tight_layout() causes RuntimeError on OSX

Elliot_Saba · May 1, 2012, 7:04pm

Hey guys, I’m trying to use tight_layout() to fix up some subplot grossness, but whenever I call it, I get:

Traceback (most recent call last):

File “test.py”, line 16, in

plt.tight_layout()

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/pyplot.py”, line 1056, in tight_layout

fig.tight_layout(pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/figure.py”, line 1415, in tight_layout

pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/tight_layout.py”, line 117, in auto_adjust_subplotpars

tight_bbox_raw = union([ax.get_tightbbox(renderer) for ax in subplots])

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/axes.py”, line 8396, in get_tightbbox

bb.append(self.title.get_window_extent(renderer))

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 743, in get_window_extent

bbox, info = self._get_layout(self._renderer)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 296, in _get_layout

ismath=False)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py”, line 164, in get_text_width_height_descent

width, height, descent = self.gc.get_text_width_height_descent(unicode(s), family, size, weight, style)

RuntimeError: CGContextRef is NULL

I’ve googled around, but no answers have been found. Is this a known issue, and if it’s not, how can I go about fixing it?

Thanks,

-E

Tony_S_Yu3 · May 2, 2012, 1:45am

When I run the macosx backend (which appears to be what you’re using), I get the following output:

tight_layout : falling back to Agg renderer

and the figure appears to be rendered with TkAgg . So it appears that it’s a known issue on the macosx backend. And, apparently, the suggested work-around is to use an Agg backend.

-Tony

···

On Tue, May 1, 2012 at 3:04 PM, Elliot Saba <staticfloat@…287…> wrote:

Hey guys, I’m trying to use tight_layout() to fix up some subplot grossness, but whenever I call it, I get:

Traceback (most recent call last):

File “test.py”, line 16, in

plt.tight_layout()

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/pyplot.py”, line 1056, in tight_layout

fig.tight_layout(pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/figure.py”, line 1415, in tight_layout

pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/tight_layout.py”, line 117, in auto_adjust_subplotpars

tight_bbox_raw = union([ax.get_tightbbox(renderer) for ax in subplots])

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/axes.py”, line 8396, in get_tightbbox

bb.append(self.title.get_window_extent(renderer))

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 743, in get_window_extent

bbox, info = self._get_layout(self._renderer)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 296, in _get_layout

ismath=False)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py”, line 164, in get_text_width_height_descent

width, height, descent = self.gc.get_text_width_height_descent(unicode(s), family, size, weight, style)

RuntimeError: CGContextRef is NULL

I’ve googled around, but no answers have been found. Is this a known issue, and if it’s not, how can I go about fixing it?

Thanks,

-E

Elliot_Saba · May 2, 2012, 3:18am

That does indeed work. Thank you.

-E

···

On Tue, May 1, 2012 at 6:45 PM, Tony Yu <tsyu80@…287…> wrote:

On Tue, May 1, 2012 at 3:04 PM, Elliot Saba <staticfloat@…287…> wrote:

Hey guys, I’m trying to use tight_layout() to fix up some subplot grossness, but whenever I call it, I get:

Traceback (most recent call last):

File “test.py”, line 16, in

plt.tight_layout()

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/pyplot.py”, line 1056, in tight_layout

fig.tight_layout(pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/figure.py”, line 1415, in tight_layout

pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/tight_layout.py”, line 117, in auto_adjust_subplotpars

tight_bbox_raw = union([ax.get_tightbbox(renderer) for ax in subplots])

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/axes.py”, line 8396, in get_tightbbox

bb.append(self.title.get_window_extent(renderer))

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 743, in get_window_extent

bbox, info = self._get_layout(self._renderer)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 296, in _get_layout

ismath=False)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py”, line 164, in get_text_width_height_descent

width, height, descent = self.gc.get_text_width_height_descent(unicode(s), family, size, weight, style)

RuntimeError: CGContextRef is NULL

I’ve googled around, but no answers have been found. Is this a known issue, and if it’s not, how can I go about fixing it?

Thanks,

-E

When I run the macosx backend (which appears to be what you’re using), I get the following output:

tight_layout : falling back to Agg renderer

and the figure appears to be rendered with TkAgg . So it appears that it’s a known issue on the macosx backend. And, apparently, the suggested work-around is to use an Agg backend.

-Tony

Michiel_de_Hoon1 · May 2, 2012, 3:37pm

This kind of error typically occurs when the graphics context is being accessed outside of the event loop. This may work for other backends, but on Mac OS X in such a case the graphics context is not defined. The solution may involve reorganizing tight_layout such that the graphics context is not being accessed outside of the event loop.
-Michiel.

···

— On Tue, 5/1/12, Elliot Saba <staticfloat@…878…287…> wrote:

From: Elliot Saba <staticfloat@…287…>
Subject: [Matplotlib-users] tight_layout() causes RuntimeError on OSX
To: “Matplotlib Users” matplotlib-users@lists.sourceforge.net
Date: Tuesday, May 1, 2012, 3:04 PM

Hey guys, I’m trying to use tight_layout() to fix up some
subplot grossness, but whenever I call it, I get:

Traceback (most recent call last):

File “test.py”, line 16, in

plt.tight_layout()

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/pyplot.py”, line 1056, in tight_layout

fig.tight_layout(pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/figure.py”, line 1415, in tight_layout

pad=pad, h_pad=h_pad, w_pad=w_pad)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/tight_layout.py”, line 117, in auto_adjust_subplotpars

tight_bbox_raw = union([ax.get_tightbbox(renderer) for ax in subplots])

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/axes.py”, line 8396, in get_tightbbox

bb.append(self.title.get_window_extent(renderer))

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 743, in get_window_extent

bbox, info = self._get_layout(self._renderer)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/text.py”, line 296, in _get_layout

ismath=False)

File “/Users//.homebrew/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py”, line 164, in get_text_width_height_descent

width, height, descent = self.gc.get_text_width_height_descent(unicode(s), family, size, weight, style)

RuntimeError: CGContextRef is NULL

I’ve googled around, but no answers have been found. Is this a known issue, and if it’s not, how can I go about fixing it?

Thanks,

-E

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