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// -*- C++ -*-
//
// Class: documentPageCache
//
// Cache that holds a number of pages in a document.
// Part of KDVI- A previewer for TeX DVI files.
//
// (C) 2004 Stefan Kebekus. Distributed under the GPL.
#ifndef _documentpagecache_h_
#define _documentpagecache_h_
#include "renderedDocumentPagePixmap.h"
#include "pageNumber.h"
#include "pageSize.h"
#include "selection.h"
#include <tqcache.h>
#include <tqguardedptr.h>
#include <tqobject.h>
class DocumentRenderer;
class TQPixmap;
class RenderedDocumentPage;
class DocumentPageCache: public TQObject
{
Q_OBJECT
TQ_OBJECT
public:
DocumentPageCache();
virtual ~DocumentPageCache();
/** This method is used to name the DocumentRenderer, that the
documentPageCache uses to render the page. The renderer can be
used any time (e.g., triggered by an internal timer event), and
must not be deleted before either the DocumentRenderer is
deleted, or another renderer has been set. */
void setRenderer(DocumentRenderer *_renderer);
void setResolution(double res);
double getResolution() const {return resolutionInDPI;}
const TextSelection& selectedText() const { return userSelection; }
void deselectText();
void selectText(const TextSelection& selection);
/** Returns the size of page 'page'. If the document does not
specify a size (which happens, e.g., for some DVI-files), then
the userPreferredSize is returned. */
SimplePageSize sizeOfPage(const PageNumber& page = 1) const;
/** Returns the size of page 'page', in pixels, using the resolution
set with setResolution(). If the document does not specify a
size (which happens, e.g., for some DVI-files), the
userPreferredSize is used. */
TQSize sizeOfPageInPixel(const PageNumber& page) const;
/** Returns a pointer to a documentPage structure, or 0, if the
documentPage could not be generated for some reason (e.g.,
because no renderer has been set). */
RenderedDocumentPagePixmap* getPage(const PageNumber& pageNr);
/** Checks if the given page is already in the cache. */
bool isPageCached(const PageNumber& pageNumber, const TQSize& size);
/** Checks if the given page is already in the cache. Here we don't care about the size
of the page. */
bool isPageCached(const PageNumber& pageNumber);
/** Returns a "width" pixels width thumbnail of the given page. This
method returns an empty TQPixmap if one of the arguments is
invalid, or if the page cannot be rendered for any reason. */
TQPixmap createThumbnail(const PageNumber& pageNr, int width);
signals:
/** This signal is emitted when setUserPreferredSize() or
setUseUserPreferredSize() is called, and the page size
changes accordingly. */
void paperSizeChanged();
/** This signal is emitted when the text selection of the current
document changes. The argument is false if no text is selected, true
otherwise. */
void textSelected(bool);
public slots:
/** Clears the contents of the cache. */
void clear();
/** Sets the userPreferredSize, which is explained below */
void setUserPreferredSize(const SimplePageSize& t);
void setUseDocumentSpecifiedSize(bool);
protected:
/** This function creates new RenderedDocumentPagePixmap objects.
If a multipage implementation needs additional functionality overwrite
this function to create objects of a suitable subclass of RenderedDocumentPagePixmap.
*/
virtual RenderedDocumentPagePixmap* createDocumentPagePixmap() const;
/** Creates the hashing key for the cache. */
TQString createKey(const PageNumber& pageNumber, const TQSize& size);
/** Creates the hashing function. The size of the page is calculated
based on the current resolution. */
TQString createKey(const PageNumber& pageNumber);
TQGuardedPtr<DocumentRenderer> renderer;
private:
/** The maximum of memory used by the cache. (32MB)
TODO: make this configurable, or detact an appropriate value at startup. */
TQ_UINT32 maxMemory;
/** This field contains resolution of the display device. In
principle. In fact, kviewshell implements zooming by calling the
setResolution()-method with values that are not exactly the
resolution of the display, but multiplied with the zoom
factor. Bottom line: the documentRenderer should act as if this
field indeed contains resolution of the display device. Whene a
documentRenderer is constructed, this field is set to the actual
resolution to give a reasonable default value. */
double resolutionInDPI;
SimplePageSize userPreferredSize;
bool useDocumentSpecifiedSize;
TextSelection userSelection;
/** This list holds the cache. */
TQCache<RenderedDocumentPagePixmap> LRUCache;
/** This is a dummy documentPage structure which is used internally
by the 'createThumbnail' method. */
RenderedDocumentPagePixmap thumbnailPage;
};
#endif
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