Add start of selection api, support for HasSelection, SelectAll and DeleteSelection...

[wxWidgets.git] / interface / wx / print.h

/////////////////////////////////////////////////////////////////////////////
// Name:        print.h
// Purpose:     interface of wxPreviewControlBar
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

/**
    @class wxPreviewControlBar

    This is the default implementation of the preview control bar, a panel
    with buttons and a zoom control.

    You can derive a new class from this and override some or all member functions
    to change the behaviour and appearance; or you can leave it as it is.

    @library{wxbase}
    @category{printing}

    @see wxPreviewFrame, wxPreviewCanvas, wxPrintPreview
*/
class wxPreviewControlBar : public wxPanel
{
public:

    /**
        Constructor.

        The @a buttons parameter may be a combination of the following, using the bitwise
        'or' operator:

        @beginFlagTable
        @flag{wxPREVIEW_PRINT}
            Create a print button.
        @flag{wxPREVIEW_NEXT}
            Create a next page button.
        @flag{wxPREVIEW_PREVIOUS}
            Create a previous page button.
        @flag{wxPREVIEW_ZOOM}
            Create a zoom control.
        @flag{wxPREVIEW_DEFAULT}
            Equivalent to a combination of @c wxPREVIEW_PREVIOUS, @c wxPREVIEW_NEXT
            and @c wxPREVIEW_ZOOM.
        @endFlagTable
    */
    wxPreviewControlBar(wxPrintPreview* preview,
                        long buttons,
                        wxWindow* parent,
                        const wxPoint& pos = wxDefaultPosition,
                        const wxSize& size = wxDefaultSize,
                        long style = 0,
                        const wxString& name = "panel");

    /**
        Destructor.
    */
    virtual ~wxPreviewControlBar();

    /**
        Creates buttons, according to value of the button style flags.

        @todo which flags??
    */
    virtual void CreateButtons();

    /**
        Gets the print preview object associated with the control bar.
    */
    virtual wxPrintPreviewBase* GetPrintPreview() const;

    /**
        Gets the current zoom setting in percent.
    */
    virtual int GetZoomControl();

    /**
        Sets the zoom control.
    */
    virtual void SetZoomControl(int percent);

};



/**
    @class wxPreviewCanvas

    A preview canvas is the default canvas used by the print preview
    system to display the preview.

    @library{wxbase}
    @category{printing}

    @see wxPreviewFrame, wxPreviewControlBar, wxPrintPreview
*/
class wxPreviewCanvas : public wxScrolledWindow
{
public:
    /**
        Constructor.
    */
    wxPreviewCanvas(wxPrintPreview* preview, wxWindow* parent,
                    const wxPoint& pos = wxDefaultPosition,
                    const wxSize& size = wxDefaultSize,
                    long style = 0,
                    const wxString& name = "canvas");

    /**
        Destructor.
    */
    virtual ~wxPreviewCanvas();

    /**
        Calls wxPrintPreview::PaintPage() to refresh the canvas.
    */
    void OnPaint(wxPaintEvent& event);
};

/**
    Preview frame modality kind.

    The elements of this enum can be used with wxPreviewFrame::Initialize() to
    indicate how should the preview frame be shown.

    @since 2.9.2
*/
enum wxPreviewFrameModalityKind
{
    /**
        Disable all the other top level windows while the preview frame is shown.

        This is the default behaviour.
     */
    wxPreviewFrame_AppModal,

    /**
        Disable only the parent window while the preview frame is shown.
     */
    wxPreviewFrame_WindowModal,

    /**
        Show the preview frame non-modally and don't disable any other windows.
     */
    wxPreviewFrame_NonModal
};

/**
    @class wxPreviewFrame

    This class provides the default method of managing the print preview interface.
    Member functions may be overridden to replace functionality, or the
    class may be used without derivation.

    @library{wxbase}
    @category{printing}

    @see wxPreviewCanvas, wxPreviewControlBar, wxPrintPreview
*/
class wxPreviewFrame : public wxFrame
{
public:
    /**
        Constructor.

        Pass a print preview object plus other normal frame arguments.
        The print preview object will be destroyed by the frame when it closes.
    */
    wxPreviewFrame(wxPrintPreviewBase* preview, wxWindow* parent,
                   const wxString& title = "Print Preview",
                   const wxPoint& pos = wxDefaultPosition,
                   const wxSize& size = wxDefaultSize,
                   long style = wxDEFAULT_FRAME_STYLE,
                   const wxString& name = wxFrameNameStr);

    /**
        Destructor.
    */
    virtual ~wxPreviewFrame();

    /**
        Creates a wxPreviewCanvas.

        Override this function to allow a user-defined preview canvas object
        to be created.
    */
    virtual void CreateCanvas();

    /**
        Creates a wxPreviewControlBar.

        Override this function to allow a user-defined preview control bar object
        to be created.
    */
    virtual void CreateControlBar();

    /**
        Creates the preview canvas and control bar.

        By default also disables the other existing top level windows to
        prepare for showing the preview frame modally. Since wxWidgets 2.9.2
        this can be changed by specifying either wxPreviewFrame_WindowModal --
        to disable just the parent window -- or wxPreviewFrame_NonModal -- to
        not disable any windows at all -- as @a kind parameter.

        This function must be called by the application prior to showing the frame.

        @param kind
            The modality kind of preview frame. @since 2.9.2
    */
    virtual void Initialize(wxPreviewFrameModalityKind kind
                                = wxPreviewFrame_AppModal);

    /**
        Enables any disabled frames in the application, and deletes the print preview
        object, implicitly deleting any printout objects associated with the print
        preview object.
    */
    void OnCloseWindow(wxCloseEvent& event);
};



/**
    @class wxPrintPreview

    Objects of this class manage the print preview process. The object is passed
    a wxPrintout object, and the wxPrintPreview object itself is passed to
    a wxPreviewFrame object. Previewing is started by initializing and showing
    the preview frame. Unlike wxPrinter::Print(), flow of control returns to the
    application immediately after the frame is shown.

    @note
    The preview shown is only exact on Windows. On other platforms, the wxDC
    used for preview is different from what is used for printing and the
    results may be significantly different, depending on how is the output
    created. In particular, printing code relying on wxDC::GetTextExtent()
    heavily (for example, wxHtmlEasyPrinting and other wxHTML classes do) is
    affected. It is recommended to use native preview functionality on
    platforms that offer it (OS X, GTK+).

    @library{wxbase}
    @category{printing}

    @see @ref overview_printing, wxPrinterDC, wxPrintDialog, wxPrintout, wxPrinter,
         wxPreviewCanvas, wxPreviewControlBar, wxPreviewFrame
*/
class wxPrintPreview : public wxObject
{
public:
    /**
        Constructor.

        Pass a printout object, an optional printout object to be used for actual
        printing, and the address of an optional block of printer data, which will
        be copied to the print preview object's print data.

        If @a printoutForPrinting is non-@NULL, a @b "Print..." button will be placed on
        the preview frame so that the user can print directly from the preview interface.

        @remarks
        Do not explicitly delete the printout objects once this destructor has been
        called, since they will be deleted in the wxPrintPreview constructor.
        The same does not apply to the @a data argument.

        Use IsOk() to check whether the wxPrintPreview object was created correctly.
    */
    wxPrintPreview(wxPrintout* printout,
                   wxPrintout* printoutForPrinting = NULL,
                   wxPrintDialogData* data = NULL);

    /**
        Destructor.

        Deletes both print preview objects, so do not destroy these objects
        in your application.
    */
    ~wxPrinter();

    /**
        Gets the preview window used for displaying the print preview image.
    */
    virtual wxPreviewCanvas* GetCanvas() const;

    /**
        Gets the page currently being previewed.
    */
    virtual int GetCurrentPage() const;

    /**
        Gets the frame used for displaying the print preview canvas
        and control bar.
    */
    virtual wxFrame* GetFrame() const;

    /**
        Returns the maximum page number.
    */
    virtual int GetMaxPage() const;

    /**
        Returns the minimum page number.
    */
    virtual int GetMinPage() const;

    /**
        Gets the preview printout object associated with the wxPrintPreview object.
    */
    virtual wxPrintout* GetPrintout() const;

    /**
        Gets the printout object to be used for printing from within the preview
        interface,
        or @NULL if none exists.
    */
    virtual wxPrintout* GetPrintoutForPrinting() const;

    /**
        Returns @true if the wxPrintPreview is valid, @false otherwise.

        It could return @false if there was a problem initializing the printer
        device context (current printer not set, for example).
    */
    virtual bool IsOk() const;

    /**
        This refreshes the preview window with the preview image.
        It must be called from the preview window's OnPaint member.

        The implementation simply blits the preview bitmap onto
        the canvas, creating a new preview bitmap if none exists.
    */
    virtual bool PaintPage(wxPreviewCanvas* canvas, wxDC& dc);

    /**
        Invokes the print process using the second wxPrintout object
        supplied in the wxPrintPreview constructor.
        Will normally be called by the @b Print... panel item on the
        preview frame's control bar.

        Returns @false in case of error -- call wxPrinter::GetLastError()
        to get detailed information about the kind of the error.
    */
    virtual bool Print(bool prompt);

    /**
        Renders a page into a wxMemoryDC. Used internally by wxPrintPreview.
    */
    virtual bool RenderPage(int pageNum);

    /**
        Sets the window to be used for displaying the print preview image.
    */
    virtual void SetCanvas(wxPreviewCanvas* window);

    /**
        Sets the current page to be previewed.
    */
    virtual bool SetCurrentPage(int pageNum);

    /**
        Sets the frame to be used for displaying the print preview canvas
        and control bar.
    */
    virtual void SetFrame(wxFrame* frame);

    /**
        Associates a printout object with the wxPrintPreview object.
    */
    virtual void SetPrintout(wxPrintout* printout);

    /**
        Sets the percentage preview zoom, and refreshes the preview canvas accordingly.
    */
    virtual void SetZoom(int percent);
};



/**
    @class wxPrinter

    This class represents the Windows or PostScript printer, and is the vehicle
    through which printing may be launched by an application.

    Printing can also be achieved through using of lower functions and classes,
    but this and associated classes provide a more convenient and general method
    of printing.

    @library{wxbase}
    @category{printing}

    @see @ref overview_printing, wxPrinterDC, wxPrintDialog, wxPrintout, wxPrintPreview
*/
class wxPrinter : public wxObject
{
public:
    /**
        Constructor.

        Pass an optional pointer to a block of print dialog data, which will be
        copied to the printer object's local data.

        @see wxPrintDialogData, wxPrintData
    */
    wxPrinter(wxPrintDialogData* data = NULL);

    /**
        Creates the default printing abort window, with a cancel button.
    */
    virtual wxWindow* CreateAbortWindow(wxWindow* parent, wxPrintout* printout);

    /**
        Returns @true if the user has aborted the print job.
    */
    bool GetAbort() const;

    /**
        Return last error. Valid after calling Print(), PrintDialog() or
        wxPrintPreview::Print().

        These functions set last error to @c wxPRINTER_NO_ERROR if no error happened.

        Returned value is one of the following:

        @beginTable
        @row2col{wxPRINTER_NO_ERROR, No error happened.}
        @row2col{wxPRINTER_CANCELLED, The user cancelled printing.}
        @row2col{wxPRINTER_ERROR, There was an error during printing.}
        @endTable
    */
    static wxPrinterError GetLastError();

    /**
        Returns the @ref overview_printing_printdata "print data" associated with
        the printer object.
    */
    virtual wxPrintDialogData& GetPrintDialogData() const;

    /**
        Starts the printing process. Provide a parent window, a user-defined wxPrintout
        object which controls the printing of a document, and whether the print dialog
        should be invoked first.

        Print() could return @false if there was a problem initializing the printer device
        context (current printer not set, for example) or the user cancelled printing.
        Call GetLastError() to get detailed information about the kind of the error.
    */
    virtual bool Print(wxWindow* parent, wxPrintout* printout,
                       bool prompt = true);

    /**
        Invokes the print dialog.

        If successful (the user did not press Cancel and no error occurred),
        a suitable device context will be returned; otherwise @NULL is returned;
        call GetLastError() to get detailed information about the kind of the error.

        @remarks
        The application must delete this device context to avoid a memory leak.
    */
    virtual wxDC* PrintDialog(wxWindow* parent);

    /**
        Default error-reporting function.
    */
    virtual void ReportError(wxWindow* parent, wxPrintout* printout,
                             const wxString& message);

    /**
        Invokes the print setup dialog.

        @remarks
        The setup dialog is obsolete from Windows 95, though retained
        for backward compatibility.
    */
    virtual bool Setup(wxWindow* parent);
};



/**
    @class wxPrintout

    This class encapsulates the functionality of printing out an application document.

    A new class must be derived and members overridden to respond to calls such as
    OnPrintPage() and HasPage() and to render the print image onto an associated wxDC.
    Instances of this class are passed to wxPrinter::Print() or
    to a wxPrintPreview object to initiate printing or previewing.

    Your derived wxPrintout is responsible for drawing both the preview image and
    the printed page. If your windows' drawing routines accept an arbitrary DC as an
    argument, you can re-use those routines within your wxPrintout subclass to draw
    the printout image. You may also add additional drawing elements within your
    wxPrintout subclass, like headers, footers, and/or page numbers. However, the
    image on the printed page will often differ from the image drawn on the screen,
    as will the print preview image -- not just in the presence of headers and
    footers, but typically in scale. A high-resolution printer presents a much
    larger drawing surface (i.e., a higher-resolution DC); a zoomed-out preview
    image presents a much smaller drawing surface (lower-resolution DC). By using
    the routines FitThisSizeToXXX() and/or MapScreenSizeToXXX() within your
    wxPrintout subclass to set the user scale and origin of the associated DC, you
    can easily use a single drawing routine to draw on your application's windows,
    to create the print preview image, and to create the printed paper image, and
    achieve a common appearance to the preview image and the printed page.

    @library{wxbase}
    @category{printing}

    @see @ref overview_printing, wxPrinterDC, wxPrintDialog, wxPageSetupDialog,
         wxPrinter, wxPrintPreview
*/
class wxPrintout : public wxObject
{
public:
    /**
        Constructor.

        Pass an optional title argument - the current filename would be a
        good idea. This will appear in the printing list (at least in MSW)
    */
    wxPrintout(const wxString& title = "Printout");

    /**
        Destructor.
    */
    virtual ~wxPrintout();

    /**
        Set the user scale and device origin of the wxDC associated with this wxPrintout
        so that the given image size fits entirely within the page rectangle and the
        origin is at the top left corner of the page rectangle.

        On MSW and Mac, the page rectangle is the printable area of the page.
        On other platforms and PostScript printing, the page rectangle is the entire paper.

        Use this if you want your printed image as large as possible, but with the caveat
        that on some platforms, portions of the image might be cut off at the edges.
    */
    void FitThisSizeToPage(const wxSize& imageSize);

    /**
        Set the user scale and device origin of the wxDC associated with this wxPrintout
        so that the given image size fits entirely within the page margins set in the
        given wxPageSetupDialogData object.

        This function provides the greatest consistency across all platforms because it
        does not depend on having access to the printable area of the paper.

        @remarks
        On Mac, the native wxPageSetupDialog does not let you set the page margins;
        you'll have to provide your own mechanism, or you can use the Mac-only class
        wxMacPageMarginsDialog.
    */
    void FitThisSizeToPageMargins(const wxSize& imageSize,
                                  const wxPageSetupDialogData& pageSetupData);

    /**
        Set the user scale and device origin of the wxDC associated with this wxPrintout
        so that the given image size fits entirely within the paper and the origin is at
        the top left corner of the paper.

        Use this if you're managing your own page margins.

        @note
        With most printers, the region around the edges of the paper are not
        printable so that the edges of the image could be cut off.

    */
    void FitThisSizeToPaper(const wxSize& imageSize);

    /**
        Returns the device context associated with the printout (given to the printout
        at start of printing or previewing).

        The application can use GetDC() to obtain a device context to draw on.

        This will be a wxPrinterDC if printing under Windows or Mac, a wxPostScriptDC
        if printing on other platforms, and a wxMemoryDC if previewing.
    */
    wxDC* GetDC() const;

    /**
        Return the rectangle corresponding to the page margins specified by the given
        wxPageSetupDialogData object in the associated wxDC's logical coordinates for
        the current user scale and device origin.

        The page margins are specified with respect to the edges of the paper on all
        platforms.
    */
    wxRect GetLogicalPageMarginsRect(const wxPageSetupDialogData& pageSetupData) const;

    /**
        Return the rectangle corresponding to the page in the associated wxDC 's
        logical coordinates for the current user scale and device origin.

        On MSW and Mac, this will be the printable area of the paper.
        On other platforms and PostScript printing, this will be the full paper
        rectangle.
    */
    wxRect GetLogicalPageRect() const;

    /**
        Return the rectangle corresponding to the paper in the associated wxDC 's
        logical coordinates for the current user scale and device origin.
    */
    wxRect GetLogicalPaperRect() const;

    /**
        Returns the number of pixels per logical inch of the printer device context.

        Dividing the printer PPI by the screen PPI can give a suitable scaling factor
        for drawing text onto the printer.

        Remember to multiply this by a scaling factor to take the preview DC size into
        account.
        Or you can just use the FitThisSizeToXXX() and MapScreenSizeToXXX routines below,
        which do most of the scaling calculations for you.

        @beginWxPythonOnly
        This method returns the output-only parameters as a tuple.
        @endWxPythonOnly

        @beginWxPerlOnly
        In wxPerl this method takes no arguments and returns a
        2-element list (w, h).
        @endWxPerlOnly
    */
    void GetPPIPrinter(int* w, int* h) const;

    /**
        Returns the number of pixels per logical inch of the screen device context.

        Dividing the printer PPI by the screen PPI can give a suitable scaling factor
        for drawing text onto the printer.

        If you are doing your own scaling, remember to multiply this by a scaling
        factor to take the preview DC size into account.

        @beginWxPythonOnly
        This method returns the output-only parameters as a tuple.
        @endWxPythonOnly

        @beginWxPerlOnly
        In wxPerl this method takes no arguments and returns a
        2-element list (w, h).
        @endWxPerlOnly
    */
    void GetPPIScreen(int* w, int* h) const;

    /**
        Called by the framework to obtain information from the application about minimum
        and maximum page values that the user can select, and the required page range to
        be printed.

        By default this returns (1, 32000) for the page minimum and maximum values, and
        (1, 1) for the required page range.

        @a minPage must be greater than zero and @a maxPage must be greater
        than @a minPage.

        @beginWxPythonOnly
        When this method is implemented in a derived Python class, it should be designed
        to take no parameters (other than the self reference) and to return a tuple of
        four integers.
        @endWxPythonOnly
    */
    virtual void GetPageInfo(int* minPage, int* maxPage, int* pageFrom,
                             int* pageTo);

    /**
        Returns the size of the printer page in millimetres.

        @beginWxPythonOnly
        This method returns the output-only parameters as a tuple.
        @endWxPythonOnly

        @beginWxPerlOnly
        In wxPerl this method takes no arguments and returns a
        2-element list (w, h).
        @endWxPerlOnly
    */
    void GetPageSizeMM(int* w, int* h) const;

    /**
        Returns the size of the printer page in pixels, called the page rectangle.

        The page rectangle has a top left corner at (0,0) and a bottom right corner at
        (w,h). These values may not be the same as the values returned from
        wxDC::GetSize(); if the printout is being used for
        previewing, a memory device context is used, which uses a bitmap size reflecting
        the current preview zoom. The application must take this discrepancy into
        account if previewing is to be supported.

        @beginWxPythonOnly
        This method returns the output-only parameters as a tuple.
        @endWxPythonOnly

        @beginWxPerlOnly
        In wxPerl this method takes no arguments and returns a
        2-element list (w, h).
        @endWxPerlOnly
    */
    void GetPageSizePixels(int* w, int* h) const;

    /**
        Returns the rectangle that corresponds to the entire paper in pixels, called the
        paper rectangle.

        This distinction between paper rectangle and page rectangle reflects the fact that
        most printers cannot print all the way to the edge of the paper.
        The page rectangle is a rectangle whose top left corner is at (0,0) and whose width
        and height are given by wxDC::GetPageSizePixels().

        On MSW and Mac, the page rectangle gives the printable area of the paper, while the
        paper rectangle represents the entire paper, including non-printable borders.
        Thus, the rectangle returned by wxDC::GetPaperRectPixels() will have a top left corner
        whose coordinates are small negative numbers and the bottom right corner will have
        values somewhat larger than the width and height given by wxDC::GetPageSizePixels().

        On other platforms and for PostScript printing, the paper is treated as if its entire
        area were printable, so this function will return the same rectangle as the page
        rectangle.
    */
    wxRect GetPaperRectPixels() const;

    /**
        Returns the title of the printout.

        @todo the python note here was wrong
    */
    virtual wxString GetTitle() const;

    /**
        Should be overridden to return @true if the document has this page, or @false
        if not.

        Returning @false signifies the end of the document. By default,
        HasPage behaves as if the document has only one page.
    */
    virtual bool HasPage(int pageNum);

    /**
        Returns @true if the printout is currently being used for previewing.

        @see GetPreview()
    */
    virtual bool IsPreview() const;

    /**
        Returns the associated preview object if any.

        If this printout object is used for previewing, returns the associated
        wxPrintPreview. Otherwise returns @NULL.

        The returned pointer is not owned by the printout and must not be
        deleted.

        @see IsPreview()

        @since 2.9.1.
     */
    wxPrintPreview *GetPreview() const;

    /**
        Set the user scale and device origin of the wxDC associated with this wxPrintout
        so that one screen pixel maps to one device pixel on the DC.
        That is, the user scale is set to (1,1) and the device origin is set to (0,0).

        Use this if you want to do your own scaling prior to calling wxDC drawing calls,
        for example, if your underlying model is floating-point and you want to achieve
        maximum drawing precision on high-resolution printers.

        You can use the GetLogicalXXXRect() routines below to obtain the paper rectangle,
        page rectangle, or page margins rectangle to perform your own scaling.

        @note
        While the underlying drawing model of Mac OS X is floating-point,
        wxWidgets's drawing model scales from integer coordinates.
    */
    void MapScreenSizeToDevice();

    /**
        This sets the user scale of the wxDC associated with this wxPrintout to the same
        scale as MapScreenSizeToPaper() but sets the logical origin to the top left corner
        of the page rectangle.
    */
    void MapScreenSizeToPage();

    /**
        This sets the user scale of the wxDC associated with this wxPrintout to the same
        scale as MapScreenSizeToPageMargins() but sets the logical origin to the top left
        corner of the page margins specified by the given wxPageSetupDialogData object.
    */
    void MapScreenSizeToPageMargins(const wxPageSetupDialogData& pageSetupData);

    /**
        Set the user scale and device origin of the wxDC associated with this wxPrintout
        so that the printed page matches the screen size as closely as possible
        and the logical origin is in the top left corner of the paper rectangle.

        That is, a 100-pixel object on screen should appear at the same size on the
        printed page.
        (It will, of course, be larger or smaller in the preview image, depending on the
        zoom factor.)

        Use this if you want WYSIWYG behaviour, e.g., in a text editor.
    */
    void MapScreenSizeToPaper();

    /**
        Shift the device origin by an amount specified in logical coordinates.
    */
    void OffsetLogicalOrigin(wxCoord xoff, wxCoord yoff);

    /**
        Called by the framework at the start of document printing. Return @false from
        this function cancels the print job.

        OnBeginDocument() is called once for every copy printed.

        @remarks
        The base OnBeginDocument() must be called (and the return value
        checked) from within the overridden function, since it calls wxDC::StartDoc().

        @beginWxPythonOnly
         If this method is overridden in a Python class then the base class version can
         be called by using the method <tt>base_OnBeginDocument(startPage, endPage)</tt>.
        @endWxPythonOnly
    */
    virtual bool OnBeginDocument(int startPage, int endPage);

    /**
        Called by the framework at the start of printing.

        OnBeginPrinting() is called once for every print job
        (regardless of how many copies are being printed).
    */
    virtual void OnBeginPrinting();

    /**
        Called by the framework at the end of document printing.

        OnEndDocument() is called once for every copy printed.

        @remarks
        The base OnEndDocument() must be called from within the overridden function,
        since it calls wxDC::EndDoc().
    */
    virtual void OnEndDocument();

    /**
        Called by the framework at the end of printing.

        OnEndPrinting is called once for every print job
        (regardless of how many copies are being printed).
    */
    virtual void OnEndPrinting();

    /**
        Called once by the framework before any other demands are made of the
        wxPrintout object.

        This gives the object an opportunity to calculate the number of pages
        in the document, for example.
    */
    virtual void OnPreparePrinting();

    /**
        Called by the framework when a page should be printed. Returning @false cancels
        the print job.
    */
    virtual bool OnPrintPage(int pageNum) = 0;

    /**
        Set the device origin of the associated wxDC so that the current logical point
        becomes the new logical origin.
    */
    void SetLogicalOrigin(wxCoord x, wxCoord y);
};