3 * \file GraphicsCacheItem.h
4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
8 * \author Angus Leeming
10 * Full author contact details are available in file CREDITS
12 * The graphics cache is a container of grfx::CacheItems.
13 * Each grfx::CacheItem, defined here represents a separate image file.
15 * The routines here can be used to load the graphics file into memory at
16 * which point (status() == grfx::Loaded).
17 * The user is then free to access image() in order to copy it and to then
18 * transform the copy (rotate, scale, clip) and to generate the pixmap.
20 * The graphics cache supports fully asynchronous:
21 * file conversion to a loadable format;
24 * Whether you get that, of course, depends on grfx::Converter and on the
25 * grfx::Image-derived image class.
28 #ifndef GRAPHICSCACHEITEM_H
29 #define GRAPHICSCACHEITEM_H
35 #include "GraphicsTypes.h"
38 #include <boost/utility.hpp>
39 #include <boost/scoped_ptr.hpp>
40 #include <boost/signals/signal0.hpp>
49 /// A grfx::Cache item holder.
50 class CacheItem : boost::noncopyable {
53 CacheItem(string const & file);
55 /// Define an empty d-tor out-of-line to keep boost::scoped_ptr happy.
59 string const & filename() const;
61 /// It's in the cache. Now start the loading process.
62 void startLoading() const;
64 /** Monitor any changes to the file.
65 * There is no point monitoring the file before startLoading() is
68 void startMonitoring() const;
70 bool monitoring() const;
71 /** Returns the check sum of filename() so that, for example, you can
72 * ascertain whether to output a new PostScript version of the file
75 unsigned long checksum() const;
77 /** Get the image associated with filename().
78 * If the image is not yet loaded, returns 0.
79 * This routine returns a pointer to const; if you want to modify it,
80 * create a copy and modify that.
82 Image const * image() const;
84 /// How far have we got in loading the image?
85 ImageStatus status() const;
87 /** Connect and you'll be informed when the loading status of the image
90 typedef boost::signal0<void>::slot_type slot_type;
92 boost::signals::connection connect(slot_type const &) const;
95 /// Use the Pimpl idiom to hide the internals.
98 /// The pointer never changes although *pimpl_'s contents may.
99 boost::scoped_ptr<Impl> const pimpl_;
104 #endif // GRAPHICSCACHEITEM_H