3 * \file GraphicsLoader.h
4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
7 * \author Angus Leeming
9 * Full author contact details are available in file CREDITS.
11 * The public face of the graphics cache.
13 * * The user supplies an image file and the display parameters.
14 * * He can change the file or the display parameters through a reset() method.
15 * * He must start the loading process explicitly with startLoading().
16 * * If he is connected through the connect() method, then he'll be informed
17 * when the loading status changes.
18 * * When (status() == Ready), he can use image() to access the loaded image
19 * and pass it to the Painter.
21 * What could be simpler?
24 #ifndef GRAPHICSLOADER_H
25 #define GRAPHICSLOADER_H
27 #include "GraphicsTypes.h"
29 #include <boost/scoped_ptr.hpp>
30 #include <boost/signal.hpp>
40 /// Must use the reset methods to make this instance usable.
42 /// The image is not transformed, just displayed as-is.
43 Loader(std::string const & file_with_path, DisplayType = ColorDisplay);
44 /// The image is transformed before display.
45 Loader(std::string const & file_with_path, Params const &);
47 Loader(Loader const &);
49 /// Define an empty d-tor out-of-line to keep boost::scoped_ptr happy.
52 Loader & operator=(Loader const &);
54 /// The file can be changed, or the display params, or both.
55 void reset(std::string const & file_with_path,
56 DisplayType = ColorDisplay) const;
58 void reset(std::string const & file_with_path, Params const &) const;
60 void reset(Params const &) const;
62 /// Returns the absolute path of the loaded (loading?) file.
63 std::string const & filename() const;
65 bool empty() const { return filename().empty(); }
67 /** starting loading of the image is done by a urgency-based
68 * decision. Here we only call LoaderQueue::touch to request it.
70 void startLoading() const;
72 /** Monitor any changes to the file.
73 * There is no point monitoring the file before startLoading() is
76 void startMonitoring() const;
78 bool monitoring() const;
79 /** Returns the check sum of filename() so that, for example, you can
80 * ascertain whether to output a new PostScript version of the file
83 unsigned long checksum() const;
85 /// How far have we got in loading the image?
86 ImageStatus status() const;
88 /** Connect and you'll be informed when the loading status of the image
91 typedef boost::signal<void()> sig_type;
92 typedef sig_type::slot_type slot_type;
94 boost::signals::connection connect(slot_type const &) const;
96 /** The loaded image with Pixmap set.
97 * If the Pixmap is not yet set (see status() for why...), returns 0.
99 Image const * image() const;
102 /// Use the Pimpl idiom to hide the internals.
104 /// The pointer never changes although *pimpl_'s contents may.
105 boost::scoped_ptr<Impl> const pimpl_;
108 } // namespace graphics
111 #endif // GRAPHICSLOADER_H