scummvm/image/image_decoder.h

123 lines
3.4 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef IMAGE_IMAGEDECODER_H
#define IMAGE_IMAGEDECODER_H
#include "common/scummsys.h"
#include "common/str.h"
namespace Common {
class SeekableReadStream;
}
namespace Graphics {
struct Surface;
}
namespace Image {
/**
* @defgroup image_decoder Image decoder
* @ingroup image
*
* @brief ImageDecoder class used for representing and managing various image decoders.
* @{
*/
/**
* A representation of an image decoder that maintains ownership of the surface
* and palette it decodes to.
*
* This is designed for still frames only.
*/
class ImageDecoder {
public:
virtual ~ImageDecoder() {}
/**
* Load an image from the specified stream.
*
* loadStream() should implicitly call destroy() to free the memory
* of the last loadStream() call.
*
* @param stream Input stream.
*
* @return Whether loading the file succeeded.
*
* @see getSurface
* @see getPalette
*/
virtual bool loadStream(Common::SeekableReadStream &stream) = 0;
/**
* Destroy this decoder's surface and palette.
*
* This should be called by a loadStream() implementation as well
* as by the destructor.
*/
virtual void destroy() = 0;
/**
* Get the decoded surface.
*
* This surface is owned by this ImageDecoder and remains valid
* until destroy() or loadStream() is called, or until the destructor of
* this ImageDecoder is called.
*
* @return The decoded surface, or 0 if no surface is present.
*/
virtual const Graphics::Surface *getSurface() const = 0;
/**
* Get the decoded palette.
*
* This palette is owned by this ImageDecoder and remains valid
* until destroy() or loadStream() is called, or until the destructor of
* this ImageDecoder is called.
*
* The format of the palette is the same as that of the PaletteManager's palette.
* (interleaved RGB values).
*
* @return The decoded palette, or undefined if no palette is present.
*/
virtual const byte *getPalette() const { return 0; }
/**
* Query whether the decoded image has a palette.
*/
virtual bool hasPalette() const { return getPaletteColorCount() != 0; }
/** Return the starting index of the palette. */
virtual byte getPaletteStartIndex() const { return 0; }
/** Return the number of colors in the palette. */
virtual uint16 getPaletteColorCount() const { return 0; }
/** Query whether the decoded image has a transparent color. */
virtual bool hasTransparentColor() const { return false; }
/** Return the transparent color. */
virtual uint32 getTransparentColor() const { return 0; }
};
/** @} */
} // End of namespace Image
#endif