SCarouselNavigationButton.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "CoreMinimal.h"
#include "Layout/Visibility.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Styling/SlateColor.h"
#include "Layout/Margin.h"
#include "Widgets/SCompoundWidget.h"
#include "Styling/StyleDefaults.h"
#include "Styling/CoreStyle.h"
#include "Widgets/Layout/SBorder.h"
#include "Widgets/SBoxPanel.h"
#include "Widgets/Layout/SBox.h"
#include "Widgets/Images/SImage.h"
#include "Widgets/Input/SButton.h"
#include "WidgetCarouselStyle.h"
#include "HAL/PlatformProcess.h"
#include "Widgets/Layout/SSpacer.h"
#include "HAL/PlatformApplicationMisc.h"
 
#define LOCTEXT_NAMESPACE "WidgetCarousel"
 
class SCarouselNavigationButton
    : public SCompoundWidget
{
    DECLARE_DELEGATE(FOnBeginPeek)
    DECLARE_DELEGATE(FOnEndPeek)
 
public:
 
    class SPeekBorder 
        : public SBorder
    {
    public:
 
        SLATE_BEGIN_ARGS(SPeekBorder)
            : _OnBeginPeek()
            , _OnEndPeek()
            , _HAlign(HAlign_Fill)
            , _VAlign(VAlign_Fill)
            , _Padding(FMargin(0))
        {}
            SLATE_EVENT(FOnBeginPeek, OnBeginPeek)
            SLATE_EVENT(FOnEndPeek, OnEndPeek)
 
            SLATE_ARGUMENT(EHorizontalAlignment, HAlign)
            SLATE_ARGUMENT(EVerticalAlignment, VAlign)
            SLATE_ATTRIBUTE(FMargin, Padding)
 
            SLATE_DEFAULT_SLOT(FArguments, Content)
 
        SLATE_END_ARGS()
 
        void Construct(const FArguments& InArgs)
        {
            OnBeginPeek = InArgs._OnBeginPeek;
            OnEndPeek = InArgs._OnEndPeek;
 
            SBorder::Construct(SBorder::FArguments()
                .HAlign(InArgs._HAlign)
                .VAlign(InArgs._VAlign)
                .Padding(InArgs._Padding)
                .BorderImage(FStyleDefaults::GetNoBrush())
                [
                    InArgs._Content.Widget
                ]);
        }
 
        void OnMouseEnter(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent)
        {
            if (FPlatformApplicationMisc::IsThisApplicationForeground())
            {
                if (OnBeginPeek.IsBound() == true)
                {
                    OnBeginPeek.Execute();
                }
            }
            SBorder::OnMouseEnter(MyGeometry, MouseEvent);
        }
 
        void OnMouseLeave(const FPointerEvent& MouseEvent)
        {
            if (FPlatformApplicationMisc::IsThisApplicationForeground())
            {
                if (OnEndPeek.IsBound() == true)
                {
                    OnEndPeek.Execute();
                }
            }
            SBorder::OnMouseLeave(MouseEvent);
        }
 
    private:
 
        FOnBeginPeek OnBeginPeek;
        FOnEndPeek OnEndPeek;
    };
 
public:
 
    enum class ENavigationButtonDirection
    {
        Left,
        Right
    };
 
    SLATE_BEGIN_ARGS(SCarouselNavigationButton)
        : _Style()
        {}
 
        SLATE_STYLE_ARGUMENT(FWidgetCarouselNavigationButtonStyle, Style)
 
        
        SLATE_EVENT(FOnClicked, OnClicked)
 
        
        SLATE_ARGUMENT(ENavigationButtonDirection, Direction)
 
        
        SLATE_EVENT(FOnBeginPeek, OnBeginPeek)
        SLATE_EVENT(FOnEndPeek, OnEndPeek)
 
    SLATE_END_ARGS()
 
    void Construct(const FArguments& InArgs)
    {
        ImageTransparency = 0.f;
        Style = InArgs._Style;
 
        ChildSlot
        [
            SNew(SBox)
            .WidthOverride(150.0f)
            [
                SNew(SPeekBorder)
                .OnBeginPeek(InArgs._OnBeginPeek)
                .OnEndPeek(InArgs._OnEndPeek)
                [
                    SNew(SHorizontalBox)
                    + SHorizontalBox::Slot()
                    [
                        SNew(SSpacer)
                        .Visibility(InArgs._Direction == ENavigationButtonDirection::Left ? EVisibility::Collapsed : EVisibility::Visible)
                    ]
                    +SHorizontalBox::Slot()
                    .HAlign(InArgs._Direction == ENavigationButtonDirection::Left ? HAlign_Left : HAlign_Right)
                    .AutoWidth()
                    [
                        SAssignNew(HiddenButton, SButton)
                        .HAlign(HAlign_Center)
                        .VAlign(VAlign_Center)
                        .ToolTipText(InArgs._ToolTipText)
                        .OnClicked(InArgs._OnClicked)
                        .ButtonStyle(FCoreStyle::Get(), "NoBorder")
                        .Cursor(EMouseCursor::Hand)
                        [
                            SAssignNew(VisibleButton, SButton)
                            .HAlign(HAlign_Center)
                            .VAlign(VAlign_Center)
                            .ToolTipText(InArgs._ToolTipText)
                            .OnClicked(InArgs._OnClicked)
                            .ButtonStyle(&Style->InnerButtonStyle)
                            .ContentPadding(FMargin(15, 30))
                            .ButtonColorAndOpacity(this, &SCarouselNavigationButton::GetButtonColor)
                            .Cursor(EMouseCursor::Hand)
                            [
                                SNew(SBox)
                                .HeightOverride(42.0f)
                                .WidthOverride(25.0f)
                                [
                                    SNew(SImage)
                                    .Image(InArgs._Direction == ENavigationButtonDirection::Left ?
                                        &Style->NavigationButtonLeftImage : &Style->NavigationButtonRightImage)
                                    .ColorAndOpacity(this, &SCarouselNavigationButton::GetButtonImageColor)
                                ]
                            ]
                        ]
                    ]
                    + SHorizontalBox::Slot()
                    [
                        SNew(SSpacer)
                        .Visibility(InArgs._Direction == ENavigationButtonDirection::Left ? EVisibility::Visible : EVisibility::Collapsed)
                    ]
                ]
            ]
        ];
    }
 
private:
 
    FSlateColor GetButtonColor() const
    {
        if (HiddenButton->IsHovered())
        {
            if (!VisibleButton->IsHovered())
            {
                FLinearColor Color = FLinearColor::White;
                Color.A = ImageTransparency;
                return Color;
            }
            else
            {
                return FLinearColor::White;
            }
        }
 
        return FLinearColor(0.0f, 0.0f, 0.0f, ImageTransparency * 0.5f);
    }
 
    FSlateColor GetButtonImageColor() const
    {
        if (HiddenButton->IsHovered() || VisibleButton->IsHovered())
        {
            if (!VisibleButton->IsHovered())
            {
                return FLinearColor(0.0f, 0.0f, 0.0f, 1.0f);
            }
 
            return FLinearColor(0.0f, 0.0f, 0.0f, ImageTransparency);
        }
 
        return FLinearColor(1.0f, 1.0f, 1.0f, ImageTransparency);
    }
 
    virtual void Tick(const FGeometry& AllottedGeometry, const double InCurrentTime, const float InDeltaTime) override
    {
        //SButton::Tick(AllottedGeometry, InCurrentTime, InDeltaTime);
 
        static const float BlendSpeed = 2.0f;
 
        float DesiredBlendSpeed = BlendSpeed * InDeltaTime;
 
        if (IsHovered())
        {
            if (ImageTransparency != 1.f && FPlatformApplicationMisc::IsThisApplicationForeground())
            {
                ImageTransparency = FMath::Min<float>(ImageTransparency + DesiredBlendSpeed, 1.f);
            }
            else
            {
                ImageTransparency = 1.f;
            }
        }
        else
        {
            if (ImageTransparency != 0.f && FPlatformApplicationMisc::IsThisApplicationForeground())
            {
                ImageTransparency = FMath::Max<float>(ImageTransparency - DesiredBlendSpeed, 0.f);
            }
            else
            {
                ImageTransparency = 0.f;
            }
        }
    }
 
private:
    const FWidgetCarouselNavigationButtonStyle* Style;
    TSharedPtr<SButton> HiddenButton;
    TSharedPtr<SButton> VisibleButton;
 
    float ImageTransparency;
    ENavigationButtonDirection Direction;
};
 
#undef LOCTEXT_NAMESPACE