Scroll view for productivity tech levels (#366)

In #334 (comment) I
said I wanted to see a scrolling list for the productivity tech levels,
but I didn't realize that scroll views and tab controls didn't get
along. They get along now, and the preferences screen won't get too tall
with extra prod researches.

The first commit has a fix that should maybe have been its own PR?
Trying to change the level of the scrap mining productivity research
would toggle dark mode instead. (If you had a lot of milestones, it was
steel smelting productivity instead.)

Yafc.UI/ImGui/ImGuiLayout.cs

@@ -267,7 +267,8 @@ public sealed class OverlappingAllocations : IDisposable {
         private readonly ImGui gui;
         private readonly bool initialDrawState;
         private readonly float initialTop;
-        private float maximumBottom;
+        internal float currentTop => gui.state.top;
+        internal float maximumBottom { get; private set; }
 
         internal OverlappingAllocations(ImGui gui, bool alsoDraw) {
             this.gui = gui;

Yafc.UI/ImGui/ImGuiUtils.cs

@@ -229,7 +229,7 @@ public static bool BuildCheckBox(this ImGui gui, string text, bool value, out bo
             gui.BuildText(text, TextBlockDisplayStyle.Default(color));
         }
 
-        if (gui.OnClick(gui.lastRect)) {
+        if (gui.enableDrawing && gui.OnClick(gui.lastRect)) {
             newValue = !value;
             return true;
         }

Yafc.UI/ImGui/ScrollArea.cs

@@ -27,6 +27,10 @@ public abstract class Scrollable(bool vertical, bool horizontal, bool collapsibl
     /// <param name="availableHeight">Available height in parent context for the Scrollable</param>
     public void Build(ImGui gui, float availableHeight, bool useBottomPadding = false) {
         this.gui = gui;
+        if (!gui.enableDrawing) {
+            return;
+        }
+
         var rect = gui.statePosition;
         float width = rect.Width;
 
@@ -151,6 +155,10 @@ public float scrollX {
     public abstract Vector2 MeasureContent(float width, ImGui gui);
 
     public bool KeyDown(SDL.SDL_Keysym key) {
+        if (gui?.enableDrawing != true) {
+            return false;
+        }
+
         bool ctrl = InputSystem.Instance.control;
         bool shift = InputSystem.Instance.shift;
 
@@ -242,7 +250,8 @@ public void FocusChanged(bool focused) { }
 /// <summary>Provides a builder to the Scrollable to render the contents.</summary>
 public abstract class ScrollAreaBase : Scrollable {
     protected ImGui contents;
-    protected readonly float height;
+    private ImGui.OverlappingAllocations? controller;
+    public float height { get; }
 
     public ScrollAreaBase(float height, Padding padding, bool collapsible = false, bool vertical = true, bool horizontal = false) : base(vertical, horizontal, collapsible) {
         contents = new ImGui(BuildContents, padding, clip: true);
@@ -254,7 +263,12 @@ protected override void PositionContent(ImGui gui, Rect viewport) {
         contents.offset = -scroll;
     }
 
-    public void Build(ImGui gui) => Build(gui, height);
+    public void Build(ImGui gui) {
+        controller?.Dispose();
+        // Copy enableDrawing permission from gui to contents.
+        controller = contents.StartOverlappingAllocations(gui.enableDrawing);
+        Build(gui, height);
+    }
 
     protected abstract void BuildContents(ImGui gui);
 
@@ -271,18 +285,17 @@ public class ScrollArea(float height, GuiBuilder builder, Padding padding = defa
     public void Rebuild() => RebuildContents();
 }
 
-public class VirtualScrollList<TData> : ScrollAreaBase {
-    private readonly Vector2 elementSize;
+public class VirtualScrollList<TData>(float height, Vector2 elementSize, VirtualScrollList<TData>.Drawer drawer, Padding padding = default,
+    Action<int, int>? reorder = null, bool collapsible = false) : ScrollAreaBase(height, padding, collapsible) {
+
     // When rendering the scrollable content, render 'blocks' of 4 rows at a time. (As far as I can tell, any positive value works. Shadow picked 4, so I kept that.)
-    private readonly int bufferRows = 4;
+    private const int BufferRows = 4;
     // The first block of bufferRows that was rendered last time BuildContents was called. If it changes while scrolling, we need to re-render the scrollable content.
     private int firstVisibleBlock;
     private int elementsPerRow;
     private IReadOnlyList<TData> _data = [];
-    private readonly int maxRowsVisible;
-    private readonly Drawer drawer;
+    private readonly int maxRowsVisible = MathUtils.Ceil(height / elementSize.Y) + BufferRows + 1;
     private float _spacing;
-    private readonly Action<int, int>? reorder;
 
     public float spacing {
         get => _spacing;
@@ -302,14 +315,7 @@ public IReadOnlyList<TData> data {
         }
     }
 
-    public VirtualScrollList(float height, Vector2 elementSize, Drawer drawer, Padding padding = default, Action<int, int>? reorder = null, bool collapsible = false) : base(height, padding, collapsible) {
-        this.elementSize = elementSize;
-        maxRowsVisible = MathUtils.Ceil(height / this.elementSize.Y) + bufferRows + 1;
-        this.drawer = drawer;
-        this.reorder = reorder;
-    }
-
-    private int CalculateFirstBlock() => Math.Max(0, MathUtils.Floor((scrollY - contents.initialPadding.top) / (elementSize.Y * bufferRows)));
+    private int CalculateFirstBlock() => Math.Max(0, MathUtils.Floor((scrollY - contents.initialPadding.top) / (elementSize.Y * BufferRows)));
 
     public override Vector2 scroll {
         get => base.scroll;
@@ -333,7 +339,7 @@ protected override void BuildContents(ImGui gui) {
         int rowCount = ((_data.Count - 1) / elementsPerRow) + 1;
         firstVisibleBlock = CalculateFirstBlock();
         // Scroll up until there are maxRowsVisible, or to the top.
-        int firstRow = Math.Max(0, Math.Min(firstVisibleBlock * bufferRows, rowCount - maxRowsVisible));
+        int firstRow = Math.Max(0, Math.Min(firstVisibleBlock * BufferRows, rowCount - maxRowsVisible));
         int index = firstRow * elementsPerRow;
 
         if (index >= _data.Count) {

Yafc.UI/ImGui/TabControl.cs

@@ -239,6 +239,8 @@ private void PerformLayout() {
         rows.Reverse();
     }
 
+    private PageDrawer? drawer;
+
     /// <summary>
     /// Call to draw this <see cref="TabControl"/> and its active page.
     /// </summary>
@@ -316,12 +318,36 @@ public void Build(ImGui gui) {
 
         using var controller = gui.StartOverlappingAllocations(false);
 
-        for (int i = 0; i < tabPages.Length; i++) {
-            controller.StartNextAllocatePass(i == activePage);
-            tabPages[i].Drawer?.Invoke(gui);
+        drawer = new(gui, controller, tabPages, activePage);
+        while (drawer.DrawNextPage()) { }
+        drawer = null;
+        #endregion
+    }
+
+    /// <summary>
+    /// Requests the tab control report its remaining available content height. As a side effect, the active tab page will pause drawing until
+    /// all other tabs have been drawn. It is not advisable to draw tab content taller than the height returned by this method.
+    /// </summary>
+    /// <remarks>It is possible for multiple tabs to call this method. If that happens, tabs that call this method earlier will get more accurate
+    /// results. That is, if Tab A calls this method, Tab B draws normally, and Tab C calls this method, Tab C will get a response based on the
+    /// height of Tab B, and can (but should not) further increase the content height. Tab A will then get a response based on the taller of tabs
+    /// B and C. Like tab C, A can (but also should not) again increase the content height. If A does, it will defeat tab C's attempt to use all
+    /// available vertical space.</remarks>
+    /// <param name="minimumHeight">The minimum height that the remaining content needs. The return value will not be smaller than this
+    /// parameter.</param>
+    /// <returns>The available content height, based on all tabs that did not call this method and any tabs that called this method after the
+    /// current tab.</returns>
+    /// <exception cref="InvalidOperationException">Thrown if this <see cref="TabControl"/> is not actively drawing tab pages.</exception>
+    public float GetRemainingContentHeight(float minimumHeight = 0) {
+        if (drawer == null) {
+            throw new InvalidOperationException($"{nameof(GetRemainingContentHeight)} must only be called from a {nameof(GuiBuilder)} that is currently building a {nameof(TabPage)}.");
         }
 
-        #endregion
+        using (drawer.RememberState()) {
+            drawer.gui.AllocateRect(0, minimumHeight);
+            while (drawer.DrawNextPage()) { }
+        }
+        return drawer.GetHeight();
     }
 
     /// <summary>
@@ -362,6 +388,42 @@ internal static void BumpTab(TabRow sourceRow, float sourceCompression, TabRow d
 
         public static implicit operator TabRow((int Start, int End, float Compression) value) => new TabRow(value.Start, value.End, value.Compression);
     }
+
+    /// <summary>
+    /// Tracks the necessary details to allow <see cref="GetRemainingContentHeight"/> to start drawing a second tab while preserving the drawing
+    /// state of the current tab. Each call to <see cref="GetRemainingContentHeight"/> will interrupt the current tab drawer and the current
+    /// <c>while (drawer.DrawNextPage()) { }</c> loop and start a new loop. The new loop will drawing the remaining tabs (unless interrupted
+    /// itself) and <see cref="GetRemainingContentHeight"/> will return the height available for use by the calling tab drawer.
+    /// </summary>
+    private sealed class PageDrawer(ImGui gui, ImGui.OverlappingAllocations controller, TabPage[] tabPages, int activePage) {
+        public ImGui gui { get; } = gui;
+        private int i = -1;
+        private float height;
+        public bool DrawNextPage() {
+            if (++i >= tabPages.Length) {
+                return false;
+            }
+            controller.StartNextAllocatePass(i == activePage);
+            tabPages[i].Drawer?.Invoke(gui);
+
+            return true;
+        }
+
+        public float GetHeight() => height = controller.maximumBottom - gui.statePosition.Top;
+
+        public IDisposable RememberState() => new State(gui, controller, i == activePage);
+
+        /// <summary>
+        /// Saves and restores the current state when <see cref="GetRemainingContentHeight"/> needs to interrupt the current tab drawing.
+        /// </summary>
+        private sealed class State(ImGui gui, ImGui.OverlappingAllocations controller, bool drawing) : IDisposable {
+            private readonly float initialTop = controller.currentTop;
+            public void Dispose() {
+                controller.StartNextAllocatePass(drawing);
+                gui.AllocateRect(0, initialTop - controller.currentTop);
+            }
+        }
+    }
 }
 
 /// <summary>

Yafc/Windows/PreferencesScreen.cs

@@ -9,7 +9,9 @@ namespace Yafc;
 public class PreferencesScreen : PseudoScreen {
     private static readonly PreferencesScreen Instance = new PreferencesScreen();
     private const int GENERAL_PAGE = 0, PROGRESSION_PAGE = 1;
-    private readonly TabControl tabControl = new(("General", DrawGeneral), ("Progression", DrawProgression));
+    private readonly TabControl tabControl;
+
+    private PreferencesScreen() => tabControl = new(("General", DrawGeneral), ("Progression", DrawProgression));
 
     public override void Build(ImGui gui) {
         BuildHeader(gui, "Preferences");
@@ -29,7 +31,9 @@ public override void Build(ImGui gui) {
         }
     }
 
-    private static void DrawProgression(ImGui gui) {
+    private static VirtualScrollList<Technology>? technologyList;
+
+    private void DrawProgression(ImGui gui) {
         ProjectPreferences preferences = Project.current.preferences;
 
         ChooseObject(gui, "Default belt:", Database.allBelts, preferences.defaultBelt, s => {
@@ -75,17 +79,29 @@ private static void DrawProgression(ImGui gui) {
             }
         }
 
-        IEnumerable<Technology> productivityTech = Database.technologies.all
-            .Where(x => x.changeRecipeProductivity.Count != 0)
-            .OrderBy(x => x.locName);
-        foreach (var tech in productivityTech) {
-            using (gui.EnterRow()) {
-                gui.BuildFactorioObjectButton(tech, ButtonDisplayStyle.Default);
-                gui.BuildText($"{tech.locName} Level: ", topOffset: 0.5f);
-                int currentLevel = Project.current.settings.productivityTechnologyLevels.GetValueOrDefault(tech, 0);
-                if (gui.BuildIntegerInput(currentLevel, out int newLevel) && newLevel >= 0) {
-                    Project.current.settings.RecordUndo().productivityTechnologyLevels[tech] = newLevel;
-                }
+        int count = technologyList?.data.Count ?? Database.technologies.all.Count(x => x.changeRecipeProductivity.Count != 0);
+        float height = tabControl.GetRemainingContentHeight(Math.Min(count, 6) * 2.75f + 0.25f);
+        if (technologyList?.height != height) {
+            technologyList = new(height, new(gui.layoutRect.Width, 2.75f), DrawTechnology) {
+                data = [.. Database.technologies.all
+                    .Where(x => x.changeRecipeProductivity.Count != 0)
+                    .OrderBy(x => x.locName)]
+            };
+        }
+
+        technologyList.Build(gui);
+        technologyList.RebuildContents();
+    }
+
+    private void DrawTechnology(ImGui gui, Technology tech, int _) {
+        using (gui.EnterGroup(new(0, .25f, 0, .75f)))
+        using (gui.EnterRow()) {
+            gui.allocator = RectAllocator.LeftRow;
+            gui.BuildFactorioObjectButton(tech, ButtonDisplayStyle.Default);
+            gui.BuildText($"{tech.locName} Level: ");
+            int currentLevel = Project.current.settings.productivityTechnologyLevels.GetValueOrDefault(tech, 0);
+            if (gui.BuildIntegerInput(currentLevel, out int newLevel) && newLevel >= 0) {
+                Project.current.settings.RecordUndo().productivityTechnologyLevels[tech] = newLevel;
             }
         }
     }

changelog.txt

@@ -32,6 +32,7 @@ Date: November 21st 2024
         - Hide blueprint parameters and the synthetic I and O items from more selection windows.
     Internal changes:
         - Dependency and automation analysis allows more ORs, e.g. "(spawner and capture-ammo) or item-to-place".
+        - Scroll views can appear on tab controls.
 ----------------------------------------------------------------------------------------------------------------------
 Version: 2.3.1
 Date: November 10th 2024