3 * \file PreviewLoader.h
4 * Read the file COPYING
6 * \author Angus Leeming
8 * Full author contact details available in file CREDITS
10 * grfx::PreviewLoader collects latex snippets together. Then, on a
11 * startLoading() call, these are dumped to file and processed, converting
12 * each snippet to a separate bitmap image file. Once a bitmap file is ready
13 * to be loaded back into LyX, the PreviewLoader emits a signal to inform
14 * the initiating process.
17 #ifndef PREVIEWLOADER_H
18 #define PREVIEWLOADER_H
25 #include <boost/utility.hpp>
26 #include <boost/scoped_ptr.hpp>
27 #include <boost/signals/signal1.hpp>
35 class PreviewLoader : boost::noncopyable {
37 /** We need buffer because we require the preamble to the
40 PreviewLoader(Buffer const & buffer);
44 /** Is there an image already associated with this snippet of LaTeX?
45 * If so, returns a pointer to it, else returns 0.
47 PreviewImage const * preview(string const & latex_snippet) const;
61 /// How far have we got in loading the image?
62 Status status(string const & latex_snippet) const;
64 /// Add a snippet of LaTeX to the queue for processing.
65 void add(string const & latex_snippet) const;
67 /// Remove this snippet of LaTeX from the PreviewLoader.
68 void remove(string const & latex_snippet) const;
70 /** We have accumulated several latex snippets with status "InQueue".
71 * Initiate their transformation into bitmap images.
73 void startLoading() const;
75 /** Connect and you'll be informed when the bitmap image file
76 * has been created and is ready for loading through
77 * grfx::PreviewImage::image().
79 typedef boost::signal1<void, PreviewImage const &>::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_;
100 #endif // PREVIEWLOADER_H