From: Nicolas <nico_75_0@ya...>  20070703 08:32:40

Thank you very much. I know very little about numpy in fact. If I don't find a pure matplotlib method, I will use your suggestion with wx. I think however matplotlib may be used only (and it will be even better as I plan to make a Qt version in the future) So, in : >>> from matplotlib.transforms import Value >>> from matplotlib.backends.backend_agg import RendererAgg >>> r = RendererAgg(50, 50, Value(72)) >>> r.draw_image(0, 0, im) What is the correct format for im ? Thanks, Nicolas On 7/2/07, Christopher Barker <Chris.Barker@...> wrote: > > I don't know how to do it with the MPL agg backend, but I think you > mentioned wx, and you can do it there instead. a wxImage can be > constructed from a buffer object, then saved as a PNG. You may need to > set the rgb and alpha portions separately. See the wxPython wiki and > search for "Image". > > Also: > > > matrix = [] > > buffer = self.get_renderer().tostring_argb() > > l, h = self.GetSize() > > for ligne in xrange(h): > > matrix.append([]) > > for colonne in xrange(l): > > i = 4*(ligne*h + colonne) > > pixel = buffer[i:i+4] > > matrix[1].append(pixel) > > This is a very slow way to create the numpy array! > > Option a: first create an empty array: > > matrix = numpy.empty((l,h,4), numpy.byte) > > then fill that in. but even better: > > you can build the array directly from the buffer string: > > matrix = numpy.fromstring(buffer, dtype=numpy.byte) > lotlibusers > >  > Christopher Barker, Ph.D. > Oceanographer > > Emergency Response Division > NOAA/NOS/OR&R (206) 5266959 voice > 7600 Sand Point Way NE (206) 5266329 fax > Seattle, WA 98115 (206) 5266317 main reception > > Chris.Barker@... > 