// -*- C++ -*- // // Class: documentRenderer // // Abstract class for rendering document types. Needs to be // subclassed by the actual parts using kviewshell. Part of // KViewshell - A generic interface for document viewers. // // (C) 2004-2005 Wilfried Huss, Stefan Kebekus. Distributed under the GPL. // #ifndef DOCUMENTRENDERER_H #define DOCUMENTRENDERER_H #include "bookmark.h" #include "pageNumber.h" #include "pageSize.h" #include #include #include #include #include class Anchor; class KURL; class RenderedDocumentPage; /** \brief loads and renders documents This abstract class is one of the two core classes that must be implemented by all authors who write plugins for the kviewshell programm. It is responsible for document loading and rendering. As a minimum, the setFile() and drawPage() must be reimplemented. This documentation mentiones only the methods and members that are important for authors of plugins. For full documentation, consult the header file documentRenderer.h. @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. @author Wilfried Huss, Stefan Kebekus */ class DocumentRenderer : public TQObject { Q_OBJECT TQ_OBJECT public: /** \brief default constructor */ DocumentRenderer(TQWidget* tqparent); virtual ~DocumentRenderer(); /** \brief loading of files This is a purely virtual method that must be re-implemented. It is called when a file should be loaded. The implementation must then do the following - initialize internal data structures so the document pointed to by 'fname' can be rendered quickly. It is not necessary actually load the file; if the implementation choses to load only parts of a large file and leave the rest on the disc, this is perfectly fine. - return 'true' on success and 'false' on failure. Before 'false' is returned, the method clear() should be called When the method returns 'true', it is expected that - the member _isModified is set to 'false' - the member 'numPages' is either set to 0 if the document is empty, or else to the number of page in the document - the vector pageSizes *must* either be empty (e.g. if your file format does not specify a page size), or must be of size totalPages(), and contain the sizes of all pages in the document. - the anchorList is filled with data; it is perfectly fine to leave the anchorList empty, if your file format does not support anchors, or if your document doesn't contain any. - the list 'bookmarks' is filled with data; it is perfectly fine to leave this list empty, if your file format does not support bookmarks or if your document doesn't contain any. - the method drawPage() works @note It is perfectly possible that setFile() is called several times in a row, with the same or with different filenames. @warning The signal documentIsChanged() must not be emitted while the method runs. @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. @param fname name of the file to open. It is not guaranteed that the file exists, that it is a file, or that it is readable. @param base original URL of the file that was opened. If the program that uses this documentRenderer was asked to open http://www.kde.org/test.dvi.bz2, then the program would download the file to a temporary file and decompress it, generating e.g. /tmp/tmp.dvi. In that case, base would be http://www.kde.org/test.dvi.bz2, and fname=/tmp/tmp.dvi. The base can be used by the documentRenderer to handle relative URLs that might be contained in a file. Otherwise, it can safely be ignored. @returns 'true' on success and 'false' on failure. Even after this method returns 'false' the class must act reasonably, i.e. by clear()ing the document */ virtual bool setFile(const TQString &fname, const KURL &base) = 0; /** \brief clearing the document renderer This method clears the renderer, so that it represents an empty document. The standard implementation doe the following: - sets 'numPages' to zero - clears the pageSizes and the anchorList - sets _isModified to 'false' Most authors of kviewshell-plugins will probably want to re-implement this to clear internal data structures of their implementations. @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. */ virtual void clear(); /* Returns true if the current document tqcontains 0 pages. */ bool isEmpty() const {return numPages == 0;} /* Tells if the document was modified after is was loaded. */ bool isModified() const {return _isModified; } /* Returns the number of pages in the document. This method can well return 0, e.g. if no document has been loaded yet, or if the current document is empty. */ PageNumber totalPages() const {return numPages; } TQPtrList getBookmarks() const { return bookmarks; } /* Returns the size of page 'page'. If the document is empty, if the page specified is not a page of the document or if the document does not specify a size (which happens, e.g., for some DVI-files), then an invalid page size is returned. */ SimplePageSize sizeOfPage(const PageNumber& page); /* Returns true if the document specifies page sizes, and false otherwise. NOTE: the information returned by this method is not always 100% reliable. Although unlikely, it is theoretically possible that this method returns 'true', but still some of the sizes returned by sizeOfPage() are invalid. */ bool hasSpecifiedPageSizes() const {return !pageSizes.isEmpty();} /** rendering of documents This purely virtual method is the most important method in the DocumentRenderer class. It must be re-implemented by authors who want to write plugins for the kviewshell program. The purpose of this method is to render a graphical representation into a documentPage structure. More specifically, the implementation needs to - call the documentPage::clear() on *page and the do all of the following, in no particular order - obtain the pointer to the TQPaintDevice from the documentPage using the documentPage::getPaintDevice() method and draw a graphical representation of the page number page->getPageNumber() into the TQPaintDevice, using the given resolution. If the member accessibilityBackground is true, the accessibilityBackgroundColor should be used for a background color, if possible. Otherwise, white should be used, if possible. If you need to compute the size of the page in pixel, do this as follows: @code SimplePageSize psize = pageSizes[page->getPageNumber() - 1]; if (psize.isValid()) { int width_in_pixel = resolution * psize.width().getLength_in_inch(); int height_in_pixel = resolution * psize.height().getLength_in_inch(); <...> } @endcode Don't use page->height() or page->width() to calculate the sizes ---KViewShell uses transformations e.g. to rotate the page, and sets the argument 'resolution' accordingly; these changes are not reflected in page->height() and page->width(). Similar problems occur if KViewShell required a shrunken version of the page, e.g. to print multiple pages on one sheet of paper. - if your document contains hyperlinks, fill the documentPage::hyperLinkList with HyperLinks, using pixel coordinates for the coordinates in the Hyperlink::box member of the Hyperlink. The Hyperlink::baseline member of the Hyperlink can be ignored. The linkText member of the Hyperlink should either be an absolute URL ("http://www.kde.org"), or be of the form "#anch", where the string "anch" is contained in the anchorList. - if your plugin supports full-text information, fill documentPage::textLinkList with HyperLinks, using pixel coordinates for the coordinates in the Hyperlink::box and Hyperlink::baseline members of the Hyperlink. The entries in the documentPage::textLinkList should have a natural ordering, "first text first" (left-to-right, up-to-down for western languages, right-to-left for hebrew, etc.). This is important so that text selection with the mouse works properly, and only continuous blocks of text can be selected. @note This method is often called in a paintEvent, so that care must be taken to return as soon as possible. No user interaction should be done during the execution. @note If your plugin supports full-text information, you probably want to re-implement the method supportsTextSearch() below. @warning As mentioned above, it may be tempting to compute the image size in pixel, using page->height() and page->width(). DON'T DO THAT. KViewShell uses transformations e.g. to rotate the page, and sets the argument 'resolution' accordingly; these changes are not reflected in page->height() and page->width(). Similar problems occur if KViewShell required a shrunken version of the page, e.g. to print multiple pages on one sheet of paper. @warning The signal documentIsChanged() must not be emitted while the method runs. @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. @param resolution this argument contains the resolution of the display device. In principle. In fact, kviewshell implements zooming by using 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 tqcontains resolution of the display device. @param page pointer to a documentPage structure that this method rendered into. */ virtual void drawPage(double resolution, RenderedDocumentPage* page) = 0; /** rendering of documents at thumbnail size This method is used to draw thumbnails. The standared implementations just calls 'drawPage' to do the job. Reimplement this if the used fileformat has embedded thumbnails. @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. */ virtual void drawThumbnail(double resolution, RenderedDocumentPage* page); /** quick extraction of text information This method returns the textinformation of the current page if available. It is only called when the page pixmap is not of interest, so it is possible to implement it much more efficiently then the drawPage() method. The default implementation just calls drawPage(). @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. @param page pointer to a documentPage structure that this method rendered into. */ virtual void getText(RenderedDocumentPage* page); /** Flag to indicate if full text is supported If your implementation of the drawPage() method supports full-text information and writes to the documentPage::textLinkList, this method should be re-implemented to return 'true'. The text-search and text-selection utilities will then be enabled in the GUI. The default implementation returns 'false'. */ virtual bool supportsTextSearch() const {return false;} /* This method will try to parse the reference part of the DVI file's URL, (either a number, which is supposed to be a page number, or src:(line)(filename)) and see if a corresponding section of the DVI file can be found. If so, it returns an anchor to that section. If not, it returns an invalid anchor. */ virtual Anchor parseReference(const TQString &reference); /* Looks up a anchor in the "anchorList". Returns the anchor found, or an invalid anchor otherwise. */ Anchor findAnchor(const TQString &); /* Quick file validity check This method is used internally, to check if a file is valid before it is re-loaded. This is used e.g. by kdvi: when a the user TeXes a file, the file changes immediately. If the 'watch file' option is set, kdvi is informed immediately. At that time, however, the TeX typesetting program still writes to the dvi file, and reloading must be postphoned till TeX finishes, and the dvi file becomes vaild. If such considerations are not an issue for you, this method does not need to be re-implemented. @warning Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. Use the member mutex to make your implemetation thread-safe. @param fileName name of the file that should be checked for validity @returns 'false' if the file 'fileName' is obviously invalid, and true otherwise. The default implementation always returns 'true'. */ virtual bool isValidFile(const TQString& fileName) const; void setAccessibleBackground(bool accessibleMode, const TQColor& background = TQColor(255, 255, 255)); signals: /** signals that the document is changed This signal can be emitted if the document or status of this class changed internally so that all associated widgets should be repainted. This could be emitted, e.g. if pages are removed from a document, or if some preferences change that have some direct influence on the way the document is rendered. When this signal is emitted, the whole GUI setup is re-computed, and all widgets are re-drawn. This can take considerable time. */ void documentIsChanged(); /** sets text in the statusbar This signal is emitted when the renderer needs to inform the user via the status bar. Since the status bar is not always visible, and since the duration that the message is shown is not quite specified, this should not be used for important information. */ void setStatusBarText( const TQString& ); protected: /** mutex used to make method thread-safe This is a recursive mutex that must be used to make the public methods of this class thread-safe. Future versions of kviewshell will use threading to keep the GUI responsive while pages are rendered. As a result, IT IS ABSOLUTELY NECESSARY that your implementation is THREAD-SAFE, if not, this can result in infrequent and very hard-to-find crashes of your programm. */ TQMutex mutex; /** number of pages in the document This member is set by the implementations of the setFile() method. It is set to zero by the constructor and in clear(). @warning Only the constructor and the methods setFile() and clear() may write to this member. */ TQ_UINT16 numPages; /** page sizes This vector contains the size of every page in the document. To accomodate for file format that do not specify a page size, it is explicitly allowed that this vector is empty, or that entries are invalid page sizes. The values in this vector are set by the setFile() method. @note if the document does not specify page sizes, this vector should --for performance reasons-- be empty, and not set to a large number of invalid page sizes. @warning Only the constructor and the methods setFile() and clear() may write to this member. */ TQValueVector pageSizes; /** bookmarks This (ordered!) list contains the bookmarks that are contained in the document. The values in this vector are set by the setFile() method, and cleared by the constructor and the clear() method. @warning Only the constructor and the methods setFile() and clear() may write to this member. */ TQPtrList bookmarks; /** map of anchors in a document. This map contains the anchors that are contained in the document. The values in this map are set by the setFile() method, and cleared by the constructor and the clear() method. @warning Only the constructor and the methods setFile() and clear() may write to this member. */ TQMap anchorList; /** pointer to the tqparent widget This pointer can be used by implementations e.g. to display error messages. This pointer can well be zero. */ TQGuardedPtr parentWidget; /** specifies if accessibilityBackgroundColor should be used If true, the drawPage() and drawThumbnail() methods should use accessibilityBackgroundColor as the backgroundcolor of the pages. */ bool accessibilityBackground; /** background color, to be used for visibly impaired users If accessibilityBackground is true, the drawPage() and drawThumbnail() methods should use this color as the backgroundcolor of the pages. */ TQColor accessibilityBackgroundColor; /** Flag if document is modified This flag indicates if the document was modified after it was loaded. It is set to 'false' in the constructor, in the clear() and setFile() method. It can be set to 'true' be methods that modify the document (e.g. the deletePages() method of the djvu implementation of this class). */ bool _isModified; }; #endif