Cairo Backend: print_surface

[chdemars]

In order to get matplotlib and mapnik to play nicely together, I had to alter backend_cairo.py by adding the following to the FigureCanvasCairo class:

def print_surface(self, fobj, *args, **kwargs):
    dpi = 72
    self.figure.dpi = dpi
    w_in, h_in = self.figure.get_size_inches()
    width_pt, height_pt = w_in * dpi, h_in * dpi
    renderer = RendererCairo(self.figure.dpi)
    renderer.set_width_height(width_pt, height_pt)
    renderer.set_ctx_from_surface(fobj)
    self.figure.draw(renderer)

Now I am a happy cartographer: I have maps and graphs on the same page all driven by a postgis database. Others might find this addition just as useful.

To use, just call:
mycanvas.print_surface(my_cairo_surface)

To move the location that the chart is printedl:
my_cairo_surface.set_device_offset(x,y)
mycanvas.print_surface(my_cairo_surface)

Cheers,
--Christopher

[pelson]

Hey @chdemars . Thanks for this, I'm not sure who our resident cairo expert is, but I expect somebody will be able to pick this up and create a PR from it (if that somebody were you, that would be even better).

Out of interest, will you be writing up the process of integrating the mpl and Mapnik somewhere? I would live to read it!

[chdemars]

I initiated a pull request on the topic. I also have created an example
script to show how to use mapnik and matplotlib together. I'm not sure
where I should submit it and it's associated data.

--Christopher

On Fri, Sep 14, 2012 at 2:07 AM, Phil Elson notifications@github.comwrote:

Hey @chdemars https://github.com/chdemars . Thanks for this, I'm not
sure who our resident cairo expert is, but I expect somebody will be able
to pick this up and create a PR from it (if that somebody were you, that
would be even better).

Out of interest, will you be writing up the process of integrating the mpl
and Mapnik somewhere? I would live to read it!

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/1245#issuecomment-8555558.

[pelson]

PR: #1245

[dmcdougall]

@pelson The PR is #1254.

[tacaswell]

The PR for this has (edit by @pelson: not) been merged. @chdemars If this isn't implemented please re-open.