tdf#92914 SwPagePreviewLayout::Paint: handle rendercontext

With this, the print preview window no longer performs direct paint.

(cherry picked from commit 46e7991b)

Conflicts:
	sw/inc/pagepreviewlayout.hxx

Change-Id: I53f05d8a3b723bc131f21a485e0ffec71484670a
Reviewed-on: https://gerrit.libreoffice.org/17394Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

sw/inc/pagepreviewlayout.hxx

@@ -575,6 +575,11 @@ public:
         @author FME
     */
     sal_uInt16 GetNumberOfPreviewPages() { return sal::static_int_cast< sal_uInt16 >(maPreviewPages.size()); }
+
+    SwViewShell& GetParentViewShell()
+    {
+        return mrParentViewShell;
+    }
 };
 
 #endif // INCLUDED_SW_INC_PAGEPREVIEWLAYOUT_HXX

sw/inc/viewsh.hxx

@@ -357,6 +357,7 @@ public:
     inline vcl::RenderContext* GetOut()     const { return mpOut; }
 
     void SetWin(vcl::Window* win) { mpWin = win; }
+    void SetOut(vcl::RenderContext* pOut) { mpOut = pOut; }
     static inline bool IsLstEndAction() { return SwViewShell::mbLstAct; }
 
     // Change of all page descriptors.

sw/source/core/view/pagepreviewlayout.cxx

@@ -984,12 +984,36 @@ SwTwips SwPagePreviewLayout::GetWinPagesScrollAmount(
 
 // methods to paint page preview layout
 
+namespace
+{
+/// Similar to RenderContextGuard, but does not touch the draw view.
+class PreviewRenderContextGuard
+{
+    VclPtr<vcl::RenderContext> m_pOriginalValue;
+    SwViewShell& m_rShell;
+
+public:
+    PreviewRenderContextGuard(SwViewShell& rShell, vcl::RenderContext* pValue)
+        : m_pOriginalValue(rShell.GetOut()),
+        m_rShell(rShell)
+    {
+        m_rShell.SetOut(pValue);
+    }
+
+    ~PreviewRenderContextGuard()
+    {
+        m_rShell.SetOut(m_pOriginalValue);
+    }
+};
+}
+
 /** paint prepared preview
 
     OD 12.12.2002 #103492#
 */
 bool SwPagePreviewLayout::Paint(vcl::RenderContext& rRenderContext, const Rectangle& rOutRect) const
 {
+    PreviewRenderContextGuard aGuard(mrParentViewShell, &rRenderContext);
     // check environment and parameters
     {
         if (!mrParentViewShell.GetWin() && !mrParentViewShell.GetOut()->GetConnectMetaFile())

sw/source/uibase/uiview/pview.cxx

@@ -234,7 +234,9 @@ void  SwPagePreviewWin::Paint(vcl::RenderContext& rRenderContext, const Rectangl
         aMM.SetScaleX(maScale);
         aMM.SetScaleY(maScale);
         rRenderContext.SetMapMode(aMM);
+        mpPgPreviewLayout->GetParentViewShell().setOutputToWindow(true);
         mpPgPreviewLayout->Paint(rRenderContext, rRect);
+        mpPgPreviewLayout->GetParentViewShell().setOutputToWindow(false);
     }
 }