Attempts to enforce system settings in the demo page panel.

Adds a block in the wx.stc.StyledTextCtrl version of DemoPageEditor that will try to match system settings for caret period.
Also adds the ability to read a switch off of sys.argv to manually disable cursor blinking.

demo/Main.py

@@ -361,6 +361,37 @@ def FindImages(text, widgetName):
     return winAppearance
 
 
+def GetCaretPeriod(win = None):
+    """
+    Attempts to identify the correct caret blinkrate to use in the Demo Code panel.
+
+    :pram wx.Window win: a window to pass to wx.SystemSettings.GetMetric.
+
+    :return: a value in milliseconds that indicates the proper period.
+    :rtype: int
+
+    :raises: ValueError if unable to resolve a proper caret blink rate.
+    """
+    try:
+        onmsec  = wx.SystemSettings.GetMetric(wx.SYS_CARET_ON_MSEC, win)
+        offmsec = wx.SystemSettings.GetMetric(wx.SYS_CARET_OFF_MSEC, win)
+
+        # check values aren't -1
+        if -1 in (onmsec, offmsec):
+            raise ValueError
+
+        # attempt to average.
+        # (wx systemsettings allows on and off time, but scintilla just takes a single period.)
+        return (onmsec +offmsec) / 2.0
+
+    except (AttributeError, ValueError):
+        # Issue where wx.SYS_CARET_ON/OFF_MSEC is unavailable.
+        # Check
+        if '--no-caret-blink' in sys.argv:
+            return 0
+        else:
+            raise ValueError("Unable to determine caret blink rate.")
+
 #---------------------------------------------------------------------------
 # Set up a thread that will scan the wxWidgets docs for window styles,
 # events and widgets screenshots
@@ -612,6 +643,12 @@ try:
             # Selection background
             self.SetSelBackground(1, '#66CCFF')
 
+            # Attempt to set caret blink rate.
+            try:
+                self.SetCaretPeriod(GetCaretPeriod(self))
+            except ValueError:
+                pass
+
             self.SetSelBackground(True, wx.SystemSettings.GetColour(wx.SYS_COLOUR_HIGHLIGHT))
             self.SetSelForeground(True, wx.SystemSettings.GetColour(wx.SYS_COLOUR_HIGHLIGHTTEXT))