fix scrolling performance of listboxes with hundreds of entries

make it approximately infinitely faster

a) add a method AdjustEntryHeightAndRecalc that just does AdjustEntryHeight and
RecalcViewData and replace all the places that do the two of those together
with that utility

b) in our SetFont now only call AdjustEntryHeightAndRecalc if the new font is
different to the old font, ignoring color which doesn't have a bearing on row
size.

c) where we originally called SetFont(GetFont()), which would have triggered
AdjustEntryHeightAndRecalc, now call the new AdjustEntryHeightAndRecalc
explicitly.

The performance problem apparently a regression from
ac7acb0ab1329913b0cec79790adcde0263960be where we seem to now end up drawing on
ourself and calling SetFont on ourself rather than on a pImpl without an
overridden SetFont. So when we redraw on scrolling we triggered a cascade of
calculations and force text layout of every row.

(cherry picked from commit 3b6e61c3968a4aaec0b594803219961f3fcc9232)

Conflicts:
include/svtools/treelistbox.hxx

Change-Id: I3c284c360f06ac383e8c38045fc4c2946f505b35
Reviewed-on: https://gerrit.libreoffice.org/3611
Reviewed-by: Tor Lillqvist <tml@iki.fi>
Tested-by: Tor Lillqvist <tml@iki.fi>

2 files changed, 25 insertions, 6 deletions

diff --git a/svtools/inc/svtools/treelistbox.hxx b/svtools/inc/svtools/treelistbox.hxx
index ba678aeb9186..d2590889ac6f 100644
--- a/svtools/inc/svtools/treelistbox.hxx
+++ b/svtools/inc/svtools/treelistbox.hxx
@@ -580,6 +580,7 @@ protected:
     sal_Bool        AreChildrenTransient() const;
     void            SetChildrenNotTransient();
 
+    void            AdjustEntryHeightAndRecalc( const Font& rFont );
 public:
 
     void                SetExtendedWinBits( ExtendedWinBits _nBits );
diff --git a/svtools/source/contnr/treelistbox.cxx b/svtools/source/contnr/treelistbox.cxx
index b6c9613f79ca..2fe94e7fe95d 100644
--- a/svtools/source/contnr/treelistbox.cxx
+++ b/svtools/source/contnr/treelistbox.cxx
@@ -1510,7 +1510,10 @@ void SvTreeListBox::InitTreeView()
 
     mbContextBmpExpanded = true;
     nContextBmpWidthMax = 0;
+
     SetFont( GetFont() );
+    AdjustEntryHeightAndRecalc( GetFont() );
+
     SetSpaceBetweenEntries( 0 );
     SetLineColor();
     InitSettings( sal_True, sal_True, sal_True );
@@ -2575,15 +2578,32 @@ void SvTreeListBox::SetExpandedNodeBmp( const Image& rBmp )
 void SvTreeListBox::SetFont( const Font& rFont )
 {
     DBG_CHKTHIS(SvTreeListBox,0);
+
     Font aTempFont( rFont );
+    Font aOrigFont( GetFont() );
     aTempFont.SetTransparent( sal_True );
+    if (aTempFont == aOrigFont)
+        return;
     Control::SetFont( aTempFont );
-    AdjustEntryHeight( aTempFont );
+
+    aTempFont.SetColor(aOrigFont.GetColor());
+    aTempFont.SetFillColor(aOrigFont.GetFillColor());
+    aTempFont.SetTransparent(aOrigFont.IsTransparent());
+
+    if (aTempFont == aOrigFont)
+        return;
+
+    AdjustEntryHeightAndRecalc( GetFont() );
+}
+
+void SvTreeListBox::AdjustEntryHeightAndRecalc( const Font& rFont )
+{
+    DBG_CHKTHIS(SvTreeListBox,0);
+    AdjustEntryHeight( rFont );
     // always invalidate, else things go wrong in SetEntryHeight
     RecalcViewData();
 }
 
-
 void SvTreeListBox::Paint( const Rectangle& rRect )
 {
     DBG_CHKTHIS(SvTreeListBox,0);
@@ -2626,8 +2646,7 @@ void SvTreeListBox::SetSpaceBetweenEntries( short nOffsLogic )
         nEntryHeight = nEntryHeight - nEntryHeightOffs;
         nEntryHeightOffs = (short)nOffsLogic;
         nEntryHeight = nEntryHeight + nOffsLogic;
-        AdjustEntryHeight( GetFont() );
-        RecalcViewData();
+        AdjustEntryHeightAndRecalc( GetFont() );
         pImp->SetEntryHeight( nEntryHeight );
     }
 }
@@ -3842,8 +3861,7 @@ void SvTreeListBox::InitSettings(sal_Bool bFont,sal_Bool bForeground,sal_Bool bB
         aFont = rStyleSettings.GetFieldFont();
         aFont.SetColor( rStyleSettings.GetWindowTextColor() );
         SetPointFont( aFont );
-        AdjustEntryHeight( aFont );
-        RecalcViewData();
+        AdjustEntryHeightAndRecalc( aFont );
     }
 
     if( bForeground || bFont )