handle empty Rectangle better in starmath

which required fixing a unit test to call Prepare, otherwise the nodes
are not ready for layout

Change-Id: I763c1b05d4dfafa73ebaee55d080876848de94f6
Reviewed-on: https://gerrit.libreoffice.org/71800
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 4 insertions, 1 deletions

diff --git a/starmath/source/node.cxx b/starmath/source/node.cxx
index 97d97582826d..fcdcbbdb2e07 100644
--- a/starmath/source/node.cxx
+++ b/starmath/source/node.cxx
@@ -2064,6 +2064,7 @@ void SmTextNode::Prepare(const SmFormat &rFormat, const SmDocShell &rDocShell, i
         SetRectHorAlign( RectHorAlign::Left );
 
     maText = GetToken().aText;
+    assert(!maText.isEmpty());
     GetFont() = rFormat.GetFont(GetFontDesc());
 
     if (IsItalic( GetFont() ))
@@ -2402,7 +2403,9 @@ void SmMathSymbolNode::AdaptToY(OutputDevice &rDev, sal_uLong nHeight)
 
     // get denominator of error factor for height
     long nTmpBorderWidth = GetFont().GetBorderWidth();
-    long nDenom = SmRect(aTmpDev, nullptr, GetText(), nTmpBorderWidth).GetHeight();
+    long nDenom = 0;
+    if (!GetText().isEmpty())
+        nDenom = SmRect(aTmpDev, nullptr, GetText(), nTmpBorderWidth).GetHeight();
 
     // scale fontwidth with this error factor
     aFntSize.setHeight( aFntSize.Height() * nHeight );