prefetch graphics also for page before and after in slidesorter

The idea is that this will make them preloaded for when the user
scrolls e.g. using PageDown.

Change-Id: Icac9b6e88b25e9b0434c5ab7a152f47866dfadc5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107823
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/sd/source/ui/slidesorter/view/SlideSorterView.cxx b/sd/source/ui/slidesorter/view/SlideSorterView.cxx
index a531943096f1..f13aa1b7eb09 100644
--- a/sd/source/ui/slidesorter/view/SlideSorterView.cxx
+++ b/sd/source/ui/slidesorter/view/SlideSorterView.cxx
@@ -654,6 +654,14 @@ void SlideSorterView::Paint (
             continue;
         pDescriptor->GetPage()->getGraphicsForPrefetch(graphics);
     }
+    // Handle also one page before and after to have those in advance on scrolling.
+    for (::tools::Long nIndex : { aRange.Min() - 1, aRange.Max() + 1 })
+    {
+        model::SharedPageDescriptor pDescriptor (mrModel.GetPageDescriptor(nIndex));
+        if (!pDescriptor)
+            continue;
+        pDescriptor->GetPage()->getGraphicsForPrefetch(graphics);
+    }
     if(graphics.size() > 1) // threading does not help with loading just one
         GraphicFilter::GetGraphicFilter().MakeGraphicsAvailableThreaded(graphics);