UnrealEngineUWP/Engine/Source/Runtime/ImageWrapper/Private/Formats/JpegImageWrapper.cpp

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#include "JpegImageWrapper.h"

#include "Math/Color.h"
#include "Misc/ScopeLock.h"

#if WITH_UNREALJPEG

#ifdef __clang__
	#pragma clang diagnostic push
	#pragma clang diagnostic ignored "-Wshadow"

	#if PLATFORM_UNIX || PLATFORM_MAC
		#pragma clang diagnostic ignored "-Wshift-negative-value"	// clang 3.7.0
	#endif
#endif

PRAGMA_DISABLE_SHADOW_VARIABLE_WARNINGS
#include "jpgd.h"
#include "jpgd.cpp"
#include "jpge.h"
#include "jpge.cpp"
PRAGMA_ENABLE_SHADOW_VARIABLE_WARNINGS

#ifdef __clang__
	#pragma clang diagnostic pop
#endif

DEFINE_LOG_CATEGORY_STATIC(JPEGLog, Log, All);


// Only allow one thread to use JPEG decoder at a time (it's not thread safe)
FCriticalSection GJPEGSection; 


/* FJpegImageWrapper structors
 *****************************************************************************/

FJpegImageWrapper::FJpegImageWrapper(int32 InNumComponents)
	: FImageWrapperBase(),
	  NumComponents(InNumComponents)
{ }


/* FImageWrapperBase interface
 *****************************************************************************/

bool FJpegImageWrapper::SetCompressed(const void* InCompressedData, int32 InCompressedSize)
{
	jpgd::jpeg_decoder_mem_stream jpeg_memStream((uint8*)InCompressedData, InCompressedSize);

	jpgd::jpeg_decoder decoder(&jpeg_memStream);
	if (decoder.get_error_code() != jpgd::JPGD_SUCCESS)
		return false;

	bool bResult = FImageWrapperBase::SetCompressed(InCompressedData, InCompressedSize);

	// We don't support 16 bit jpegs
	BitDepth = 8;

	Width = decoder.get_width();
	Height = decoder.get_height();

	switch (decoder.get_num_components())
	{
	case 1:
		Format = ERGBFormat::Gray;
		break;
	case 3:
		Format = ERGBFormat::RGBA;
		break;
	default:
		return false;
	}

	return bResult;
}


bool FJpegImageWrapper::SetRaw(const void* InRawData, int32 InRawSize, const int32 InWidth, const int32 InHeight, const ERGBFormat InFormat, const int32 InBitDepth)
{
	check((InFormat == ERGBFormat::RGBA || InFormat == ERGBFormat::BGRA || InFormat == ERGBFormat::Gray) && InBitDepth == 8);

	bool bResult = FImageWrapperBase::SetRaw(InRawData, InRawSize, InWidth, InHeight, InFormat, InBitDepth);

	return bResult;
}


void FJpegImageWrapper::Compress(int32 Quality)
{
	if (CompressedData.Num() == 0)
	{
		FScopeLock JPEGLock(&GJPEGSection);
		
		if (Quality == 0) {Quality = 85;}
		ensure(Quality >= 1 && Quality <= 100);
		Quality = FMath::Clamp(Quality, 1, 100);

		check(RawData.Num());
		check(Width > 0);
		check(Height > 0);

		// re-order components if required - JPEGs expect RGBA
		if(RawFormat == ERGBFormat::BGRA)
		{
			FColor* Colors = (FColor*)RawData.GetData();
			const int32 NumColors = RawData.Num() / 4;
			for(int32 ColorIndex = 0; ColorIndex < NumColors; ColorIndex++)
			{
				Colors[ColorIndex].B = Colors[ColorIndex].B ^ Colors[ColorIndex].R;
				Colors[ColorIndex].R = Colors[ColorIndex].R ^ Colors[ColorIndex].B;
				Colors[ColorIndex].B = Colors[ColorIndex].B ^ Colors[ColorIndex].R;
			}
		}

		CompressedData.Reset(RawData.Num());
		CompressedData.AddUninitialized(RawData.Num());

		int OutBufferSize = CompressedData.Num();

		jpge::params Parameters;
		Parameters.m_quality = Quality;
		bool bSuccess = jpge::compress_image_to_jpeg_file_in_memory(
			CompressedData.GetData(), OutBufferSize, Width, Height, NumComponents, RawData.GetData(), Parameters);
		
		check(bSuccess);

		CompressedData.RemoveAt(OutBufferSize, CompressedData.Num() - OutBufferSize);
	}
}


void FJpegImageWrapper::Uncompress(const ERGBFormat InFormat, int32 InBitDepth)
{
	// Ensure we haven't already uncompressed the file.
	if (RawData.Num() != 0)
	{
		return;
	}

	// Get the number of channels we need to extract
	int Channels = 0;
	if ((InFormat == ERGBFormat::RGBA || InFormat == ERGBFormat::BGRA) && InBitDepth == 8)
	{
		Channels = 4;
	}
	else if (InFormat == ERGBFormat::Gray && InBitDepth == 8)
	{
		Channels = 1;
	}
	else
	{
		check(false);
	}

	FScopeLock JPEGLock(&GJPEGSection);

	check(CompressedData.Num());

	int32 NumColors;
	uint8* OutData = jpgd::decompress_jpeg_image_from_memory(
		CompressedData.GetData(), CompressedData.Num(), &Width, &Height, &NumColors, Channels, (int)InFormat);


	RawData.Reset(Width * Height * Channels);
	RawData.AddUninitialized(Width * Height * Channels);
	if (OutData)
	{
		FMemory::Memcpy(RawData.GetData(), OutData, RawData.Num());
		FMemory::Free(OutData);
	}
}


#endif //WITH_JPEG