3 * \file PreviewLoader.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 * lyx::graphics::PreviewLoader collects latex snippets together. Then, on a
12 * startLoading() call, these are dumped to file and processed, converting
13 * each snippet to a separate bitmap image file. Once a bitmap file is ready
14 * to be loaded back into LyX, the PreviewLoader emits a signal to inform
15 * the initiating process.
18 #ifndef PREVIEWLOADER_H
19 #define PREVIEWLOADER_H
21 #include <boost/noncopyable.hpp>
22 #include <boost/scoped_ptr.hpp>
23 #include <boost/signal.hpp>
34 class PreviewLoader : boost::noncopyable {
36 /** We need buffer because we require the preamble to the
39 PreviewLoader(Buffer const & buffer);
43 /** Is there an image already associated with this snippet of LaTeX?
44 * If so, returns a pointer to it, else returns 0.
46 PreviewImage const * preview(std::string const & latex_snippet) const;
60 /// How far have we got in loading the image?
61 Status status(std::string const & latex_snippet) const;
63 /// Add a snippet of LaTeX to the queue for processing.
64 void add(std::string const & latex_snippet) const;
66 /// Remove this snippet of LaTeX from the PreviewLoader.
67 void remove(std::string const & latex_snippet) const;
69 /** We have accumulated several latex snippets with status "InQueue".
70 * Initiate their transformation into bitmap images.
72 void startLoading() const;
74 /** Connect and you'll be informed when the bitmap image file
75 * has been created and is ready for loading through
76 * lyx::graphics::PreviewImage::image().
78 typedef boost::signal<void(PreviewImage const &)> sig_type;
79 typedef sig_type::slot_type slot_type;
81 boost::signals::connection connect(slot_type const &) const;
83 /** When PreviewImage has finished loading the image file into memory,
84 * it tells the PreviewLoader to tell the outside world
86 void emitSignal(PreviewImage const &) const;
88 /// Which buffer owns this loader.
89 Buffer const & buffer() const;
92 /// Use the Pimpl idiom to hide the internals.
94 /// The pointer never changes although *pimpl_'s contents may.
95 boost::scoped_ptr<Impl> const pimpl_;
98 } // namespace graphics
101 #endif // PREVIEWLOADER_H