Pixel Offset Example Not Working

Community matplotlib-users
1

Hi there,

Just wondering if anyone knows how to do a pixel offset in matplotlib?

I've tried running the example in
http://www.scipy.org/Cookbook/Matplotlib/Transformations#line-58 but
it appears to have been trashed by changes to the api. The functions
in the no-offset_copy function version don't exist any more and their
replacements don't work the same way, and the offset_copy function is
not available. (At least I am assuming it is because of updates rather
then my copy of Matplotlib being out of date: 0.99.1.1) This is a very
useful function if you're doing discrete data plots like I am and you
want uniform clusters of points.

Thanks for your time.

Regards,

Mikey

2

offset_copy is still available, but unfortunately doesn't work with the cookbook example because of a bug that was inadvertently introduced into matplotlib.

The bug is that offset_copy should have been defined as:

   def offset_copy(trans, fig=None, x=0.0, y=0.0, units='inches'):

instead of:

   def offset_copy(trans, fig, x=0.0, y=0.0, units='inches'):

That is, the "fig" argument was originally optional, and in July 2008 I accidentally was made it "required".

This will be fixed in the next release of matplotlib -- in the meantime the workaround to get the Cookbook recipe to work is to call offset_copy like this:

        return offset_copy(ax.transData, None, x=x, y=y, units='dots')

If that change doesn't fix the recipe for you, please send a full traceback of the error so we can diagnose the problem. (FWIW -- I don't have edit privileges for the cookbook page, or I would go in and fix this...)

Cheers,
Mike

mikey wrote:

···

Hi there,

Just wondering if anyone knows how to do a pixel offset in matplotlib?

I've tried running the example in
http://www.scipy.org/Cookbook/Matplotlib/Transformations#line-58 but
it appears to have been trashed by changes to the api. The functions
in the no-offset_copy function version don't exist any more and their
replacements don't work the same way, and the offset_copy function is
not available. (At least I am assuming it is because of updates rather
then my copy of Matplotlib being out of date: 0.99.1.1) This is a very
useful function if you're doing discrete data plots like I am and you
want uniform clusters of points.

Thanks for your time.

Regards,

Mikey

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Michael Droettboom
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3

There is an "official" transformations tutorial now in the mpl docs
which is updated to the current API

http://matplotlib.sourceforge.net/users/transforms_tutorial.html

JDH

···

On Fri, Feb 26, 2010 at 9:47 AM, mikey <abc.mikey@...982...> wrote:

Hi there,

Just wondering if anyone knows how to do a pixel offset in matplotlib?

I've tried running the example in
http://www.scipy.org/Cookbook/Matplotlib/Transformations#line-58 but