scrolling very slow in calc

even on a short spreadsheet scrolling up and down leaves
the first/last row (depending on the direction of scroll)
unchanged until the scrolling stops.

http://people.freedesktop.org/~mst/calc_4.2_scrolling.webm

On larger document there are rendering artifacts during scrolling which go away
after scrolling for me and mstahl, but a bunch of people can show us piles of
horribly broken spreadsheets after scrolling, esp wheel scrolling

Revert "fdo#75026: Sometimes we need to update grid view...

while not being active."

This reverts commit 52cc88d6.

Revert "fdo#68961: Check visible range during scrolling, and re-paint if necessary."

This reverts commit e36c8a67.

Revert "Repaint grid view when the visible area changes."

This reverts commit b54c1a53.

Conflicts:
	sc/source/ui/app/scmod.cxx

Revert "Update visible ranges when updating the scroll bars."

This reverts commit 391a57ef.

Change-Id: Ie170308cba18a9a74c7c72daf07dfa0a4ef7bd13
Reviewed-on: https://gerrit.libreoffice.org/10350Tested-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>
Tested-by: Kohei Yoshida <libreoffice@kohei.us>

sc/source/ui/inc/tabview.hxx

@@ -204,12 +204,6 @@ private:
 
     void            PaintRangeFinderEntry (ScRangeFindData* pData, SCTAB nTab);
 
-    /**
-     * Check the visible grid area to see if the visible range has changed. If
-     * so, update the stored visible range, and re-paint the grid area.
-     */
-    void UpdateGrid();
-
 protected:
     void            UpdateHeaderWidth( const ScVSplitPos* pWhich = NULL,
                                         const SCROW* pPosY = NULL );

sc/source/ui/view/gridwin4.cxx

@@ -390,6 +390,8 @@ void ScGridWindow::Draw( SCCOL nX1, SCROW nY1, SCCOL nX2, SCROW nY2, ScUpdateMod
 
     OSL_ENSURE( ValidCol(nX2) && ValidRow(nY2), "GridWin Draw Bereich zu gross" );
 
+    UpdateVisibleRange();
+
     if (nX2 < maVisibleRange.mnCol1 || nY2 < maVisibleRange.mnRow1)
         return;
                     // unsichtbar

sc/source/ui/view/tabview.cxx

@@ -1198,8 +1198,6 @@ void ScTabView::ScrollX( long nDeltaX, ScHSplitPos eWhich, bool bUpdBars )
         if (pColOutline[eWhich]) pColOutline[eWhich]->ScrollPixel( nDiff );
         if (bUpdBars)
             UpdateScrollBars();
-        else
-            UpdateGrid();
     }
 
     if (nDeltaX==1 || nDeltaX==-1)
@@ -1285,8 +1283,6 @@ void ScTabView::ScrollY( long nDeltaY, ScVSplitPos eWhich, bool bUpdBars )
         if (pRowOutline[eWhich]) pRowOutline[eWhich]->ScrollPixel( nDiff );
         if (bUpdBars)
             UpdateScrollBars();
-        else
-            UpdateGrid();
     }
 
     if (nDeltaY==1 || nDeltaY==-1)

sc/source/ui/view/tabview3.cxx

@@ -2089,16 +2089,6 @@ void ScTabView::PaintRangeFinderEntry (ScRangeFindData* pData, const SCTAB nTab)
     }
 }
 
-void ScTabView::UpdateGrid()
-{
-    if (!UpdateVisibleRange())
-        // Visible range hasn't changed. No need to re-paint.
-        return;
-
-    SC_MOD()->AnythingChanged();                // if visible area has changed
-    PaintGrid();
-}
-
 void ScTabView::PaintRangeFinder( long nNumber )
 {
     ScInputHandler* pHdl = SC_MOD()->GetInputHdl( aViewData.GetViewShell() );

sc/source/ui/view/tabview4.cxx

@@ -421,7 +421,12 @@ void ScTabView::UpdateScrollBars()
     }
 
     //      set visible area for online spelling
-    UpdateGrid();
+
+    if ( aViewData.IsActive() )
+    {
+        if (UpdateVisibleRange())
+            SC_MOD()->AnythingChanged();                // if visible area has changed
+    }
 }
 
 #ifndef HDR_SLIDERSIZE