Create Px class to represent raw host pixel value.

CHANGELOG.md

@@ -6,6 +6,7 @@
 New:
 - Wasm JS added as a target for common Redwood modules. There is no Treehouse support today.
 - Add `onScroll` property to `Row` and `Column`. This property is invoked when `overflow = Overflow.Scroll` and the container is scrolled.
+- Add `Px` class to represent a raw pixel value in the host's coordinate system.
 
 Changed:
 - The `TreehouseApp` type is now an abstract class. This should make it easier to write unit tests for code that integrates Treehouse.

redwood-layout-compose/api/redwood-layout-compose.klib.api

@@ -51,6 +51,6 @@ final val app.cash.redwood.layout.compose/app_cash_redwood_layout_compose_Vertic
 final val app.cash.redwood.layout.compose/app_cash_redwood_layout_compose_WidthImpl$stableprop // app.cash.redwood.layout.compose/app_cash_redwood_layout_compose_WidthImpl$stableprop|#static{}app_cash_redwood_layout_compose_WidthImpl$stableprop[0]
 
 final fun app.cash.redwood.layout.compose/Box(app.cash.redwood.layout.api/Constraint?, app.cash.redwood.layout.api/Constraint?, app.cash.redwood.ui/Margin?, app.cash.redwood.layout.api/CrossAxisAlignment?, app.cash.redwood.layout.api/CrossAxisAlignment?, app.cash.redwood/Modifier?, kotlin/Function3<app.cash.redwood.layout.compose/BoxScope, androidx.compose.runtime/Composer, kotlin/Int, kotlin/Unit>, androidx.compose.runtime/Composer?, kotlin/Int, kotlin/Int) // app.cash.redwood.layout.compose/Box|Box(app.cash.redwood.layout.api.Constraint?;app.cash.redwood.layout.api.Constraint?;app.cash.redwood.ui.Margin?;app.cash.redwood.layout.api.CrossAxisAlignment?;app.cash.redwood.layout.api.CrossAxisAlignment?;app.cash.redwood.Modifier?;kotlin.Function3<app.cash.redwood.layout.compose.BoxScope,androidx.compose.runtime.Composer,kotlin.Int,kotlin.Unit>;androidx.compose.runtime.Composer?;kotlin.Int;kotlin.Int){}[0]
-final fun app.cash.redwood.layout.compose/Column(app.cash.redwood.layout.api/Constraint?, app.cash.redwood.layout.api/Constraint?, app.cash.redwood.ui/Margin?, app.cash.redwood.layout.api/Overflow?, app.cash.redwood.layout.api/CrossAxisAlignment?, app.cash.redwood.layout.api/MainAxisAlignment?, kotlin/Function1<kotlin/Double, kotlin/Unit>?, app.cash.redwood/Modifier?, kotlin/Function3<app.cash.redwood.layout.compose/ColumnScope, androidx.compose.runtime/Composer, kotlin/Int, kotlin/Unit>, androidx.compose.runtime/Composer?, kotlin/Int, kotlin/Int) // app.cash.redwood.layout.compose/Column|Column(app.cash.redwood.layout.api.Constraint?;app.cash.redwood.layout.api.Constraint?;app.cash.redwood.ui.Margin?;app.cash.redwood.layout.api.Overflow?;app.cash.redwood.layout.api.CrossAxisAlignment?;app.cash.redwood.layout.api.MainAxisAlignment?;kotlin.Function1<kotlin.Double,kotlin.Unit>?;app.cash.redwood.Modifier?;kotlin.Function3<app.cash.redwood.layout.compose.ColumnScope,androidx.compose.runtime.Composer,kotlin.Int,kotlin.Unit>;androidx.compose.runtime.Composer?;kotlin.Int;kotlin.Int){}[0]
-final fun app.cash.redwood.layout.compose/Row(app.cash.redwood.layout.api/Constraint?, app.cash.redwood.layout.api/Constraint?, app.cash.redwood.ui/Margin?, app.cash.redwood.layout.api/Overflow?, app.cash.redwood.layout.api/MainAxisAlignment?, app.cash.redwood.layout.api/CrossAxisAlignment?, kotlin/Function1<kotlin/Double, kotlin/Unit>?, app.cash.redwood/Modifier?, kotlin/Function3<app.cash.redwood.layout.compose/RowScope, androidx.compose.runtime/Composer, kotlin/Int, kotlin/Unit>, androidx.compose.runtime/Composer?, kotlin/Int, kotlin/Int) // app.cash.redwood.layout.compose/Row|Row(app.cash.redwood.layout.api.Constraint?;app.cash.redwood.layout.api.Constraint?;app.cash.redwood.ui.Margin?;app.cash.redwood.layout.api.Overflow?;app.cash.redwood.layout.api.MainAxisAlignment?;app.cash.redwood.layout.api.CrossAxisAlignment?;kotlin.Function1<kotlin.Double,kotlin.Unit>?;app.cash.redwood.Modifier?;kotlin.Function3<app.cash.redwood.layout.compose.RowScope,androidx.compose.runtime.Composer,kotlin.Int,kotlin.Unit>;androidx.compose.runtime.Composer?;kotlin.Int;kotlin.Int){}[0]
+final fun app.cash.redwood.layout.compose/Column(app.cash.redwood.layout.api/Constraint?, app.cash.redwood.layout.api/Constraint?, app.cash.redwood.ui/Margin?, app.cash.redwood.layout.api/Overflow?, app.cash.redwood.layout.api/CrossAxisAlignment?, app.cash.redwood.layout.api/MainAxisAlignment?, kotlin/Function1<app.cash.redwood.ui/Px, kotlin/Unit>?, app.cash.redwood/Modifier?, kotlin/Function3<app.cash.redwood.layout.compose/ColumnScope, androidx.compose.runtime/Composer, kotlin/Int, kotlin/Unit>, androidx.compose.runtime/Composer?, kotlin/Int, kotlin/Int) // app.cash.redwood.layout.compose/Column|Column(app.cash.redwood.layout.api.Constraint?;app.cash.redwood.layout.api.Constraint?;app.cash.redwood.ui.Margin?;app.cash.redwood.layout.api.Overflow?;app.cash.redwood.layout.api.CrossAxisAlignment?;app.cash.redwood.layout.api.MainAxisAlignment?;kotlin.Function1<app.cash.redwood.ui.Px,kotlin.Unit>?;app.cash.redwood.Modifier?;kotlin.Function3<app.cash.redwood.layout.compose.ColumnScope,androidx.compose.runtime.Composer,kotlin.Int,kotlin.Unit>;androidx.compose.runtime.Composer?;kotlin.Int;kotlin.Int){}[0]
+final fun app.cash.redwood.layout.compose/Row(app.cash.redwood.layout.api/Constraint?, app.cash.redwood.layout.api/Constraint?, app.cash.redwood.ui/Margin?, app.cash.redwood.layout.api/Overflow?, app.cash.redwood.layout.api/MainAxisAlignment?, app.cash.redwood.layout.api/CrossAxisAlignment?, kotlin/Function1<app.cash.redwood.ui/Px, kotlin/Unit>?, app.cash.redwood/Modifier?, kotlin/Function3<app.cash.redwood.layout.compose/RowScope, androidx.compose.runtime/Composer, kotlin/Int, kotlin/Unit>, androidx.compose.runtime/Composer?, kotlin/Int, kotlin/Int) // app.cash.redwood.layout.compose/Row|Row(app.cash.redwood.layout.api.Constraint?;app.cash.redwood.layout.api.Constraint?;app.cash.redwood.ui.Margin?;app.cash.redwood.layout.api.Overflow?;app.cash.redwood.layout.api.MainAxisAlignment?;app.cash.redwood.layout.api.CrossAxisAlignment?;kotlin.Function1<app.cash.redwood.ui.Px,kotlin.Unit>?;app.cash.redwood.Modifier?;kotlin.Function3<app.cash.redwood.layout.compose.RowScope,androidx.compose.runtime.Composer,kotlin.Int,kotlin.Unit>;androidx.compose.runtime.Composer?;kotlin.Int;kotlin.Int){}[0]
 final fun app.cash.redwood.layout.compose/Spacer(app.cash.redwood.ui/Dp, app.cash.redwood.ui/Dp, app.cash.redwood/Modifier?, androidx.compose.runtime/Composer?, kotlin/Int, kotlin/Int) // app.cash.redwood.layout.compose/Spacer|Spacer(app.cash.redwood.ui.Dp;app.cash.redwood.ui.Dp;app.cash.redwood.Modifier?;androidx.compose.runtime.Composer?;kotlin.Int;kotlin.Int){}[0]

redwood-layout-composeui/src/androidUnitTest/kotlin/app/cash/redwood/layout/composeui/ComposeUiFlexContainerTest.kt

@@ -24,6 +24,7 @@ import app.cash.paparazzi.Paparazzi
 import app.cash.redwood.layout.AbstractFlexContainerTest
 import app.cash.redwood.layout.TestFlexContainer
 import app.cash.redwood.layout.widget.FlexContainer
+import app.cash.redwood.ui.Px
 import app.cash.redwood.widget.Widget
 import app.cash.redwood.widget.compose.ComposeWidgetChildren
 import app.cash.redwood.yoga.FlexDirection
@@ -79,13 +80,13 @@ class ComposeUiFlexContainerTest(
       },
     )
 
-    override fun onScroll(onScroll: ((Double) -> Unit)?) {
+    override fun onScroll(onScroll: ((Px) -> Unit)?) {
       delegate.onScroll(onScroll)
     }
 
-    override fun scroll(offset: Double) {
+    override fun scroll(offset: Px) {
       runBlocking {
-        delegate.scrollState?.scrollTo(offset.toInt())
+        delegate.scrollState?.scrollTo(offset.value.toInt())
       }
     }
 

redwood-layout-composeui/src/commonMain/kotlin/app/cash/redwood/layout/composeui/ComposeUiFlexContainer.kt

@@ -48,6 +48,7 @@ import app.cash.redwood.layout.api.MainAxisAlignment
 import app.cash.redwood.layout.api.Overflow
 import app.cash.redwood.ui.Density
 import app.cash.redwood.ui.Margin
+import app.cash.redwood.ui.Px
 import app.cash.redwood.widget.compose.ComposeWidgetChildren
 import app.cash.redwood.yoga.Direction
 import app.cash.redwood.yoga.FlexDirection
@@ -69,7 +70,7 @@ internal class ComposeUiFlexContainer(
   private var height by mutableStateOf(Constraint.Wrap)
   private var overflow by mutableStateOf(Overflow.Clip)
   private var margin by mutableStateOf(Margin.Zero)
-  private var onScroll: ((Double) -> Unit)? by mutableStateOf(null)
+  private var onScroll: ((Px) -> Unit)? by mutableStateOf(null)
   override var density = Density(1.0)
 
   internal var testOnlyModifier: Modifier? = null
@@ -91,7 +92,7 @@ internal class ComposeUiFlexContainer(
     this.overflow = overflow
   }
 
-  override fun onScroll(onScroll: ((Double) -> Unit)?) {
+  override fun onScroll(onScroll: ((Px) -> Unit)?) {
     this.onScroll = onScroll
   }
 
@@ -164,7 +165,7 @@ internal class ComposeUiFlexContainer(
     if (onScroll != null) {
       val offset by remember { derivedStateOf { scrollState.value.toDouble() } }
       LaunchedEffect(offset) {
-        onScroll(offset)
+        onScroll(Px(offset))
       }
     }
   }

redwood-layout-dom/src/commonMain/kotlin/app/cash/redwood/layout/dom/HTMLElementRedwoodLayoutWidgetFactory.kt

@@ -35,6 +35,7 @@ import app.cash.redwood.layout.widget.Row
 import app.cash.redwood.layout.widget.Spacer
 import app.cash.redwood.ui.Dp
 import app.cash.redwood.ui.Margin
+import app.cash.redwood.ui.Px
 import app.cash.redwood.widget.HTMLElementChildren
 import app.cash.redwood.widget.Widget
 import org.w3c.dom.Document
@@ -105,7 +106,7 @@ private class HTMLFlexContainer(
     value.overflowSetter(overflow.toCss())
   }
 
-  override fun onScroll(onScroll: ((Double) -> Unit)?) {
+  override fun onScroll(onScroll: ((Px) -> Unit)?) {
     scrollEventListener?.let { eventListener ->
       value.removeEventListener("scroll", eventListener)
       scrollEventListener = null
@@ -119,7 +120,7 @@ private class HTMLFlexContainer(
             "column" -> value.scrollLeft
             else -> throw AssertionError()
           }
-          onScroll(offset)
+          onScroll(Px(offset))
         }
       }.also { scrollEventListener = it }
       value.addEventListener("scroll", eventListener)

redwood-layout-schema/redwood-api.xml

@@ -6,7 +6,7 @@
     <property tag="4" name="overflow" type="app.cash.redwood.layout.api.Overflow"/>
     <property tag="5" name="horizontalAlignment" type="app.cash.redwood.layout.api.MainAxisAlignment"/>
     <property tag="6" name="verticalAlignment" type="app.cash.redwood.layout.api.CrossAxisAlignment"/>
-    <event tag="7" name="onScroll" params="kotlin.Double" nullable="true"/>
+    <event tag="7" name="onScroll" params="app.cash.redwood.ui.Px" nullable="true"/>
     <children tag="1" name="children"/>
   </widget>
   <widget tag="2" type="app.cash.redwood.layout.Column">
@@ -16,7 +16,7 @@
     <property tag="4" name="overflow" type="app.cash.redwood.layout.api.Overflow"/>
     <property tag="5" name="horizontalAlignment" type="app.cash.redwood.layout.api.CrossAxisAlignment"/>
     <property tag="6" name="verticalAlignment" type="app.cash.redwood.layout.api.MainAxisAlignment"/>
-    <event tag="7" name="onScroll" params="kotlin.Double" nullable="true"/>
+    <event tag="7" name="onScroll" params="app.cash.redwood.ui.Px" nullable="true"/>
     <children tag="1" name="children"/>
   </widget>
   <widget tag="3" type="app.cash.redwood.layout.Spacer">

redwood-layout-schema/src/main/kotlin/app/cash/redwood/layout/widgets.kt

@@ -25,6 +25,7 @@ import app.cash.redwood.schema.Property
 import app.cash.redwood.schema.Widget
 import app.cash.redwood.ui.Dp
 import app.cash.redwood.ui.Margin
+import app.cash.redwood.ui.Px
 
 /**
  * Lays out widgets horizontally in a row.
@@ -88,7 +89,7 @@ public data class Row(
    */
   @Property(7)
   @Default("null")
-  val onScroll: ((offset: Double) -> Unit)?,
+  val onScroll: ((offset: Px) -> Unit)?,
 
   /**
    * A slot to add widgets in.
@@ -160,7 +161,7 @@ public data class Column(
    */
   @Property(7)
   @Default("null")
-  val onScroll: ((offset: Double) -> Unit)?,
+  val onScroll: ((offset: Px) -> Unit)?,
 
   /**
    * A slot to add widgets in.

redwood-layout-shared-test/src/commonMain/kotlin/app/cash/redwood/layout/AbstractFlexContainerTest.kt

@@ -23,6 +23,7 @@ import app.cash.redwood.layout.api.Overflow
 import app.cash.redwood.layout.widget.Column
 import app.cash.redwood.layout.widget.Row
 import app.cash.redwood.ui.Margin
+import app.cash.redwood.ui.Px
 import app.cash.redwood.ui.dp
 import app.cash.redwood.widget.ChangeListener
 import app.cash.redwood.widget.Widget
@@ -617,7 +618,7 @@ abstract class AbstractFlexContainerTest<T : Any> {
       }
     }
 
-    container.scroll(1000.0)
+    container.scroll(Px(1000.0))
 
     verifySnapshot(container)
 
@@ -636,8 +637,8 @@ interface TestFlexContainer<T : Any> :
   fun mainAxisAlignment(mainAxisAlignment: MainAxisAlignment)
   fun margin(margin: Margin)
   fun overflow(overflow: Overflow)
-  fun onScroll(onScroll: ((Double) -> Unit)?)
-  fun scroll(offset: Double)
+  fun onScroll(onScroll: ((Px) -> Unit)?)
+  fun scroll(offset: Px)
   fun add(widget: Widget<T>)
   fun addAt(index: Int, widget: Widget<T>)
   fun removeAt(index: Int)

redwood-layout-testing/api/redwood-layout-testing.klib.api

@@ -34,7 +34,7 @@ final class app.cash.redwood.layout.testing/BoxValue : app.cash.redwood.testing/
 }
 
 final class app.cash.redwood.layout.testing/ColumnValue : app.cash.redwood.testing/WidgetValue { // app.cash.redwood.layout.testing/ColumnValue|null[0]
-    constructor <init>(app.cash.redwood/Modifier = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.ui/Margin = ..., app.cash.redwood.layout.api/Overflow = ..., app.cash.redwood.layout.api/CrossAxisAlignment = ..., app.cash.redwood.layout.api/MainAxisAlignment = ..., kotlin/Function1<kotlin/Double, kotlin/Unit>? = ..., kotlin.collections/List<app.cash.redwood.testing/WidgetValue> = ...) // app.cash.redwood.layout.testing/ColumnValue.<init>|<init>(app.cash.redwood.Modifier;app.cash.redwood.layout.api.Constraint;app.cash.redwood.layout.api.Constraint;app.cash.redwood.ui.Margin;app.cash.redwood.layout.api.Overflow;app.cash.redwood.layout.api.CrossAxisAlignment;app.cash.redwood.layout.api.MainAxisAlignment;kotlin.Function1<kotlin.Double,kotlin.Unit>?;kotlin.collections.List<app.cash.redwood.testing.WidgetValue>){}[0]
+    constructor <init>(app.cash.redwood/Modifier = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.ui/Margin = ..., app.cash.redwood.layout.api/Overflow = ..., app.cash.redwood.layout.api/CrossAxisAlignment = ..., app.cash.redwood.layout.api/MainAxisAlignment = ..., kotlin/Function1<app.cash.redwood.ui/Px, kotlin/Unit>? = ..., kotlin.collections/List<app.cash.redwood.testing/WidgetValue> = ...) // app.cash.redwood.layout.testing/ColumnValue.<init>|<init>(app.cash.redwood.Modifier;app.cash.redwood.layout.api.Constraint;app.cash.redwood.layout.api.Constraint;app.cash.redwood.ui.Margin;app.cash.redwood.layout.api.Overflow;app.cash.redwood.layout.api.CrossAxisAlignment;app.cash.redwood.layout.api.MainAxisAlignment;kotlin.Function1<app.cash.redwood.ui.Px,kotlin.Unit>?;kotlin.collections.List<app.cash.redwood.testing.WidgetValue>){}[0]
 
     final val children // app.cash.redwood.layout.testing/ColumnValue.children|{}children[0]
         final fun <get-children>(): kotlin.collections/List<app.cash.redwood.testing/WidgetValue> // app.cash.redwood.layout.testing/ColumnValue.children.<get-children>|<get-children>(){}[0]
@@ -49,7 +49,7 @@ final class app.cash.redwood.layout.testing/ColumnValue : app.cash.redwood.testi
     final val modifier // app.cash.redwood.layout.testing/ColumnValue.modifier|{}modifier[0]
         final fun <get-modifier>(): app.cash.redwood/Modifier // app.cash.redwood.layout.testing/ColumnValue.modifier.<get-modifier>|<get-modifier>(){}[0]
     final val onScroll // app.cash.redwood.layout.testing/ColumnValue.onScroll|{}onScroll[0]
-        final fun <get-onScroll>(): kotlin/Function1<kotlin/Double, kotlin/Unit>? // app.cash.redwood.layout.testing/ColumnValue.onScroll.<get-onScroll>|<get-onScroll>(){}[0]
+        final fun <get-onScroll>(): kotlin/Function1<app.cash.redwood.ui/Px, kotlin/Unit>? // app.cash.redwood.layout.testing/ColumnValue.onScroll.<get-onScroll>|<get-onScroll>(){}[0]
     final val overflow // app.cash.redwood.layout.testing/ColumnValue.overflow|{}overflow[0]
         final fun <get-overflow>(): app.cash.redwood.layout.api/Overflow // app.cash.redwood.layout.testing/ColumnValue.overflow.<get-overflow>|<get-overflow>(){}[0]
     final val verticalAlignment // app.cash.redwood.layout.testing/ColumnValue.verticalAlignment|{}verticalAlignment[0]
@@ -74,7 +74,7 @@ final class app.cash.redwood.layout.testing/RedwoodLayoutTestingWidgetFactory :
 }
 
 final class app.cash.redwood.layout.testing/RowValue : app.cash.redwood.testing/WidgetValue { // app.cash.redwood.layout.testing/RowValue|null[0]
-    constructor <init>(app.cash.redwood/Modifier = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.ui/Margin = ..., app.cash.redwood.layout.api/Overflow = ..., app.cash.redwood.layout.api/MainAxisAlignment = ..., app.cash.redwood.layout.api/CrossAxisAlignment = ..., kotlin/Function1<kotlin/Double, kotlin/Unit>? = ..., kotlin.collections/List<app.cash.redwood.testing/WidgetValue> = ...) // app.cash.redwood.layout.testing/RowValue.<init>|<init>(app.cash.redwood.Modifier;app.cash.redwood.layout.api.Constraint;app.cash.redwood.layout.api.Constraint;app.cash.redwood.ui.Margin;app.cash.redwood.layout.api.Overflow;app.cash.redwood.layout.api.MainAxisAlignment;app.cash.redwood.layout.api.CrossAxisAlignment;kotlin.Function1<kotlin.Double,kotlin.Unit>?;kotlin.collections.List<app.cash.redwood.testing.WidgetValue>){}[0]
+    constructor <init>(app.cash.redwood/Modifier = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.layout.api/Constraint = ..., app.cash.redwood.ui/Margin = ..., app.cash.redwood.layout.api/Overflow = ..., app.cash.redwood.layout.api/MainAxisAlignment = ..., app.cash.redwood.layout.api/CrossAxisAlignment = ..., kotlin/Function1<app.cash.redwood.ui/Px, kotlin/Unit>? = ..., kotlin.collections/List<app.cash.redwood.testing/WidgetValue> = ...) // app.cash.redwood.layout.testing/RowValue.<init>|<init>(app.cash.redwood.Modifier;app.cash.redwood.layout.api.Constraint;app.cash.redwood.layout.api.Constraint;app.cash.redwood.ui.Margin;app.cash.redwood.layout.api.Overflow;app.cash.redwood.layout.api.MainAxisAlignment;app.cash.redwood.layout.api.CrossAxisAlignment;kotlin.Function1<app.cash.redwood.ui.Px,kotlin.Unit>?;kotlin.collections.List<app.cash.redwood.testing.WidgetValue>){}[0]
 
     final val children // app.cash.redwood.layout.testing/RowValue.children|{}children[0]
         final fun <get-children>(): kotlin.collections/List<app.cash.redwood.testing/WidgetValue> // app.cash.redwood.layout.testing/RowValue.children.<get-children>|<get-children>(){}[0]
@@ -89,7 +89,7 @@ final class app.cash.redwood.layout.testing/RowValue : app.cash.redwood.testing/
     final val modifier // app.cash.redwood.layout.testing/RowValue.modifier|{}modifier[0]
         final fun <get-modifier>(): app.cash.redwood/Modifier // app.cash.redwood.layout.testing/RowValue.modifier.<get-modifier>|<get-modifier>(){}[0]
     final val onScroll // app.cash.redwood.layout.testing/RowValue.onScroll|{}onScroll[0]
-        final fun <get-onScroll>(): kotlin/Function1<kotlin/Double, kotlin/Unit>? // app.cash.redwood.layout.testing/RowValue.onScroll.<get-onScroll>|<get-onScroll>(){}[0]
+        final fun <get-onScroll>(): kotlin/Function1<app.cash.redwood.ui/Px, kotlin/Unit>? // app.cash.redwood.layout.testing/RowValue.onScroll.<get-onScroll>|<get-onScroll>(){}[0]
     final val overflow // app.cash.redwood.layout.testing/RowValue.overflow|{}overflow[0]
         final fun <get-overflow>(): app.cash.redwood.layout.api/Overflow // app.cash.redwood.layout.testing/RowValue.overflow.<get-overflow>|<get-overflow>(){}[0]
     final val verticalAlignment // app.cash.redwood.layout.testing/RowValue.verticalAlignment|{}verticalAlignment[0]

redwood-layout-uiview/src/commonMain/kotlin/app/cash/redwood/layout/uiview/UIViewFlexContainer.kt

@@ -20,6 +20,7 @@ import app.cash.redwood.layout.api.Constraint
 import app.cash.redwood.layout.api.Overflow
 import app.cash.redwood.ui.Default
 import app.cash.redwood.ui.Density
+import app.cash.redwood.ui.Px
 import app.cash.redwood.widget.ChangeListener
 import app.cash.redwood.widget.UIViewChildren
 import app.cash.redwood.yoga.FlexDirection
@@ -74,7 +75,7 @@ internal class UIViewFlexContainer(
     yogaView.scrollEnabled = overflow == Overflow.Scroll
   }
 
-  override fun onScroll(onScroll: ((Double) -> Unit)?) {
+  override fun onScroll(onScroll: ((Px) -> Unit)?) {
     yogaView.onScroll = onScroll
   }