* Fleshed out IPythonWidget's style control.

* Removed magic override code to reflect new magic design.
* Misc. cleanup.

IPython/frontend/qt/console/console_widget.py

@@ -576,15 +576,15 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
             if self.gui_completion:
                 self._completion_widget.show_items(cursor, items) 
             else:
-                text = self.format_as_columns(items)
+                text = self._format_as_columns(items)
                 self._append_plain_text_keeping_prompt(text)
 
-    def format_as_columns(self, items, separator='  '):
+    def _format_as_columns(self, items, separator='  '):
         """ Transform a list of strings into a single string with columns.
 
         Parameters
         ----------
-        items : sequence [str]
+        items : sequence of strings
             The strings to process.
 
         separator : str, optional [default is two spaces]
@@ -600,10 +600,10 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
         font_metrics = QtGui.QFontMetrics(self.font)
         displaywidth = max(5, (self.width() / font_metrics.width(' ')) - 1)
 
-        # Some degenerate cases
+        # Some degenerate cases.
         size = len(items)
         if size == 0: 
-            return "\n"
+            return '\n'
         elif size == 1:
             return '%s\n' % str(items[0])
 
@@ -643,7 +643,7 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
                 del texts[-1]
             for col in range(len(texts)):
                 texts[col] = texts[col].ljust(colwidths[col])
-            string += "%s\n" % str(separator.join(texts))
+            string += '%s\n' % str(separator.join(texts))
         return string
 
     def _get_block_plain_text(self, block):

IPython/frontend/qt/console/ipython_widget.py

@@ -10,7 +10,7 b' class IPythonWidget(FrontendWidget):'
     """ A FrontendWidget for an IPython kernel.
     """
 
-    # The default stylesheet for prompts, colors, etc.
+    # The default stylesheet: black text on a white background.
     default_stylesheet = """
         .error { color: red; }
         .in-prompt { color: navy; }
@@ -19,6 +19,17 b' class IPythonWidget(FrontendWidget):'
         .out-prompt-number { font-weight: bold; }
     """
 
+    # A dark stylesheet: white text on a black background.
+    dark_stylesheet = """
+        QPlainTextEdit { background-color: black; color: white }
+        QFrame { border: 1px solid grey; }
+        .error { color: red; }
+        .in-prompt { color: lime; }
+        .in-prompt-number { color: lime; font-weight: bold; }
+        .out-prompt { color: red; }
+        .out-prompt-number { color: red; font-weight: bold; }
+    """
+
     #---------------------------------------------------------------------------
     # 'QObject' interface
     #---------------------------------------------------------------------------
@@ -27,34 +38,10 b' class IPythonWidget(FrontendWidget):'
         super(IPythonWidget, self).__init__(parent)
 
         # Initialize protected variables.
-        self._magic_overrides = {}
         self._prompt_count = 0
 
         # Set a default stylesheet.
-        self.set_style_sheet(self.default_stylesheet)
-
-    #---------------------------------------------------------------------------
-    # 'ConsoleWidget' abstract interface
-    #---------------------------------------------------------------------------
-
-    def _execute(self, source, hidden):
-        """ Reimplemented to override magic commands.
-        """
-        magic_source = source.strip()
-        if magic_source.startswith('%'):
-            magic_source = magic_source[1:]
-        magic, sep, arguments = magic_source.partition(' ')
-        if not magic:
-            magic = magic_source
-
-        callback = self._magic_overrides.get(magic)
-        if callback:
-            output = callback(arguments)
-            if output:
-                self.appendPlainText(output)
-            self._show_interpreter_prompt()
-        else:
-            super(IPythonWidget, self)._execute(source, hidden)
+        self.reset_style_sheet()
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface
@@ -119,26 +106,15 b' class IPythonWidget(FrontendWidget):'
     # 'IPythonWidget' interface
     #---------------------------------------------------------------------------
 
-    def set_magic_override(self, magic, callback):
-        """ Overrides an IPython magic command. This magic will be intercepted
-            by the frontend rather than passed on to the kernel and 'callback'
-            will be called with a single argument: a string of argument(s) for
-            the magic. The callback can (optionally) return text to print to the
-            console.
+    def reset_style_sheet(self):
+        """ Sets the style sheet to the default style sheet.
         """
-        self._magic_overrides[magic] = callback
-
-    def remove_magic_override(self, magic):
-        """ Removes the override for the specified magic, if there is one.
-        """
-        try:
-            del self._magic_overrides[magic]
-        except KeyError:
-            pass
+        self.set_style_sheet(self.default_stylesheet)
 
     def set_style_sheet(self, stylesheet):
         """ Sets the style sheet.
         """
+        self.setStyleSheet(stylesheet)
         self.document().setDefaultStyleSheet(stylesheet)
 
 

IPython/frontend/qt/console/pygments_highlighter.py

@@ -66,7 +66,7 b" def get_tokens_unprocessed(self, text, stack=('root',)):"
 RegexLexer.get_tokens_unprocessed = get_tokens_unprocessed
 
 
-class BlockUserData(QtGui.QTextBlockUserData):
+class PygmentsBlockUserData(QtGui.QTextBlockUserData):
     """ Storage for the user data associated with each line.
     """
 
@@ -81,7 +81,7 b' class BlockUserData(QtGui.QTextBlockUserData):'
         attrs = ['syntax_stack']
         kwds = ', '.join([ '%s=%r' % (attr, getattr(self, attr)) 
                            for attr in attrs ])
-        return 'BlockUserData(%s)' % kwds
+        return 'PygmentsBlockUserData(%s)' % kwds
 
 
 class PygmentsHighlighter(QtGui.QSyntaxHighlighter):
@@ -117,7 +117,8 b' class PygmentsHighlighter(QtGui.QSyntaxHighlighter):'
             index += l
 
         if hasattr(self._lexer, '_saved_state_stack'):
-            data = BlockUserData(syntax_stack=self._lexer._saved_state_stack)
+            data = PygmentsBlockUserData(
+                syntax_stack=self._lexer._saved_state_stack)
             self.currentBlock().setUserData(data)
             # Clean up for the next go-round.
             del self._lexer._saved_state_stack
@@ -174,6 +175,8 b' class PygmentsHighlighter(QtGui.QSyntaxHighlighter):'
         return result
 
     def _get_color(self, color):
+        """ Returns a QColor built from a Pygments color string.
+        """
         qcolor = QtGui.QColor()
         qcolor.setRgb(int(color[:2], base=16),
                       int(color[2:4], base=16),