Do some sanity checks in DoDrawText to make sure we actually have some glyphs

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@20055 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/cocoa/dc.mm b/src/cocoa/dc.mm
index b6c71aaca8cece9464c0fe1062e48d059658208f..7b54beb5905ea94d5842545115c59ce5e867555d 100644 (file)
--- a/src/cocoa/dc.mm
+++ b/src/cocoa/dc.mm
@@ -107,7 +107,11 @@ void wxDC::DoDrawText(const wxString& text, wxCoord x, wxCoord y)
 
     NSRange glyphRange = [sm_cocoaNSLayoutManager glyphRangeForTextContainer:sm_cocoaNSTextContainer];
     NSRect usedRect = [sm_cocoaNSLayoutManager usedRectForTextContainer:sm_cocoaNSTextContainer];
-
+    // NOTE: We'll crash trying to get the location of glyphAtIndex:0 if
+    // there is no length or we don't start at zero
+    if(!glyphRange.length)
+        return;
+    wxASSERT_MSG(glyphRange.location==0,"glyphRange must begin at zero");
 
     NSAffineTransform *transform = [NSAffineTransform transform];
     [transform translateXBy:x yBy:y];