docs/latex/wx/htmlprn.tex

   1 \membersection{Printing}\label{printing}
   2
   3 The wxHTML library provides printing facilities.
   4
   5 You can redirect output displayed by \helpref{wxHtmlWindow}{wxhtmlwindow}
   6 to the printer DC using this (or similar) code (see {\bf printing} sample for
   7 more details) :
   8
   9 \begin{verbatim}
  10 //
  11 //  This method prints page number one to dc:
  12 //
  13
  14 void MyPrintout::DrawPageOne(wxDC *dc)
  15 {
  16   int leftMargin = 20;
  17   int topMargin = 50;
  18          // You must compute the margins there.
  19          // Caution! These values are NOT in printer DC's units.
  20          // These values are in screen pixels.
  21          // (see bellow)
  22
  23   // Here we obtain internal cell representation of HTML document:
  24   // (html is our pointer to wxHtmlWindow object)
  25   wxHtmlContainerCell *cell = html -> GetInternalRepresentation();
  26
  27   // Now we have to check in case our real page size is reduced
  28   // (e.g. because we're drawing to a print preview memory DC)
  29   int pageWidth, pageHeight;
  30   int w, h;
  31   dc->GetSize(&w, &h);                        // DC size
  32   GetPageSizePixels(&pageWidth, &pageHeight); // real size
  33
  34   // Now we must scale it. This equation will map wxHtmlWindow
  35   // to page in this way:
  36   // |--this is whole page as printed---------|
  37   // |        |                      |        |
  38   // |        |                      |        |
  39   // |-margin-|-----wxHtmlWindow-----|-margin-|
  40   //
  41   // So page width is 2*leftMargin + [wxHtmlWindow size]
  42   // (measured in screen pixels).
  43   // We will scale the printer DC so that wxHtmlWindow's content
  44   // spreads from left to right:
  45   float scale = (float)(
  46                   (float)(pageWidth) /
  47                   (float)(2 * leftMargin + cell -> GetMaxLineWidth()));
  48
  49   // If printer pageWidth == current DC width, then this doesn't
  50   // change. But w might be the preview bitmap width, so scale down.
  51   float overallScale = scale * (float)(w/(float)pageWidth);
  52
  53   // Set the user scale so that our computations take effect:
  54   dc->SetUserScale(overallScale, overallScale);
  55   dc->SetBackgroundMode(wxTRANSPARENT);
  56
  57   // And this is - finally - HTML stuff:
  58   cell -> Draw(*dc, leftMargin, topMargin, 0, cell -> GetHeight());
  59 }
  60 \end{verbatim}
  61
  62 (Thanks to Julian Smart for sample)