scummvm/graphics/thumbnail.h
Adrian Frühwirth 00e59a3122 ALL: Load savegame thumbnail only when necessary
This commit introduces the following changes:

1. Graphics::loadThumbnail()

   Now returns a boolean and takes a new argument skipThumbnail which
   defaults to false. In case of true, loadThumbnail() reads past the
   thumbnail data in the input stream instead of actually loading the
   thumbnail. This simplifies savegame handling where, up until now,
   many engines always read the whole savegame metadata (including
   the thumbnail) and then threw away the thumbnail when not needed
   (which is in almost all cases, the most common exception being
   MetaEngine::querySaveMetaInfos() which is responsible for loading
   savegame metadata for displaying it in the GUI launcher.

2. readSavegameHeader()

   Engines which already implement such a method (name varies) now take
   a new argument skipThumbnail (default: true) which is passed
   through to loadThumbnail(). This means that the default case for
   readSavegameHeader() is now _not_ loading the thumbnail from a
   savegame and just reading past it. In those cases, e.g.
   querySaveMetaInfos(), where we actually are interested in loading
   the thumbnail readSavegameHeader() needs to explicitely be called
   with skipThumbnail == false.

   Engines whose readSavegameHeader() (name varies) already takes an
   argument loadThumbnail have been adapted to have a similar
   prototype and semantics.
   I.e. readSaveHeader(in, loadThumbnail, header) now is
   readSaveHeader(in, header, skipThumbnail).

3. Error handling

   Engines which previously did not check the return value of
   readSavegameHeader() (name varies) now do so ensuring that possibly
   broken savegames (be it a broken thumbnail or something else) don't
   make it into the GUI launcher list in the first place.
2018-04-07 09:26:20 +02:00

89 lines
2.4 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef GRAPHICS_THUMBNAIL_H
#define GRAPHICS_THUMBNAIL_H
#include "common/scummsys.h"
namespace Common{
class SeekableReadStream;
class WriteStream;
}
namespace Graphics {
struct Surface;
/**
* Checks for presence of the thumbnail save header.
* Seeks automatically back to start position after check.
*
* @param in stream to check for header
*/
bool checkThumbnailHeader(Common::SeekableReadStream &in);
/**
* Skips a thumbnail, if present.
*
* @param in stream to process
*/
bool skipThumbnail(Common::SeekableReadStream &in);
/**
* Loads a thumbnail from the given input stream.
*/
bool loadThumbnail(Common::SeekableReadStream &in, Graphics::Surface *&thumbnail, bool skipThumbnail = false);
/**
* Saves a thumbnail to the given write stream.
* Automatically creates a thumbnail from screen contents.
*/
bool saveThumbnail(Common::WriteStream &out);
/**
* Saves a (given) thumbnail to the given write stream.
*/
bool saveThumbnail(Common::WriteStream &out, const Graphics::Surface &thumb);
/**
* Grabs framebuffer into surface
*
* @param surf a surface
* @return false if a error occurred
*/
bool createScreenShot(Graphics::Surface &surf);
/**
* Scales a passed surface, creating a new surface with the result
* @param srcImage Source image to scale
* @param xSize New surface width
* @param ySize New surface height
* @remarks Caller is responsible for freeing the returned surface
*/
Graphics::Surface *scale(const Graphics::Surface &srcImage, int xSize, int ySize);
} // End of namespace Graphics
#endif