savefig() saves different aspect ratio than show()

The following script (using matplotlib 1.3.1) should create a 1-row, 3 column subplot with only one panel. The figure is displayed with show (which looks as desired) and also saved as a pdf using savefig. However, savefig has squeezed the wide figure into the normal aspect ratio, which it should not do.

#!/usr/bin/env python
import matplotlib
matplotlib.use('Qt4Agg')
from matplotlib.pyplot import *
from numpy import *

figure()
mgr = get_current_fig_manager()
mgr.window.setGeometry(0,0,800,200)
subplot(1,3,1)
x=linspace(0,2*pi,100)
plot(x,sin(x))
savefig('test.pdf')
show()

Does it do what you intend if you insert plt.draw() before the savefig?

Tried it - didn't help.

Somehow the call to setGeometry is not realized by matplotlib. My only workaround right now is to first set the position and size with setGeometry and then to set the size again with set_size_inches like so

f=gcf()
f.set_size_inches(800./f.dpi,200./f.dpi)

This works fine, but I still need the call to setGeometry because I want to specify where on the screen the figure appears.

Could you try calling the repaint method()?

where do I find that repaint method?

@a6073758

This is a documented "feature" of savefig: http://matplotlib.org/api/figure_api.html#matplotlib.figure.Figure.savefig

dpi: [ None | scalar > 0 ]
    The resolution in dots per inch. If None it will default to the value savefig.dpi in the matplotlibrc file.

Which essentially is saying, savefig ignores figure.dpi and instead uses the global rc param. I don't like it (I have a reputation for not liking much when it comes to rcParams) but it is documented so I'm going to go ahead and close the issue. It might be worth sparking a discussion on the mailing list about the behaviour if we want to change it, though the breakage that it may cause might make that a hard sell.

Thanks for raising the issue @a6073758.

@pelson

@pelson not sure I agree. I think the problem is the use of the qt geometry calls which rdint get propagate back to mpl from the gui layer.

@tacaswell

@tacaswell is correct, this is not a question of dpi at all.
If the example is run using ipython --pylab=qt, then it works for me on 1.3.1. Or, even without the --pylab, using a call to ion() is enough. When the figure is rendered on the screen, the geometry does change the output of fig.get_size_inches(), and savefig uses the modified dimensions.
It's not clear that there is anything we should change here.

My apologies.

I would also add that fig.set_size_inches(forward=True) will resize the figure on-screen as well. Another alternative is to set the figure size when you create the figure ex

fig, ax = plt.subplots(1, 3, figsize=(3, 6))

I think that this should be closed as the problem is the OP doing and end-run around the mpl gui management layer but there are already ways for the management layer to push back down to the gui.

There is also a call-back already in place (I only tested Qt) that updates the figure size in inches if you resize the window with the mouse. Interestingly, if you run this as a script, it does not work, but if you run the same commands in ipython (with their matplotlib magic), the change in size does propagate back up. This smells like another case of gui/interactive stuff barely working out side of ipython/interactive session.

@efiring

I also came across this issue, but for a much simpler case.

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

fig = plt.figure(figsize=(11.7,  8.3), dpi=72.0)
ax = fig.add_subplot(111, projection='3d')

data = np.array([[0.0, 0.0, 0.0],
                 [0.0, 0.0, 1.0],
                 [1.0, 0.0, 1.0],
                 [1.0, 1.0, 1.0],
                 [1.0, 1.0, 0.0]])

cs = ax.plot(data[:,0], data[:,1], data[:,2], 'b-')

ax.set_aspect('equal')
ax.auto_scale_xyz([0.0, 1.0], [0.0, 1.0], [0.0, 1.0])

#plt.draw()
#ax.apply_aspect()

plt.savefig('c:/temptemp/test_aspect.png')
plt.show()

The workaround plt.draw() suggested by @efiring worked for me.
Also is calling the Axes method ax.apply_aspect()

I am pretty sure that this issue it related to #1104,
maybe some callback function is not triggered correctly.

Any solution to this?

@nikosT

@nikosT Its a closed issue. Were you arguing it should be re-opened for some reason?

Any solution to this?

found it: call fig.tight_layout() before plt.savefig
maybe plt.show triggers it automatically but savefig does not

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savefig() saves different aspect ratio than show() #3139

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savefig() saves different aspect ratio than show() #3139

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efiring commented on Jun 16, 2014

a6073758 commented on Jun 16, 2014

Tillsten commented on Jun 16, 2014

a6073758 commented on Jun 17, 2014

pelson commented on Jun 17, 2014

tacaswell commented on Jun 17, 2014

efiring commented on Jun 17, 2014

pelson commented on Jun 18, 2014

tacaswell commented on Jun 25, 2014

solarjoe commented on Jan 18, 2016

nikosT commented on Nov 1, 2017

jklymak commented on Nov 1, 2017

BugCheck141 commented on Apr 23, 2020

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