lyx_mirror/src/graphics/GraphicsLoader.h
2020-12-19 22:52:51 +02:00

117 lines
3.1 KiB
C++

// -*- C++ -*-
/**
* \file GraphicsLoader.h
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author Angus Leeming
*
* Full author contact details are available in file CREDITS.
*
* The public face of the graphics cache.
*
* * The user supplies an image file and the display parameters.
* * He can change the file or the display parameters through a reset() method.
* * He must start the loading process explicitly with startLoading().
* * If he is connected through the connect() method, then he'll be informed
* when the loading status changes.
* * When (status() == Ready), he can use image() to access the loaded image
* and pass it to the Painter.
*
* What could be simpler?
*/
#ifndef GRAPHICSLOADER_H
#define GRAPHICSLOADER_H
#include "GraphicsTypes.h"
#include "support/signals.h"
namespace lyx {
namespace support { class FileName; }
namespace graphics {
class Image;
class Params;
class Loader {
public:
/// Must use the reset methods to make this instance usable.
Loader(support::FileName const & doc_file);
/// The image is not transformed, just displayed as-is.
Loader(support::FileName const & doc_file, support::FileName const & file_with_path, bool display = true);
/// The image is transformed before display.
Loader(support::FileName const & doc_file, support::FileName const & file_with_path, Params const &);
///
Loader(support::FileName const & doc_file, Loader const &);
///
Loader(Loader const & other);
/// Needed for the pimpl
~Loader();
Loader & operator=(Loader const &);
/// The file can be changed, or the display params, or both.
void reset(support::FileName const & file_with_path, bool display = true) const;
///
void reset(support::FileName const & file_with_path, Params const &) const;
///
void reset(Params const &) const;
/// Returns the absolute path of the loaded (loading?) file.
support::FileName const & filename() const;
///
/** starting loading of the image is done by a urgency-based
* decision. Here we only call LoaderQueue::touch to request it.
*/
void startLoading() const;
/** Tries to reload the image.
*/
void reload() const;
/** Monitor any changes to the file.
* There is no point monitoring the file before startLoading() is
* invoked.
*/
void startMonitoring() const;
///
bool monitoring() const;
///
void checkModifiedAsync() const;
/// How far have we got in loading the image?
ImageStatus status() const;
/** Connect and you'll be informed when the loading status of the image
* changes.
*/
typedef signal<void()> sig;
typedef sig::slot_type slot;
///
connection connect(slot const &) const;
/** The loaded image with Pixmap set.
* If the Pixmap is not yet set (see status() for why...), returns 0.
*/
Image const * image() const;
double displayPixelRatio() const;
void setDisplayPixelRatio(double scale);
private:
/// Use the Pimpl idiom to hide the internals.
class Impl;
/// The pointer never changes although *pimpl_'s contents may.
Impl * pimpl_;
};
} // namespace graphics
} // namespace lyx
#endif // GRAPHICSLOADER_H