispatchable.scala
new file mode 100644
index 0000000..397083c
--- /dev/null
+++ b/src/main/scala/ocelot/desktop/ui/event/Dispatchable.scala
@@ -0,0 +1,28 @@
+package ocelot.desktop.ui.event
+
+sealed trait Dispatchable {
+  def consume(): Unit
+
+  def consumed: Boolean
+}
+
+trait Event extends Dispatchable {
+  private var _consumed: Boolean = false
+
+  def consume(): Unit = {
+    _consumed = true
+  }
+
+  def consumed: Boolean = _consumed
+}
+
+/**
+  * A wrapper for an event that is dispatched during the capture phase.
+  */
+case class Capturing[A <: CapturingEvent](event: A) extends Dispatchable {
+  override def consume(): Unit = {
+    event.consume()
+  }
+
+  override def consumed: Boolean = event.consumed
+}
diff --git a/src/main/scala/ocelot/desktop/ui/event/Event.scala b/src/main/scala/ocelot/desktop/ui/event/Event.scala
deleted file mode 100644
index a547eec..0000000
--- a/src/main/scala/ocelot/desktop/ui/event/Event.scala
+++ /dev/null
@@ -1,11 +0,0 @@
-package ocelot.desktop.ui.event
-
-trait Event extends AnyRef {
-  private var _consumed: Boolean = false
-
-  def consume(): Unit = {
-    _consumed = true
-  }
-
-  def consumed: Boolean = _consumed
-}
diff --git a/src/main/scala/ocelot/desktop/ui/event/EventAware.scala b/src/main/scala/ocelot/desktop/ui/event/EventAware.scala
index 3459153..97f86e3 100644
--- a/src/main/scala/ocelot/desktop/ui/event/EventAware.scala
+++ b/src/main/scala/ocelot/desktop/ui/event/EventAware.scala
@@ -7,7 +7,7 @@ trait EventAware {
 
   def shouldReceiveEventsFor(address: String): Boolean = false
 
-  def handleEvent(event: Event): Unit = {
+  def handleEvent(event: Dispatchable): Unit = {
     eventHandlers(event)
   }
 }
diff --git a/src/main/scala/ocelot/desktop/ui/event/KeyEvent.scala b/src/main/scala/ocelot/desktop/ui/event/KeyEvent.scala
index c35d148..ed6865e 100644
--- a/src/main/scala/ocelot/desktop/ui/event/KeyEvent.scala
+++ b/src/main/scala/ocelot/desktop/ui/event/KeyEvent.scala
@@ -6,4 +6,4 @@ object KeyEvent {
   }
 }
 
-case class KeyEvent(state: KeyEvent.State.Value, code: Int, char: Char) extends Event
+case class KeyEvent(state: KeyEvent.State.Value, code: Int, char: Char) extends CapturingEvent
diff --git a/src/main/scala/ocelot/desktop/ui/event/MouseEvent.scala b/src/main/scala/ocelot/desktop/ui/event/MouseEvent.scala
index 58c4c07..2ac0bda 100644
--- a/src/main/scala/ocelot/desktop/ui/event/MouseEvent.scala
+++ b/src/main/scala/ocelot/desktop/ui/event/MouseEvent.scala
@@ -12,4 +12,4 @@ object MouseEvent {
   }
 }
 
-case class MouseEvent(state: MouseEvent.State.Value, button: MouseEvent.Button.Value) extends Event
+case class MouseEvent(state: MouseEvent.State.Value, button: MouseEvent.Button.Value) extends CapturingEvent
diff --git a/src/main/scala/ocelot/desktop/ui/event/ScrollEvent.scala b/src/main/scala/ocelot/desktop/ui/event/ScrollEvent.scala
index 5cfa4b2..291546e 100644
--- a/src/main/scala/ocelot/desktop/ui/event/ScrollEvent.scala
+++ b/src/main/scala/ocelot/desktop/ui/event/ScrollEvent.scala
@@ -1,3 +1,3 @@
 package ocelot.desktop.ui.event
 
-case class ScrollEvent(offset: Int) extends Event
+case class ScrollEvent(offset: Int) extends CapturingEvent
diff --git a/src/main/scala/ocelot/desktop/ui/widget/EventHandlers.scala b/src/main/scala/ocelot/desktop/ui/widget/EventHandlers.scala
index 1288216..7b0901b 100644
--- a/src/main/scala/ocelot/desktop/ui/widget/EventHandlers.scala
+++ b/src/main/scala/ocelot/desktop/ui/widget/EventHandlers.scala
@@ -1,27 +1,27 @@
 package ocelot.desktop.ui.widget
 
-import ocelot.desktop.ui.event.Event
+import ocelot.desktop.ui.event.{Dispatchable, Event}
 
 import scala.collection.mutable.ArrayBuffer
 
-class EventHandlers extends PartialFunction[Event, Unit] {
+class EventHandlers extends PartialFunction[Dispatchable, Unit] {
   private val handlers = ArrayBuffer.empty[EventHandler]
 
   def +=(handler: EventHandler): Unit = handlers += handler
 
   def -=(handler: EventHandler): Unit = handlers -= handler
 
-  override def isDefinedAt(event: Event): Boolean = handlers.exists(_.isDefinedAt(event))
+  override def isDefinedAt(event: Dispatchable): Boolean = handlers.exists(_.isDefinedAt(event))
 
-  override def apply(event: Event): Unit = {
+  override def apply(event: Dispatchable): Unit = {
     for (handler <- handlers) {
       if (event.consumed) {
         return
       }
 
-      handler.applyOrElse(event, (_: Event) => ())
+      handler.applyOrElse(event, (_: Dispatchable) => ())
     }
   }
 
-  type EventHandler = PartialFunction[Event, Unit]
+  type EventHandler = PartialFunction[Dispatchable, Unit]
 }
diff --git a/src/main/scala/ocelot/desktop/ui/widget/Widget.scala b/src/main/scala/ocelot/desktop/ui/widget/Widget.scala
index 5adc139..d26ca2e 100644
--- a/src/main/scala/ocelot/desktop/ui/widget/Widget.scala
+++ b/src/main/scala/ocelot/desktop/ui/widget/Widget.scala
@@ -59,6 +59,10 @@ class Widget extends EventAware with Updatable with Disposable {
 
   final def root: Option[RootWidget] = _root
 
+  final def ancestors: Iterator[Widget] = {
+    Iterator.unfold(this)(_.parent.map(w => (w, w)))
+  }
+
   def enabled: Boolean = true
 
   def minimumSize: Size2D = layout.minimumSize

From 87b13e66b123667db13c74739130584fb70f29e7 Mon Sep 17 00:00:00 2001
From: Fingercomp <fingercomp@fomalhaut.me>
Date: Thu, 14 Aug 2025 19:15:53 +0300
Subject: [PATCH 2/3] Remove the window focusing hack

---
 src/main/scala/ocelot/desktop/ui/UiHandler.scala   | 14 --------------
 .../ocelot/desktop/ui/widget/window/Window.scala   |  4 ++--
 2 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/src/main/scala/ocelot/desktop/ui/UiHandler.scala b/src/main/scala/ocelot/desktop/ui/UiHandler.scala
index df9d718..00ac4a0 100644
--- a/src/main/scala/ocelot/desktop/ui/UiHandler.scala
+++ b/src/main/scala/ocelot/desktop/ui/UiHandler.scala
@@ -501,11 +501,6 @@ object UiHandler extends Logging {
         for (mouseTarget <- mouseTarget) {
           dispatchCapturing(mouseTarget)(event)
         }
-
-        // TODO: this should be done in the event capturing phase in [[Window]] itself.
-        for (mouseTarget <- mouseTarget if !mouseTarget.isInstanceOf[Window]) {
-          focusParentWindow(mouseTarget.parent)
-        }
       } else {
         dispatchEvent(hierarchy)(Capturing(event))
         dispatchEvent(hierarchy.reverseIterator)(event)
@@ -525,15 +520,6 @@ object UiHandler extends Logging {
     root.update()
   }
 
-  @tailrec
-  private def focusParentWindow(parent: Option[Widget]): Unit = {
-    parent match {
-      case Some(window: Window) => window.focus()
-      case Some(widget) => focusParentWindow(widget.parent)
-      case None =>
-    }
-  }
-
   private def updateWindowSizeAndPosition(): Unit = {
     val width = Display.getWidth
     val height = Display.getHeight
diff --git a/src/main/scala/ocelot/desktop/ui/widget/window/Window.scala b/src/main/scala/ocelot/desktop/ui/widget/window/Window.scala
index b7955b3..d94b0c7 100644
--- a/src/main/scala/ocelot/desktop/ui/widget/window/Window.scala
+++ b/src/main/scala/ocelot/desktop/ui/widget/window/Window.scala
@@ -4,7 +4,7 @@ import ocelot.desktop.Settings
 import ocelot.desktop.geometry.{Rect2D, Size2D, Vector2D}
 import ocelot.desktop.ui.UiHandler
 import ocelot.desktop.ui.event.handlers.MouseHandler
-import ocelot.desktop.ui.event.{DragEvent, KeyEvent, MouseEvent}
+import ocelot.desktop.ui.event.{Capturing, DragEvent, KeyEvent, MouseEvent}
 import ocelot.desktop.ui.widget.Widget
 import ocelot.desktop.util.Persistable
 import org.lwjgl.input.Keyboard
@@ -30,7 +30,7 @@ trait Window extends Widget with Persistable with MouseHandler {
   override protected def receiveDragEvents: Boolean = true
 
   eventHandlers += {
-    case MouseEvent(MouseEvent.State.Pressed, _) =>
+    case Capturing(MouseEvent(MouseEvent.State.Pressed, _)) =>
       focus()
 
     case ev @ DragEvent(DragEvent.State.Start, MouseEvent.Button.Left, mousePos) =>

From 1c74adc329212790c96235ea842f6a293fd199d2 Mon Sep 17 00:00:00 2001
From: Fingercomp <fingercomp@fomalhaut.me>
Date: Thu, 14 Aug 2025 21:16:50 +0300
Subject: [PATCH 3/3] Intercept mouse press events when dragging scroll bar
 thumbs

---
 src/main/scala/ocelot/desktop/ui/UiHandler.scala    |  2 --
 .../scala/ocelot/desktop/ui/widget/ScrollView.scala | 13 +++++++------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/main/scala/ocelot/desktop/ui/UiHandler.scala b/src/main/scala/ocelot/desktop/ui/UiHandler.scala
index 00ac4a0..8f2ef55 100644
--- a/src/main/scala/ocelot/desktop/ui/UiHandler.scala
+++ b/src/main/scala/ocelot/desktop/ui/UiHandler.scala
@@ -7,7 +7,6 @@ import ocelot.desktop.graphics.Graphics
 import ocelot.desktop.ui.event.handlers.HoverHandler
 import ocelot.desktop.ui.event.sources.{BrainEvents, KeyEvents, MouseEvents, ScrollEvents}
 import ocelot.desktop.ui.event.{Capturing, CapturingEvent, Dispatchable, MouseEvent}
-import ocelot.desktop.ui.widget.window.Window
 import ocelot.desktop.ui.widget.{RootWidget, Widget}
 import ocelot.desktop.util._
 import ocelot.desktop.{OcelotDesktop, Settings}
@@ -24,7 +23,6 @@ import java.nio.channels.Channels
 import java.nio.file.Paths
 import javax.imageio.ImageIO
 import javax.swing.JFileChooser
-import scala.annotation.tailrec
 import scala.collection.mutable
 import scala.collection.mutable.ArrayBuffer
 import scala.concurrent.duration.DurationInt
diff --git a/src/main/scala/ocelot/desktop/ui/widget/ScrollView.scala b/src/main/scala/ocelot/desktop/ui/widget/ScrollView.scala
index 6628931..3fe45e1 100644
--- a/src/main/scala/ocelot/desktop/ui/widget/ScrollView.scala
+++ b/src/main/scala/ocelot/desktop/ui/widget/ScrollView.scala
@@ -7,7 +7,7 @@ import ocelot.desktop.graphics.Graphics
 import ocelot.desktop.ui.UiHandler
 import ocelot.desktop.ui.event.handlers.HoverHandler
 import ocelot.desktop.ui.event.sources.KeyEvents
-import ocelot.desktop.ui.event.{MouseEvent, ScrollEvent}
+import ocelot.desktop.ui.event.{Capturing, MouseEvent, ScrollEvent}
 import ocelot.desktop.ui.layout.Layout
 import ocelot.desktop.ui.widget.ScrollView.{DecayFactor, DragState, MaxScrollVelocity, MinThumbSize, ScrollVelocity}
 import ocelot.desktop.util.Logging
@@ -49,10 +49,15 @@ class ScrollView(val inner: Widget) extends Widget with Logging with HoverHandle
         scrollToEnd = false
       }
 
-    case MouseEvent(MouseEvent.State.Pressed, MouseEvent.Button.Left) =>
+    case Capturing(event @ MouseEvent(MouseEvent.State.Pressed, MouseEvent.Button.Left)) =>
       val pos = UiHandler.mousePosition
 
+      if (vThumbBounds.contains(pos) || hThumbBounds.contains(pos)) {
+        event.consume()
+      }
+      
       dragState = if (vThumbBounds.contains(pos)) {
+        scrollToEnd = false
         DragState.Vertical(yOffset, pos)
       } else if (hThumbBounds.contains(pos)) {
         DragState.Horizontal(xOffset, pos)
@@ -60,10 +65,6 @@ class ScrollView(val inner: Widget) extends Widget with Logging with HoverHandle
         DragState.None
       }
 
-      if (dragState.isVertical) {
-        scrollToEnd = false
-      }
-
     case MouseEvent(MouseEvent.State.Released, MouseEvent.Button.Left) =>
       dragState = DragState.None
   }