Simplify and improve layout system

Sources/SkipUI/SkipUI/Color/Color.swift

@@ -25,7 +25,7 @@ public struct Color: ShapeStyle, Hashable, Sendable {
 
     @Composable public override func ComposeContent(context: ComposeContext) {
         let animatable = colorImpl().asAnimatable(context: context)
-        let modifier = context.modifier.background(animatable.value).fillSize(expandContainer: false)
+        let modifier = context.modifier.background(animatable.value).fillSize()
         Box(modifier: modifier)
     }
 

Sources/SkipUI/SkipUI/Components/Image.swift

@@ -317,7 +317,7 @@ public struct Image : View, Equatable {
         switch resizingMode {
         case .stretch:
             let scale = contentScale(aspectRatio: aspectRatio, contentMode: contentMode)
-            let modifier = Modifier.fillSize(expandContainer: false)
+            let modifier = Modifier.fillSize()
             androidx.compose.foundation.Image(painter: painter, contentDescription: nil, modifier: modifier, contentScale: scale, colorFilter: colorFilter)
         default: // TODO: .tile
             let modifier = Modifier.wrapContentSize(unbounded: true).size((painter.intrinsicSize.width / scale).dp, (painter.intrinsicSize.height / scale).dp)

Sources/SkipUI/SkipUI/Components/Spacer.swift

@@ -43,9 +43,9 @@ public struct Spacer : View {
         let fillModifier: Modifier
         switch axis {
         case .horizontal:
-            fillModifier = EnvironmentValues.shared._fillWidth?(true) ?? Modifier
+            fillModifier = EnvironmentValues.shared._fillWidth?() ?? Modifier
         case .vertical:
-            fillModifier = EnvironmentValues.shared._fillHeight?(true) ?? Modifier
+            fillModifier = EnvironmentValues.shared._fillHeight?() ?? Modifier
         case nil:
             fillModifier = Modifier
         }

Sources/SkipUI/SkipUI/Compose/ComposeContainer.swift

@@ -37,43 +37,34 @@ import androidx.compose.ui.Modifier
 @Composable public func ComposeContainer(axis: Axis? = nil, eraseAxis: Bool = false, scrollAxes: Axis.Set = [], modifier: Modifier = Modifier, fillWidth: Bool = false, fixedWidth: Bool = false, fillHeight: Bool = false, fixedHeight: Bool = false, then: Modifier = Modifier, content: @Composable (Modifier) -> Void) {
     // Use remembered expansion values to recompose on change
     let isFillWidth = remember { mutableStateOf(fillWidth) }
-    let isNonExpandingFillWidth = remember { mutableStateOf(false) }
     let isFillHeight = remember { mutableStateOf(fillHeight) }
-    let isNonExpandingFillHeight = remember { mutableStateOf(false) }
 
-    // Create the correct modifier for the current values. We use IntrinsicSize.Max for non-expanding fills so that child
-    // views who want to take up available space without expanding this container can do so by calling `fillMaxWidth/Height`
-    //
-    // We have a special case when our content is framed, meaning at least one dimension is fixed. If a non-fixed dimension
-    // wants a non-expanding fill, we do not set IntrinsicSize.Max and use an expanding fill instead
-    // TODO: This special case works in practice thus far, but I do not fully understand it
+    // Create the correct modifier for the current values. We must use IntrinsicSize.Max for fills in a scroll direction
+    // because Compose's fillMax modifiers have no effect in the scroll direction. We can't use IntrinsicSize for scrolling
+    // containers, however
     var modifier = modifier
     let inheritedScrollAxes = EnvironmentValues.shared._scrollAxes
     var totalScrollAxes = inheritedScrollAxes
     if fixedWidth {
         totalScrollAxes.remove(Axis.Set.horizontal)
-    } else {
-        if isFillWidth.value {
+    } else if isFillWidth.value {
+        if fillWidth {
+            modifier = modifier.fillWidth()
+        } else if inheritedScrollAxes.contains(Axis.Set.horizontal) {
+            modifier = modifier.width(IntrinsicSize.Max)
+        } else {
             modifier = modifier.fillWidth()
-        } else if isNonExpandingFillWidth.value {
-            if !fixedHeight {
-                modifier = modifier.width(IntrinsicSize.Max)
-            } else {
-                modifier = modifier.fillWidth()
-            }
         }
     }
     if fixedHeight {
         totalScrollAxes.remove(Axis.Set.vertical)
-    } else {
-        if isFillHeight.value {
+    } else if isFillHeight.value {
+        if fillHeight {
+            modifier = modifier.fillHeight()
+        } else if inheritedScrollAxes.contains(Axis.Set.vertical) {
+            modifier = modifier.height(IntrinsicSize.Max)
+        } else {
             modifier = modifier.fillHeight()
-        } else if isNonExpandingFillHeight.value {
-            if !fixedWidth {
-                modifier = modifier.height(IntrinsicSize.Max)
-            } else {
-                modifier = modifier.fillHeight()
-            }
         }
     }
     totalScrollAxes.formUnion(scrollAxes)
@@ -96,43 +87,21 @@ import androidx.compose.ui.Modifier
 
         // Set the 'fillWidth' and 'fillHeight' blocks to trigger a side effect to update our container's expansion state, which can
         // cause it to recompose and recalculate its own modifier. We must use `SideEffect` or the recomposition never happens
-        $0.set_fillWidth { expandContainer in
-            let fillModifier = EnvironmentValues.shared._fillWidthModifier
-            let isExpanding = expandContainer || fillModifier != nil
-            if isExpanding && !isFillWidth.value {
+        $0.set_fillWidth {
+            if !isFillWidth.value {
                 SideEffect {
                     isFillWidth.value = true
                 }
             }
-            if !isExpanding && !isNonExpandingFillWidth.value {
-                SideEffect {
-                    isNonExpandingFillWidth.value = true
-                }
-            }
-            if let fillModifier, fillModifier != Modifier {
-                return fillModifier
-            } else {
-                return Modifier.fillMaxWidth()
-            }
+            return EnvironmentValues.shared._fillWidthModifier ?? Modifier.fillMaxWidth()
         }
-        $0.set_fillHeight { expandContainer in
-            let fillModifier = EnvironmentValues.shared._fillHeightModifier
-            let isExpanding = expandContainer || fillModifier != nil
-            if isExpanding && !isFillHeight.value {
+        $0.set_fillHeight {
+            if !isFillHeight.value {
                 SideEffect {
                     isFillHeight.value = true
                 }
             }
-            if !isExpanding && !isNonExpandingFillHeight.value {
-                SideEffect {
-                    isNonExpandingFillHeight.value = true
-                }
-            }
-            if let fillModifier, fillModifier != Modifier {
-                return fillModifier
-            } else {
-                return Modifier.fillMaxHeight()
-            }
+            return EnvironmentValues.shared._fillHeightModifier ?? Modifier.fillMaxHeight()
         }
     } in: {
         // Render the container content with the above environment setup

Sources/SkipUI/SkipUI/Compose/ComposeExtensions.swift

@@ -20,32 +20,32 @@ extension Modifier {
     /// This is a replacement for `fillMaxWidth` designed for situations when the composable may be in an `HStack` and does not want to push other items out.
     ///
     /// - Warning: Containers with child content should use the `ComposeContainer` composable instead.
-    @Composable public func fillWidth(expandContainer: Bool = true) -> Modifier {
+    @Composable public func fillWidth() -> Modifier {
         guard let fill = EnvironmentValues.shared._fillWidth else {
             return fillMaxWidth()
         }
-        return then(fill(expandContainer))
+        return then(fill())
     }
 
     /// Fill available remaining height.
     ///
     /// This is a replacement for `fillMaxHeight` designed for situations when the composable may be in an `VStack` and does not want to push other items out.
     ///
     /// - Warning: Containers with child content should use the `ComposeContainer` composable instead.
-    @Composable public func fillHeight(expandContainer: Bool = true) -> Modifier {
+    @Composable public func fillHeight() -> Modifier {
         guard let fill = EnvironmentValues.shared._fillHeight else {
             return fillMaxHeight()
         }
-        return then(fill(expandContainer))
+        return then(fill())
     }
 
     /// Fill available remaining size.
     ///
     /// This is a replacement for `fillMaxSize` designed for situations when the composable may be in an `HStack` or `VStack` and does not want to push other items out.
     ///
     /// - Warning: Containers with child content should use the `ComposeContainer` composable instead.
-    @Composable public func fillSize(expandContainer: Bool = true) -> Modifier {
-        return fillWidth(expandContainer: expandContainer).fillHeight(expandContainer: expandContainer)
+    @Composable public func fillSize() -> Modifier {
+        return fillWidth().fillHeight()
     }
 
     /// Add padding equivalent to the given safe area.

Sources/SkipUI/SkipUI/Compose/ComposeLayouts.swift

@@ -54,25 +54,23 @@ import androidx.compose.ui.unit.dp
 /// Compose a view with the given frame.
 @Composable func FrameLayout(view: View, context: ComposeContext, minWidth: CGFloat?, idealWidth: CGFloat?, maxWidth: CGFloat?, minHeight: CGFloat?, idealHeight: CGFloat?, maxHeight: CGFloat?, alignment: Alignment) {
     let scrollAxes = EnvironmentValues.shared._scrollAxes
-    var modifier = context.modifier
+    var thenModifier: Modifier = Modifier
     if maxWidth == .infinity {
-        modifier = modifier.fillWidth(expandContainer: !scrollAxes.contains(Axis.Set.horizontal))
         if let minWidth, minWidth > 0.0 {
-            modifier = modifier.requiredWidthIn(min: minWidth.dp)
+            thenModifier = thenModifier.requiredWidthIn(min: minWidth.dp)
         }
     } else if minWidth != nil || maxWidth != nil {
-        modifier = modifier.requiredWidthIn(min: minWidth != nil ? minWidth!.dp : Dp.Unspecified, max: maxWidth != nil ? maxWidth!.dp : Dp.Unspecified)
+        thenModifier = thenModifier.requiredWidthIn(min: minWidth != nil ? minWidth!.dp : Dp.Unspecified, max: maxWidth != nil ? maxWidth!.dp : Dp.Unspecified)
     }
     if maxHeight == .infinity {
-        modifier = modifier.fillHeight(expandContainer: !scrollAxes.contains(Axis.Set.vertical))
         if let minHeight, minHeight > 0.0 {
-            modifier = modifier.requiredHeightIn(min: minHeight.dp)
+            thenModifier = thenModifier.requiredHeightIn(min: minHeight.dp)
         }
     } else if minHeight != nil || maxHeight != nil {
-        modifier = modifier.requiredHeightIn(min: minHeight != nil ? minHeight!.dp : Dp.Unspecified, max: maxHeight != nil ? maxHeight!.dp : Dp.Unspecified)
+        thenModifier = thenModifier.requiredHeightIn(min: minHeight != nil ? minHeight!.dp : Dp.Unspecified, max: maxHeight != nil ? maxHeight!.dp : Dp.Unspecified)
     }
     let isContainerView = view.strippingModifiers(perform: { $0 is HStack || $0 is VStack || $0 is ZStack })
-    ComposeContainer(modifier: modifier, fixedWidth: maxWidth != nil && maxWidth != Double.infinity, fixedHeight: maxHeight != nil && maxHeight != Double.infinity) { modifier in
+    ComposeContainer(modifier: context.modifier, fillWidth: maxWidth == Double.infinity, fixedWidth: maxWidth != nil && maxWidth != Double.infinity, fillHeight: maxHeight == Double.infinity, fixedHeight: maxHeight != nil && maxHeight != Double.infinity, then: thenModifier) { modifier in
         // Apply the sizing modifier directly to containers, which would otherwise fit their size to their content instead
         if isContainerView {
             let contentContext = context.content(modifier: modifier)
@@ -232,7 +230,7 @@ import androidx.compose.ui.unit.dp
 
 @Composable func PositionLayout(x: CGFloat, y: CGFloat, context: ComposeContext, target: @Composable (ComposeContext) -> Void) {
     // SwiftUI expands to fill the available space and places within that
-    Box(modifier: context.modifier.fillSize(expandContainer: false)) {
+    Box(modifier: context.modifier.fillSize()) {
         let density = LocalDensity.current
         let xPx = with(density) { x.dp.roundToPx() }
         let yPx = with(density) { y.dp.roundToPx() }

Sources/SkipUI/SkipUI/Containers/ZStack.swift

@@ -46,12 +46,7 @@ public struct ZStack : View {
             let contentContext = context.content()
             ComposeContainer(eraseAxis: true, modifier: context.modifier) { modifier in
                 Box(modifier: modifier, contentAlignment: alignment.asComposeAlignment()) {
-                    EnvironmentValues.shared.setValues {
-                        $0.set_fillWidthModifier(Modifier)
-                        $0.set_fillHeightModifier(Modifier)
-                    } in: {
-                        views.forEach { $0.Compose(context: contentContext) }
-                    }
+                    views.forEach { $0.Compose(context: contentContext) }
                 }
             }
         } else {
@@ -74,23 +69,17 @@ public struct ZStack : View {
                 arguments.rememberedNewIds.clear()
             }
             Box(contentAlignment: alignment.asComposeAlignment()) {
-                EnvironmentValues.shared.setValues {
-                    // The ComposeContainer uses the presence of these modifiers to influence container expansion behavior
-                    $0.set_fillWidthModifier(Modifier)
-                    $0.set_fillHeightModifier(Modifier)
-                } in: {
-                    for view in state {
-                        let id = arguments.idMap(view)
-                        var modifier: Modifier = Modifier
-                        if let animation, arguments.newIds.contains(id) || arguments.rememberedNewIds.contains(id) || !arguments.ids.contains(id) {
-                            let transition = TransitionModifierView.transition(for: view) ?? OpacityTransition.shared
-                            let spec = animation.asAnimationSpec()
-                            let enter = transition.asEnterTransition(spec: spec)
-                            let exit = transition.asExitTransition(spec: spec)
-                            modifier = modifier.animateEnterExit(enter: enter, exit: exit)
-                        }
-                        view.Compose(context: context.content(modifier: modifier))
+                for view in state {
+                    let id = arguments.idMap(view)
+                    var modifier: Modifier = Modifier
+                    if let animation, arguments.newIds.contains(id) || arguments.rememberedNewIds.contains(id) || !arguments.ids.contains(id) {
+                        let transition = TransitionModifierView.transition(for: view) ?? OpacityTransition.shared
+                        let spec = animation.asAnimationSpec()
+                        let enter = transition.asEnterTransition(spec: spec)
+                        let exit = transition.asExitTransition(spec: spec)
+                        modifier = modifier.animateEnterExit(enter: enter, exit: exit)
                     }
+                    view.Compose(context: context.content(modifier: modifier))
                 }
             }
         }, label: "ZStack")

Sources/SkipUI/SkipUI/Environment/EnvironmentValues.swift

@@ -414,13 +414,13 @@ extension EnvironmentValues {
         set { setBuiltinValue(key: "_contentPadding", value: newValue, defaultValue: { EdgeInsets() }) }
     }
 
-    var _fillHeight: (@Composable (Bool) -> Modifier)? {
-        get { builtinValue(key: "_fillHeight", defaultValue: { nil }) as! (@Composable (Bool) -> Modifier)? }
+    var _fillHeight: (@Composable () -> Modifier)? {
+        get { builtinValue(key: "_fillHeight", defaultValue: { nil }) as! (@Composable () -> Modifier)? }
         set { setBuiltinValue(key: "_fillHeight", value: newValue, defaultValue: { nil }) }
     }
 
-    var _fillWidth: (@Composable (Bool) -> Modifier)? {
-        get { builtinValue(key: "_fillWidth", defaultValue: { nil }) as! (@Composable (Bool) -> Modifier)? }
+    var _fillWidth: (@Composable () -> Modifier)? {
+        get { builtinValue(key: "_fillWidth", defaultValue: { nil }) as! (@Composable () -> Modifier)? }
         set { setBuiltinValue(key: "_fillWidth", value: newValue, defaultValue: { nil }) }
     }
 

Sources/SkipUI/SkipUI/Graphics/Gradient.swift

@@ -126,7 +126,7 @@ public struct LinearGradient : ShapeStyle, Sendable {
 
     #if SKIP
     @Composable public override func ComposeContent(context: ComposeContext) {
-        let modifier = context.modifier.background(asBrush(opacity: 1.0, animationContext: nil)!).fillSize(expandContainer: false)
+        let modifier = context.modifier.background(asBrush(opacity: 1.0, animationContext: nil)!).fillSize()
         Box(modifier: modifier)
     }
 
@@ -180,7 +180,7 @@ public struct EllipticalGradient : ShapeStyle, Sendable {
     #if SKIP
     @Composable public override func ComposeContent(context: ComposeContext) {
         // Trick to scale our (circular) radial brush into an ellipse when this gradient is used as a view
-        BoxWithConstraints(modifier: context.modifier.fillSize(expandContainer = false).clipToBounds()) {
+        BoxWithConstraints(modifier: context.modifier.fillSize().clipToBounds()) {
             let aspectRatio = maxWidth / maxHeight
             let modifier = Modifier.fillMaxSize().scale(max(aspectRatio, Float(1.0)), max(Float(1.0) / aspectRatio, Float(1.0))).background(asBrush(opacity = 1.0, animationContext: nil)!!)
             Box(modifier: modifier)
@@ -239,7 +239,7 @@ public struct RadialGradient : ShapeStyle, Sendable {
 
     #if SKIP
     @Composable public override func ComposeContent(context: ComposeContext) {
-        let modifier = context.modifier.background(asBrush(opacity: 1.0, animationContext: nil)!).fillSize(expandContainer: false)
+        let modifier = context.modifier.background(asBrush(opacity: 1.0, animationContext: nil)!).fillSize()
         Box(modifier: modifier)
     }
 

Sources/SkipUI/SkipUI/Layout/GeometryReader.swift

@@ -27,7 +27,7 @@ public struct GeometryReader : View {
     #if SKIP
     @Composable public override func ComposeContent(context: ComposeContext) {
         let rememberedGlobalFramePx = remember { mutableStateOf<Rect?>(nil) }
-        Box(modifier: context.modifier.fillSize(expandContainer: false).onGloballyPositioned {
+        Box(modifier: context.modifier.fillSize().onGloballyPositioned {
             rememberedGlobalFramePx.value = $0.boundsInRoot()
         }) {
             if let globalFramePx = rememberedGlobalFramePx.value {

Tests/SkipUITests/ImageTests.swift

@@ -213,7 +213,7 @@ final class ImageTests: XCSnapshotTestCase {
                 let imageVector = ImageVector.vectorResource(id: drawableID)
                 let painter = rememberVectorPainter(imageVector)
                 //Icon(imageVector: imageVector, contentDescription: "demo icon", modifier: Modifier.fillSize(expandContainer: false))
-                androidx.compose.foundation.Image(painter: painter, contentDescription: "demo icon", modifier: Modifier.fillSize(expandContainer: false), contentScale: ContentScale.Fit, colorFilter: ColorFilter.tint(tintColor))
+                androidx.compose.foundation.Image(painter: painter, contentDescription: "demo icon", modifier: Modifier.fillSize(), contentScale: ContentScale.Fit, colorFilter: ColorFilter.tint(tintColor))
             }
             .background(Color.black)
             .foregroundStyle(Color.white)