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NAME

       wxPrintout - Functions for wxPrintout class

DESCRIPTION

       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() (not implemented in wx) and HasPage() (not implemented in wx) and to  render
       the  print  image  onto  an  associated  wxDC.  Instances  of  this  class  are  passed to
       wxPrinter:print/4 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.

       See:   Overview   printing,   wxPrinterDC   (not   implemented   in   wx),  wxPrintDialog,
       wxPageSetupDialog, wxPrinter, wxPrintPreview

       wxWidgets docs: wxPrintout

DATA TYPES

       wxPrintout() = wx:wx_object()

EXPORTS

       new(Title :: string(), OnPrintPage, Opts :: [Option]) ->
              wxPrintout:wxPrintout()

              Types:

                 OnPrintPage =
                     fun((wxPrintout(), Page :: integer()) -> boolean())
                 Option =
                     {onPreparePrinting, fun((wxPrintout()) -> ok)} |
                     {onBeginPrinting, fun((wxPrintout()) -> ok)} |
                     {onEndPrinting, fun((wxPrintout()) -> ok)} |
                     {onBeginDocument,
                      fun((wxPrintout(),
                           StartPage :: integer(),
                           EndPage :: integer()) ->
                              boolean())} |
                     {onEndDocument, fun((wxPrintout()) -> ok)} |
                     {hasPage, fun((wxPrintout(), Page :: integer()) -> ok)} |
                     {getPageInfo,
                      fun((wxPrintout()) ->
                              {MinPage :: integer(),
                               MaxPage :: integer(),
                               PageFrom :: integer(),
                               PageTo :: integer()})}

              Constructor.

              Creates a wxPrintout object with a callback fun and optionally other callback funs.
              The This argument is the wxPrintout object reference to this object

              Notice: The callbacks may not call other processes.

       destroy(This :: wxPrintout()) -> ok

              Destructor.

       getDC(This) -> wxDC:wxDC()

              Types:

                 This = wxPrintout()

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

              The application can use getDC/1 to obtain a device context to draw on.

              This will be a wxPrinterDC (not implemented in wx) if  printing  under  Windows  or
              Mac,  a  wxPostScriptDC  if  printing  on  other  platforms,  and  a  wxMemoryDC if
              previewing.

       getPageSizeMM(This) -> {W :: integer(), H :: integer()}

              Types:

                 This = wxPrintout()

              Returns the size of the printer page in millimetres.

       getPageSizePixels(This) -> {W :: integer(), H :: integer()}

              Types:

                 This = wxPrintout()

              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/1;
              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.

       getPaperRectPixels(This) ->
                             {X :: integer(),
                              Y :: integer(),
                              W :: integer(),
                              H :: integer()}

              Types:

                 This = wxPrintout()

              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.

       getPPIPrinter(This) -> {W :: integer(), H :: integer()}

              Types:

                 This = wxPrintout()

              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.

       getPPIScreen(This) -> {W :: integer(), H :: integer()}

              Types:

                 This = wxPrintout()

              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.

       getTitle(This) -> unicode:charlist()

              Types:

                 This = wxPrintout()

              Returns the title of the printout.

       isPreview(This) -> boolean()

              Types:

                 This = wxPrintout()

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

              See: GetPreview() (not implemented in wx)

       fitThisSizeToPaper(This, ImageSize) -> ok

              Types:

                 This = wxPrintout()
                 ImageSize = {W :: integer(), H :: integer()}

              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.

       fitThisSizeToPage(This, ImageSize) -> ok

              Types:

                 This = wxPrintout()
                 ImageSize = {W :: integer(), H :: integer()}

              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.

       fitThisSizeToPageMargins(This, ImageSize, PageSetupData) -> ok

              Types:

                 This = wxPrintout()
                 ImageSize = {W :: integer(), H :: integer()}
                 PageSetupData = wxPageSetupDialogData:wxPageSetupDialogData()

              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.

              Remark: 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.

       mapScreenSizeToPaper(This) -> ok

              Types:

                 This = wxPrintout()

              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.

       mapScreenSizeToPage(This) -> ok

              Types:

                 This = wxPrintout()

              This sets the user scale of the wxDC associated with this wxPrintout  to  the  same
              scale  as mapScreenSizeToPaper/1 but sets the logical origin to the top left corner
              of the page rectangle.

       mapScreenSizeToPageMargins(This, PageSetupData) -> ok

              Types:

                 This = wxPrintout()
                 PageSetupData = wxPageSetupDialogData:wxPageSetupDialogData()

              This sets the user scale of the wxDC associated with this wxPrintout  to  the  same
              scale  as  mapScreenSizeToPageMargins/2 but sets the logical origin to the top left
              corner of the page margins specified by the given wxPageSetupDialogData object.

       mapScreenSizeToDevice(This) -> ok

              Types:

                 This = wxPrintout()

              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 macOS  is  floating-point,  wxWidgets's
              drawing model scales from integer coordinates.

       getLogicalPaperRect(This) ->
                              {X :: integer(),
                               Y :: integer(),
                               W :: integer(),
                               H :: integer()}

              Types:

                 This = wxPrintout()

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

       getLogicalPageRect(This) ->
                             {X :: integer(),
                              Y :: integer(),
                              W :: integer(),
                              H :: integer()}

              Types:

                 This = wxPrintout()

              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.

       getLogicalPageMarginsRect(This, PageSetupData) ->
                                    {X :: integer(),
                                     Y :: integer(),
                                     W :: integer(),
                                     H :: integer()}

              Types:

                 This = wxPrintout()
                 PageSetupData = wxPageSetupDialogData:wxPageSetupDialogData()

              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.

       setLogicalOrigin(This, X, Y) -> ok

              Types:

                 This = wxPrintout()
                 X = Y = integer()

              Set  the  device  origin  of  the associated wxDC so that the current logical point
              becomes the new logical origin.

       offsetLogicalOrigin(This, Xoff, Yoff) -> ok

              Types:

                 This = wxPrintout()
                 Xoff = Yoff = integer()

              Shift the device origin by an amount specified in logical coordinates.