From a92a8d40ce567ecf5b0baacd9a93a94aac9a4a2d Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Tue, 16 Jul 2019 22:42:53 +0200
Subject: 2019-07-16 18:30:00

---
 metapost/context/base/mpiv/mp-chem.mpiv | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

(limited to 'metapost/context/base/mpiv/mp-chem.mpiv')

diff --git a/metapost/context/base/mpiv/mp-chem.mpiv b/metapost/context/base/mpiv/mp-chem.mpiv
index 4ed9eaa8f..c5f79a88c 100644
--- a/metapost/context/base/mpiv/mp-chem.mpiv
+++ b/metapost/context/base/mpiv/mp-chem.mpiv
@@ -513,10 +513,21 @@ def chem_transformed (suffix $) = % not vardef!
     fi
 enddef ;
 
+% vardef chem_draw (expr what, r, c) (text extra) =
+%     draw what
+%         withpen pencircle scaled r
+%         withcolor c
+%         extra ;
+% enddef ;
+
 vardef chem_draw (expr what, r, c) (text extra) =
     draw what
         withpen pencircle scaled r
-        withcolor c
+        if string c :
+            if c <> "" : withcolor c fi
+        else :
+            withcolor c
+        fi
         extra ;
 enddef ;
 
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