Learn how easy it is to sync an existing GitHub or Google Code repo to a SourceForge project!

## Re: [Matplotlib-users] imshow, imsave to PIL image conversion

 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: rugspin - 2010-06-02 12:33:56 ```Thanks Jae-Joon and Friedrich I will try out both solutions. Regards Hans Jae-Joon Lee wrote: > > On Tue, Jun 1, 2010 at 2:22 PM, rugspin wrote: >> That's doing it, thought there might be an internal way within >> matplotlib, >> but I could figure one. > > If you need more hard-core way of doing this, > > a = np.arange(16384).reshape(128, 128) > > from matplotlib.colors import Normalize > import matplotlib.cm as cm > norm = Normalize(vmin=0, vmax=16383) > cmap = cm.summer > > A = (cmap(norm(a))*255).astype(np.uint8) > > import Image > pilim = Image.fromarray(A, "RGBA") > > ------------------------------------------------------------------------------ > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@... > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > -- View this message in context: http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28753655.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```

 [Matplotlib-users] imshow, imsave to PIL image conversion From: rugspin - 2010-05-31 23:49:35 ```I have a small problem how to convert an image from matplotlib to PIL right now doing somthing like this: ------------------------------------------ from scipy import * from pylab import * from PIL import Image a = arange(16384).reshape(128,128) imsave( "test.png", a, cmap=cm.summer,vmin=0,vmax=16383) b = Image.open("test.png" ) ------------------------------------------ so I have a 128x128 array, get a 128x128 size png by making use of a colormap and get a 128x128 size PIL image. But so far I could figure out a way to do this directly without writing a temporary png and reading it again, which is quite slow. My important point here is to keep the the pixel resolution. I would be glad about some help Regards Hans -- View this message in context: http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28736246.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: Angus McMorland - 2010-06-01 03:17:53 Attachments: Message as HTML ```On 31 May 2010 19:49, rugspin wrote: > > I have a small problem how to convert an image from matplotlib to PIL > > right now doing somthing like this: > ------------------------------------------ > from scipy import * > from pylab import * > from PIL import Image > > a = arange(16384).reshape(128,128) > imsave( "test.png", a, cmap=cm.summer,vmin=0,vmax=16383) > b = Image.open("test.png" ) > ------------------------------------------ > The Image.fromarray function should do what you want. For example, import numpy as np # note: use of "from foo import *" import Image # is discouraged where possible a = np.arange(128)[None,:] * np.ones(128)[:,None] b = Image.fromarray(a) c = np.asarray(b) np.all(c == a) -> True I hope that helps, Angus. -- AJC McMorland Post-doctoral research fellow Neurobiology, University of Pittsburgh ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: Angus McMorland - 2010-06-01 03:21:34 Attachments: Message as HTML ```On 31 May 2010 23:17, Angus McMorland wrote: > On 31 May 2010 19:49, rugspin wrote: > >> >> I have a small problem how to convert an image from matplotlib to PIL >> >> right now doing somthing like this: >> ------------------------------------------ >> from scipy import * >> from pylab import * >> from PIL import Image >> >> a = arange(16384).reshape(128,128) >> imsave( "test.png", a, cmap=cm.summer,vmin=0,vmax=16383) >> b = Image.open("test.png" ) >> ------------------------------------------ >> > > The Image.fromarray function should do what you want. For example, > > import numpy as np # note: use of "from foo import *" > import Image # is discouraged where possible > > a = np.arange(128)[None,:] * np.ones(128)[:,None] > Sorry - I was playing around with a few iterations of this line, and didn't provide the most useful one. Your example: a = np.arange(128**2).reshape(128,128) should also work fine. > b = Image.fromarray(a) > c = np.asarray(b) > np.all(c == a) > -> True > > I hope that helps, > > Angus. > -- AJC McMorland Post-doctoral research fellow Neurobiology, University of Pittsburgh ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: rugspin - 2010-06-01 09:18:47 ``` Angus McMorland-2 wrote: > > On 31 May 2010 23:17, Angus McMorland wrote: > >> On 31 May 2010 19:49, rugspin wrote: >> >>> >>> I have a small problem how to convert an image from matplotlib to PIL >>> >>> right now doing somthing like this: >>> ------------------------------------------ >>> from scipy import * >>> from pylab import * >>> from PIL import Image >>> >>> a = arange(16384).reshape(128,128) >>> imsave( "test.png", a, cmap=cm.summer,vmin=0,vmax=16383) >>> b = Image.open("test.png" ) >>> ------------------------------------------ >>> >> >> The Image.fromarray function should do what you want. For example, >> >> import numpy as np # note: use of "from foo import *" >> import Image # is discouraged where possible >> >> a = np.arange(128)[None,:] * np.ones(128)[:,None] >> > > Sorry - I was playing around with a few iterations of this line, and > didn't > provide the most useful one. Your example: > > a = np.arange(128**2).reshape(128,128) > > should also work fine. > > >> b = Image.fromarray(a) >> c = np.asarray(b) >> np.all(c == a) >> -> True >> >> I hope that helps, >> >> Angus. >> > > -- > AJC McMorland > Post-doctoral research fellow > Neurobiology, University of Pittsburgh > > ------------------------------------------------------------------------------ > > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@... > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > Thank you Angus but that's not exactly what i was looking for. The fromarray function is very basic, so I would have to take care of all the RGBA of the array. the imshow and imsave functions take care of all that for example adding a colormap. After choosing a reasonable colormap (vmin, vmax, ....) I would like to convert this into a PIL image. Best Regard Hans -- View this message in context: http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28739401.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: Jae-Joon Lee - 2010-06-01 16:34:26 ```You may use StringIO. from scipy import * from pylab import * from PIL import Image import cStringIO a = arange(16384).reshape(128,128) f = cStringIO.StringIO() imsave(f, a, cmap=cm.summer,vmin=0,vmax=16383, format="png") # you'd better set the format explicitly. f.reset() b = Image.open(f) f.close() IHTH, -JJ On Tue, Jun 1, 2010 at 5:18 AM, rugspin wrote: > > > > Angus McMorland-2 wrote: >> >> On 31 May 2010 23:17, Angus McMorland wrote: >> >>> On 31 May 2010 19:49, rugspin wrote: >>> >>>> >>>> I have a small problem how to convert an image from matplotlib to PIL >>>> >>>> right now doing somthing like this: >>>> ------------------------------------------ >>>> from scipy import * >>>> from pylab import * >>>> from PIL import Image >>>> >>>> a = arange(16384).reshape(128,128) >>>> imsave( "test.png", a, cmap=cm.summer,vmin=0,vmax=16383) >>>> b = Image.open("test.png" ) >>>> ------------------------------------------ >>>> >>> >>> The Image.fromarray function should do what you want. For example, >>> >>> import numpy as np   # note: use of "from foo import *" >>> import Image             # is discouraged where possible >>> >>> a = np.arange(128)[None,:] * np.ones(128)[:,None] >>> >> >> Sorry - I was playing around with a few iterations of this line, and >> didn't >> provide the most useful one. Your example: >> >> a = np.arange(128**2).reshape(128,128) >> >> should also work fine. >> >> >>> b = Image.fromarray(a) >>> c = np.asarray(b) >>> np.all(c == a) >>>   -> True >>> >>> I hope that helps, >>> >>> Angus. >>> >> >> -- >> AJC McMorland >> Post-doctoral research fellow >> Neurobiology, University of Pittsburgh >> >> ------------------------------------------------------------------------------ >> >> >> _______________________________________________ >> Matplotlib-users mailing list >> Matplotlib-users@... >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >> >> > > Thank you Angus > but that's not exactly what i was looking for. The fromarray function is > very basic, so I would have to take care of all the RGBA of the array. the > imshow and imsave functions take care of all that for example adding a > colormap. After choosing a reasonable colormap (vmin, vmax, ....) I would > like to convert this into a PIL image. > > Best Regard > Hans > > -- > View this message in context: http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28739401.html > Sent from the matplotlib - users mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@... > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: rugspin - 2010-06-01 18:22:58 ```Thanks Jae-Joo That's doing it, thought there might be an internal way within matplotlib, but I could figure one. I'm quite confused with the canvas, dpi, ... Regards Hans Jae-Joon Lee wrote: > > You may use StringIO. > > from scipy import * > from pylab import * > from PIL import Image > > import cStringIO > > > a = arange(16384).reshape(128,128) > > f = cStringIO.StringIO() > imsave(f, a, cmap=cm.summer,vmin=0,vmax=16383, format="png") # you'd > better set the format explicitly. > f.reset() > b = Image.open(f) > f.close() > > IHTH, > > -JJ > > > On Tue, Jun 1, 2010 at 5:18 AM, rugspin wrote: >> >> >> >> Angus McMorland-2 wrote: >>> >>> On 31 May 2010 23:17, Angus McMorland wrote: >>> >>>> On 31 May 2010 19:49, rugspin wrote: >>>> >>>>> >>>>> I have a small problem how to convert an image from matplotlib to PIL >>>>> >>>>> right now doing somthing like this: >>>>> ------------------------------------------ >>>>> from scipy import * >>>>> from pylab import * >>>>> from PIL import Image >>>>> >>>>> a = arange(16384).reshape(128,128) >>>>> imsave( "test.png", a, cmap=cm.summer,vmin=0,vmax=16383) >>>>> b = Image.open("test.png" ) >>>>> ------------------------------------------ >>>>> >>>> >>>> The Image.fromarray function should do what you want. For example, >>>> >>>> import numpy as np   # note: use of "from foo import *" >>>> import Image             # is discouraged where possible >>>> >>>> a = np.arange(128)[None,:] * np.ones(128)[:,None] >>>> >>> >>> Sorry - I was playing around with a few iterations of this line, and >>> didn't >>> provide the most useful one. Your example: >>> >>> a = np.arange(128**2).reshape(128,128) >>> >>> should also work fine. >>> >>> >>>> b = Image.fromarray(a) >>>> c = np.asarray(b) >>>> np.all(c == a) >>>>   -> True >>>> >>>> I hope that helps, >>>> >>>> Angus. >>>> >>> >>> -- >>> AJC McMorland >>> Post-doctoral research fellow >>> Neurobiology, University of Pittsburgh >>> >>> ------------------------------------------------------------------------------ >>> >>> >>> _______________________________________________ >>> Matplotlib-users mailing list >>> Matplotlib-users@... >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>> >>> >> >> Thank you Angus >> but that's not exactly what i was looking for. The fromarray function is >> very basic, so I would have to take care of all the RGBA of the array. >> the >> imshow and imsave functions take care of all that for example adding a >> colormap. After choosing a reasonable colormap (vmin, vmax, ....) I would >> like to convert this into a PIL image. >> >> Best Regard >> Hans >> >> -- >> View this message in context: >> http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28739401.html >> Sent from the matplotlib - users mailing list archive at Nabble.com. >> >> >> ------------------------------------------------------------------------------ >> >> _______________________________________________ >> Matplotlib-users mailing list >> Matplotlib-users@... >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >> > > ------------------------------------------------------------------------------ > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@... > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > -- View this message in context: http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28745632.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: Friedrich Romstedt - 2010-06-01 19:35:07 Attachments: canvas.py ```> That's doing it, thought there might be an internal way within matplotlib, > but I could figure one. I think you can use the agg backend and the corresponding Canvas'es method canvas.tostring_rgb() . Then you can load this in PIL by Image.fromstring. Well, I simply send you my PIL backend. Tell me if it's still working ... Friedrich ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: Jae-Joon Lee - 2010-06-01 22:39:32 ```On Tue, Jun 1, 2010 at 2:22 PM, rugspin wrote: > That's doing it, thought there might be an internal way within matplotlib, > but I could figure one. If you need more hard-core way of doing this, a = np.arange(16384).reshape(128, 128) from matplotlib.colors import Normalize import matplotlib.cm as cm norm = Normalize(vmin=0, vmax=16383) cmap = cm.summer A = (cmap(norm(a))*255).astype(np.uint8) import Image pilim = Image.fromarray(A, "RGBA") ```
 Re: [Matplotlib-users] imshow, imsave to PIL image conversion From: rugspin - 2010-06-02 12:33:56 ```Thanks Jae-Joon and Friedrich I will try out both solutions. Regards Hans Jae-Joon Lee wrote: > > On Tue, Jun 1, 2010 at 2:22 PM, rugspin wrote: >> That's doing it, thought there might be an internal way within >> matplotlib, >> but I could figure one. > > If you need more hard-core way of doing this, > > a = np.arange(16384).reshape(128, 128) > > from matplotlib.colors import Normalize > import matplotlib.cm as cm > norm = Normalize(vmin=0, vmax=16383) > cmap = cm.summer > > A = (cmap(norm(a))*255).astype(np.uint8) > > import Image > pilim = Image.fromarray(A, "RGBA") > > ------------------------------------------------------------------------------ > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@... > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > -- View this message in context: http://old.nabble.com/imshow%2C-imsave-to-PIL-image-conversion-tp28736246p28753655.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```