Re: [Matplotlib-users] Basemap white space

2010-04-13 Thread Friedrich Romstedt 
2010/4/12 Filipe Pires Alvarenga Fernandes ocef...@gmail.com:
 Thanks for point TKinter to me. However, I'm stuck again.

 I've tried two approaches, one is following what you suggested:

  Tkinter  
 import Tkinter as tk
 root = tk.Tk()
 from PIL import Image, ImageTk
 image = ImageTk.PhotoImage(Image.open('map.png')) # load saved image
 #image = ImageTk.PhotoImage(im) # load image from StringIO
 tk.Label(root, image=image).pack()

 The other is to convert the PIL image to array and show with imshow()

  PIL to array 
 from matplotlib.image import pil_to_array
 rgba = pil_to_array(Image.open('map.png')) # load saved image
 #rgba = pil_to_array(im) # load image from StringIO
 rgba = rgba.astype(np.float32)/255.
 imshow(rgba)

 Both work fine for a saved image. However, they return strange errors
 when I tried to apply them to the image from StringIO, or even for a
 saved image in the same script used to generate them. I guess that
 something I import from matplotlib is causing a conflict here.

 Here are the error messages:

  Tkinter  
 _tkinter.TclError: image pyimage9 doesn't exist


  PIL to array 
 terminate called after throwing an instance of 'char const*'

Hi,

with the Tkinter PhotoImage, I think it's intended for use with
Tkinter.Canvas, and not compatible with Label.  For what I know, it
works fine for me with Canvas (Windows).  I guess what you end up with
is not a real PhotoImage but something faky.

Now, I cannot execute your script and dive in myself, because I
switched to another laptop, where I have to compile everything ... So
in some days, I will know more.

With the pil_to_image issue, I really have no idea.  It's really quite
strange, isn't it?  I mean, it should return a newly created
numpy.ndarray, and shouldn't borrow any memory with the PIL Image?  I
really don't know at the moment, I'm sorry.

For the Tkinter issue, from your script it seems that you simply want
to display it, so give the Canvas a try.  I used it in
http://github.com/friedrichromstedt/diagram_cl/blob/master/panels/tk/diagram.py
, start with update() and __init__().

hth for now,
Friedrich

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Re: [Matplotlib-users] Basemap white space

2010-04-12 Thread Filipe Pires Alvarenga Fernandes 
Thanks for point TKinter to me. However, I'm stuck again.

I've tried two approaches, one is following what you suggested:

 Tkinter  
import Tkinter as tk
root = tk.Tk()
from PIL import Image, ImageTk
image = ImageTk.PhotoImage(Image.open('map.png')) # load saved image
#image = ImageTk.PhotoImage(im) # load image from StringIO
tk.Label(root, image=image).pack()

The other is to convert the PIL image to array and show with imshow()

 PIL to array 
from matplotlib.image import pil_to_array
rgba = pil_to_array(Image.open('map.png')) # load saved image
#rgba = pil_to_array(im) # load image from StringIO
rgba = rgba.astype(np.float32)/255.
imshow(rgba)

Both work fine for a saved image. However, they return strange errors
when I tried to apply them to the image from StringIO, or even for a
saved image in the same script used to generate them. I guess that
something I import from matplotlib is causing a conflict here.

Here are the error messages:

 Tkinter  
_tkinter.TclError: image pyimage9 doesn't exist


 PIL to array 
terminate called after throwing an instance of 'char const*'

I'm attaching the script.
Aborted
# -*- coding: utf-8 -*-
import matplotlib
import numpy as np
import matplotlib.pyplot as plt
import StringIO, Image

#matplotlib.use('Agg')
matplotlib.use('TkAgg')

from mpl_toolkits.basemap import Basemap

lonmin = -87.5
lonmax = -22.5
latmin = -59.5
latmax =  14.5

m = Basemap( projection = 'merc', llcrnrlat = latmin, urcrnrlat = latmax, llcrnrlon = lonmin, urcrnrlon = lonmax, resolution = 'c' )
fig  = plt.figure()
ax   = fig.add_subplot(111)
m.ax = ax
m.bluemarble()

 trim image 
imgdata = StringIO.StringIO()
fig.savefig(imgdata, dpi=150, format='png')
imgdata.seek(0)  # rewind the data
im = Image.open(imgdata)

def trim(im, border):
  from PIL import ImageChops
  bg = Image.new(im.mode, im.size, border)
  diff = ImageChops.difference(im, bg)
  bbox = diff.getbbox()
  if bbox:
  return im.crop(bbox)
  else:
  # found no content
  raise ValueError(cannot trim; image was empty)

im = trim(im,'white')

 PIL to array 
#from matplotlib.image import pil_to_array
#rgba = pil_to_array(Image.open('mapa.png'))
##rgba = pil_to_array(im)
#rgba = rgba.astype(np.float32)/255.
#imshow(rgba)
#show()

 error when used in the script:
terminate called after throwing an instance of 'char const*'
Aborted

 Tkinter  
import Tkinter as tk
root = tk.Tk()
from PIL import Image, ImageTk
image = ImageTk.PhotoImage(Image.open('mapa.png'))
#image = ImageTk.PhotoImage(im)
tk.Label(root, image=image).pack()

 error when used in the script:
_tkinter.TclError: image pyimage9 doesn't exist --
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Re: [Matplotlib-users] Basemap white space

2010-04-08 Thread Filipe Fernandes 
Sorry, my bad. I always hit reply without checking... it is not the
first time did that,

Here is the solution for the list sake:

 trim image 
import StringIO, Image
imgdata = StringIO.StringIO()
fig.savefig(imgdata, dpi=300, format='png')
imgdata.seek(0)
im = Image.open(imgdata)

def trim(im, border):
  from PIL import ImageChops
  bg = Image.new(im.mode, im.size, border)
  diff = ImageChops.difference(im, bg)
  bbox = diff.getbbox()
  if bbox:
  return im.crop(bbox)
  else:
  # found no content
  raise ValueError(cannot trim; image was empty)

im = trim(im,'white')
im.show()


The StringIO trick is a copy-and-paste from the matplotlib faq. And the
trim function I got from here:

http://mail.python.org/pipermail/image-sig/2008-July/005092.html


Thanks for the discussion, I learned a lot abouth the Agg backend.


BTW: What I meant by limitation is the fact that Agg has no GUI like the
nice QT window I was using before. The users of this script have no
experience with scripting languages and enjoyed choosing the format and
filename using a GUI interface.

In addition, PIL's show() use an external linux program xv. In the end
I wanted to eliminate one external linux program (Imagemagik convert)
but ended up with another one...

Best, Filipe

On 04/06/2010 05:01 PM, Friedrich Romstedt wrote:
 2010/4/5 Filipe Fernandes ocef...@gmail.com:
 Thanks a lot. In the end the StringIO-solution worked fine. The only
 limitation is that this works only for the Agg backend.
 [...]
 
 I'm happy to hear this.  As far as I know, using the Agg backend is
 not a limitation, because it provides fully anti-aliased output.
 Besides being available on all platforms (?).
 
 Let me make a small hint: The matplotlib-users mailing list is
 configured that by default replies go to the sender only, not to
 matplotlib-users, so maybe you want to let the list know about your
 solution?
 
 Anyway I'm happy for your Thanks,
 so thanks too,
 Friedrich

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Re: [Matplotlib-users] Basemap white space

2010-04-08 Thread Friedrich Romstedt 
2010/4/8 Filipe Fernandes ocef...@gmail.com:
 BTW: What I meant by limitation is the fact that Agg has no GUI like the
 nice QT window I was using before. The users of this script have no
 experience with scripting languages and enjoyed choosing the format and
 filename using a GUI interface.

I'm quite convinced that you can have the figure in multiple Canvases
at the same time.  Or create the FigureCanvasAgg or the call to
.savefig() only on save time.  In every widget framework, it should be
fairly easy to build a custom gui having a customised Save ...
button, I guess?

 In addition, PIL's show() use an external linux program xv. In the end
 I wanted to eliminate one external linux program (Imagemagik convert)
 but ended up with another one...

When using Tkinter, you can use ImageTk:

im = {some PIL Image}  # Some image to be shown
canvas = {some Tkinter.Canvas}  # For drawing graphics

viewport = ImageTk.PhotoImage(im)

canvas.create_image((0, 0), image = viewport, anchor = 'nw')  # Put
the image on the Tkinter.Canvas.  Modify according your needs.

# Now the PIL Image has been rendered on the canvas.

# Maybe do canvas.update() or call the master's .update(),
# or call some .mainloop() entry function.  For instance, use the
# Tkinter.Tk instance's method .mainloop().

When renewing the graphics, don't forget to canvas.delete({tag}) using
the {tag} returned by canvas.create_image(), otherwise you will
probably loose perfomance.

There are examples on matplotlib.sourceforge.net how to use Tkinter
with matplotlib.

hth,
Friedrich

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Re: [Matplotlib-users] Basemap white space

2010-03-30 Thread Filipe Pires Alvarenga Fernandes 
Thanks Friedrich,

However, my knowledge of python is very limited, even though I think I
understood what you suggested I do not know how to get the shape (of
the figure?) for this part:

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

error is:

Traceback (most recent call last):
  File blueearth-map.py, line 108, in module
    fig.set_size_inches(float(shape[0]) / dpi, float(shape[1]) / dpi)
TypeError: 'function' object is unsubscriptable

It seems that it ended up calling a function shape instead of a variable shape.

I'm sending attached the script if you are interested in looking at it.

Thanks again. Filipe.


On Sun, Mar 28, 2010 at 3:35 PM, Friedrich Romstedt
friedrichromst...@gmail.com wrote:

 2010/3/28 Filipe Pires Alvarenga Fernandes ocef...@gmail.com:
  Hello list
  I've trying for a while a python only solution to remove white spaces that
  Basemap generate to keep the aspect ratio. I found these two threads that
  explain  the issue better:

 I think maybe you can make use of the Agg Backend to achieve a
 Python-only solution to obtain a PIL Image from a figure without
 bypassing over the HDD:

 Furthemore, if this doesn't work, maybe you can use a StringIO as
 file, then seek() the StringIO and reread with PIL from the
 file-like StringIO, or something like that?

 #
 # Render the Figure to a PIL Image ...
 #

 # Prepare figure to be of pixel extent *shape* ...

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

 # Create the rendering Canvas ...
 #
 # We also convert the picture to an RGB string.

 canvas = matplotlib.backends.backend_agg.FigureCanvasAgg(figure)
 canvas.draw()
 image_string = canvas.tostring_rgb()

 # Create a PIL Image from RGB string ...

 image = Image.fromstring(RGB, shape, image_string)

 # Now do whatever you want with the Image.

 Friedrich
#!/usr/bin/env python
# -*- coding: utf-8 -*-

# blueearth-map.py
# update brazillian states database, this one is too old

import sys
import os

 import basemap and pylab 
try:
  from mpl_toolkits.basemap import Basemap
except ImportError:
print Basemap not found.

try:
import matplotlib
matplotlib.use('Agg')
from pylab import *
except ImportError:
print Matplotlib not found.

# parse args (ugly!)
if len(sys.argv) == 6:
lonmin = float(sys.argv[2])
lonmax = float(sys.argv[3])
latmin = float(sys.argv[4])
latmax = float(sys.argv[5])
lonlat = np.loadtxt(sys.argv[1])
lonpt  = lonlat[:,0]
latpt  = lonlat[:,1]
elif len(sys.argv) == 5:
lonmin = float(sys.argv[1])
lonmax = float(sys.argv[2])
latmin = float(sys.argv[3])
latmax = float(sys.argv[4])
else:
sys.exit(\nMust provide at least 4 arguments!!!
 A 2 column file with longitue and latitute of the points (optional)
 and the lon lat limits for the map.
 e.g.: blueearth-map lonlat.dat -87.5  -22.5  -59.5   14.5\n)

m = Basemap( projection = 'merc',
 llcrnrlat = latmin, urcrnrlat = latmax,
 llcrnrlon = lonmin, urcrnrlon = lonmax,
 resolution = 'c' ) # crude coastlines resolution

 create figure and associate axes with Basemap 
fig  = figure()
ax   = fig.add_subplot(111)
m.ax = ax

m.drawstates()
m.drawcountries(linewidth=1.2)
m.bluemarble()
 add a non bluearth alternative
#m.drawcoastlines()
#m.drawlsmask(land_color='grey',ocean_color='None', lakes=True)

 plot points 
try:
lonpt
xc,yc = m(lonpt,latpt)
#m.plot(xc,yc,'ro', alpha = 0.5, markersize=2)
m.plot(xc,yc,'ro', markersize=2)
if lonpt.min()  lonmin:
print \n some points are out of bounds (min longitude) \n
if lonpt.max()  lonmax:
print \n some points are out of bounds (max longitude) \n
if latpt.min()  latmin:
print \n some points are out of bounds (min latitude) \n
if latpt.max()  latmax:
print \n some points are out of bounds (max latitude) \n
except:
print \n No lon/lat file to plot \n

savefig('blueearthmap.png', dpi=300)

 trim method 1 
from PIL import Image
im = Image.open(blueearthmap.png)

def trim(im, border):
  from PIL import ImageChops
  bg = Image.new(im.mode, im.size, border)
  diff = ImageChops.difference(im, bg)
  bbox = diff.getbbox()
  if bbox:
  return im.crop(bbox)
  else:
  # found no content
  raise ValueError(cannot trim; image was empty)

im2=trim(im,'white')
show() # allow user to save to a different filename and format, but it won't be cropped!
im2.save('blueearthmap.png',format='png')
#-

 trim method 2 
#os.system('convert -trim blueearthmap.png blueearthmap.png')
#show()

#-
 trim method 3 
#Render the Figure to a PIL Image
# Prepare figure to be of pixel extent *shape*
dpi = fig.dpi
fig.set_size_inches(float(shape[0]) / dpi, float(shape[1]) / dpi)

# Create the rendering Canvas. We also convert the picture to an RGB

Re: [Matplotlib-users] Basemap white space

2010-03-30 Thread Friedrich Romstedt 
2010/3/30 Filipe Pires Alvarenga Fernandes ocef...@gmail.com:
 However, my knowledge of python is very limited, even though I think I
 understood what you suggested I do not know how to get the shape (of
 the figure?) for this part:

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

 error is:

 Traceback (most recent call last):
   File blueearth-map.py, line 108, in module
     fig.set_size_inches(float(shape[0]) / dpi, float(shape[1]) / dpi)
 TypeError: 'function' object is unsubscriptable

 It seems that it ended up calling a function shape instead of a variable 
 shape.

You're completely right, I assumed that you fill in some 2-element
vector in *shape*, it was intended as an /argument/.  The function
attemted to be indexed is imported from numpy by matplotlib.pyplot:
There is a code line from numpy import *.

So, simply put some line somewhere like:

shape = [500, 500]  .

You have to set or have to calculate the figure's shape in pixels
somewhere, because you need it to convert the rgb string back into a
PIL image.  It's not that nice, I know, for your problem?

Friedrich

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Re: [Matplotlib-users] Basemap white space

2010-03-28 Thread Friedrich Romstedt 
2010/3/28 Filipe Pires Alvarenga Fernandes ocef...@gmail.com:
 Hello list
 I've trying for a while a python only solution to remove white spaces that
 Basemap generate to keep the aspect ratio. I found these two threads that
 explain  the issue better:

I think maybe you can make use of the Agg Backend to achieve a
Python-only solution to obtain a PIL Image from a figure without
bypassing over the HDD:

Furthemore, if this doesn't work, maybe you can use a StringIO as
file, then seek() the StringIO and reread with PIL from the
file-like StringIO, or something like that?

#
# Render the Figure to a PIL Image ...
#

# Prepare figure to be of pixel extent *shape* ...

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

# Create the rendering Canvas ...
#
# We also convert the picture to an RGB string.

canvas = matplotlib.backends.backend_agg.FigureCanvasAgg(figure)
canvas.draw()
image_string = canvas.tostring_rgb()

# Create a PIL Image from RGB string ...

image = Image.fromstring(RGB, shape, image_string)

# Now do whatever you want with the Image.

Friedrich

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[Matplotlib-users] Basemap white space

2010-03-27 Thread Filipe Pires Alvarenga Fernandes 
Hello list

I've trying for a while a python only solution to remove white spaces that
Basemap generate to keep the aspect ratio. I found these two threads that
explain  the issue better:

http://www.mail-archive.com/matplotlib-users@lists.sourceforge.net/msg14430.html
http://www.mail-archive.com/matplotlib-users@lists.sourceforge.net/msg14262.html

In the past I relied on  ImageMagick's convert command with the  -trim
white option for the job. However, just recently I came across with this
other list and a  PIL solution:

http://mail.python.org/pipermail/image-sig/2008-July/005092.html

Here is how I'm doing:

savefig('mapa.png', dpi=300)

from PIL import Image
im = Image.open(mapa.png)

def trim(im, border):
  from PIL import ImageChops
  bg = Image.new(im.mode, im.size, border)
  diff = ImageChops.difference(im, bg)
  bbox = diff.getbbox()
  if bbox:
  return im.crop(bbox)
  else:
  # found no content
  raise ValueError(cannot trim; image was empty)

im2=trim(im,'white')
im2.show()

This works and the aspect ratio is preserved, but as you can see, it is not
a very smart implementation.  I save and then reload it again...
any suggestions to improve this are welcome.

Also, I have not tried this on figures with labels and annotations.

Thanks for any input.

*
Filipe Pires Alvarenga Fernandes

University of Massachusetts Dartmouth
200 Mill Road - Fairhaven, MA
Tel: (508) 910-6381
Email: falvarengafernan...@umassd.edu
 ocef...@yahoo.com.br
 ocef...@gmail.com

http://ocefpaf.tiddlyspot.com/
*
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