Add wxPrintout::SetUp() to reuse the same code in all ports

MSW, GTK, OSX and Postscript implementations all did almost exactly the
same thing to initialize wxPrintout, so extract this common code into a
new wxPrintout method and just call it instead.

There should be no changes in behaviour.

include/wx/prntbase.h

@@ -281,6 +281,10 @@ public:
 
     virtual wxString GetTitle() const { return m_printoutTitle; }
 
+    // Port-specific code should call this function to initialize this object
+    // with everything it needs, instead of using individual accessors below.
+    bool SetUp(wxDC& dc);
+
     wxDC *GetDC() const { return m_printoutDC; }
     void SetDC(wxDC *dc) { m_printoutDC = dc; }
 

src/common/prntbase.cpp

@@ -638,6 +638,33 @@ void wxPrintout::GetPageInfo(int *minPage, int *maxPage, int *fromPage, int *toP
     *toPage = 1;
 }
 
+bool wxPrintout::SetUp(wxDC& dc)
+{
+    SetPPIScreen(wxGetDisplayPPI());
+
+    // We need to know printer PPI. In most ports, this can be retrieved from
+    // the printer DC, but in others it is computed (probably for legacy
+    // reasons) outside of wxDC code, so don't override it if it had been
+    // already set.
+    if ( !m_PPIPrinterX || !m_PPIPrinterY )
+    {
+        SetPPIPrinter(dc.GetPPI());
+        if ( !m_PPIPrinterX || !m_PPIPrinterY )
+        {
+            // But if we couldn't get it in any way, we can't continue.
+            return false;
+        }
+    }
+
+    SetDC(&dc);
+
+    dc.GetSize(&m_pageWidthPixels, &m_pageHeightPixels);
+    m_paperRectPixels = wxRect(0, 0, m_pageWidthPixels, m_pageHeightPixels);
+    dc.GetSizeMM(&m_pageWidthMM, &m_pageHeightMM);
+
+    return true;
+}
+
 void wxPrintout::FitThisSizeToPaper(const wxSize& imageSize)
 {
     // Set the DC scale and origin so that the given image size fits within the

src/generic/printps.cpp

@@ -105,24 +105,8 @@ bool wxPostScriptPrinter::Print(wxWindow *parent, wxPrintout *printout, bool pro
         return false;
     }
 
-    wxSize ScreenPixels = wxGetDisplaySize();
-    wxSize ScreenMM = wxGetDisplaySizeMM();
-
-    printout->SetPPIScreen( (int) ((ScreenPixels.GetWidth() * 25.4) / ScreenMM.GetWidth()),
-                            (int) ((ScreenPixels.GetHeight() * 25.4) / ScreenMM.GetHeight()) );
-    printout->SetPPIPrinter( dc->GetResolution(),
-                             dc->GetResolution() );
-
     // Set printout parameters
-    printout->SetDC(dc);
+    printout->SetUp(*dc);
-
-    int w, h;
-    dc->GetSize(&w, &h);
-    printout->SetPageSizePixels((int)w, (int)h);
-    printout->SetPaperRectPixels(wxRect(0, 0, w, h));
-    int mw, mh;
-    dc->GetSizeMM(&mw, &mh);
-    printout->SetPageSizeMM((int)mw, (int)mh);
 
     // Create an abort window
     wxBeginBusyCursor();

src/gtk/print.cpp

@@ -1024,19 +1024,8 @@ void wxGtkPrinter::BeginPrint(wxPrintout *printout, GtkPrintOperation *operation
         return;
     }
 
-    printout->SetPPIScreen(wxGetDisplayPPI());
+    printout->SetUp(*m_dc);
-    printout->SetPPIPrinter( printDC->GetResolution(),
-                             printDC->GetResolution() );
 
-    printout->SetDC(m_dc);
-
-    int w, h;
-    m_dc->GetSize(&w, &h);
-    printout->SetPageSizePixels((int)w, (int)h);
-    printout->SetPaperRectPixels(wxRect(0, 0, w, h));
-    int mw, mh;
-    m_dc->GetSizeMM(&mw, &mh);
-    printout->SetPageSizeMM((int)mw, (int)mh);
     printout->OnPreparePrinting();
 
     // Get some parameters from the printout, if defined.

src/msw/printwin.cpp

@@ -115,36 +115,14 @@ bool wxWindowsPrinter::Print(wxWindow *parent, wxPrintout *printout, bool prompt
         return false;
     }
 
-    wxPrinterDCImpl *impl = (wxPrinterDCImpl*) dc->GetImpl();
+    // Set printout parameters
-
+    if (!printout->SetUp(*dc))
-    HDC hdc = ::GetDC(NULL);
-    int logPPIScreenX = ::GetDeviceCaps(hdc, LOGPIXELSX);
-    int logPPIScreenY = ::GetDeviceCaps(hdc, LOGPIXELSY);
-    ::ReleaseDC(NULL, hdc);
-
-    int logPPIPrinterX = ::GetDeviceCaps((HDC) impl->GetHDC(), LOGPIXELSX);
-    int logPPIPrinterY = ::GetDeviceCaps((HDC) impl->GetHDC(), LOGPIXELSY);
-    if (logPPIPrinterX == 0 || logPPIPrinterY == 0)
     {
         delete dc;
         sm_lastError = wxPRINTER_ERROR;
         return false;
     }
 
-    printout->SetPPIScreen(logPPIScreenX, logPPIScreenY);
-    printout->SetPPIPrinter(logPPIPrinterX, logPPIPrinterY);
-
-    // Set printout parameters
-    printout->SetDC(dc);
-
-    int w, h;
-    dc->GetSize(&w, &h);
-    printout->SetPageSizePixels((int)w, (int)h);
-    printout->SetPaperRectPixels(dc->GetPaperRect());
-
-    dc->GetSizeMM(&w, &h);
-    printout->SetPageSizeMM((int)w, (int)h);
-
     // Create an abort window
     wxBusyCursor busyCursor;
 
@@ -169,7 +147,7 @@ bool wxWindowsPrinter::Print(wxWindow *parent, wxPrintout *printout, bool prompt
     wxPrintAbortDialog *win = CreateAbortWindow(parent, printout);
     wxYield();
 
-    ::SetAbortProc(GetHdcOf(*impl), wxAbortProc);
+    ::SetAbortProc(GetHdcOf(*dc), wxAbortProc);
 
     if (!win)
     {

src/osx/core/printmac.cpp

@@ -585,8 +585,6 @@ bool wxMacPrinter::Print(wxWindow *parent, wxPrintout *printout, bool prompt)
         return false;
     }
 
-    printout->SetPPIScreen(wxGetDisplayPPI());
-
     PMResolution res;
     PMPrinter printer;
     wxOSXPrintData* nativeData = (wxOSXPrintData*)
@@ -607,15 +605,7 @@ bool wxMacPrinter::Print(wxWindow *parent, wxPrintout *printout, bool prompt)
     printout->SetPPIPrinter(int(res.hRes), int(res.vRes));
 
     // Set printout parameters
-    printout->SetDC(dc);
+    printout->SetUp(*dc);
-
-    int w, h;
-    dc->GetSize(&w, &h);
-    printout->SetPageSizePixels((int)w, (int)h);
-    printout->SetPaperRectPixels(dc->GetPaperRect());
-    wxCoord mw, mh;
-    dc->GetSizeMM(&mw, &mh);
-    printout->SetPageSizeMM((int)mw, (int)mh);
 
     // Create an abort window
     wxBeginBusyCursor();