How to save file in to image in desired resolution in matplotlib?

Community matplotlib-users
1

Dear All,
I am using one image of 235X130 and plotting the curve on it, now when i save it it goes in the resoltuion of 800X600,
I want to keep the resolution intact.What can be done for that to keep the resolution same?
I am using
savefig(’/home/jaguar/Softwares/Development/Python/bunty.png’)
Thanks in advance!
Regards
Yogesh

2

Hi Yogesh,

You can adjust the resolution by changing the figure size and the dpi in
savefig.

Keyword of figure:
*figsize* width x height in inches; defaults to rc figure.figsize

Keyword of 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.

e.g.
import matplotlib
matplotlib.use('Agg')
from matplotlib import pyplot as plt

# aim: 235X130
fig = plt.figure(figsize=(23.5, 13.0))
ax = plt.axes([0.0, 0.0, 1.0, 1.0])
ax.plot([1, 2, 4], lw=5)
ax.set_xticks()
ax.set_yticks()

fig.savefig('test.png', dpi=10)

Kind regards,
Matthias

···

On Wednesday 31 March 2010 09:24:10 yogesh karpate wrote:

Dear All,
               I am using one image of 235X130 and plotting the curve on
it, now when i save it it goes in the resoltuion of 800X600,
I want to keep the resolution intact.What can be done for that to keep the
resolution same?
I am using
savefig('/home/jaguar/Softwares/Development/Python/bunty.png')
Thanks in advance!
Regards
Yogesh

3

The list config got me, so to the list too ...

2010/3/31 Matthias Michler <MatthiasMichler@...361...>:

Dear All,
               I am using one image of 235X130 and plotting the curve on
it, now when i save it it goes in the resoltuion of 800X600,
I want to keep the resolution intact.What can be done for that to keep the
resolution same?

You can adjust the resolution by changing the figure size and the dpi in
savefig.

I think, but am not shure, that a problem could be that text is scaled
according to dpi, such that ugly things result with e.g. dpi = 2 or
so. You can also use, when you have an 2-element iterable *shape*
created, holding the pixel extent:

dpi = fig.dpi
fig.set_size_inches(shape[0] / dpi, shape[1] / dpi)

The standard dpi is sensible, otherwise it's for sure possible to
override beforehand.

Then your save command should give the desired result. I have no time
to check, sorry, may you do that :slight_smile: Thanks.

Friedrich

···

On Wednesday 31 March 2010 09:24:10 yogesh karpate wrote: