SWindowTitleBar.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 "Styling/SlateColor.h"
#include "Input/Reply.h"
#include "Widgets/SWidget.h"
#include "Layout/Margin.h"
#include "Animation/CurveSequence.h"
#include "Widgets/SNullWidget.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SCompoundWidget.h"
#include "Widgets/SBoxPanel.h"
#include "Widgets/SOverlay.h"
#include "Styling/SlateTypes.h"
#include "Styling/CoreStyle.h"
#include "Widgets/SWindow.h"
#include "Application/SlateApplicationBase.h"
#include "Widgets/Images/SImage.h"
#include "Widgets/Layout/SBox.h"
#include "Widgets/Layout/SBorder.h"
#include "Widgets/Layout/SSpacer.h"
#include "Widgets/Text/STextBlock.h"
#include "Widgets/Input/SButton.h"
#include "Framework/MetaData/DriverMetaData.h"
 
namespace SWindowTitleBarDefs
{
    static const float WindowFlashFrequency = 5.5f;
 
    static const float WindowFlashDuration = 1.0f;
}
 
 
class SAppIconWidget
    : public SCompoundWidget
{
    SLATE_BEGIN_ARGS( SAppIconWidget )
        : _IconColorAndOpacity( FLinearColor::White )
    {
        _AccessibleText = NSLOCTEXT("AppIconWidget", "System", "System Menu");
    }
 
    SLATE_ATTRIBUTE( FSlateColor, IconColorAndOpacity )
 
    SLATE_END_ARGS( )
    
    void Construct( const FArguments& Args )
    {
        SetCanTick(false);
 
        IconImage = FSlateApplicationBase::Get().MakeImage(
            FSlateApplicationBase::Get().GetAppIcon(),
            Args._IconColorAndOpacity,
            EVisibility::HitTestInvisible
        );
 
        this->ChildSlot
        .Padding(FAppStyle::Get().GetMargin("AppIconPadding"))
        [
            IconImage.ToSharedRef()
        ];
    }
 
    void SetIcon(const FSlateBrush* InIcon, const FMargin& InIconPadding)
    {
        ChildSlot.Padding(InIconPadding);
        IconImage->SetImage(InIcon);
    }
 
    virtual EWindowZone::Type GetWindowZoneOverride() const override
    {
        // Pretend we are a REAL system menu so the user can click to open a menu, or double-click to close the app on Windows
        return EWindowZone::SysMenu;
    }
 
private:
    TSharedPtr<SImage> IconImage;
};
 
 
class SWindowTitleBar
    : public SCompoundWidget
    , public IWindowTitleBar
{
public:
 
    SLATE_BEGIN_ARGS(SWindowTitleBar)
        : _Style(&FCoreStyle::Get().GetWidgetStyle<FWindowStyle>("Window"))
        , _ShowAppIcon(true)
    { }
        SLATE_STYLE_ARGUMENT(FWindowStyle, Style)
        SLATE_ARGUMENT(bool, ShowAppIcon)
        SLATE_ATTRIBUTE(FText, Title)
        SLATE_ATTRIBUTE(FText, CloseButtonToolTipText)
    SLATE_END_ARGS()
    
public:
 
    SLATE_API void Construct( const FArguments& InArgs, const TSharedRef<SWindow>& InWindow, const TSharedPtr<SWidget>& InCenterContent, EHorizontalAlignment InCenterContentAlignment );
 
    virtual EWindowZone::Type GetWindowZoneOverride() const override
    {
        return EWindowZone::TitleBar;
    }
 
    //~ Begin IWindowTitleBar Interface
    SLATE_API virtual void Flash() override;
    SLATE_API virtual void UpdateWindowMenu(TSharedPtr<SWidget> MenuContent) override;
    SLATE_API virtual void UpdateBackgroundContent(TSharedPtr<SWidget> BackgroundContent) override;
    SLATE_API virtual void SetAllowMenuBar(bool bInAllowMenuBar) override;
    //~ Begin IWindowTitleBar Interface
    
protected:
 
    float GetFlashValue( ) const
    {
        if (TitleFlashSequence.IsPlaying())
        {
            float Lerp = TitleFlashSequence.GetLerp();
 
            const float SinRateMultiplier = 2.0f * PI * SWindowTitleBarDefs::WindowFlashDuration * SWindowTitleBarDefs::WindowFlashFrequency;
            float SinTerm = 0.5f * (FMath::Sin( Lerp * SinRateMultiplier ) + 1.0f);
 
            float FadeTerm = 1.0f - Lerp;
 
            return SinTerm * FadeTerm;
        }
        return 0.0f;
    }
 
    SLATE_API virtual void MakeTitleBarContentWidgets( TSharedPtr< SWidget >& OutLeftContent, TSharedPtr< SWidget >& OutRightContent );
 
    SLATE_API TSharedRef<SWidget> MakeTitleBarContent( TSharedPtr<SWidget> CenterContent, EHorizontalAlignment CenterContentAlignment );
 
    FSlateColor GetWindowTitleContentColor( ) const
    {   
        // Color of the title area contents - modulates the icon and buttons
        float Flash = GetFlashValue();
 
        return FMath::Lerp(FLinearColor::White, FLinearColor::Black, Flash);
    }
 
private:
 
    // Callback for clicking the close button.
    FReply CloseButton_OnClicked();
 
    // Callback for getting the image of the close button.
    const FSlateBrush* GetCloseImage() const;
 
    // Callback for clicking the maximize button
    FReply MaximizeRestoreButton_OnClicked( );
 
    // Callback for getting the image of the maximize/restore button.
    const FSlateBrush* GetMaximizeRestoreImage( ) const;
 
    // Callback for clicking the minimize button.
    FReply MinimizeButton_OnClicked( );
 
    // Callback for getting the image of the minimize button.
    const FSlateBrush* GetMinimizeImage( ) const;
    
    const FSlateBrush* GetWindowTitlebackgroundImage( ) const;
    
    EVisibility GetWindowFlashVisibility( ) const;
    
    FSlateColor GetWindowTitleAreaColor( ) const;
 
    FText HandleWindowTitleText( ) const;
 
    FText GetMaximizeButtonToolTip() const;
 
protected:
 
    // Holds a weak pointer to the owner window.
    TWeakPtr<SWindow> OwnerWindowPtr;
 
private:
 
    // Holds the window style to use (for buttons, text, etc.).
    const FWindowStyle* Style;
 
    // Holds the content widget of the title area.
    TSharedPtr<SWidget> TitleArea;
 
    // Holds the curve sequence for the window flash animation.
    FCurveSequence TitleFlashSequence;
 
    // Holds the minimize button.
    TSharedPtr<SButton> MinimizeButton;
 
    // Holds the maximize/restore button.
    TSharedPtr<SButton> MaximizeRestoreButton;
 
    // Holds the close button.
    TSharedPtr<SButton> CloseButton;
 
    TAttribute<FText> Title;
    TAttribute<FText> CloseButtonToolTipText;
 
    SHorizontalBox::FSlot* WindowMenuSlot;
    SHorizontalBox::FSlot* RightSideContentSlot;
 
    TSharedPtr<SAppIconWidget> AppIconWidget;
    bool ShowAppIcon;
    bool bAllowMenuBar = false;
};