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UnrealEngine/Engine/Source/Runtime/ImageWrapper/Private/Formats/PngImageWrapper.h
2025-05-18 13:04:45 +08:00

133 lines
3.9 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "CoreTypes.h"
#include "ImageWrapperBase.h"
#if WITH_UNREALPNG
THIRD_PARTY_INCLUDES_START
#include "zlib.h"
// make sure no other versions of libpng headers are picked up
#if WITH_LIBPNG_1_6
#include "ThirdParty/libPNG/libPNG-1.6.44/png.h"
#include "ThirdParty/libPNG/libPNG-1.6.44/pngstruct.h"
#include "ThirdParty/libPNG/libPNG-1.6.44/pnginfo.h"
#else
#include "ThirdParty/libPNG/libPNG-1.5.2/png.h"
#include "ThirdParty/libPNG/libPNG-1.5.2/pnginfo.h"
#endif
#include <setjmp.h>
THIRD_PARTY_INCLUDES_END
/**
* PNG implementation of the helper class.
*
* The implementation of this class is almost entirely based on the sample from the libPNG documentation.
* See http://www.libpng.org/pub/png/libpng-1.2.5-manual.html for details.
*
* InitCompressed and InitRaw will set initial state and you will then be able to fill in Raw or
* CompressedData by calling Uncompress or Compress respectively.
*/
class FPngImageWrapper
: public FImageWrapperBase
{
public:
/** Default Constructor. */
FPngImageWrapper();
public:
//~ FImageWrapper interface
virtual void Compress(int32 Quality) override;
virtual void Reset() override;
virtual bool SetCompressed(const void* InCompressedData, int64 InCompressedSize) override;
virtual void Uncompress(const ERGBFormat InFormat, int32 InBitDepth) override;
virtual bool CanSetRawFormat(const ERGBFormat InFormat, const int32 InBitDepth) const override;
virtual ERawImageFormat::Type GetSupportedRawFormat(const ERawImageFormat::Type InFormat) const override;
/**
* Does this image type support embedded metadata in its header?
*
* PNG is an example of an image type which supports adding user-defined metadata to its header.
*/
virtual bool SupportsMetadata() const override;
/**
* Adds a key and value to this image's metadata. Will be saved in the image's header and restored when the image is loaded.
*
* @param InKey Metadata consists of key value pairs.
* @param InValue Metadata consists of key value pairs.
*/
virtual void AddMetadata(const FString& InKey, const FString& InValue) override;
/**
* Queries a key from this image's metadata. If it exists, returns its corresponding value.
*
* @param InKey The key to locate.
* @param outValue If the key exists, this is its value.
*
* Returns true if the key exists.
*/
virtual bool TryGetMetadata(const FString& InKey, FString& OutValue) const override;
public:
/**
* Query whether this is a valid PNG type.
*
* @return true if data a PNG
*/
bool IsPNG() const;
/**
* Load the header information, returns true if successful.
*
* @return true if successful
*/
bool LoadPNGHeader();
/** Helper function used to uncompress PNG data from a buffer */
void UncompressPNGData(const ERGBFormat InFormat, const int32 InBitDepth);
protected:
// Callbacks for the pnglibs
static void user_read_compressed(png_structp png_ptr, png_bytep data, png_size_t length);
static void user_write_compressed(png_structp png_ptr, png_bytep data, png_size_t length);
static void user_flush_data(png_structp png_ptr);
static void user_error_fn(png_structp png_ptr, png_const_charp error_msg);
static void user_warning_fn(png_structp png_ptr, png_const_charp warning_msg);
static void* user_malloc(png_structp png_ptr, png_size_t size);
static void user_free(png_structp png_ptr, png_voidp struct_ptr);
private:
/** The read offset into our array. */
int64 ReadOffset;
/** The color type as defined in the header. */
int32 ColorType;
/** The number of channels. */
uint8 Channels;
#if PLATFORM_ANDROID
//Other platforms rely on libPNG internal mechanism to achieve concurrent compression\decompression on multiple threads
/** setjmp buffer for error recovery. */
jmp_buf SetjmpBuffer;
#endif
/** Metadata for/from our header. */
TMap<FString, FString> TextBlocks;
};
#endif //WITH_UNREALPNG