I'm brand new to Sage, and would like to follow the path of least resistance to playing around with images. I tried to follow these instructions, but got tripped up.
On May 23, 7:55 am, "David Joyner" <[EMAIL PROTECTED]> wrote: > Harald: > > I know this is an old question but my feeling was in wasn't really > answered properly, > possibly because I inadvertantly took it off track with a response > which had an aside on > SAGE searching. > > Since PIL has come up a few times on SAGE lists in vague ways, I > thought I'd try to > be more detailed. Here is a way using SAGE which might help. First, > it requires some preparation. > > I'll assume you have installed sage in SAGEROOT (an absolute > pathname). (I'm going > to go into more detail that I know you need Harald since I hope to help others > who might know less about SAGE too). > > You must install PIL fromhttp://www.pythonware.com/products/pil/. Here's how: > > (a) download the tarball from a link on the URL mentioned above, > sayhttp://effbot.org/downloads/Imaging-1.1.6.tar.gz; > (b) extract it to SAGEROOT/local/lib/python/site-packages > (c) cd SAGEROOT/local/lib/python2.5/site-packages/Imaging-1.1.6 > (d) run ../../../../bin/python setup.py install Instead of doing this, I ran sage -i PIL-1.1.5.spkg per the instructions of Simon King. So far so good. > (e) install ImageMagick (unless you have xv installed, which you > probably don't); > in ubuntu, it's > sudo apt-get install imagemagick (or sudo apt-cache search > imagemagick, and install > a bunch of related packages too); > (f) in sage, type > sage: from PIL import Image > sage: im = Image.open("PATH/mypic.jpg") I'm good up to this point. im is an object with a bunch of methods that I can look at with tab completion. > sage: im.show(command="display") No dice. I get the following Traceback: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/Users/jm843/.sage/sage_notebook/worksheets/admin/0/code/ 31.py", line 6, in <module> im.show(command="display") File "/Applications/sage/local/lib/python2.5/site-packages/sympy/ plotting/", line 1, in <module> File "/Applications/sage/local/lib/python2.5/site-packages/PIL/ Image.py", line 1349, in show _showxv(self, title, command) File "/Applications/sage/local/lib/python2.5/site-packages/PIL/ Image.py", line 1913, in _showxv file = image._dump(format=format) File "/Applications/sage/local/lib/python2.5/site-packages/PIL/ Image.py", line 429, in _dump self.load() File "/Applications/sage/local/lib/python2.5/site-packages/PIL/ ImageFile.py", line 180, in load d = Image._getdecoder(self.mode, d, a, self.decoderconfig) File "/Applications/sage/local/lib/python2.5/site-packages/PIL/ Image.py", line 328, in _getdecoder raise IOError("decoder %s not available" % decoder_name) IOError: decoder jpeg not available I'm on a mac here, and I already had ImageMagick installed through MacPorts. Since the above didn't work, so i also installed xv. Macports installs things into /opt/local/bin jmerrill:~ jm843$ which xv /opt/local/bin/xv I have /opt/local/bin on my searchpath when I open a terminal, but I suspect Sage just doesn't know where to find this stuff. I tried running sys.path.append('/opt/local/bin') from within a notebook, but it doesn't seem to change anything. > Of course, im.[TAB] gives you more commands to play with and the online > tutorialhttp://www.pythonware.com/library/pil/handbook/introduction.htm > helps too. > > Hope this is more helpful, even if it a little late. > > - David Joyner I'm grateful for any suggestions. Is PIL the easiest route to playing around with images? I'd really like to be able to get a grayscale image into an array of numbers so that I can play with convolutions and thresholding and the like. Regards, Jason Merrill --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
