Add traces

Author: elijah-semyonov

compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/gestures/Draggable.kt

@@ -570,7 +570,11 @@ private class DefaultDraggableState(val onDelta: (Float) -> Unit) : DraggableSta
 
 private sealed class DragEvent {
  class DragStarted(val startPoint: Offset) : DragEvent()
- class DragStopped(val velocity: Velocity) : DragEvent()
+ class DragStopped(val velocity: Velocity) : DragEvent() {
+ init {
+ println("DragStopped with velocity: $velocity")
+ }
+ }
  object DragCancelled : DragEvent()
  class DragDelta(val delta: Offset) : DragEvent()
 }

compose/ui/ui/src/commonMain/kotlin/androidx/compose/ui/input/pointer/util/VelocityTracker.kt

@@ -71,7 +71,7 @@ class VelocityTracker {
  * This can be expensive. Only call this when you need the velocity.
  */
  fun calculateVelocity(): Velocity {
- return Velocity(xVelocityTracker.calculateVelocity(), yVelocityTracker.calculateVelocity())
+ return Velocity(xVelocityTracker.calculateVelocity(), yVelocityTracker.calculateVelocity(true))
  }
 
  /**
@@ -186,7 +186,7 @@ class VelocityTracker1D internal constructor(
  *
  * This can be expensive. Only call this when you need the velocity.
  */
- fun calculateVelocity(): Float {
+ fun calculateVelocity(print: Boolean = false): Float {
  val dataPoints = reusableDataPointsArray
  val time = reusableTimeArray
  var sampleCount = 0
@@ -224,7 +224,7 @@ class VelocityTracker1D internal constructor(
  calculateImpulseVelocity(dataPoints, time, sampleCount, isDataDifferential)
  }
  Strategy.Lsq2 -> {
- calculateLeastSquaresVelocity(dataPoints, time, sampleCount)
+ calculateLeastSquaresVelocity(dataPoints, time, sampleCount, print)
  }
  } * 1000 // Multiply by "1000" to convert from units/ms to units/s
  }
@@ -250,19 +250,30 @@ class VelocityTracker1D internal constructor(
  private fun calculateLeastSquaresVelocity(
  dataPoints: FloatArray,
  time: FloatArray,
- sampleCount: Int
+ sampleCount: Int,
+ print: Boolean = false
  ): Float {
  // The 2nd coefficient is the derivative of the quadratic polynomial at
  // x = 0, and that happens to be the last timestamp that we end up
  // passing to polyFitLeastSquares.
+ if (print) {
+ println("Calculating velocity:")
+ for (i in 0 until sampleCount) {
+ println("${dataPoints[i]} at ${time[i]}")
+ }
+ }
  return try {
- polyFitLeastSquares(
+ val velocity = polyFitLeastSquares(
  time,
  dataPoints,
  sampleCount,
  2,
  reusableVelocityCoefficients
  )[1]
+ if (print) {
+ println("velocity: $velocity")
+ }
+ velocity
  } catch (exception: IllegalArgumentException) {
  0f
  }
@@ -317,6 +328,8 @@ fun VelocityTracker.addPointerInputChange(event: PointerInputChange) {
  return
  }
 
+ println("addPointerInputChange y: ${event.position.y}; pressed: ${event.pressed}")
+
  // To calculate delta, for each step we want to do currentPosition - previousPosition.
  // Initially the previous position is the previous position of the current event
  var previousPointerPosition = event.previousPosition

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/SyntheticEventSender.kt

@@ -101,6 +101,7 @@ internal class SyntheticEventSender(
  private fun sendSyntheticMove(pointersSourceEvent: PointerInputEvent) {
  val previousEvent = previousEvent ?: return
  val idToPosition = pointersSourceEvent.pointers.associate { it.id to it.position }
+ println("synthetic move ${pointersSourceEvent.pointers[0].position.y}")
  sendInternal(
  previousEvent.copySynthetic(
  type = PointerEventType.Move,

compose/ui/ui/src/uikitMain/kotlin/androidx/compose/ui/window/ComposeWindow.uikit.kt

@@ -62,6 +62,7 @@ import org.jetbrains.skiko.SkikoKeyboardEvent
 import org.jetbrains.skiko.SkikoPointerEvent
 import org.jetbrains.skiko.currentNanoTime
 import platform.CoreGraphics.CGPoint
+import org.jetbrains.skiko.SkikoPointerEventKind
 import org.jetbrains.skiko.available
 import platform.CoreGraphics.CGAffineTransformIdentity
 import platform.CoreGraphics.CGAffineTransformInvert