Question about the data path

Community matplotlib-users
1

I'm using matplotlib in an application I distribute. For Windows and Mac
users I distribute a frozen application which includes python,
matplotlib, etc. and I'm wondering how best to include the matplotlib
data files.

matplotlib searches for its data files in __init__._get_data_path. It
seems to search shared locations first, then locations that would be
relevant to a frozen application. Is that safe? I worry that if a user
of my app has their own version of matplotlib (possibly a very different
version than I've included) then the data files might be different.

If this really is an issue, then what to do?

For Mac I can put the data files deep in the app in
Contents/Frameworks/Python.Framework/2.4/share/matplotlib, which is the
second location looked at (after environment variable MATPLOTLIBDATA).

For Windows, there doesn't seem any way out. The Windows frozen test is
dead last.

···

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Also, should I worry about the user's local matplotlibrc file (which
again might be for the wrong version or might never have been created or
configured at all -- the main problem I've hit so far is that the
auto-created default of this file is always wrong about the back
end--picking gtkagg even though I don't even build gtk support).

Again, that looks difficult or impossible because the search order is
for the usual user locations first, then look in the data directory.

Any advice would be most appreciated.

-- Russell

2

I'm using matplotlib in an application I distribute. For Windows and Mac
users I distribute a frozen application which includes python,
matplotlib, etc. and I'm wondering how best to include the matplotlib
data files.

matplotlib searches for its data files in __init__._get_data_path. It
seems to search shared locations first, then locations that would be
relevant to a frozen application. Is that safe? I worry that if a user
of my app has their own version of matplotlib (possibly a very different
version than I've included) then the data files might be different.

If this really is an issue, then what to do?

The only way you could have conflicting data sources is if
MATPLOTLIBDATA is defined in your environment. If someone is capable
of setting that I am inclined to think they might know what to do in
case of an error. If that env var is not set, then mpl looks inside
the its module. Different installs will not see the others. We
finally have a special case for frozen installations. It has
primarily been made for py2exe, in which you should have a folder
called 'matplotlibdata' in your app's bundle.

For Mac I can put the data files deep in the app in
Contents/Frameworks/Python.Framework/2.4/share/matplotlib, which is the
second location looked at (after environment variable MATPLOTLIBDATA).

The second location should be:
....Frameworks/Python.Framework/2.4/lib/python2.4/matplotlib/mpl-data

Are you using an old version of matplotlib?

For Windows, there doesn't seem any way out. The Windows frozen test is
dead last.

You can remove the MATPLOTLIBDATA env var from os.environ in your code.

---

Also, should I worry about the user's local matplotlibrc file (which
again might be for the wrong version or might never have been created or
configured at all -- the main problem I've hit so far is that the
auto-created default of this file is always wrong about the back
end--picking gtkagg even though I don't even build gtk support).

Again, that looks difficult or impossible because the search order is
for the usual user locations first, then look in the data directory.

In my experience with distributing apps with matplotlib, I have known
in advanced the packages I want to use. For example, if I know I am
going to bundle Tkinter and numpy, then I make sure I have the
following before using any matplotlib commands.

import matplotlib
matplotlib.use('TkAgg')
matplotlib.rcParams['numerix'] = 'numpy'

This makes sure your app uses you desired backend modules no matter
what the global config says.

Good luck,
     Charlie

···

On 6/2/06, Russell E. Owen <rowen@...529...> wrote: