SCanvas.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Misc/Attribute.h"
#include "Layout/Visibility.h"
#include "SlotBase.h"
#include "Widgets/SWidget.h"
#include "Layout/Children.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SPanel.h"
 
class FArrangedChildren;
class FPaintArgs;
class FSlateWindowElementList;
 
class SCanvas : public SPanel
{
    SLATE_DECLARE_WIDGET_API(SCanvas, SPanel, SLATE_API)
 
public:
 
    class FSlot : public TWidgetSlotWithAttributeSupport<FSlot>, public TAlignmentWidgetSlotMixin<FSlot>
    {
    public:
        SLATE_SLOT_BEGIN_ARGS_OneMixin(FSlot, TSlotBase<FSlot>, TAlignmentWidgetSlotMixin<FSlot>)
            SLATE_ATTRIBUTE(FVector2D, Position)
            SLATE_ATTRIBUTE(FVector2D, Size)
        SLATE_SLOT_END_ARGS()
 
        void SetPosition( TAttribute<FVector2D> InPosition )
        {
            Position.Assign(*this, MoveTemp(InPosition));
        }
        FVector2D GetPosition() const
        {
            return Position.Get();
        }
 
        void SetSize( TAttribute<FVector2D> InSize )
        {
            Size.Assign(*this, MoveTemp(InSize));
        }
        FVector2D GetSize() const
        {
            return Size.Get();
        }
 
    public:
        FSlot()
            : TWidgetSlotWithAttributeSupport<FSlot>()
            , TAlignmentWidgetSlotMixin<FSlot>(HAlign_Left, VAlign_Top)
            , Position(*this, FVector2D::ZeroVector)
            , Size(*this, FVector2D(1.0f, 1.0f))
        { }
 
        SLATE_API void Construct(const FChildren& SlotOwner, FSlotArguments&& InArg);
        static SLATE_API void RegisterAttributes(FSlateWidgetSlotAttributeInitializer& AttributeInitializer);
 
    private:
        TSlateSlotAttribute<FVector2D> Position;
 
        TSlateSlotAttribute<FVector2D> Size;
    };
 
    SLATE_BEGIN_ARGS( SCanvas )
        {
            _Visibility = EVisibility::SelfHitTestInvisible;
        }
 
        SLATE_SLOT_ARGUMENT( FSlot, Slots )
 
    SLATE_END_ARGS()
 
    SLATE_API SCanvas();
    SLATE_API virtual ~SCanvas();
 
    SLATE_API void Construct( const FArguments& InArgs );
 
    static SLATE_API FSlot::FSlotArguments Slot();
 
    using FScopedWidgetSlotArguments = TPanelChildren<FSlot>::FScopedWidgetSlotArguments;
    SLATE_API FScopedWidgetSlotArguments AddSlot();
 
    SLATE_API int32 RemoveSlot( const TSharedRef<SWidget>& SlotWidget );
 
    SLATE_API void ClearChildren();
 
    int32 NumSlots() const { return Children.Num(); }
 
public:
 
    //~ SWidget overrides
    SLATE_API virtual void OnArrangeChildren( const FGeometry& AllottedGeometry, FArrangedChildren& ArrangedChildren ) const override;
    SLATE_API virtual int32 OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const override;
    SLATE_API virtual FChildren* GetChildren() override;
 
protected:
    //~ Begin SWidget overrides.
    SLATE_API virtual FVector2D ComputeDesiredSize(float) const override;
    //~ End SWidget overrides.
 
protected:
 
    TPanelChildren< FSlot > Children;
};