Desktop: Treat Swing drag and move mouse events as Compose move events

Difference between Swing drag and move events:
- move events are fired only in the bounds of the window and when mouse isn't pressed
- drag events are fired when mouse is pressed and can be fired even if the mouse outside of the pressed window

Currently we treat drag events only as Modifier.pointerInput events.
And move events only as Modifier.onPointerMove events

This CL allows:
- handle any mouse move/drag events with Modifier.pointerInput
- use mouse hover (Modifier.onPointerMove) with the pressed mouse button

But after this some components should handle Modifier.onPointerMove(onExit={}) differently.
For example, we need to keep scrollbar highlighted when we move mouse outside of the scrollbar.

Before this CL this was handled automatically, because we didn't send move events when we drag the mouse.
But it shouldn't be handled automatically, developer should explicitly write this logic
(keep scrollbar highlighted when we drag it)

Fixes:
JetBrains/compose-multiplatform#134
JetBrains/compose-multiplatform#530

Change-Id: If510840c2c7e4bf2e192f9990e5a05cec592635a
Test: manual ./gradlew :compose:desktop:desktop:desktop-samples:run1 -Pandroidx.compose.multiplatformEnabled=true
Test: drag Scrollbar and move mouse outside

compose/foundation/foundation/src/desktopMain/kotlin/androidx/compose/foundation/Scrollbar.desktop.kt

@@ -32,6 +32,7 @@ import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -194,7 +195,13 @@ private fun Scrollbar(
     }
 
     var containerSize by remember { mutableStateOf(0) }
-    var isHover by remember { mutableStateOf(false) }
+    var isHovered by remember { mutableStateOf(false) }
+
+    val isHighlighted by remember {
+        derivedStateOf {
+            isHovered || dragInteraction.value is DragInteraction.Start
+        }
+    }
 
     val minimalHeight = style.minimalHeight.toPx()
     val sliderAdapter = remember(adapter, containerSize, minimalHeight) {
@@ -213,7 +220,7 @@ private fun Scrollbar(
     }
 
     val color by animateColorAsState(
-        if (isHover) style.hoverColor else style.unhoverColor,
+        if (isHighlighted) style.hoverColor else style.unhoverColor,
         animationSpec = TweenSpec(durationMillis = style.hoverDurationMillis)
     )
 
@@ -231,8 +238,8 @@ private fun Scrollbar(
         },
         modifier
             .pointerMoveFilter(
-                onExit = { isHover = false; true },
-                onEnter = { isHover = true; true }
+                onExit = { isHovered = false; false },
+                onEnter = { isHovered = true; false }
             )
             .scrollOnPressOutsideSlider(isVertical, sliderAdapter, adapter, containerSize),
         measurePolicy

compose/ui/ui/src/desktopMain/kotlin/androidx/compose/desktop/ComposeLayer.desktop.kt

@@ -175,7 +175,7 @@ internal class ComposeLayer {
         })
         wrapped.addMouseMotionListener(object : MouseMotionAdapter() {
             override fun mouseDragged(event: MouseEvent) = events.post {
-                owners.onMouseDragged(
+                owners.onMouseMoved(
                     (event.x * density.density).toInt(),
                     (event.y * density.density).toInt(),
                     event
@@ -185,7 +185,8 @@ internal class ComposeLayer {
             override fun mouseMoved(event: MouseEvent) = events.post {
                 owners.onMouseMoved(
                     (event.x * density.density).toInt(),
-                    (event.y * density.density).toInt()
+                    (event.y * density.density).toInt(),
+                    event
                 )
             }
         })

compose/ui/ui/src/desktopMain/kotlin/androidx/compose/ui/platform/DesktopOwner.desktop.kt

@@ -60,6 +60,7 @@ import androidx.compose.ui.input.pointer.PointerInputEventProcessor
 import androidx.compose.ui.input.pointer.PointerInputFilter
 import androidx.compose.ui.input.pointer.PointerMoveEventFilter
 import androidx.compose.ui.input.pointer.PositionCalculator
+import androidx.compose.ui.input.pointer.ProcessResult
 import androidx.compose.ui.input.pointer.TestPointerInputEventData
 import androidx.compose.ui.layout.RootMeasurePolicy
 import androidx.compose.ui.layout.boundsInWindow
@@ -317,9 +318,9 @@ internal class DesktopOwner(
         root.draw(DesktopCanvas(canvas))
     }
 
-    internal fun processPointerInput(event: PointerInputEvent) {
+    internal fun processPointerInput(event: PointerInputEvent): ProcessResult {
         measureAndLayout()
-        pointerInputEventProcessor.process(event, this)
+        return pointerInputEventProcessor.process(event, this)
     }
 
     override fun processPointerInput(nanoTime: Long, pointers: List<TestPointerInputEventData>) {

compose/ui/ui/src/desktopMain/kotlin/androidx/compose/ui/platform/DesktopOwners.desktop.kt

@@ -143,20 +143,20 @@ internal class DesktopOwners(
         pointerId += 1
     }
 
-    fun onMouseDragged(x: Int, y: Int, nativeEvent: MouseEvent? = null) {
-        lastOwner?.processPointerInput(pointerInputEvent(nativeEvent, x, y, isMousePressed))
+    fun onMouseMoved(x: Int, y: Int, nativeEvent: MouseEvent? = null) {
+        val event = pointerInputEvent(nativeEvent, x, y, isMousePressed)
+        val result = lastOwner?.processPointerInput(event)
+        if (result?.anyMovementConsumed != true) {
+            val position = Offset(x.toFloat(), y.toFloat())
+            lastOwner?.onPointerMove(position)
+        }
     }
 
     fun onMouseScroll(x: Int, y: Int, event: MouseScrollEvent) {
         val position = Offset(x.toFloat(), y.toFloat())
         lastOwner?.onMouseScroll(position, event)
     }
 
-    fun onMouseMoved(x: Int, y: Int) {
-        val position = Offset(x.toFloat(), y.toFloat())
-        lastOwner?.onPointerMove(position)
-    }
-
     fun onMouseEntered(x: Int, y: Int) {
         val position = Offset(x.toFloat(), y.toFloat())
         lastOwner?.onPointerEnter(position)