QoL improvements for parts with a large number of subtypes

B9PartSwitch/B9PartSwitch.csproj

@@ -46,6 +46,9 @@
     <Reference Include="UnityEngine.CoreModule">
       <Private>False</Private>
     </Reference>
+    <Reference Include="UnityEngine.TextRenderingModule">
+      <Private>False</Private>
+    </Reference>
     <Reference Include="UnityEngine.UI">
       <Private>False</Private>
     </Reference>

B9PartSwitch/PartSwitch/PartSwitchFlightDialog.cs

@@ -3,6 +3,8 @@
 using System.Linq;
 using TMPro;
 using B9PartSwitch.UI;
+using UnityEngine;
+using UnityEngine.UI;
 
 namespace B9PartSwitch
 {
@@ -76,6 +78,8 @@ private static DialogGUIBase[] CreateOptions(ModuleB9PartSwitch module, IList<Ca
 
             SwitcherSubtypeDescriptionGenerator subtypeDescriptionGenerator = new SwitcherSubtypeDescriptionGenerator(module);
 
+            options.Add(new DialogGUIContentSizer(ContentSizeFitter.FitMode.Unconstrained, ContentSizeFitter.FitMode.PreferredSize));
+
             foreach (PartSubtype subtype in module.subtypes)
             {
                 if (!subtype.IsUnlocked()) continue;
@@ -104,7 +108,26 @@ private static DialogGUIBase[] CreateOptions(ModuleB9PartSwitch module, IList<Ca
 
             options.Add(new DialogGUIButton(Localization.PartSwitchFlightDialog_CancelString, delegate { } ));
 
-            return options.ToArray();
+            const float buttonHeight = 35;
+            if (buttonHeight * options.Count < 0.75f * Screen.height) return options.ToArray();
+
+            DialogGUIBase[] scrollList = {
+                new DialogGUIContentSizer(ContentSizeFitter.FitMode.Unconstrained, ContentSizeFitter.FitMode.PreferredSize),
+                new DialogGUIScrollList(
+                    new Vector2(1, 0.75f * Screen.height),
+                    false,
+                    true,
+                    new DialogGUIVerticalLayout(
+                        true,
+                        true,
+                        4,
+                        new RectOffset(6, 24, 10, 10),
+                        TextAnchor.MiddleCenter,
+                        options.ToArray()
+                    )
+                )
+            };
+            return scrollList;
         }
     }
 }

B9PartSwitch/UI/UIPartActionSubtypeSelector.cs

@@ -111,6 +111,21 @@ public override void Setup(UIPartActionWindow window, Part part, PartModule part
             subtypeTitleText.text = switcherModule.CurrentSubtype.title;
 
             subtypeButtons[currentButtonIndex].Activate();
+
+            // up to 7 subtypeButtons fit in the PAW without scrolling
+            if (subtypeButtons.Count > 7)
+            {
+                scrollMain.scrollSensitivity = subtypeButtons.Count;
+                // scrollMain.horizontalNormalizedPosition is the left edge of the viewport relative to the content.
+                // scrollMain.viewport.rect.width will be 200+(2/3) units after layout stuff is finished.  Sadly, it is 0 when this code runs so we can't make use of it here.
+                // Each button is effectively 28 units wide, meaning the viewport is 7+(1/6) buttons wide.
+                // If we scroll past the last button, the buttons will bounce back so that the last button is touching the viewport's right edge.
+                // That bounce could make a player lose their place in the button list (plus it just looks bad).  Therefore, we don't use 1.0 to set the viewport full right.
+                const float viewportWidthInButtons = 7+1/6f;
+                if (currentButtonIndex < 4) scrollMain.horizontalNormalizedPosition = 0f;
+                else if (subtypeButtons.Count - currentButtonIndex < 5) scrollMain.horizontalNormalizedPosition = (subtypeButtons.Count - viewportWidthInButtons) / subtypeButtons.Count;
+                else scrollMain.horizontalNormalizedPosition = (currentButtonIndex + 4 - viewportWidthInButtons) / subtypeButtons.Count;
+            }
         }
 
         private void PreviousSubtype()