Unreal Engine: Display the input action prompt sprite in Rich Text Block depend on binding of input action key mapping of Enhanced input system.

RichTextBlockInputActionDecorator.cpp

// Copyright by Thanut Panichyotai (@LuviKunG)
// CC BY-SA 4.0
// https://creativecommons.org/licenses/by-sa/4.0/

#include "Widgets/RichTextBlockInputActionDecorator.h"

#include "EnhancedInputSubsystems.h"
#include "InputMappingContext.h"
#include "Fonts/FontMeasure.h"
#include "Kismet/GameplayStatics.h"
#include "UserSettings/EnhancedInputUserSettings.h"
#include "Widgets/Layout/SScaleBox.h"

class SRichInlineImageSet : public SCompoundWidget
{
public:
	SLATE_BEGIN_ARGS(SRichInlineImageSet)
		{
		}

	SLATE_END_ARGS()

	void Construct(const FArguments& InArgs, const TArray<FSlateBrush*> Brushes, const FTextBlockStyle& TextStyle)
	{
		const TSharedRef<SHorizontalBox> HorizontalBox = SNew(SHorizontalBox);
		for (const FSlateBrush* Brush : Brushes)
		{
			auto Slot = HorizontalBox->AddSlot();
			Slot.AutoWidth();
			Slot[CreateBox(InArgs, Brush, TextStyle)];
		}
		ChildSlot[HorizontalBox];
	}

private:
	TSharedRef<SBox> CreateBox(const FArguments& InArgs, const FSlateBrush* Brush, const FTextBlockStyle& TextStyle)
	{
		check(Brush);
		const TSharedRef<FSlateFontMeasure> FontMeasure = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();
		const float IconHeight = FMath::Min(static_cast<float>(FontMeasure->GetMaxCharacterHeight(TextStyle.Font, 1.0f)), Brush->ImageSize.Y);
		const float IconWidth = Brush->ImageSize.X;
		return SNew(SBox).HeightOverride(IconHeight).WidthOverride(IconWidth)[SNew(SScaleBox).Stretch(EStretch::ScaleToFit).StretchDirection(EStretchDirection::DownOnly).VAlign(VAlign_Center)[SNew(SImage).Image(Brush)]];
	}
};

class FRichTextInputActionDecorator : public FRichTextDecorator
{
public:
	FRichTextInputActionDecorator(URichTextBlock* InOwner, URichTextBlockInputActionDecorator* InDecorator);

	virtual bool Supports(const FTextRunParseResults& RunParseResult, const FString& Text) const override
	{
		const FString TagName = TEXT("action");
		const FString TagAction = TEXT("name");
		return RunParseResult.Name == TagName && RunParseResult.MetaData.Contains(TagAction);
	}

protected:
	URichTextBlockInputActionDecorator* Decorator;

	virtual TSharedPtr<SWidget> CreateDecoratorWidget(const FTextRunInfo& RunInfo, const FTextBlockStyle& TextStyle) const override
	{
		const FString TagName = TEXT("name");
		constexpr bool bWarnIfMissing = true;
		TArray<FSlateBrush*> Brushes;
		if (Decorator->FindImageInputActions(*RunInfo.MetaData[TagName], Brushes, bWarnIfMissing); Brushes.Num() > 0)
		{
			return SNew(SRichInlineImageSet, Brushes, TextStyle);
		}
		return TSharedPtr<SWidget>();
	}
};

FRichTextInputActionDecorator::FRichTextInputActionDecorator(URichTextBlock* InOwner, URichTextBlockInputActionDecorator* InDecorator): FRichTextDecorator(InOwner)
{
	Decorator = InDecorator;
}

URichTextBlockInputActionDecorator::URichTextBlockInputActionDecorator(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
{
	bUseDefaultImagePrompt = true;
}

TSharedPtr<ITextDecorator> URichTextBlockInputActionDecorator::CreateDecorator(URichTextBlock* InOwner)
{
	return MakeShareable(new FRichTextInputActionDecorator(InOwner, this));
}

void URichTextBlockInputActionDecorator::FindImageInputActions(const FName& InName, TArray<FSlateBrush*>& OutBrushes, bool bWarnIfMissing)
{
	FindSlashBrushInputActions(InName, OutBrushes, bWarnIfMissing);
	if (bUseDefaultImagePrompt && OutBrushes.IsEmpty())
	{
		OutBrushes.Add(&DefaultBrush);
	}
}

void URichTextBlockInputActionDecorator::FindSlashBrushInputActions(const FName& InName, TArray<FSlateBrush*>& OutBrushes, bool bWarnIfMissing) const
{
	OutBrushes.Reset();
	if (InName.IsNone())
		return;
	const UGameInstance* GameInstance = GetWorld()->GetGameInstance();
	if (!GameInstance)
		return;
	const ULocalPlayer* LocalPlayer = GameInstance->GetFirstGamePlayer();
	if (!LocalPlayer)
		return;
	const UEnhancedInputLocalPlayerSubsystem* InputLocalPlayerSubsystem = LocalPlayer->GetSubsystem<UEnhancedInputLocalPlayerSubsystem>();
	if (!InputLocalPlayerSubsystem)
		return;
	const UEnhancedInputUserSettings* UserSettings = InputLocalPlayerSubsystem->GetUserSettings();
	if (!UserSettings)
		return;
	const UEnhancedPlayerMappableKeyProfile* CurrentKeyMap = UserSettings->GetCurrentKeyProfile();
	if (!CurrentKeyMap)
		return;
	const TMap<FName, FKeyMappingRow>& PlayerMappingRows = CurrentKeyMap->GetPlayerMappingRows();
	for (TTuple<FName, FKeyMappingRow> MappingRow : PlayerMappingRows)
	{
		const FKeyMappingRow& KeyMappingRow = MappingRow.Value;
		for (const FPlayerKeyMapping& KeyMapping : KeyMappingRow.Mappings)
		{
			const UInputAction* InputAction = KeyMapping.GetAssociatedInputAction();
			if (!InputAction)
				continue;
			const FName ActionName = InputAction->GetFName();
			if (ActionName == InName)
			{
				FKey Key = KeyMapping.GetCurrentKey();
				const FName KeyName = Key.GetFName();
				if (FRichImageRow* ImageRow = FindImageRow(KeyName, bWarnIfMissing))
					OutBrushes.AddUnique(&ImageRow->Brush);
			}
		}
	}
	if (OutBrushes.Num() > 0)
	{
		// NOTE: There are already configured input mappings for the given action name. Skip checking the registered input mapping contexts.
		return;
	}
	for (const TObjectPtr<const UInputMappingContext> InputMappingContext : UserSettings->GetRegisteredInputMappingContexts())
	{
		const TArray<FEnhancedActionKeyMapping>& Mappings = InputMappingContext->GetMappings();
		for (const FEnhancedActionKeyMapping& Mapping : Mappings)
		{
			const FName ActionName = Mapping.Action.GetFName();
			if (ActionName == InName)
			{
				FKey Key = Mapping.Key;
				const FName KeyName = Key.GetFName();
				if (FRichImageRow* ImageRow = FindImageRow(KeyName, bWarnIfMissing))
					OutBrushes.AddUnique(&ImageRow->Brush);
			}
		}
	}
}

FRichImageRow* URichTextBlockInputActionDecorator::FindImageRow(const FName& InName, bool bWarnIfMissing) const
{
	if (ImageSetArray.IsEmpty())
		return nullptr;
	for (const TObjectPtr<UDataTable>& ImageSet : ImageSetArray)
	{
		if (ImageSet)
		{
			const FString ContextString;
			if (FRichImageRow* Row = ImageSet->FindRow<FRichImageRow>(InName, ContextString, bWarnIfMissing))
				return Row;
		}
	}
	return nullptr;
}

RichTextBlockInputActionDecorator.h

// Copyright by Thanut Panichyotai (@LuviKunG)
// CC BY-SA 4.0
// https://creativecommons.org/licenses/by-sa/4.0/

#pragma once

#include "CoreMinimal.h"
#include "Components/RichTextBlock.h"
#include "Components/RichTextBlockDecorator.h"
#include "Components/RichTextBlockImageDecorator.h"
#include "Framework/Text/ITextDecorator.h"
#include "UObject/Object.h"
#include "RichTextBlockInputActionDecorator.generated.h"

/**
 * Allows you to setup an input action decorator that can be configured.
 */
UCLASS(Abstract, Blueprintable)
class REPLACE_YOUR_API URichTextBlockInputActionDecorator : public URichTextBlockDecorator
{
	GENERATED_BODY()

public:
	URichTextBlockInputActionDecorator(const FObjectInitializer& ObjectInitializer);
	
	virtual TSharedPtr<ITextDecorator> CreateDecorator(URichTextBlock* InOwner) override;

	/**
	 * Find the image input actions.
	 * @param InName Name of the input action. This is the same name of the enhanced input action file name.
	 * @param OutBrushes The brushes to output.
	 * @param bWarnIfMissing Whether to warn if the input action is missing.
	 */
	void FindImageInputActions(const FName& InName, TArray<FSlateBrush*>& OutBrushes, bool bWarnIfMissing);

protected:
	/** Determines whether to use the default image prompt. */
	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Configurations", DisplayName = "Use Default Image Prompt")
	bool bUseDefaultImagePrompt;
	/** The default image prompt slate brush. Must be set if 'bUseDefaultImagePrompt' is true. */
	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Configurations", DisplayName = "Default Image Prompt Slate Brush", meta = (EditCondition = "bUseDefaultImagePrompt"))
	FSlateBrush DefaultBrush;

	/** The image set array. The row structure must be 'RichImageRow'. */
	UPROPERTY(EditAnywhere, Category = "Appearance", meta = (RequiredAssetDataTags = "RowStructure=/Script/UMG.RichImageRow"))
	TArray<TObjectPtr<UDataTable>> ImageSetArray;

	/**
	 * Find the slash brush input actions.
	 * @param InName Name of the input action. This is the same name of the enhanced input action file name.
	 * @param OutBrushes The brushes to output.
	 * @param bWarnIfMissing Whether to warn if the input action is missing.
	 */
	void FindSlashBrushInputActions(const FName& InName, TArray<FSlateBrush*>& OutBrushes, bool bWarnIfMissing) const;

	/**
	 * Find the image row.
	 * This will search the image set array.
	 * @param TagOrId The tag or id of the image row.
	 * @param bWarnIfMissing Whether to warn if the image row is missing.
	 * @return The image row if found, otherwise nullptr.
	 */
	FRichImageRow* FindImageRow(const FName& TagOrId, bool bWarnIfMissing) const;
};