SClippingHorizontalBox.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Framework/MultiBox/MultiBoxDefs.h"
#include "Framework/SlateDelegates.h"
#include "Styling/CoreStyle.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SBoxPanel.h"
 
class FArrangedChildren;
class FPaintArgs;
class FSlateWindowElementList;
class SComboButton;
 
DECLARE_DELEGATE_RetVal_OneParam(FMenuEntryResizeParams, FOnGetWidgetResizeParams, const TSharedRef<SWidget>&);
 
namespace UE::Slate
{
 
struct FClippingInfo
{
    TSharedPtr<SWidget> Widget;
    FMenuEntryResizeParams ResizeParams;
    double X = 0.0;
    double Width = 0.0;
    bool bIsStretchable = false;
    bool bAppearsInOverflow = false;
    bool bWasClipped = false;
};
 
void PrioritizedResize(
    float InAllottedWidth,
    float InWrapButtonWidth,
    const FMargin& InWrapButtonPadding,
    int32 InWrapButtonIndex,
    TArray<FClippingInfo>& InOutClippingInfos,
    TOptional<float>& OutWrapButtonX
);
 
}; // namespace UE::Slate
 
class SClippingHorizontalBox : public SHorizontalBox
{
public:
    SLATE_BEGIN_ARGS(SClippingHorizontalBox) 
        : _AllowWrapButton(true)
        , _StyleSet(&FCoreStyle::Get())
        , _StyleName(NAME_None)
        , _IsFocusable(true) { }
        SLATE_ARGUMENT(TOptional<bool>, AllowWrapButton)
        SLATE_ARGUMENT(FOnGetContent, OnWrapButtonClicked)
        SLATE_ARGUMENT(const ISlateStyle*, StyleSet)
        SLATE_ARGUMENT(FName, StyleName)
        SLATE_ARGUMENT(bool, IsFocusable)
        SLATE_ARGUMENT(FOnGetWidgetResizeParams, OnGetWidgetResizeParams)
    SLATE_END_ARGS()
 
    
    virtual int32 OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const override;
    virtual FVector2D ComputeDesiredSize(float) const override;
 
    virtual void OnArrangeChildren( const FGeometry& AllottedGeometry, FArrangedChildren& ArrangedChildren ) const override;
 
    void Construct( const FArguments& InArgs );
 
    void AddWrapButton();
 
    TArray<TWeakPtr<SWidget>> GetClippedWidgets() const
    {
        return ClippedWidgets;
    }
 
private:
    void OnWrapButtonOpenChanged(bool bIsOpen);
    EActiveTimerReturnType UpdateWrapButtonStatus(double CurrentTime, float DeltaTime);
 
    TSharedPtr<SComboButton> WrapButton;
 
    bool bAllowWrapButton = true;
 
    FOnGetContent OnWrapButtonClicked;
 
    TSharedPtr<FActiveTimerHandle> WrapButtonOpenTimer;
 
    bool bIsFocusable = true;
 
    float WrapButtonWidth = 0.0f; // Fixed width, initialized after button creation
    int32 WrapButtonIndex = -1; // 0 is left-most index, -1 is right-most index (Python style).
 
    const ISlateStyle* StyleSet = nullptr;
    FName StyleName;
 
    FOnGetWidgetResizeParams OnGetWidgetResizeParams;
 
    mutable TArray<TWeakPtr<SWidget>> ClippedWidgets;
};