matplotlib-users Mailing List for matplotlib (Page 4)

>>>>> "Darren" == Darren Dale <dd...@co...> writes:

    Darren> I am displaying some images and overlaying a scalebar. The
    Darren> image on the screen displays the requested white text and
    Darren> bar, but they are black in the eps image.

Hi Darren,

I'm having trouble replicating the problem.  Make sure you have an
up-to-date matplotlib.  For example, in CVS, I get the expected
behavior in agg and ps with

  from pylab import *
  subplot(111, axisbg='red')
  text(0.5, 3.5,'this is black', color=0)  
  text(0.5, 2.5,'this is black', color='k')
  text(0.5, 1.5,'this is white', color=1)  
  text(0.5, 0.5,'this is white', color='w')
  axis([0,2,0,4])
  savefig('test.ps')
  show()

If you are still having troubles, please submit a complete test
script, and the output of --verbose-helpful when you run it.

Is it possible you have a pre 0.72 CVS?  There were a couple of bugs I
introduced into PS CVS before the last release, but I think I cleaned
them up.

Hope this helps,
JDH

I am displaying some images and overlaying a scalebar. The image on the screen 
displays the requested white text and bar, but they are black in the eps image.

text(1,1,'Hi John!',color=1) ---> black text in eps
text(1,1,'Hi Jochen!',color='w') ---> black text in eps

text(1,1,'I thought this would work...',color=[1,1,1]) ---> black text in eps
text(1,1,'but it didnt, so I tried this...',color='y') ---> yellow text in eps
text(1,1,'and this...',color=[1,1,0]) ---> yellow text in eps

text(1,1,'and finally this.',color=[1,1,.99]) ---> white text in eps

I tried to track this through backend_ps.py, where:
@ line 103:
    def set_color(self, r, g, b, store=1):
        if (r,g,b) != self.color:
            if r==g and r==b:
                self._pswriter.write("%1.3f setgray\n"%r)
                print "%1.3f setgray"%r

>>> 1.000 setgray

becomes this in the eps file: 0.000 setgray

I think there is too much going on behind the scenes for me to follow. This is as far as I could get.

-- 

Darren

>>>>> "Jan" == Jan Rienyer Gadil <jr...@gm...> writes:

    Jan> i am trying the table_demo.py on IDLE and i am getting this
    Jan> error message: Traceback (most recent call last): File
    Jan> "C:\Python23\practices\table.py", line 5, in -toplevel- from
    Jan> colours import get_colours ImportError: No module named
    Jan> colours

You have to download the examples directory which contains
table_demo.py -- it is available as a zip file at
http://matplotlib.sourceforge.net/matplotlib_examples_0.72.zip 

This dir contains colours.py, which table_demo imports.

JDH

>>>>> "Alex" == Alex Rada <ale...@gm...> writes:

    Alex> HI, and now I can load pylab but have problems to see
    Alex> images, infact if I try:

    >>>> from pylab import * plot([1,2,3])

There are a number of subtleties in trying to get matplotlib working
from the python shell, as described at
http://matplotlib.sf.net/interactive.html .

Try running a script

  from pylab import plot, show
  plot([1,2,3])
  show()

from the bash shell with

> python myscript.py --verbose-helpful

Do you get a plot?  If not, please post the output generated by the
script.  

JDH

HI,

and now I can load pylab but have problems to see images, infact if I try:

 >>> from pylab import *
 >>> plot([1,2,3])

I get:

art_render_invoke: no image source given
art_render_invoke: no image source given
art_render_invoke: no image source given
art_render_invoke: no image source given
art_render_invoke: no image source given
art_render_invoke: no image source given
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
*** attempt to put segment in horiz list twice
art_render_invoke: no image source given
[<matplotlib.lines.Line2D instance at 0xb7bea96c>]

maybe I have not the right backend settings!? I'm using GTK (backend : 
GTK, in my .matplotlibrc), I tried to install agg, but I have problems 
with the makefile...

Alex...

Alex Rada wrote:
> ImportError: No module named Numeric

You need to tell Matplotlib that you are using numarray instead of Numeric.

It can be specified in your matplotlibrc file or at runtime:

 > python myscript.py --numarray # use numarray
 > python myscript.py --Numeric # use Numeric

See section 1.2.1 of the users guide.

Robert

Hi all,

I newly installed matplotlib 0.71 on my slackware 10 with numarray 1.1 
and python 2.4, the installation goes well, but when I try to launch 
pylab I get the following error:
-------------------------------------------------------------------------------------------------------------------
Python 2.4 (#1, Feb 19 2005, 22:46:12)
[GCC 3.3.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> from pylab import *
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python2.4/site-packages/pylab.py", line 1, in ?
    from matplotlib.pylab import *
  File "/usr/lib/python2.4/site-packages/matplotlib/pylab.py", line 186, 
in ?
    import cm
  File "/usr/lib/python2.4/site-packages/matplotlib/cm.py", line 5, in ?
    import colors
  File "/usr/lib/python2.4/site-packages/matplotlib/colors.py", line 32, 
in ?
    from numerix import array, arange, take, put, Float, Int, where, \
  File 
"/usr/lib/python2.4/site-packages/matplotlib/numerix/__init__.py", line 
59, in ?
    from Numeric import *
ImportError: No module named Numeric
-------------------------------------------------------------------------------------------------------------------------

thanks for the help,

Alex

i am trying the table_demo.py on IDLE and i am getting this error message:

Traceback (most recent call last):
  File "C:\Python23\practices\table.py", line 5, in -toplevel-
    from colours import get_colours
ImportError: No module named colours

i am using python 2.3 (enthought edition) with matplotlib 0.71 on Win XP.
here's the demo code by the way (copy/pasted):

#!/usr/bin/env python
import matplotlib

from pylab import *
from colours import get_colours

axes([0.2, 0.2, 0.7, 0.6])   # leave room below the axes for the table

data = [[  66386,  174296,   75131,  577908,   32015],
        [  58230,  381139,   78045,   99308,  160454],
        [  89135,   80552,  152558,  497981,  603535],
        [  78415,   81858,  150656,  193263,   69638],
        [ 139361,  331509,  343164,  781380,   52269]]

colLabels = ('Freeze', 'Wind', 'Flood', 'Quake', 'Hail')
rowLabels = ['%d year' % x for x in (100, 50, 20, 10, 5)]

# Get some pastel shades for the colours
colours = get_colours(len(colLabels))
colours.reverse()
rows = len(data)

ind = arange(len(colLabels)) + 0.3  # the x locations for the groups
cellText = []
width = 0.4     # the width of the bars
yoff = array([0.0] * len(colLabels)) # the bottom values for stacked bar chart
for row in xrange(rows):
    bar(ind, data[row], width, bottom=yoff, color=colours[row])
    yoff = yoff + data[row]
    cellText.append(['%1.1f' % (x/1000.0) for x in yoff])

# Add a table at the bottom of the axes
colours.reverse()
cellText.reverse()
the_table = table(cellText=cellText,
                  rowLabels=rowLabels, rowColours=colours,
                  colLabels=colLabels,
                  loc='bottom')
ylabel("Loss $1000's")
vals = arange(0, 2500, 500)
yticks(vals*1000, ['%d' % val for val in vals])
xticks([])
title('Loss by Disaster')
#savefig('table_demo_small', dpi=75)
#savefig('table_demo_large', dpi=300)

show()

John et al.,

I would like to phase in matplotlib to replace Matlab ASAP for plotting 
physical oceanographic observations, primarily current profile 
measurements.  I (and many other physical oceanographers) primarily use 
contourf to plot filled contours; I only rarely use line contours.  It 
looks to me like gcntr.c has the necessary functionality--the ability to 
output polygons enclosing regions between a pair of specified levels. 
Is someone already working on exposing that functionality in matplotlib, 
or is it planned?

It appears that gcntr.c also has the ability to handle missing data via 
setting elements of the reg array to zero, and that this could be 
exposed fairly easily in the contour method in axes.py by adding "reg" 
to the set of kwargs.  Correct?  If so, is this also planned?

The question of missing data handling in contour plotting brings up the 
more general issue of how to handle data gaps in plots.  For example, 
the ocean current profiles that I measure using a Doppler profiler 
extend to varying depths, and sometimes have holes in the middle where 
there are not enough acoustic scatterers to give a signal.  This sort of 
thing--data gaps--is universal in physical oceanography.  One of 
Matlab's major strengths is the way it handles them, using nan as a bad 
value flag.  Plotting a line with the plot command, the line is broken 
at each nan; so if there is a hole in the data, the plot shows exactly 
that.  The same for contouring: nans are automatically used as a mask.

Obviously, not everyone needs this kind of automatic handling of data 
gaps, but I think it would be very useful for many applications, so I 
hope it can be considered as a possible goal.  At the plotting level, 
collections may make it easier to implement than would have been the 
case in the early days of matplotlib.  At the array manipulation level, 
the implementation could involve either masked arrays or nans.  I would 
greatly prefer the Matlab-style nan approach, but I don't know whether 
this would work with Numeric.  Maybe in Numeric3?  Numarray appears 
better equipped, with its ieeespecial.py module.

Thanks for the enormous amount of beautiful work you have already done!

Eric

>>>>> "Malte" == Malte Marquarding <Mal...@cs...> writes:

    Malte> Hi, is it possible to only autoscale on one axis.  I'd like
    Malte> to set the xlimits but have the ylimits autoscaled.

Any problem with?

  plot(something)  # y and y are autoscaled
  xlim(0,2)        # set your own xlim

JDH

>>>>> "Darren" == Darren Dale <dd...@co...> writes:

    Darren> I like the new matshow function. Is it possible to update
    Darren> the data? I was looking for the equivalent of an imshow
    Darren> object's set_data method, but it is not exposed to
    Darren> matshow.

matshow returns the image object, so you should be able to call
set_data on this instance.  Of course, the new array needs to have the
same aspect ratio as the original if you want the aspect preserving
features of matshow.

    Darren> This is a nice function for plotting microscopy images,
    Darren> since the aspect ratio is fixed. Is there any object to
    Darren> allowing the origin kwarg to do reorient the origin of the
    Darren> image?  --

I don't think so.  Take a look at the implementation of matshow in
pylab.py.  It is broken into two pieces.  The hard part is being done
in matplotlib.figure.figaspect, which creates the figure with the
right aspect ratio -- as long as you create an axes with equal width
and height, your axes will have the right aspect too.

You can use this figaspect yourself, and then simply call imshow with
the args you want.

  from matplotlib.figure import figaspect
  w,h = figaspect(arr)
  fig = figure(figsize=(w,h))
  ax  = fig.add_axes([0.15, 0.09, 0.775, 0.775])
  ax.imshow(arr, origin='upper', interpolation='nearest')

JDH

>>>>> "Darren" == Darren Dale <dd...@co...> writes:


    Darren> I am using ipython -pylab, and can reproduce this error
    Darren> with the following unusual steps:

Thanks Darren,

I think the easiest thing to do here is raise on the call to
set_position if w==0 or h ==0

JDH

I am using ipython -pylab, and can reproduce this error with the following 
unusual steps:

a=rand(500,500)
figimage(a)
ax=gca()
ax.set_position([0,1,0,1]) # this is should be [0,0,1,1]
draw()
# traceback here, thats expected...
# fix my mistake
ax.set_position([0,0,1,1])
# now moving the mouse pointer over the image causes the crash report to be 
generated.

The first call to set_position I got the order confused with imshow's extent, 
which is [xmin,xmax,ymin,ymax] instead of the usual [xmin,ymin,dx,dy]. Like I 
said, its a bizarre set of circumstances, but I thought I should report it.

-- 

Darren

I like the new matshow function. Is it possible to update the data? I was 
looking for the equivalent of an imshow object's set_data method, but it is 
not exposed to matshow.

This is a nice function for plotting microscopy images, since the aspect ratio 
is fixed. Is there any object to allowing the origin kwarg to do reorient the 
origin of the image?
-- 

Darren

Hi,

is it possible to only autoscale on one axis.
I'd like to set the xlimits but have the ylimits autoscaled.

Cheers,
Malte.

If one reads the docs (Goals) one finds the answer
"Yet to be added is a blocking function, like x, y = mouse_press(*args) "


Cheers,
Malte.

 From what I can gather, I can change the line colors and widths in the 
contour routine but cannot specify a line style
such as dashed, dotted etc.

Is this true? If so I would like to have this capability - it makes 
black and white plots easier to interpret.

In any case the contour in 0.72 works great - thanks

--JIm

>>>>> "Chris" == Chris Barker <Chr...@no...> writes:

    Chris> Hi all, Is there a way to get the size of a text object? I
    Chris> can't seem to find a method that does that. The
    Chris> functionality must be in there somewhere, or having
    Chris> different reference points wouldn't work.

The size of a text object is tricky.  Do you mean the width and height
in points?  Or in data coords?  The x,y location of text is in one
coordinate system (axes, figure or data), but the width and height are
not.  To convert between coordinate systems (eg points or display
versus data) the way mpl does it is to one transform coord system to
display and use the other coordinate system to inverse transform.
This would enable you to get, for example, a text bounding box in data
coords, but could be screwed up by a figure resize.

If you tell me more precisely what you are trying to achieve, I might
be able to help you or think about design changes to accommodate it.
FYI, this is an issue that crops up a lot and is vexing.  What one
would like to be able to do is use a layout engine and say, place
object one above and to the right of object 2 with a pad of 2 points.

The text instance can give you its bounding box in display if you pass
it the backend renderer -- this is required because the width and
height can be backend dependent.  I suppose you are using OO agg based
on your previous posts.  One problem with the current design that is
that the agg canvas doesn't generate it's renderer until draw time
(with caching), but you need access to the renderer before draw time
for layout that depends on text.  If we move this logic to a
get_renderer method, you can use it at draw time.  I'll attach a
replacement backend_agg.FigureCanvasAgg class to support this below

    from matplotlib.figure import Figure
    from matplotlib.backends.backend_agg import FigureCanvasAgg

    fig = Figure()
    canvas = FigureCanvasAgg(fig)
    renderer = canvas.get_renderer()
    ax = fig.add_subplot(111)
    ax.plot([1,2,3])
    t = ax.text(1,2,'hi mom')
    bbox =  t.get_window_extent(renderer)
    print 'display', bbox.get_bounds()  #l,b,w,h

    # get the axes data coords bbox of this display bounding box
    from matplotlib.transforms import inverse_transform_bbox
    axbox = inverse_transform_bbox(ax.transData, bbox)

    print 'data coords', axbox.get_bounds()

    fig.savefig('test')




In backend_agg.py FigureCanvasAgg, replace the draw method with the following 2
methods

    def draw(self):
        """
        Draw the figure using the renderer
        """
        if __debug__: verbose.report('FigureCanvasAgg.draw', 'debug-annoying')

        renderer = self.get_renderer()
        self.figure.draw(renderer)

    def get_renderer(self):
        l,b,w,h = self.figure.bbox.get_bounds()
        key = w, h, self.figure.dpi.get()
        try: self._lastKey, self.renderer
        except AttributeError: need_new_renderer = True
        else:  need_new_renderer = (self._lastKey != key)

        if need_new_renderer:
            self.renderer = RendererAgg(w, h, self.figure.dpi)
            self._lastKey = key
        return self.renderer


Hope this gets you started -- if you provide more details we maybe
able to improve from here.

JDG

Hi all,

Is there a way to get the size of a text object? I can't seem to find a 
method that does that. The functionality must be in there somewhere, or 
having different reference points wouldn't work.

-thanks, Chris



-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

OOPS, forgot the enclosure.

-Chris

-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

Xavier Gnata wrote:
> Hi,
> 
> How can I save (and relaod) a matrix into a binary file *with* matrix 
> shape and type storage.
> I have a feature request :
> Basically, it would be great to be able to do something like :
> 
> X  = rand(100,100)
> BSave('foo.dat', X)
> Y =  BLoad('foo.dat')

I don't know of an existing function that does this, but it would not be 
hard to roll your own. All you need to do is first write the dimensions 
and type of the array to the file, then the binary data. To read it back 
in, you'd first read in the meta data, then the binary data, and you're 
done.

I've enclosed a quickie prototype (using Numeric, I think numarray may 
have tofile() and fromfile() methods, and it handles typecode differently.

By the way, there may be something in SciPy for this, and it's also 
possible that arrays can be pickled.

This is also a better question for the NumPy list than this list.

-Chris





-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

>>>>> "Humufr" == Humufr  <hu...@ya...> writes:
    Humufr> matplotlib CVS version.

There was a bug in the autoscaler in CVS briefly before the 0.72
release, but this was fixed.  I reformatted your example into python
code and it runs fine with current CVS.  

I appreciate the report, but could I ask you to do 2 things next time?
Please send proper python code which exposes the the bug (eg your
lists are not python lists) and report either the matplotlib version
that exposes the bug, or if you are using CVS, the revision number.

For example, if you suspect a bug in the ticking (where the autoscaler
lives)

> cvs status lib/matplotlib/ticker.py

===================================================================
File: ticker.py         Status: Up-to-date
 
   Working revision:    1.14
   Repository revision: 1.14    /cvsroot/matplotlib/matplotlib/lib/matplotlib/ticker.py,v

There is a problem with sourceforge that non-developer CVS checkouts
have long lags (eg the CVS version you get may be older than the
latest release!) but sourceforge says they are trying to fix this.

Thanks!
JDH

>>>>> "Rich" == Rich Drewes <dr...@in...> writes:


    Rich> Thanks for your response.  I am familiar with implot however
    Rich> I've never been able to get it to plot with distinct pixel
    Rich> boundaries.  What I want is a figimage-like plot with
    Rich> distinct, single-color regions, just larger regions, so that
    Rich> the entire screen window is filled.  No smoothing or
    Rich> interpolation, just big chunky pixels.

Hi Rich,

You'll probably want to use

  imshow(X, interpolation='nearest')

to prevent smoothing / interpolation.

    Rich> "you can define an Axes with size [0,1,0,1]"

    Rich> The order of the points is wrong there, and you set me
    Rich> straight.

OK, I'll fix that for the next release, thanks.

See also the matshow command new to 0.72 which created an axes with
the same aspect ration as your array.

JDH

John Hunter wrote:
>     Robert> Is it possible to include a marker from one or more
>     Robert> scatter plots in the legend?
> 
> This is a bit tricky -- scatter plots can vary in size and color.

Well, in my newbie-ness I wasn't aware that this was the case.

> What should one use for the legend marker?  So the short answer is no.
> My question for you is, "how *should* it work?"
> 
> Not if you are using homogeneous marker sizes and colors, I suggest
> using plot markers tweaking the properties, as in
> 
>   line, = plot(x,y,linestyle='None', marker='s', 
>                markerfacecolor='red', markeredgecolor='g',
>                markersize=20, markeredgewith=3)
> 

For me, this is exactly how it should work - thanks!

Robert

Hi,

I remember reading quite a while ago that event blocking  (request/reply) was 
on the list of todos.

Is it possible to wait for an event to be fired, i.e. having a function 
request an event and return when it has been emitted.

All examples only show "GUI" actions on events.


Cheers,
Malte.