added support for \operatorname (closes #553)

ivanov · ivanov · commit c459dc5d07bb · 2011-10-25T02:49:31.000-07:00
I started with the version of the related code written by Freddie Witherden and committed to (the now abandoned?) mathtex spinoff project which didn't makes its way back to matplotlib. However, that code: http://code.google.com/p/mathtex/source/detail?r=75 allowed only to lower- and upper-case letters to be used inside of \operatorname. I have improved it to allow the usage of any simple character - including the insertion of spaces - such that $\operator{arg\,max}$ actually inserts a space between arg max
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,3 +1,7 @@
+2011-10-25 added support for \operatorname to mathtext,
+           including the ability to insert spaces, such as
+           $\operatorname{arg\,max}$ - PI
+
 2011-08-18 Change api of Axes.get_tightbbox and add an optional
            keyword parameter *call_axes_locator*. - JJL
 
diff --git a/lib/matplotlib/mathtext.py b/lib/matplotlib/mathtext.py
@@ -2269,6 +2269,12 @@ def __init__(self):
                     + (group | Error("Expected \overline{value}"))
                     ).setParseAction(self.overline).setName("overline")
 
+        operatorname = Group(
+                        Suppress(Literal(r"\operatorname"))
+                     + ((start_group + ZeroOrMore(simple)  + end_group)
+                        | Error("Expected \operatorname{value}"))
+                     ).setParseAction(self.operatorname).setName("operatorname")
+
         placeable   <<(function
                      ^ (c_over_c | symbol)
                      ^ accent
@@ -2279,6 +2285,7 @@ def __init__(self):
                      ^ genfrac
                      ^ sqrt
                      ^ overline
+                     ^ operatorname
                      )
 
         simple      <<(space
@@ -2578,6 +2585,18 @@ def function(self, s, loc, toks):
         hlist.function_name = toks[0]
         return hlist
 
+    def operatorname(self, s, loc, toks):
+        self.push_state()
+        state = self.get_state()
+        state.font = 'rm'
+        # Change the font of Chars, but leave Kerns alone
+        for c in toks[0]:
+            if isinstance(c,Char):
+                c.font = 'rm'
+                c._update_metrics()
+        self.pop_state()
+        return Hlist(toks[0])
+
     def start_group(self, s, loc, toks):
         self.push_state()
         # Deal with LaTeX-style font tokens
