qzdoom-gpl/src/m_png.h

/*
** m_png.h
**
**---------------------------------------------------------------------------
** Copyright 2002-2005 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/

#include "v_video.h"

// PNG Writing --------------------------------------------------------------

// Start writing an 8-bit palettized PNG file.
// The passed file should be a newly created file.
// This function writes the PNG signature and the IHDR, gAMA, PLTE, and IDAT
// chunks.
bool M_CreatePNG (FILE *file, const DCanvas *canvas, const PalEntry *pal);

// Creates a grayscale 1x1 PNG file. Used for savegames without savepics.
bool M_CreateDummyPNG (FILE *file);

// Appends any chunk to a PNG file started with M_CreatePNG.
bool M_AppendPNGChunk (FILE *file, DWORD chunkID, const BYTE *chunkData, DWORD len);

// Adds a tEXt chunk to a PNG file started with M_CreatePNG.
bool M_AppendPNGText (FILE *file, const char *keyword, const char *text);

// Appends the IEND chunk to a PNG file.
bool M_FinishPNG (FILE *file);

// PNG Reading --------------------------------------------------------------

class FileReader;
struct PNGHandle
{
	struct Chunk
	{
		DWORD		ID;
		DWORD		Offset;
		DWORD		Size;
	};

	FileReader		*File;
	bool			bDeleteFilePtr;
	TArray<Chunk>	Chunks;
	TArray<char *>	TextChunks;
	unsigned int	ChunkPt;

	PNGHandle(FILE *file);
	PNGHandle(FileReader *file);
	~PNGHandle();
};

// Verify that a file really is a PNG file. This includes not only checking
// the signature, but also checking for the IEND chunk. CRC checking of
// each chunk is not done. If it is valid, you get a PNGHandle to pass to
// the following functions.
PNGHandle *M_VerifyPNG (FileReader *file);
PNGHandle *M_VerifyPNG (FILE *file);

// Finds a chunk in a PNG file. The file pointer will be positioned at the
// beginning of the chunk data, and its length will be returned. A return
// value of 0 indicates the chunk was either not present or had 0 length.
unsigned int M_FindPNGChunk (PNGHandle *png, DWORD chunkID);

// Finds a chunk in the PNG file, starting its search at whatever chunk
// the file pointer is currently positioned at.
unsigned int M_NextPNGChunk (PNGHandle *png, DWORD chunkID);

// Finds a PNG text chunk with the given signature and returns a pointer
// to a NULL-terminated string if present. Returns NULL on failure.
// (Note: tEXt, not zTXt.)
char *M_GetPNGText (PNGHandle *png, const char *keyword);
bool M_GetPNGText (PNGHandle *png, const char *keyword, char *buffer, size_t buffsize);

// Creates a simple canvas containing the contents of the PNG file's IDAT
// chunk(s). Only 8-bit images are supported.
DCanvas *M_CreateCanvasFromPNG (PNGHandle *png);

// The file must be positioned at the start of the first IDAT. It reads
// image data into the provided buffer. Returns true on success.
bool M_ReadIDAT (FileReader *file, BYTE *buffer, int width, int height, int pitch,
				 BYTE bitdepth, BYTE colortype, BYTE interlace, unsigned int idatlen);