Add horizontal scrolling and support for nesting ScrollingPanes

Silksong.ModMenu/Elements/ScrollingPane.cs

@@ -1,14 +1,16 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Silksong.ModMenu.Internal;
 using UnityEngine;
 using UnityEngine.UI;
+using UObject = UnityEngine.Object;
 
 namespace Silksong.ModMenu.Elements;
 
 /// <summary>
-/// A vertically scrolling panel that can contain an arbitrary amount of content.
+/// A scrolling panel that can contain an arbitrary amount of content.
 /// </summary>
 public class ScrollingPane : MenuDisposable, INavigableMenuEntity
 {
@@ -19,8 +21,6 @@ public class ScrollingPane : MenuDisposable, INavigableMenuEntity
 
     /// <summary>
     /// The scrolling pane's content.
-    /// This entity cannot be a <see cref="ScrollingPane"/>,
-    /// and cannot contain any <see cref="ScrollingPane"/> children.
     /// </summary>
     public INavigableMenuEntity? Content
     {
@@ -29,12 +29,6 @@ public INavigableMenuEntity? Content
         {
             if (field == value)
                 return;
-            if (value?.GetType().IsSubclassOf(typeof(ScrollingPane)) ?? false)
-                throw new System.ArgumentException(
-                    $"A {nameof(ScrollingPane)} cannot have another {nameof(ScrollingPane)} as its direct content entity.",
-                    value.GetType().FullName
-                );
-
             field?.ClearParents();
             field = value;
             field?.SetParents(this, contentPane);
@@ -65,7 +59,7 @@ public ScrollingPane(INavigableMenuEntity content)
 
         AddScrollNavHelpers();
 
-        OnDispose += () => Object.Destroy(scrollPane);
+        OnDispose += () => UObject.Destroy(scrollPane);
         Visibility.OnVisibilityChanged += visibleInHierarchy =>
             scrollPane.SetActive(visibleInHierarchy);
 
@@ -77,8 +71,45 @@ public ScrollingPane(INavigableMenuEntity content)
     /// </summary>
     public Vector2 ViewportSize
     {
-        get => scrollRect.viewport.sizeDelta;
-        set => scrollRect.viewport.sizeDelta = value;
+        get => scrollPane.RectTransform.sizeDelta;
+        set => scrollPane.RectTransform.sizeDelta = value;
+    }
+
+    /// <summary>
+    /// Whether this pane scrolls only vertically, only horizontally, or in both axes.
+    /// </summary>
+    public ScrollAxes Axes
+    {
+        get =>
+            (scrollRect.vertical ? ScrollAxes.Vertical : 0)
+            | (scrollRect.horizontal ? ScrollAxes.Horizontal : 0);
+        set
+        {
+            scrollRect.vertical = value.HasFlag(ScrollAxes.Vertical);
+            scrollRect.horizontal = value.HasFlag(ScrollAxes.Horizontal);
+        }
+    }
+
+    /// <summary>
+    /// Semantic states for which axes a <see cref="ScrollingPane"/> can scroll in.
+    /// </summary>
+    [Flags]
+    public enum ScrollAxes
+    {
+        /// <summary>
+        /// Exclusively vertical scrolling.
+        /// </summary>
+        Vertical = 0x01,
+
+        /// <summary>
+        /// Exclusively horizontal scrolling.
+        /// </summary>
+        Horizontal = 0x10,
+
+        /// <summary>
+        /// Scrolling in both the vertical and horizontal axes.
+        /// </summary>
+        Both = Vertical | Horizontal,
     }
 
     /// <summary>
@@ -102,7 +133,7 @@ public float SmoothScrollTime
     public void ScrollTo(MenuElement element, bool smooth = false)
     {
         if (element.VisibleInHierarchy)
-            focusController.ScrollTo(element.RectTransform, smooth);
+            focusController.ScrollTo(element.Container.transform, smooth);
     }
 
     /// <summary>
@@ -117,7 +148,7 @@ public void ScrollTo(int index, bool smooth = false)
     {
         var element = Content?.AllElements().ElementAtOrDefault(index);
         if (element != null && element.VisibleInHierarchy)
-            focusController.ScrollTo(element.RectTransform, smooth);
+            focusController.ScrollTo(element.Container.transform, smooth);
     }
 
     /// <summary>
@@ -137,24 +168,15 @@ public void UpdateLayout(Vector2 localAnchorPos)
         if (resizeQueued)
         {
             resizeQueued = false;
-            foreach (Transform child in contentPane.transform)
-            {
-                if (child.GetComponent<ScrollRect>())
-                    throw new System.InvalidOperationException(
-                        $"A {nameof(ScrollingPane)} cannot have other scrolling views nested within it."
-                    );
-            }
 
             var contentRT = (RectTransform)contentPane.transform;
 
             contentRT.sizeDelta = Vector2.zero;
             Content?.UpdateLayout(Vector2.zero);
-            var bounds = RectTransformUtility.CalculateRelativeRectTransformBounds(contentRT);
-            Vector2 min = bounds.min,
-                max = bounds.max;
+            var (min, max) = CalculateContentBounds();
 
             contentRT.sizeDelta = max - min;
-            contentAnchor = contentRT.sizeDelta / 2f - max;
+            contentAnchor = contentRT.sizeDelta * 0.5f - max;
             anchorOffset = new Vector2(0, max.y);
         }
 
@@ -191,8 +213,66 @@ public void SetGameObjectParent(GameObject parent) =>
     private void AddScrollNavHelpers()
     {
         foreach (var element in Content?.AllElements().OfType<SelectableElement>() ?? [])
+        {
             // This component removes itself when the object it's attached to is re-parented
-            element.SelectableComponent.gameObject.AddComponentIfNotPresent<ScrollNavigationHelper>();
+            element
+                .SelectableComponent.gameObject.AddComponentIfNotPresent<ScrollNavigationHelper>()
+                .container = element.Container.transform;
+        }
+    }
+
+    /// <summary>
+    /// Calculates the cumulative bounds of all children of the content pane in local coordinates,
+    /// skipping over anything that is contained within another ScrollRect.
+    /// </summary>
+    private (Vector2 min, Vector2 max) CalculateContentBounds()
+    {
+        Vector3 min = Vector3.one * float.MaxValue,
+            max = Vector3.one * float.MinValue;
+        Matrix4x4 worldToLocal = contentPane.transform.worldToLocalMatrix;
+
+        foreach (
+            Transform descendant in EnumerateDescendantsConditional(
+                contentPane.transform,
+                shouldSkip: ChildrenOfScrollPanesExceptScrollbars
+            )
+        )
+        {
+            if (descendant is not RectTransform rt || !descendant.gameObject.activeInHierarchy)
+                continue;
+            foreach (Vector3 corner in rt.GetCorners())
+            {
+                Vector3 localCorner = worldToLocal.MultiplyPoint3x4(corner);
+                min = Vector3.Min(localCorner, min);
+                max = Vector3.Max(localCorner, max);
+            }
+        }
+
+        return (min, max);
+
+        static bool ChildrenOfScrollPanesExceptScrollbars(Transform x) =>
+            x.parent.TryGetComponent<ScrollSliderController>(out var sliderCtrl)
+            && (!sliderCtrl.VerticalSlider || x != sliderCtrl.VerticalSlider.transform)
+            && (!sliderCtrl.HorizontalSlider || x != sliderCtrl.HorizontalSlider.transform);
+    }
+
+    /// <summary>
+    /// Enumerates the entire Transform hierarchy, skipping branches when it finds
+    /// a transform for which the given <paramref name="shouldSkip"/> predicate is true.
+    /// </summary>
+    private static IEnumerable<Transform> EnumerateDescendantsConditional(
+        Transform transform,
+        Func<Transform, bool> shouldSkip
+    )
+    {
+        foreach (Transform item in transform)
+        {
+            if (shouldSkip(item))
+                continue;
+            yield return item;
+            foreach (var item2 in EnumerateDescendantsConditional(item, shouldSkip))
+                yield return item2;
+        }
     }
 
     #endregion

Silksong.ModMenu/Internal/CustomScrollRect.cs

@@ -0,0 +1,25 @@
+using UnityEngine;
+using UnityEngine.EventSystems;
+using UnityEngine.UI;
+
+namespace Silksong.ModMenu.Internal;
+
+/// <summary>
+/// Identical to the regular <see cref="ScrollRect"/>, except it fixes the known bug
+/// (See <see href="https://discussions.unity.com/t/934765">this Unity help forum post</see>)
+/// where mousewheel/touchpad scrolling is always the opposite of what it should intuitively be for one scroll direction.
+/// </summary>
+internal class CustomScrollRect : ScrollRect
+{
+    public override void OnScroll(PointerEventData data)
+    {
+        if (horizontal)
+        {
+            if (vertical)
+                data.scrollDelta *= new Vector2(-1, 1);
+            else
+                data.scrollDelta *= -1;
+        }
+        base.OnScroll(data);
+    }
+}

Silksong.ModMenu/Internal/MenuPrefabs.cs

@@ -73,6 +73,7 @@ private MenuPrefabs(UIManager uiManager)
         textLabelTemplate.name = "TextLabel";
         textLabelTemplate.GetComponent<Text>().raycastTarget = false;
         Object.DontDestroyOnLoad(textLabelTemplate);
+        textLabelTemplate.RectTransform.sizeDelta = new Vector2(0, 105);
 
         textChoiceTemplate = Object.Instantiate(
             canvas.FindChild("GameOptionsMenuScreen/Content/CamShakeSetting")!
@@ -99,13 +100,16 @@ private MenuPrefabs(UIManager uiManager)
         textButtonTemplate.SetActive(false);
         textButtonTemplate.name = "TextButtonContainer";
         Object.DontDestroyOnLoad(textButtonTemplate);
+        textButtonTemplate.RectTransform.sizeDelta = Vector2.zero;
 
         var buttonChild = textButtonTemplate.FindChild("GameOptionsButton")!;
         buttonChild.name = "TextButton";
         // We have to remove this component as it's on a different GameObject to the Text,
         // so it won't be removed by the LocalizedTextExtensions
         buttonChild.RemoveComponent<AutoLocalizeTextUI>();
         buttonChild.FindChild("Menu Button Text")!.RemoveComponent<ChangeTextFontScaleOnHandHeld>();
+        var buttonChildRT = buttonChild.RectTransform;
+        buttonChildRT.sizeDelta = buttonChildRT.sizeDelta with { x = 0 };
 
         // Add a (centered) description to the menu button
         GameObject clonedDescription = Object.Instantiate(choiceChild.FindChild("Description")!);
@@ -152,6 +156,7 @@ private MenuPrefabs(UIManager uiManager)
         sliderTemplate.SetActive(false);
         sliderTemplate.name = "SliderContainer";
         Object.DontDestroyOnLoad(sliderTemplate);
+        sliderTemplate.RectTransform.sizeDelta = Vector2.zero;
 
         var sliderChild = sliderTemplate.FindChild("MasterSlider")!;
         sliderChild.name = "Slider";
@@ -273,7 +278,7 @@ out GameObject contentPane
         var obj = Object.Instantiate(scrollPaneTemplate);
         scrollRect = obj.GetComponent<ScrollRect>();
         focusController = obj.GetComponent<ScrollFocusController>();
-        contentPane = obj.FindChild("Content")!;
+        contentPane = obj.FindChild("Viewport/Content")!;
         return obj;
     }
 
@@ -289,33 +294,41 @@ private static GameObject ConstructScrollPanePrefab(UIManager uiManager)
         var scrollPane = new GameObject("ScrollPane") { layer = (int)PhysLayers.UI };
         scrollPane.SetActive(false);
         Object.DontDestroyOnLoad(scrollPane);
-        scrollPane.AddComponent<Image>().color = Color.clear; // necessary for the RectMask2D
-        scrollPane.AddComponent<RectMask2D>();
-        var scrollPaneRT = (RectTransform)scrollPane.transform;
-        scrollPaneRT.sizeDelta = new Vector2(1570, 876f);
+        var scrollPaneRT = scrollPane.AddComponent<RectTransform>();
+        scrollPaneRT.sizeDelta = new Vector2(
+            1510,
+            Mathf.Ceil(SpacingConstants.VSPACE_MEDIUM * 8.334f)
+        );
         scrollPaneRT.pivot = new Vector2(0.5f, 1);
 
+        var viewport = new GameObject("Viewport") { layer = (int)PhysLayers.UI };
+        viewport.transform.SetParentReset(scrollPane.transform);
+        viewport.AddComponent<Image>().color = Color.clear; // necessary for the RectMask2D
+        viewport.AddComponent<RectMask2D>();
+        var viewportRT = viewport.RectTransform;
+        viewportRT.FitToParent();
+
         var content = new GameObject("Content") { layer = (int)PhysLayers.UI };
-        content.transform.SetParentReset(scrollPane.transform);
-        content.AddComponent<Image>().color = Color.clear; // ensures it has a RectTransform
-        var contentRT = (RectTransform)content.transform;
+        content.transform.SetParentReset(viewport.transform);
+        content.AddComponent<Image>().color = Color.clear; // ensures it has a RectTransform, used for visualization in some tests
+        var contentRT = content.RectTransform;
         contentRT.anchorMax = contentRT.anchorMin = contentRT.pivot = new Vector2(0.5f, 1);
 
         #endregion
-        #region "Scrollbar"
+        #region Vertical "Scrollbar"
 
-        var scrollbar = Object.Instantiate(
+        var vScrollbar = Object.Instantiate(
             uiManager.achievementsMenuScreen.gameObject.FindChild("Content/Scrollbar")!,
             scrollPaneRT,
             false
         );
-        scrollbar.name = "Scrollbar";
+        vScrollbar.name = "Scrollbar V";
 
-        ((RectTransform)scrollbar.transform.Find("Background")).FitToParentVertical();
+        vScrollbar.FindChild("Background")!.RectTransform.FitToParentVertical();
 
-        var scrollbarRT = (RectTransform)scrollbar.transform;
-        var slideAreaRT = (RectTransform)scrollbarRT.Find("Sliding Area");
-        var handleRT = (RectTransform)slideAreaRT.Find("Handle/TopFleur");
+        var vScrollbarRT = vScrollbar.RectTransform;
+        var slideAreaRT = vScrollbar.FindChild("Sliding Area")!.RectTransform;
+        var handleRT = vScrollbar.FindChild("Sliding Area/Handle/TopFleur")!.RectTransform;
 
         slideAreaRT.FitToParent();
         slideAreaRT.sizeDelta = new Vector2(0, -150);
@@ -328,27 +341,49 @@ private static GameObject ConstructScrollPanePrefab(UIManager uiManager)
         Object.DestroyImmediate(slideAreaRT.Find("Handle").gameObject);
         handleRT.gameObject.name = "Handle";
 
-        scrollbarRT.sizeDelta = new Vector2(50, 0);
-        scrollbarRT.FitToParentVertical(anchorX: 1);
-        scrollbarRT.anchoredPosition3D = scrollbarRT.anchoredPosition3D with { z = -1 };
-        Object.DestroyImmediate(scrollbar.GetComponent<Scrollbar>());
-        var scrollSlider = scrollbar.AddComponent<Slider>();
-        scrollSlider.handleRect = handleRT;
-        scrollSlider.direction = Slider.Direction.BottomToTop;
-        scrollSlider.maxValue = 1;
-        scrollSlider.minValue = 0;
+        vScrollbarRT.sizeDelta = new Vector2(50, 0);
+        vScrollbarRT.FitToParentVertical(anchorX: 1);
+        vScrollbarRT.anchoredPosition3D = vScrollbarRT.anchoredPosition3D with { z = -1 };
+        vScrollbarRT.pivot = new Vector2(0, 0.5f);
+        Object.DestroyImmediate(vScrollbar.GetComponent<Scrollbar>());
+        var vScrollSlider = vScrollbar.AddComponent<Slider>();
+        vScrollSlider.handleRect = handleRT;
+        vScrollSlider.direction = Slider.Direction.BottomToTop;
+        vScrollSlider.maxValue = 1;
+        vScrollSlider.minValue = 0;
+        vScrollSlider.value = 1;
+
+        #endregion
+        #region Horizontal "Scrollbar"
+
+        var hScrollbar = Object.Instantiate(vScrollbar, scrollPane.transform, false);
+        hScrollbar.name = "Scrollbar H";
+        var hScrollbarRT = hScrollbar.RectTransform;
+        hScrollbarRT.anchorMin = hScrollbarRT.anchorMax = new Vector2(0.5f, 0);
+        hScrollbarRT.pivot = new Vector2(1, 0.5f);
+        hScrollbar.AddComponent<RotatedParentSizeFitter>().fitToWidth = true;
+
+        var hScrollSlider = hScrollbar.GetComponent<Slider>();
+        hScrollSlider.direction = Slider.Direction.TopToBottom;
+        hScrollSlider.value = 0.5f;
 
         #endregion
 
-        var scrollRect = scrollPane.AddComponent<ScrollRect>();
+        var scrollRect = scrollPane.AddComponent<CustomScrollRect>();
         scrollRect.horizontal = false;
         scrollRect.vertical = true;
         scrollRect.verticalScrollbarVisibility = ScrollRect.ScrollbarVisibility.AutoHide;
+        scrollRect.horizontalScrollbarVisibility = ScrollRect.ScrollbarVisibility.AutoHide;
         scrollRect.movementType = ScrollRect.MovementType.Clamped;
         scrollRect.scrollSensitivity = 80;
-        scrollRect.viewport = scrollPaneRT;
+        scrollRect.viewport = viewportRT;
         scrollRect.content = contentRT;
-        scrollPane.AddComponent<ScrollSliderController>().VerticalSlider = scrollSlider;
+        scrollRect.normalizedPosition = new Vector2(0.5f, 1);
+
+        var sliderController = scrollPane.AddComponent<ScrollSliderController>();
+        sliderController.VerticalSlider = vScrollSlider;
+        sliderController.HorizontalSlider = hScrollSlider;
+
         scrollPane.AddComponent<ScrollFocusController>();
 
         return scrollPane;