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 * grfx::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
22 #include <boost/utility.hpp>
23 #include <boost/scoped_ptr.hpp>
24 #include <boost/signals/signal1.hpp>
32 class PreviewLoader : boost::noncopyable {
34 /** We need buffer because we require the preamble to the
37 PreviewLoader(Buffer const & buffer);
41 /** Is there an image already associated with this snippet of LaTeX?
42 * If so, returns a pointer to it, else returns 0.
44 PreviewImage const * preview(string const & latex_snippet) const;
58 /// How far have we got in loading the image?
59 Status status(string const & latex_snippet) const;
61 /// Add a snippet of LaTeX to the queue for processing.
62 void add(string const & latex_snippet) const;
64 /// Remove this snippet of LaTeX from the PreviewLoader.
65 void remove(string const & latex_snippet) const;
67 /** We have accumulated several latex snippets with status "InQueue".
68 * Initiate their transformation into bitmap images.
70 void startLoading() const;
72 /** Connect and you'll be informed when the bitmap image file
73 * has been created and is ready for loading through
74 * grfx::PreviewImage::image().
76 typedef boost::signal1<void, PreviewImage const &>::slot_type slot_type;
78 boost::signals::connection connect(slot_type const &) const;
80 /** When PreviewImage has finished loading the image file into memory,
81 * it tells the PreviewLoader to tell the outside world
83 void emitSignal(PreviewImage const &) const;
85 /// Which buffer owns this loader.
86 Buffer const & buffer() const;
89 /// Use the Pimpl idiom to hide the internals.
91 /// The pointer never changes although *pimpl_'s contents may.
92 boost::scoped_ptr<Impl> const pimpl_;
97 #endif // PREVIEWLOADER_H