DrawingBoardWidget.cpp

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// Fill out your copyright notice in the Description page of Project Settings.
 
 
#include "DrawingBoardWidget.h"
 
#include "GameLogging.h"
#include "IImageWrapper.h"
#include "IImageWrapperModule.h"
#include "UImageButton.h"
#include "Components/Button.h"
#include "Components/Image.h"
#include "Components/Overlay.h"
#include "Engine/Canvas.h"
#include "Kismet/KismetRenderingLibrary.h"
#include "PNGCombineManager.h"
 
UDrawingBoardWidget::UDrawingBoardWidget(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
{
    // ConstructorHelpers::FObjectFinder<UTextureRenderTarget2D> rtCanvasRef(TEXT("/Script/Engine.TextureRenderTarget2D'/Game/CustomContents/UI/DrawingBoard/RT_Canvas.RT_Canvas'"));
    // if (rtCanvasRef.Succeeded())
    // {
    //  RT_Canvas = rtCanvasRef.Object;
    // }
}
 
void UDrawingBoardWidget::NativeConstruct()
{
    Super::NativeConstruct();
    
    // Button Event
    Button_Clear->OnButtonClickedEvent.AddDynamic(this, &UDrawingBoardWidget::ClearCanvas);
    Button_Save->OnButtonClickedEvent.AddDynamic(this, &UDrawingBoardWidget::SaveCanvas);
}
 
FReply UDrawingBoardWidget::NativeOnMouseButtonDown(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
    // Check Mouse is in Canvas
    const FGeometry CanvasGeometry = Image_Canvas->GetCachedGeometry();
    if (!CanvasGeometry.IsUnderLocation(InMouseEvent.GetScreenSpacePosition()))
    {
        return FReply::Unhandled();
    }
    
    // Get Mouse Position in Local Image Coordinate System
    // Save Current MousePos to prevMousePos
    prevMousePos = GetLocalMousePos(InMouseEvent.GetScreenSpacePosition());
    bIsDrawing = true;
    
    // Draw Point Once
    // PRINT_STRING(TEXT("%s"), *InMouseEvent.GetEffectingButton().GetFName().ToString());
    if (InMouseEvent.IsMouseButtonDown(EKeys::LeftMouseButton))         // Draw
    {
        DrawPoint(GetLocalMousePos(InMouseEvent.GetScreenSpacePosition()), FLinearColor::Black);
    }
    else if (InMouseEvent.IsMouseButtonDown(EKeys::RightMouseButton))   // Erase
    {
        DrawPoint(GetLocalMousePos(InMouseEvent.GetScreenSpacePosition()), FLinearColor::White);        
    }
    
    return FReply::Handled();
}
 
FReply UDrawingBoardWidget::NativeOnMouseButtonUp(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
    // Get Mouse Position in Local Image Coordinate System
    // Save ZeroVector to prevMousePos
    prevMousePos = GetLocalMousePos(FVector2D::ZeroVector);
    bIsDrawing = false;
    
    return FReply::Handled();
}
 
FReply UDrawingBoardWidget::NativeOnMouseMove(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
    // return When Mouse Not Pressed
    if (!bIsDrawing) return Super::NativeOnMouseMove(InGeometry, InMouseEvent);
    
    if (InMouseEvent.IsMouseButtonDown(EKeys::LeftMouseButton))         // Draw
    {
        DrawLines(GetLocalMousePos(InMouseEvent.GetScreenSpacePosition()), FLinearColor::Black);
    }
    else if (InMouseEvent.IsMouseButtonDown(EKeys::RightMouseButton))   // Erase
    {
        DrawLines(GetLocalMousePos(InMouseEvent.GetScreenSpacePosition()), FLinearColor::White);
    }
    
    return FReply::Handled();
}
 
void UDrawingBoardWidget::DrawPoint(FVector2D mousePos, FLinearColor drawColor)
{
    // Begin Draw Canvas To Render Target
    UCanvas* canvas = nullptr;
    FVector2D size;
    FDrawToRenderTargetContext context;
    UKismetRenderingLibrary::BeginDrawCanvasToRenderTarget(this, RT_Canvas, canvas, size, context);
    
    // Set thickness Whether now in Draw or Erase
    float thickness = (drawColor == FLinearColor::Black) ? 10 : 30;
    // Draw Box
    canvas->K2_DrawBox(mousePos, FVector2D(1, 1), thickness, drawColor);
    
    UKismetRenderingLibrary::EndDrawCanvasToRenderTarget(this, context);
}
 
void UDrawingBoardWidget::DrawLines(FVector2D mousePos, FLinearColor drawColor)
{
    // Begin Draw Canvas To Render Target
    UCanvas* canvas = nullptr;
    FVector2D size;
    FDrawToRenderTargetContext context;
    UKismetRenderingLibrary::BeginDrawCanvasToRenderTarget(this, RT_Canvas, canvas, size, context);
    
    // Calculate Draw Positions
    FVector2D currPos = prevMousePos;
    int32 div = 64;
    FVector2D drawOffset = (mousePos - currPos) / div;
    
    // Draw
    for (int32 i = 1; i < div; ++i)
    {
        currPos = prevMousePos + drawOffset * i;
        
        // Set thickness Whether now in Draw or Erase
        float thickness = (drawColor == FLinearColor::Black) ? 10 : 30;
        // Draw Line
        canvas->K2_DrawLine(prevMousePos, currPos, thickness, drawColor);
    }
    prevMousePos = mousePos;
    
    UKismetRenderingLibrary::EndDrawCanvasToRenderTarget(this, context);
}
 
FVector2D UDrawingBoardWidget::GetLocalMousePos(FVector2D mousePos)
{
    // Get Absolute Local Pos
    const FGeometry& geometry = Image_Canvas->GetCachedGeometry();
    FVector2D localPos = geometry.AbsoluteToLocal(mousePos);
    
    // Get Canvas Size
    const FVector2D canvasSize = geometry.GetLocalSize();
    // Transform localPos(in Image_Canvas Coord) to RT_Canvas Coord && Clamp upto RT_Canvas' Border
    localPos.X = FMath::Clamp((localPos.X / canvasSize.X * RT_Canvas->SizeX), 0.f, RT_Canvas->SizeX);
    localPos.Y = FMath::Clamp((localPos.Y / canvasSize.Y * RT_Canvas->SizeY), 0.f, RT_Canvas->SizeY);
    return localPos;
}
 
void UDrawingBoardWidget::ClearCanvas()
{
    UKismetRenderingLibrary::ClearRenderTarget2D(this, RT_Canvas, RT_Canvas->ClearColor);
}
 
void UDrawingBoardWidget::SaveCanvas()
{
    // File Path
    const FString filePath = FPaths::ProjectSavedDir() / TEXT("WriteImage/");
    IFileManager::Get().MakeDirectory(*filePath, true);
    // File Name
    FString fileName = FDateTime::Now().ToString(TEXT("%Y_%m_%d_%H_%M_%S.png"));
    
    // Export Render Target to png
    UKismetRenderingLibrary::ExportRenderTarget(this, RT_Canvas, filePath, fileName);
    // UE_LOG(LogTemp, Warning, TEXT("%s | %s"), *filePath, *fileName);
    
    SaveRenderTargetToPNG(RT_Canvas, filePath / fileName);
}
 
bool UDrawingBoardWidget::SaveRenderTargetToPNG(UTextureRenderTarget2D* RenderTarget, const FString& FullFilePath)
{
    FTextureRenderTargetResource* RTResource = RenderTarget->GameThread_GetRenderTargetResource();
    if (!RTResource)
    {
        return false;
    }
 
    // Get Width & Height
    const int32 Width  = RenderTarget->SizeX;
    const int32 Height = RenderTarget->SizeY;
 
    // Set Bitmap array
    TArray<FColor> Bitmap;
    Bitmap.AddUninitialized(Width * Height);
 
    // Read BGRA8 pixels in RenderTarget
    RTResource->ReadPixels(Bitmap);
 
    // PNG Encoder
    IImageWrapperModule& ImageWrapperModule =
        FModuleManager::LoadModuleChecked<IImageWrapperModule>("ImageWrapper");
 
    TSharedPtr<IImageWrapper> ImageWrapper =
        ImageWrapperModule.CreateImageWrapper(EImageFormat::PNG);
 
    if (!ImageWrapper.IsValid())
    {
        return false;
    }
 
    ImageWrapper->SetRaw(
        Bitmap.GetData(),
        Bitmap.GetAllocatedSize(),
        Width,
        Height,
        ERGBFormat::BGRA,
        8
    );
 
    // Compress to PNG
    const TArray64<uint8>& PNGData = ImageWrapper->GetCompressed(100);
 
    // Make Directory
    const FString Directory = FPaths::GetPath(FullFilePath);
    IFileManager::Get().MakeDirectory(*Directory, true);
 
    return FFileHelper::SaveArrayToFile(PNGData, *FullFilePath);
}