patch SdrPageWindow in SdXImpressDocument::paintTile()

This is based on commit 424312aa99307da9f0ee60ea6e3213b2b3dc26b4
amd I don't quite understand everything that happens, because
the drawing layer classes have all kinds of comments except those
that would explain the purpose or usage of the classes. My
understanding is that drawing layer keeps all kinds of state
in Sdr* classes and when drawing it tries to find those based
on the OutputDevice. But since tiled drawing uses its own
VirtualDevice for the drawing, the search fails and a temporary state
is used that's always setup up and cleared again. Which is wasteful,
and not having the state around also means that e.g. when clicking
a checkbox for impress master background, with idle painting
disabled there's nothing to react to the event and cause a tile
repaint.

Change-Id: Ic9036680c628d67615a82dcc4f585ab827b91525
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/121779
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/sd/source/ui/unoidl/unomodel.cxx b/sd/source/ui/unoidl/unomodel.cxx
index a246aab75b34..f5d3b51c72d4 100644
--- a/sd/source/ui/unoidl/unomodel.cxx
+++ b/sd/source/ui/unoidl/unomodel.cxx
@@ -58,6 +58,8 @@
 #include <svx/svdundo.hxx>
 #include <svx/unoapi.hxx>
 #include <svx/unofill.hxx>
+#include <svx/sdrpagewindow.hxx>
+#include <svx/sdrpaintwindow.hxx>
 #include <editeng/flditem.hxx>
 #include <editeng/fontitem.hxx>
 #include <toolkit/awt/vclxdevice.hxx>
@@ -2220,6 +2222,25 @@ void SdXImpressDocument::paintTile( VirtualDevice& rDevice,
     if (!pViewSh)
         return;
 
+    // Setup drawing layer to work properly. Since we use a custom VirtualDevice
+    // for the drawing, SdrPaintView::BeginCompleteRedraw() will call FindPaintWindow()
+    // unsuccessfully and use a temporary window that doesn't keep state. So patch
+    // the existing SdrPageWindow to use a temporary, and this way the state will be kept.
+    // Well, at least that's how I understand it based on Writer's RenderContextGuard,
+    // as the drawing layer classes lack documentation.
+    SdrPageWindow* patchedPageWindow = nullptr;
+    SdrPaintWindow* previousPaintWindow = nullptr;
+    std::unique_ptr<SdrPaintWindow> temporaryPaintWindow;
+    if(SdrView* pDrawView = pViewSh->GetDrawView())
+    {
+        if(SdrPageView* pSdrPageView = pDrawView->GetSdrPageView())
+        {
+            patchedPageWindow = pSdrPageView->FindPageWindow(*getDocWindow());
+            temporaryPaintWindow.reset(new SdrPaintWindow(*pDrawView, rDevice));
+            previousPaintWindow = patchedPageWindow->patchPaintWindow(*temporaryPaintWindow);
+        }
+    }
+
     // Scaling. Must convert from pixels to twips. We know
     // that VirtualDevices use a DPI of 96.
     // We specifically calculate these scales first as we're still
@@ -2257,6 +2278,9 @@ void SdXImpressDocument::paintTile( VirtualDevice& rDevice,
 
     LokChartHelper::PaintAllChartsOnTile(rDevice, nOutputWidth, nOutputHeight,
                                          nTilePosX, nTilePosY, nTileWidth, nTileHeight);
+
+    if(patchedPageWindow != nullptr)
+        patchedPageWindow->unpatchPaintWindow(previousPaintWindow);
 }
 
 void SdXImpressDocument::selectPart(int nPart, int nSelect)