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/*
* Copyright (C) 2006 - 2010 René Rebe
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2. A copy of the GNU General
* Public License can be found in the file LICENSE.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANT-
* ABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
* Public License for more details.
*
* Alternatively, commercial licensing options are available from the
* copyright holder ExactCODE GmbH Germany.
*/
/* The Image decoder and coder collection.
*
* The class itself has static methods to perform the de- and
* encoding. These methods search thru a loader list to match the
* file magick (on decoding) or the specified codec / file extension
* on encoding.
*
* The codec might attach a freestanding instance of itself onto the
* image on decode to allow on-the-fly decoding and reuse of coded
* data while re-encoding an image where nothing or just meta data was
* touched while the pixel data remains unmodified.
*
* Also some specialized methods are available to optimize some
* operations that sometimes can work on encoded data.
*/
#ifndef IMAGELOADER_HH
#define IMAGELOADER_HH
#include <stdio.h>
#include <list>
#include <algorithm>
#include <iosfwd>
#include "Image.hh"
// just forward
class Image;
class ImageCodec
{
public:
ImageCodec ();
ImageCodec (Image* __image);
virtual ~ImageCodec ();
virtual std::string getID () = 0;
// helpers for parsing the codec spec and filename extension
static std::string getCodec (std::string& filename);
static std::string getExtension (const std::string& filename);
// NEW API, allowing the use of any STL i/o stream derived source. The index i
// is the page, image, index number within the file (TIFF, GIF, ICO, etc.)
static int Read (std::istream* stream, Image& image,
std::string codec = "", const std::string& decompress = "", int index = 0);
static bool Write (std::ostream* stream, Image& image,
std::string codec, std::string ext = "",
int quality = 75, const std::string& compress = "");
static ImageCodec* MultiWrite (std::ostream* stream,
std::string codec, std::string ext = "");
// OLD API, only left for compatibility.
// Not const string& because the filename is parsed and the copy is changed intern.
//
// Removed soon!
static int Read (std::string file, Image& image, const std::string& decompress = "", int index = 0);
static bool Write (std::string file, Image& image,
int quality = 75, const std::string& compress = "");
// Per codec methods, only one set needs to be implemented, the one with
// index invoke the one without by default (compatibility, ease of implemntation
// fallback), the ones without return error (as in "not implemented").
virtual int readImage (std::istream* stream, Image& image,
const std::string& decompress);
virtual int readImage (std::istream* stream, Image& image,
const std::string& decompress, int index);
virtual bool writeImage (std::ostream* stream, Image& image,
int quality, const std::string& compress) = 0;
virtual ImageCodec* instanciateForWrite (std::ostream* stream);
// slightly named differently to match the public factory name
virtual bool Write (Image& image,
int quality = 75, const std::string& compress = "", int index = 0);
// not pure-virtual so not every codec needs a NOP
virtual /*bool*/ void decodeNow (Image* image);
// optional optimizing and/or lossless implementations (JPEG, et al.)
virtual bool flipX (Image& image);
virtual bool flipY (Image& image);
virtual bool rotate (Image& image, double angle);
virtual bool crop (Image& image, unsigned int x, unsigned int y, unsigned int w, unsigned int h);
virtual bool toGray (Image& image);
virtual bool scale (Image& image, double xscale, double yscale);
protected:
struct loader_ref {
const char* ext;
ImageCodec* loader;
bool primary_entry;
bool via_codec_only;
};
static std::list<loader_ref>* loader;
static void registerCodec (const char* _ext,
ImageCodec* _loader,
bool _via_codec_only = false,
bool push_back = false);
static void unregisterCodec (ImageCodec* _loader);
// freestanding instance, attached to an image
const Image* _image;
};
#endif
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