Re: [Matplotlib-users] controllin the background of a plot

thanks ben,
(sorry for sending answer twice)

> When you call savefig(), you can pass it the kwarg option of
> bbox_inches='tight' and that should help get rid of any extra area you
> may have.
>
> Ben Root
I tried to follow your advice. however it did not help. This is what I do:

- get the current figure with gcf.
- read an image from a file with imread
- save it to the canvas with imsave
- hide the axes
- call fig.savefig('out.svg', transparent=True, bbox_inches='tight', 
pad_inches=0)

then I create a PIL Image and return it to the calling web server.

The image is displayed with a fat (1.5 cm) gray border which I do not want.

thanks for any further intelligence

robert

here is my code cleansed of irrelevant parts

# supporting method creating the plot
def makeHlwdChart(self, values = ['a', 'd', 'e', 'f', 'b']):
     # get current axes object
     frame1 = plt.gca()
     # get current figure
     fig = plt.gcf()
     # read the image file
     pic = plt.imread(imp_path)
     # the picture is upside down so rotate and fip it
     pic = np.fliplr(np.rot90(pic, k=2))
     # draw it on the canvas
     plt.imshow(pic, figure=fig)
     # hide axes
     frame1.axes.get_xaxis().set_visible(False)
     frame1.axes.get_yaxis().set_visible(False)

     fig.savefig('out.svg', transparent=True, bbox_inches='tight', 
pad_inches=0)

     return pic

# method called from the web server
def __call__(self, w=300, h=300, default_format = 'PNG', set_headers=False):
     # lock graphics
     imageThreadLock.acquire()
     # we don't want different threads to write on each other's canvases,
     # make sure we have a new one
     pylab.close()
     # makeHlwdChart draws on the canvas, so we do not need its return value
     makeHlwdChart(self, values)
     canvas = pylab.get_current_fig_manager().canvas
     canvas.draw()
     imageSize = canvas.get_width_height()
     imageRgb = canvas.tostring_rgb()
     img = Image.fromstring("RGB", imageSize, imageRgb)
     #size = int(w), int(h)
     #img.thumbnail(size, Image.ANTIALIAS)
     format = img.format and img.format or default_format
     thumbnail_file = StringIO()
     ## quality parameter doesn't affect lossless formats
     img.save(thumbnail_file, format, quality=88)
     thumbnail_file.seek(0)
     if set_headers:
         self.request.RESPONSE.setHeader('Pragma', 'no-cache')
         self.request.RESPONSE.setHeader('Content-Type', 'image/%s' % 
format)

     # unlock graphics
     imageThreadLock.release()

     return thumbnail_file.getvalue()