Radial menus are in good shape

Source/Integration/RadialMenu.cpp

@@ -1,6 +1,8 @@
 #include "RadialMenu.h"
 #include "Rendering/DrawElements.h"
 #include "Engine/Texture2D.h"
+#include "Fonts/FontMeasure.h"
+#include "Framework/Application/SlateApplication.h"
 #include "Styling/SlateBrush.h"
 #include "Widgets/SLeafWidget.h"
 
@@ -8,17 +10,30 @@
 TArray<FRadialMenuItem> FRadialMenuItem::Calculate(const FRadialMenuConfig &Config)
 {
     TArray<FRadialMenuItem> Items;
-    if (Config.NumItems < 0) return Items;
+    const int32 NumItems = Config.MenuItems.Num();
+    if (NumItems <= 0) return Items;
 
-    int32 NumRight = (Config.NumItems / 2);
-    int32 NumLeft = Config.NumItems - NumRight;
-    Items.SetNum(Config.NumItems);
+    int32 NumRight = (NumItems / 2);
+    int32 NumLeft = NumItems - NumRight;
+    Items.SetNum(NumItems);
+
+    // Measure each non-empty label first; the spoke layout's item height
+    // is derived from the tallest label.
+    const TSharedRef<FSlateFontMeasure> FontMeasure = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();
+    double MaxTextHeight = 5.0;
+    for (int32 I = 0; I < NumItems; I++)
+    {
+        if (Config.MenuItems[I].IsEmpty()) continue;
+        Items[I].TextSize = FontMeasure->Measure(Config.MenuItems[I], Config.Font);
+        MaxTextHeight = FMath::Max(MaxTextHeight, Items[I].TextSize.Y);
+    }
+    const float ItemHeight = static_cast<float>(MaxTextHeight * 1.2);
 
     View LeftItems(Items.GetData(), NumLeft);
     View RightItems(Items.GetData() + NumLeft, NumRight);
 
-    CalculateSpokes(LeftItems, Config.NumItems, Config.ItemHeight, Config.InnerRadius, Config.MinSpoke);
-    CalculateSpokes(RightItems, Config.NumItems, Config.ItemHeight, Config.InnerRadius, Config.MinSpoke);
+    CalculateSpokes(LeftItems, NumItems, ItemHeight, Config.InnerRadius, Config.MinSpoke);
+    CalculateSpokes(RightItems, NumItems, ItemHeight, Config.InnerRadius, Config.MinSpoke);
     double LeftWidth = WidestSpoke(LeftItems);
     double RightWidth = WidestSpoke(RightItems);
     double HalfWidth = FMath::Max(LeftWidth, RightWidth) + Config.Spread;
@@ -29,6 +44,29 @@ TArray<FRadialMenuItem> FRadialMenuItem::Calculate(const FRadialMenuConfig &Conf
     return Items;
 }
 
+TArray<FVector2D> FRadialMenuItem::CalculateDirections(int32 NumItems)
+{
+    TArray<FVector2D> Result;
+    if (NumItems <= 0) return Result;
+
+    const int32 NumRight = (NumItems / 2);
+    const int32 NumLeft = NumItems - NumRight;
+    Result.SetNum(NumItems);
+
+    // Left side: SpokeVector with X flipped (matches FlipHorizontal in Calculate).
+    for (int32 I = 0; I < NumLeft; I++)
+    {
+        FVector2D V = SpokeVector(I, NumLeft, NumItems);
+        V.X = -V.X;
+        Result[I] = V;
+    }
+    for (int32 I = 0; I < NumRight; I++)
+    {
+        Result[NumLeft + I] = SpokeVector(I, NumRight, NumItems);
+    }
+    return Result;
+}
+
 FVector2D FRadialMenuItem::SpokeVector(int32 I, int32 NSide, int32 NTotal)
 {
     double SpokeAngle = 1.0 / NTotal;
@@ -130,6 +168,13 @@ public:
         Invalidate(EInvalidateWidgetReason::Layout);
     }
 
+    void SetPointer(FVector2D NewPointer)
+    {
+        if (PointerVector == NewPointer) return;
+        PointerVector = NewPointer;
+        Invalidate(EInvalidateWidgetReason::Paint);
+    }
+
 protected:
     virtual FVector2D ComputeDesiredSize(float) const override
     {
@@ -144,6 +189,14 @@ protected:
                 Max.X = FMath::Max(Max.X, P.X);
                 Max.Y = FMath::Max(Max.Y, P.Y);
             }
+            if (Item.TextSize.X <= 0) continue;
+            const double Gap = Config.Spread * 0.5;
+            const double TextLeft = Item.RightSide ? (Item.Point3.X + Gap) : (Item.Point3.X - Gap - Item.TextSize.X);
+            const double TextRight = Item.RightSide ? (Item.Point3.X + Gap + Item.TextSize.X) : (Item.Point3.X - Gap);
+            Min.X = FMath::Min(Min.X, TextLeft);
+            Max.X = FMath::Max(Max.X, TextRight);
+            Min.Y = FMath::Min(Min.Y, Item.Point3.Y - Item.TextSize.Y * 0.5);
+            Max.Y = FMath::Max(Max.Y, Item.Point3.Y + Item.TextSize.Y * 0.5);
         }
         // Symmetric around the origin so the menu draws centered.
         double HalfW = FMath::Max(FMath::Abs(Min.X), FMath::Abs(Max.X));
@@ -162,7 +215,7 @@ protected:
         {
             const FRadialMenuItem& Item = Items[I];
             const bool bSelected = (I == Config.SelectedItem);
-            const FLinearColor& Color = bSelected ? Config.SelectedColor : Config.LineColor;
+            const FLinearColor& Color = bSelected ? Config.SelectedColor : Config.ItemColor;
             const float Thickness = bSelected ? Config.SelectedThickness : Config.LineThickness;
             TArray<FVector2D> Points;
             Points.Add(Center + Item.Point1);
@@ -171,168 +224,140 @@ protected:
             FSlateDrawElement::MakeLines(OutDrawElements, LayerId, PaintGeom, Points, ESlateDrawEffect::None, Color, true, Thickness);
         }
 
-        if (Config.DotRadius <= 0.0f) return LayerId;
-        if (Config.DotTexture == nullptr) return LayerId;
-
-        FSlateBrush DotBrush;
-        DotBrush.SetResourceObject(Config.DotTexture);
-        const FVector2D DotSize(Config.DotRadius * 2.0f);
+        // Draw item labels, vertically centered on Point3.  Right-side items
+        // are left-aligned to Point3; left-side items are right-aligned.
         for (int32 I = 0; I < Items.Num(); I++)
         {
             const FRadialMenuItem& Item = Items[I];
+            if (Item.TextSize.X <= 0) continue;
             const bool bSelected = (I == Config.SelectedItem);
-            const FLinearColor& Color = bSelected ? Config.SelectedColor : Config.LineColor;
-            for (const FVector2D& Point : { Item.Point1, Item.Point3 })
+            const FLinearColor& Color = bSelected ? Config.SelectedColor : Config.ItemColor;
+            const double Gap = Config.Spread * 0.5;
+            FVector2D TextPos;
+            TextPos.X = Item.RightSide ? (Item.Point3.X + Gap) : (Item.Point3.X - Gap - Item.TextSize.X);
+            TextPos.Y = Item.Point3.Y - Item.TextSize.Y * 0.5;
+            FSlateDrawElement::MakeText(
+                OutDrawElements,
+                LayerId + 1,
+                AllottedGeometry.ToPaintGeometry(Item.TextSize, FSlateLayoutTransform(Center + TextPos)),
+                Config.MenuItems[I],
+                Config.Font,
+                ESlateDrawEffect::None,
+                Color);
+        }
+
+        if (Config.DotRadius > 0.0f && Config.DotTexture != nullptr)
+        {
+            FSlateBrush DotBrush;
+            DotBrush.SetResourceObject(Config.DotTexture);
+            const FVector2D DotSize(Config.DotRadius * 2.0f);
+            for (int32 I = 0; I < Items.Num(); I++)
             {
-                const FVector2D LocalPoint = Center + Point;
-                FSlateDrawElement::MakeBox(
-                    OutDrawElements,
-                    LayerId,
-                    AllottedGeometry.ToPaintGeometry(DotSize, FSlateLayoutTransform(LocalPoint - FVector2D(Config.DotRadius))),
-                    &DotBrush,
-                    ESlateDrawEffect::None,
-                    Color);
+                const FRadialMenuItem& Item = Items[I];
+                const bool bSelected = (I == Config.SelectedItem);
+                const FLinearColor& Color = bSelected ? Config.SelectedColor : Config.ItemColor;
+                for (const FVector2D& Point : { Item.Point1, Item.Point3 })
+                {
+                    const FVector2D LocalPoint = Center + Point;
+                    FSlateDrawElement::MakeBox(
+                        OutDrawElements,
+                        LayerId + 1,
+                        AllottedGeometry.ToPaintGeometry(DotSize, FSlateLayoutTransform(LocalPoint - FVector2D(Config.DotRadius))),
+                        &DotBrush,
+                        ESlateDrawEffect::None,
+                        Color);
+                }
             }
         }
-        return LayerId;
+
+        // Teardrop: visualizes PointerVector inside InnerRadius.  The texture's
+        // tip naturally points up (0,-1); rotate it to align with PointerVector.
+        // When PointerVector is (0,0), the teardrop stays upright at the center.
+        if (Config.TeardropRadius > 0.0f && Config.Teardrop != nullptr)
+        {
+            FSlateBrush TeardropBrush;
+            TeardropBrush.SetResourceObject(Config.Teardrop);
+            const FVector2D TeardropSize(Config.TeardropRadius * 2.0f);
+            const FVector2D TeardropCenter = Center + PointerVector * Config.InnerRadius;
+            const float Angle = PointerVector.IsZero()
+                ? 0.0f
+                : static_cast<float>(FMath::Atan2(PointerVector.X, -PointerVector.Y));
+            FSlateDrawElement::MakeRotatedBox(
+                OutDrawElements,
+                LayerId + 1,
+                AllottedGeometry.ToPaintGeometry(TeardropSize, FSlateLayoutTransform(TeardropCenter - FVector2D(Config.TeardropRadius))),
+                &TeardropBrush,
+                ESlateDrawEffect::None,
+                Angle);
+        }
+        return LayerId + 1;
     }
 
 private:
     FRadialMenuConfig Config;
 
     TArray<FRadialMenuItem> Items;
+
+    FVector2D PointerVector = {0,0};
 };
 
 
-void URadialMenuWidget::SetNumItems(int32 NewNumItems)
+void URadialMenuWidget::SetMenuItems(const TArray<FString>& NewMenuItems)
 {
-    if (Config.NumItems == NewNumItems) return;
+    if (Config.MenuItems == NewMenuItems) return;
 
-    Config.NumItems = NewNumItems;
+    Config.MenuItems = NewMenuItems;
+    Config.SelectedItem = -1;
+    PointerVector = FVector2D();
     SynchronizeProperties();
 }
 
-void URadialMenuWidget::SetItemHeight(float NewItemHeight)
+FString URadialMenuWidget::GetSelectedMenuItem() const
 {
-    if (Config.ItemHeight == NewItemHeight) return;
-
-    Config.ItemHeight = NewItemHeight;
-    SynchronizeProperties();
+    if (!Config.MenuItems.IsValidIndex(Config.SelectedItem)) return FString();
+    return Config.MenuItems[Config.SelectedItem];
 }
 
-void URadialMenuWidget::SetInnerRadius(float NewInnerRadius)
+void URadialMenuWidget::SetSelectedItem(int32 NewSelectedItem)
 {
-    if (Config.InnerRadius == NewInnerRadius) return;
-
-    Config.InnerRadius = NewInnerRadius;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetMinSpoke(float NewMinSpoke)
-{
-    if (Config.MinSpoke == NewMinSpoke) return;
-
-    Config.MinSpoke = NewMinSpoke;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetSpread(float NewSpread)
-{
-    if (Config.Spread == NewSpread) return;
-
-    Config.Spread = NewSpread;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetLineThickness(float NewLineThickness)
-{
-    if (Config.LineThickness == NewLineThickness) return;
-
-    Config.LineThickness = NewLineThickness;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetLineColor(FLinearColor NewLineColor)
-{
-    if (Config.LineColor == NewLineColor) return;
-
-    Config.LineColor = NewLineColor;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetDotTexture(UTexture2D* NewDotTexture)
-{
-    if (Config.DotTexture == NewDotTexture) return;
-
-    Config.DotTexture = NewDotTexture;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetDotRadius(float NewDotRadius)
-{
-    if (Config.DotRadius == NewDotRadius) return;
-
-    Config.DotRadius = NewDotRadius;
-    SynchronizeProperties();
-}
-
-bool URadialMenuWidget::SetSelectedItem(int32 NewSelectedItem)
-{
-    if (Config.SelectedItem == NewSelectedItem) return false;
+    if (Config.SelectedItem == NewSelectedItem) return;
 
     Config.SelectedItem = NewSelectedItem;
     SynchronizeProperties();
-    return true;
-}
-
-void URadialMenuWidget::SetSelectedColor(FLinearColor NewSelectedColor)
-{
-    if (Config.SelectedColor == NewSelectedColor) return;
-
-    Config.SelectedColor = NewSelectedColor;
-    SynchronizeProperties();
-}
-
-void URadialMenuWidget::SetSelectedThickness(float NewSelectedThickness)
-{
-    if (Config.SelectedThickness == NewSelectedThickness) return;
-
-    Config.SelectedThickness = NewSelectedThickness;
-    SynchronizeProperties();
 }
 
 void URadialMenuWidget::SynchronizeProperties()
 {
     Super::SynchronizeProperties();
 
-    Items = FRadialMenuItem::Calculate(Config);
-    if (Items.Num() == 0)
+    if (Directions.Num() != Config.MenuItems.Num())
     {
-        PointerVector = FVector2D(0,0);
+        Directions = FRadialMenuItem::CalculateDirections(Config.MenuItems.Num());
     }
     if (MySlateWidget.IsValid())
     {
         MySlateWidget->SetConfig(Config);
+        MySlateWidget->SetPointer(PointerVector);
     }
 }
 
-bool URadialMenuWidget::AddPointer(FVector2D Direction, float Scale)
+void URadialMenuWidget::AddPointer(FVector2D Direction, float Scale)
 {
-    if (!IsVisible())
+    if ((!IsVisible()) || (Directions.Num() == 0))
     {
-        return false;
-    }
-    
-    if (Items.Num() == 0)
-    {
-        return false;
+        PointerVector = FVector2D();
+        SetSelectedItem(-1);
+        if (MySlateWidget.IsValid()) MySlateWidget->SetPointer(PointerVector);
+        return;
     }
 
     PointerVector += (Direction * Scale);
 
     if (PointerVector.Length() < 0.5)
     {
-        return SetSelectedItem(-1);
+        SetSelectedItem(-1);
+        if (MySlateWidget.IsValid()) MySlateWidget->SetPointer(PointerVector);
+        return;
     }
 
     if (PointerVector.Length() > 1.0)
@@ -342,24 +367,19 @@ bool URadialMenuWidget::AddPointer(FVector2D Direction, float Scale)
 
     int32 BestIndex = -1;
     double BestDot = -2.0;
-    for (int32 I = 0; I < Items.Num(); I++)
+    for (int32 I = 0; I < Directions.Num(); I++)
     {
-        FVector2D SpokeDir = Items[I].Point1;
+        FVector2D SpokeDir = Directions[I];
         if (!SpokeDir.Normalize()) continue;
         double Dot = FVector2D::DotProduct(SpokeDir, PointerVector);
         if (Dot <= BestDot) continue;
         BestDot = Dot;
         BestIndex = I;
     }
-    return SetSelectedItem(BestIndex);
+    SetSelectedItem(BestIndex);
+    if (MySlateWidget.IsValid()) MySlateWidget->SetPointer(PointerVector);
 }
 
-FLinearColor URadialMenuWidget::GetItemColor(int N) const
-{
-    return (N == Config.SelectedItem) ? Config.SelectedColor : Config.LineColor;
-}
-
-
 TSharedRef<SWidget> URadialMenuWidget::RebuildWidget()
 {
     MySlateWidget = SNew(SRadialMenu, Config);

Source/Integration/RadialMenu.h

@@ -7,6 +7,7 @@
 
 #include "CoreMinimal.h"
 #include "Components/Widget.h"
+#include "Fonts/SlateFontInfo.h"
 #include "RadialMenu.generated.h"
 
 class SRadialMenu;
@@ -19,10 +20,10 @@ struct FRadialMenuConfig
     GENERATED_BODY()
 
     UPROPERTY(EditAnywhere, Category="RadialMenu")
-    int32 NumItems = 8;
+    TArray<FString> MenuItems;
 
     UPROPERTY(EditAnywhere, Category="RadialMenu")
-    float ItemHeight = 20.0f;
+    FSlateFontInfo Font;
 
     UPROPERTY(EditAnywhere, Category="RadialMenu")
     float InnerRadius = 20.0f;
@@ -37,7 +38,7 @@ struct FRadialMenuConfig
     float LineThickness = 4.0f;
 
     UPROPERTY(EditAnywhere, Category="RadialMenu")
-    FLinearColor LineColor = FLinearColor::White;
+    FLinearColor ItemColor = FLinearColor::White;
 
     UPROPERTY(EditAnywhere, Category="RadialMenu")
     TObjectPtr<UTexture2D> DotTexture;
@@ -45,6 +46,12 @@ struct FRadialMenuConfig
     UPROPERTY(EditAnywhere, Category="RadialMenu")
     float DotRadius = 3.0f;
 
+    UPROPERTY(EditAnywhere, Category="RadialMenu")
+    TObjectPtr<UTexture2D> Teardrop;
+
+    UPROPERTY(EditAnywhere, Category="RadialMenu")
+    float TeardropRadius = 0.0f;
+
     UPROPERTY(EditAnywhere, Category="RadialMenu")
     int32 SelectedItem = -1;
 
@@ -73,8 +80,16 @@ struct FRadialMenuItem
     UPROPERTY(BlueprintReadOnly)
     bool RightSide = false;
 
+    UPROPERTY(BlueprintReadOnly)
+    FVector2D TextSize = {0,0};
+
     static TArray<FRadialMenuItem> Calculate(const FRadialMenuConfig &Config);
 
+    // Like Calculate, but only produces the unit-vector direction of
+    // each spoke.  Cheaper to evaluate when only the spoke directions
+    // are needed (e.g. for hit-testing a pointer against the wheel).
+    static TArray<FVector2D> CalculateDirections(int32 NumItems);
+
 private:
     using View = TArrayView<FRadialMenuItem>;
 
@@ -112,59 +127,29 @@ class URadialMenuWidget : public UWidget
 
 public:
     UFUNCTION(BlueprintCallable)
-    void SetNumItems(int32 NewNumItems);
+    void SetMenuItems(const TArray<FString>& NewMenuItems);
 
     UFUNCTION(BlueprintCallable)
-    void SetItemHeight(float NewItemHeight);
+    void ClearMenuItems() { SetMenuItems({}); }
 
     UFUNCTION(BlueprintCallable)
-    void SetInnerRadius(float NewInnerRadius);
-
-    UFUNCTION(BlueprintCallable)
-    void SetMinSpoke(float NewMinSpoke);
-
-    UFUNCTION(BlueprintCallable)
-    void SetSpread(float NewSpread);
-
-    UFUNCTION(BlueprintCallable)
-    void SetLineThickness(float NewLineThickness);
-
-    UFUNCTION(BlueprintCallable)
-    void SetLineColor(FLinearColor NewLineColor);
-
-    UFUNCTION(BlueprintCallable)
-    void SetDotTexture(UTexture2D* NewDotTexture);
-
-    UFUNCTION(BlueprintCallable)
-    void SetDotRadius(float NewDotRadius);
-
-    UFUNCTION(BlueprintCallable)
-    bool SetSelectedItem(int32 NewSelectedItem);
-
-    UFUNCTION(BlueprintCallable)
-    void SetSelectedColor(FLinearColor NewSelectedColor);
-
-    UFUNCTION(BlueprintCallable)
-    void SetSelectedThickness(float NewSelectedThickness);
-
-    UFUNCTION(BlueprintCallable)
-    const TArray<FRadialMenuItem> &GetItems() const { return Items; }
+    void SetSelectedItem(int32 NewSelectedItem);
 
     // Returns true if the selected item changed.
     UFUNCTION(BlueprintCallable)
-    bool AddPointer(FVector2D Direction, float Scale);
+    void AddPointer(FVector2D Direction, float Scale);
 
     UFUNCTION(BlueprintCallable)
     FVector2D GetPointer() const { return PointerVector; }
 
     UFUNCTION(BlueprintCallable)
-    FLinearColor GetItemColor(int N) const;
+    FString GetSelectedMenuItem() const;
 
 protected:
     UPROPERTY(EditAnywhere)
     FRadialMenuConfig Config;
 
-    TArray<FRadialMenuItem> Items;
+    TArray<FVector2D> Directions;
 
     FVector2D PointerVector = {0,0};