Plotting masked data working?

Hi, John and all,

  is the recent patch for use of masked data in plotting lines (and contours) working?
What is the simplest example of using it?

I got this with recent CVS

           python examples/ -numarray :
Traceback (most recent call last):
  File "examples/", line 19, in ?
    lines = plot(x, y, 'r', x, ym1, 'g', x, ym2, 'bo')
  File "/usr/lib/python2.3/site-packages/matplotlib/", line 1930, in plot
    ret = gca().plot(*args, **kwargs)
  File "/usr/lib/python2.3/site-packages/matplotlib/", line 2411, in plot
  File "/usr/lib/python2.3/site-packages/matplotlib/", line 739, in add_line
    self.update_datalim_numerix( xdata, ydata )
  File "/usr/lib/python2.3/site-packages/matplotlib/", line 724, in update_datalim_numerix
    self.dataLim.update_numerix(x, y, not self.has_data())
TypeError: Bbox::update_numerix expected numerix array

This is independent from using Numeric or numarray. Some grepp-ing of source shows that this
"TypeError" message comes from src/_transforms.cpp (lines 439, 445).

This short code fragment (lines 426-439 of src/_transforms.cpp) should make clear where the error occured:

Bbox::update_numerix(const Py::Tuple &args) {
  //update the boox from the numerix arrays x and y


  Py::Object xo = args[0];
  Py::Object yo = args[1];

  PyArrayObject *x = (PyArrayObject *) PyArray_ContiguousFromObject(xo.ptr(), PyArray_DOUBLE, 1,1);

  if (x==NULL)
    throw Py::TypeError("Bbox::update_numerix expected numerix array");


So, the trouble is with converting class MaskedArray to (Numeric) array. Sorry, I am not able
to help with the fix. I wonder, if someone can run the successfully.