speed up rendering annotatins, cache meta height

shaves 2% off scrolling profile on a large word doc

Change-Id: I283e3f99c1c385f3d20ea573d15ca59b4629c14d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152978
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/sw/source/uibase/docvw/AnnotationWin2.cxx b/sw/source/uibase/docvw/AnnotationWin2.cxx
index 06efbfdb581f..2c4bc7ce3d5e 100644
--- a/sw/source/uibase/docvw/AnnotationWin2.cxx
+++ b/sw/source/uibase/docvw/AnnotationWin2.cxx
@@ -1262,14 +1262,25 @@ int SwAnnotationWin::GetPrefScrollbarWidth() const
 
 sal_Int32 SwAnnotationWin::GetMetaHeight() const
 {
-    const int fields = GetNumFields();
+    if (!moMetaHeight)
+    {
+        const int fields = GetNumFields();
 
-    sal_Int32 nRequiredHeight = 0;
-    weld::Label* aLabels[3] = { mxMetadataAuthor.get(), mxMetadataDate.get(), mxMetadataResolved.get() };
-    for (int i = 0; i < fields; ++i)
-        nRequiredHeight += aLabels[i]->get_preferred_size().Height();
+        sal_Int32 nRequiredHeight = 0;
+        weld::Label* aLabels[3] = { mxMetadataAuthor.get(), mxMetadataDate.get(), mxMetadataResolved.get() };
+        for (int i = 0; i < fields; ++i)
+            nRequiredHeight += aLabels[i]->get_preferred_size().Height();
+        moMetaHeight = nRequiredHeight;
+    }
+    return *moMetaHeight;
+}
 
-    return nRequiredHeight;
+void SwAnnotationWin::DataChanged(const DataChangedEvent& rDCEvt)
+{
+    if ((rDCEvt.GetType() == DataChangedEventType::SETTINGS) && (rDCEvt.GetFlags() & AllSettingsFlags::STYLE))
+    {
+        moMetaHeight.reset();
+    }
 }
 
 sal_Int32 SwAnnotationWin::GetNumFields() const