matplotlib-users — Discussion related to using matplotlib

Re: [Matplotlib-users] The meaning of the figure(dpi=xxx) parameter

[matthew a. <ma...@ca...>]

It seems to me, from the user's point of view, that the DPI is a rendering
option, not a plotting option. I should be able to take the same plot:

p = plot(sin(x))

and render it to screen 

show(p, dpi=96, size=(8, 6))

OR

show(p, pixelsize=(768, 576))

or render it for printing:

savefig('p.png', dpi=300, size=(6, 4))

OR

savefig('p.png', pixelsize=(1800, 1200))

OR

savefig('p.eps', size=(6, 4))

I think people are going to want different DPI settings for screen vs.  
printing. So perhaps dpi should be an option to show() and savefig()
rather than to plot?

And rather than having different DPI defaults for each backend, I would 
have thought it better to have two global default DPI settings, one for 
the screen and one for the printer. You would also want two default plot 
sizes in inches.

In a sane world you wouldn't need to set the DPI for the screen, you could
trust X or Windows to provide it, but in practice what X says isn't always
useful.

You might even consider adding a print() command that renders a plot with 
the default printing settings to a file (or even straight to the 
printer?). Perhaps savefig() should use the default printing settings when 
exporting an .eps file? (Although the DPI is ignored the plot size is 
still relevant.)

I hope you find these ponderings useful. I am still a bit ignorant about
aspects of matplotlib so I'll hope you'll excuse me for that.

Cheers,
Matthew.

On Mon, 8 Mar 2004, John Hunter wrote:

> None of this matters, of course, for PS, which is resolution
> independent.
> 
> dpi is not really suitably named because of this additional parameter
> PIXELS_PER_INCH.  dpi is really a resolution parameter.  When you
> increase dpi, the relative sizes of everything in your image should
> increase proportionately (line widths, text sizes, etc) but you have
> more pixels of resolution.  When you increase figure size for a give
> dpi, everything should appear smaller because the physical size of the
> objects in your canvas haven't changed, but your canvas has increased.
> 
> I'm open to suggestions on how to make this better.
> 
> JDH

Re: [Matplotlib-users] The meaning of the figure(dpi=xxx) parameter

[John H. <jdh...@ac...>]

>>>>> "Al" == Al Schapira <a.d...@wo...> writes:

    Al> In order to get the size of the overall plot window to
    Al> anywhere near full screen, I've had to use something like

    Al> 	figure(1, figsize=(18,12), dpi=72) or figure(1,
    Al> figsize=(9,6), dpi=144)

    Al> Both produce the same overall size plot window (11.25" wide by
    Al> 8" tall), but in the latter case, the text size is much larger
    Al> than in the latter case. Likewise the linewidths.

    Al> Can you please explain the interaction among the dpi value,
    Al> the font sizes displayed, and the overall plot size.

Hi Al, 

This is a complicated issue and I don't have a full answer for you.
The problem is compounded by the fact that I am trying to make the DPI
parameter produce figures that look the same across the backends, and
different backends have often have an additional parameter that makes
assumptions about the number of pixels per inch on your display - eg
gd assumes 96, and these are not under my control.  

The total figure width in pixels is figure width in inches * dpi;
ditto for height.  If you set dpi to your device PIXELS_PER_INCH, the
width should be correct if you measure it on the screen with a ruler.
You will probably need to set PIXELS_PER_INCH for the backend you are
using to be correct for your display.  This is a parameter the
respective backend files, eg, in matplotlib/backends/backend_gtk.py.
For backend_agg, you will have to change it both in
src/_backend_agg.cpp and matplotlib/backends/backend_agg.py.  This is
something I would like to rationalize and perhaps move to the rc file.
I suggest setting it to your display width / pixels width, eg, 116 in
your example.  Then

  figure( (8,6), dpi=116)

should produce a an 8 inch by 6 inch figure.  Let me know.  Then
default dpi can be set in the rc file.

None of this matters, of course, for PS, which is resolution
independent.

dpi is not really suitably named because of this additional parameter
PIXELS_PER_INCH.  dpi is really a resolution parameter.  When you
increase dpi, the relative sizes of everything in your image should
increase proportionately (line widths, text sizes, etc) but you have
more pixels of resolution.  When you increase figure size for a give
dpi, everything should appear smaller because the physical size of the
objects in your canvas haven't changed, but your canvas has increased.

I'm open to suggestions on how to make this better.

JDH

Re: [Matplotlib-users] creating shaded areas

[John H. <jdh...@ac...>]

>>>>> "Andrew" == Andrew Straw <str...@as...> writes:

    Andrew> 2) Is it a bug that the polygon is not filled

Yes, none of the rest of the drawing interface uses Polygon so I
hadn't noticed it.  In patches.py, replace line 330 with 

        renderer.draw_polygon(gc, rgbFace, vertices)

Below is your (modified) original script, with comments that answer
your questions.  With the patch above and some changes I made, it now
works (cool).  It would be nice to figure out how to properly include
this in the regular API.

JDH

from matplotlib.matlab import *
from matplotlib.patches import Rectangle, Polygon

def filly(x,y1,y2,**kwargs):
     ax = gca()
     xy = []
     for xi, yi in zip(x,y1):
         xy.append( (xi,yi) )
     for xi, yi in zip(x[::-1],y2[::-1]):
         xy.append( (xi,yi) )
     xy.append( xy[0] )


     # see
     # http://matplotlib.sourceforge.net/matplotlib.transforms.html
     # for information on the new transform system.  You can place
     # objects in a variety of coord systems, most freqeuntly data or
     # axes.  data are the old-style coords you are used to.  axes
     # coords are normalized on a 0-1 scale.  The xaxis and yaxis
     # instances store default transforms so you can easily create new
     # objects in either coord system.  ax.xaxis.transData transforms
     # data units to display units for the xaxis.  ax.xaxis.transAxis
     # transforms axis units to display units.  You have done it right
     # here.
     polygon = Polygon(
         ax.dpi, ax.bbox,
         xy,
         transx = ax.xaxis.transData, # what does this do?
         transy = ax.yaxis.transData, # and this??
         **kwargs)

     ax.add_patch(polygon)
     return polygon

figure(1)
t = arange(0.0, 1.0, 0.01)
s_mean = 0.5*sin(2*2*pi*t)
s_lo = s_mean-0.1
s_hi = s_mean+0.1
#plot(t,s_mean,'k')
filly(t,s_lo,s_hi,fill=1,facecolor='g')

# I haven't decided yet on how to handle autoscaling with patches
# since there is no efficient easy way to get the patch's extent in
# data coords.  Instead, I update the datalim manually in plot
# commands that use pataches
gca().xaxis.datalim.update((min(t), max(t)))
gca().yaxis.datalim.update((min(s_lo), max(s_hi)))

# now this should work since the data lim are updated
gca().xaxis.autoscale_view() 
gca().yaxis.autoscale_view()
#savefig('filly')
show()

[Matplotlib-users] The meaning of the figure(dpi=xxx) parameter

[Al S. <a.d...@wo...>]

In order to get the size of the overall plot window to anywhere near
full screen, I've had to use something like 

	figure(1, figsize=(18,12), dpi=72)
or	figure(1, figsize=(9,6),   dpi=144)

Both produce the same overall size plot window (11.25" wide by 8" tall),
but in the latter case, the text size is much larger than in the latter
case. Likewise the linewidths.

Can you please explain the interaction among the dpi value, the font
sizes displayed, and the overall plot size.

Note: If I omit the dpi parameter, the plot window remains at its
default (approx 4" x 3") size.  The only way I've gotten the window size
to change at all is by adding the dpi parameter to the fiigure() call,
hence the question.

FYI, this is under RH linux 9, with XFree86 4.3.0-2.

The display is a 15" diagonal (12" horizontal, 9" vertical) Dell laptop
with 1400x1050 NVIDIA GeForce 4 (generic) graphics. Naively, this looks
like the H-res is 1400/12" = 116.66 dpi and the V-res is 1050/9" =
116.66 dpi also.

Should I set dpi to the resolution of my display (117) or to the
resolution of the X fonts (75 or 100)?

Thanks,
-- 
Al Schapira <a.d...@wo...>

Re: [Matplotlib-users] simple api question

[John H. <jdh...@ac...>]

>>>>> "Kuzminski," == Kuzminski, Stefan R <SKu...@fa...> writes:

    Kuzminski> Thanks, that worked for the line being plotted,
    Kuzminski> although the legend box and axis are still aliased.
    Kuzminski> Part of my requirements include supporting
    Kuzminski> presentation quality printing.  I would like to just
    Kuzminski> use Agg as GD has dependency issues and keeps popping
    Kuzminski> up other problems ( not to mention how great the Agg
    Kuzminski> output looks ).  But that great looking anti-aliasing
    Kuzminski> doesn't print well, so ideally there would be a
    Kuzminski> 'global' level flag that controls aliasing ( or not )
    Kuzminski> for everything drawn.  I know when the image is being
    Kuzminski> created for viewing or for printing and so can set the
    Kuzminski> flag accordingly.

I'll work on getting the rest of the objects to respect the
antialiased flag.  You can control antialiasing for all lines globally
with rcParams

  http://matplotlib.sourceforge.net/faq.html#CUSTOM


JDH

RE: [Matplotlib-users] simple api question

[Kuzminski, S. R <SKu...@fa...>]

Thanks, that worked for the line being plotted, although the legend box
and axis are still aliased.  Part of my requirements include supporting
presentation quality printing.  I would like to just use Agg as GD has
dependency issues and keeps popping up other problems ( not to mention
how great the Agg output looks ).  But that great looking anti-aliasing
doesn't print well, so ideally there would be a 'global' level flag that
controls aliasing ( or not ) for everything drawn.  I know when the
image is being created for viewing or for printing and so can set the
flag accordingly.

S

-----Original Message-----
From: John Hunter [mailto:jdh...@ni...]=20
Sent: Monday, March 08, 2004 8:16 AM
To: Kuzminski, Stefan R
Cc: mat...@li...
Subject: Re: [Matplotlib-users] simple api question

>>>>> "Kuzminski," =3D=3D Kuzminski, Stefan R <SKu...@fa...>
writes:

    Kuzminski,> I got the .51 release, looks great.  I need to
    Kuzminski,> set_antialiased() on the Renderer, but I'm not sure
    Kuzminski,> how to get the renderer object correctly.  If I call
    Kuzminski,> gca() I get the SubPlot, but the renderer member is
    Kuzminski,> None.  Any advice would be appreciated.

There is no way to set antialiased on the renderer itself, just on the
individual objects (lines etc).
 =20
  plot([1,2,3], antialiased=3DFalse)

or=20

  lines =3D plot(x1,y1,x2,y2)
  set(lines, 'antialiased', False)

or set lines.antialiased in matplotlibrc to the default you want.

Unfortunately, agg does not yet respect antialiased =3D=3D False for all
primitives, currently only lines.

See also

  http://matplotlib.sourceforge.net/faq.html#MATPLOTLIBRC
  http://matplotlib.sourceforge.net/faq.html#CUSTOM

Can you tell me what you're trying to do?

JDH

Re: [Matplotlib-users] simple api question

[John H. <jdh...@ac...>]

>>>>> "Kuzminski," == Kuzminski, Stefan R <SKu...@fa...> writes:

    Kuzminski,> I got the .51 release, looks great.  I need to
    Kuzminski,> set_antialiased() on the Renderer, but I'm not sure
    Kuzminski,> how to get the renderer object correctly.  If I call
    Kuzminski,> gca() I get the SubPlot, but the renderer member is
    Kuzminski,> None.  Any advice would be appreciated.

There is no way to set antialiased on the renderer itself, just on the
individual objects (lines etc).
  
  plot([1,2,3], antialiased=False)

or 

  lines = plot(x1,y1,x2,y2)
  set(lines, 'antialiased', False)

or set lines.antialiased in matplotlibrc to the default you want.

Unfortunately, agg does not yet respect antialiased == False for all
primitives, currently only lines.

See also

  http://matplotlib.sourceforge.net/faq.html#MATPLOTLIBRC
  http://matplotlib.sourceforge.net/faq.html#CUSTOM

Can you tell me what you're trying to do?

JDH

Re: [Matplotlib-users] Bug in PS output with multi-line ticklabels

[John H. <jdh...@ac...>]

>>>>> "Al" == Al Schapira <a.d...@wo...> writes:

    Al> [ I posted this directly to
    Al> mat...@li... previously, but I
    Al> didn't see it show up there. Sorry if you got this
    Al> before. --Al]

I have seen it, just haven't had a chance to look at it yet.  It's on
the list...

JDH

[Matplotlib-users] simple api question

[Kuzminski, S. R <SKu...@fa...>]

I got the .51 release, looks great.  I need to set_antialiased() on the
Renderer, but I'm not sure how to get the renderer object correctly.  If
I call gca() I get the SubPlot, but the renderer member is None.  Any
advice would be appreciated.

=20

thanks,

S

Re: [Matplotlib-users] error with embedding_in_wx.py

[John H. <jdh...@ac...>]

>>>>> "John" == John Wohlbier <jd...@go...> writes:

    John> Another clue, when I try another example with wx I get:
    John> wohlbier@gyrotwystron examples $ python dynamic_demo_wx.py
    John> Traceback (most recent call last): File
    John> "dynamic_demo_wx.py", line 34, in ?  from
    John> matplotlib.backends import Figure, Toolbar, FigureManager
    John> ImportError: cannot import name Figure wohlbier@gyrotwystron
    John> examples $

    John> Does this mean anything?

Well, it appears dynamic_demo_wx has not been updated to the latest
API.  Ignore this one for now.


What happens when you do

  > python2.3 simple_plot.py -dWX

Does it help to do

  > python2.3 embedding_in_wx.py -dWX

It shouldn't because you have selected wx as your default backend in
matplotlibrc, but I find your problem a little mysterious so I'm
grasping here.

Please send me the embedding_in_wx.py you are trying to run as an
attachement so I can see if I can replicate it on my system.

JDH

[Matplotlib-users] error with multi-line vertical ticklabels

[Al S. <a.d...@wo...>]

[ I posted this directly to mat...@li... previously,
but I didn't see it show up there. Sorry if you got this before. --Al]

I found that multi-line ticklabels work fine in normal (hortizontal) 
mode.  However, after a  "set(t, 'rotation', 'vertical')"  the plot fails 
as shown below. The plot window pops up, then disappears.
System is RH linux 9, matplotlib 0.51, pygtk 2.0.0,

Are multi-line labels supported?  In vertical mode too?

Thanks for your help.

	-Al Schapira, a.d...@wo...


### This is based upon the "vertical_ticklabels.py" in /examples.

[ads@ADS1 py]$ cat vertical_ticklabels.py
from matplotlib.matlab import *

plot([1,2,3,4], [1,4,9,16])
set(gca(), 'xticks', [1,2,3,4])

t = set(gca(), 'xticklabels', ['Frogs\nOKAY 1', 'Hogs\nFine 2', 
Bogs\nGOOD 3', 'Slogs'])

set(t, 'rotation', 'vertical')  # UNCOMMENT THIS to make the above fail

show()

[ads@ADS1 py]$ python vertical_ticklabels.py

The program 'vertical_ticklabels.py' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadMatch (invalid parameter attributes)'.
   (Details: serial 1083 error_code 8 request_code 73 minor_code 0)
   (Note to programmers: normally, X errors are reported asynchronously;
    that is, you will receive the error a while after causing it.
    To debug your program, run it with the --sync command line
    option to change this behavior. You can then get a meaningful
    backtrace from your debugger if you break on the gdk_x_error() 
function.)

[Matplotlib-users] Bug in PS output with multi-line ticklabels

[Al S. <a.d...@wo...>]

[ I posted this directly to mat...@li... previously,
but I didn't see it show up there. Sorry if you got this before. --Al]

I am generating a plot with multi-line ticklabels.
Although the plot displays normally, clicking on the SAVE icon fails
(after selecting a target file name ending with .ps).

I tracked this down as far as afm.get_str_bbox(), line 307 in afm.py

It appears to me that the '\n' character in my multi-line label is
causing the following error:

   File "/usr/local/lib/python2.3/site-packages/matplotlib/afm.py", line
307, in get_str_bbox
    wx, name, bbox = self._metrics[ord(c)]
KeyError: 10

Note that '\n' == 10.  I confirmed the failure with a tiny example:
Run the following and click on the SAVE icon, enter a file name ending
in .ps, and observe the failure.

################################
from matplotlib.matlab import *

plot([1,2,3,4], [1,4,9,16])
set(gca(), 'xticks', [1,2,3,4])

t = set(gca(), 'xticklabels', ['Frogs\nOKAY 1', 'Hogs\nFine 2',
'Bogs\nGOOD 3', 'Slogs'])

show()
################################

Although I realize that computing the bounding box of a multi-line text
is a bit more complex, I would really like to see this supported.

Also, I don't know in how many other places the embedded '\n' will cause
problems.

Thanks.

-- 
Al Schapira <a.d...@wo...>

Re: [Matplotlib-users] error with embedding_in_wx.py

[John W. <jd...@go...>]

Another clue, when I try another example with wx I get:

wohlbier@gyrotwystron examples $ python dynamic_demo_wx.py
Traceback (most recent call last):
  File "dynamic_demo_wx.py", line 34, in ?
    from matplotlib.backends import Figure, Toolbar, FigureManager
ImportError: cannot import name Figure
wohlbier@gyrotwystron examples $

Does this mean anything?

jgw

>
>     John> I get the error even using 0.51. Maybe my wxPython is
>     John> broken. Do you know of a way I can test it?
>
> The example runs fine on my systm.
>
> Something funny is going on.  wx does not attempt to load mathtext,
> either in 0.51 or in CVS.  That, and the fact that you are getting a
> gthread error, make me suspect you are actually loading the gtk
> backend.
>
> Are you trying to run embedding_in_wx from the prompt or from a
> development environment such as pycrust?  If you run from the prompt,
> you shouldn't see that error.  If not, you may be loading the default
> backend (GTK) first in your development environment and then trying to
> run embedding_in_wx.
>
> For example, if you first import matplotlib and later try to run
> embedding_in_wx in the same python/pycrust session, you will get
> yourself into a world of trouble, since the default import loads GTK and
> the second one WX.  These two cannot peacefully coexist.
>
> Try running the examples from the linux shell or DOS prompt first. Have
> you read the information about how to select the various backends on
> http://matplotlib.sourceforge.net/backends.html?
>
> You can change your default backend (eg to WX) in you .matplotlibrc
> file.
>
>   http://matplotlib.sourceforge.net/faq.html#MATPLOTLIBRC
>   http://matplotlib.sourceforge.net/.matplotlibrc
>
> If you still encounter problems, please tell me exactly what you are
> doing: what platform, how you are trying to run the example etc...
>
> Hope this helps,
> JDH

Re: [Matplotlib-users] error with embedding_in_wx.py

[John W. <jd...@go...>]

I have been running from the prompt all along. The command line is:

wohlbier@gyrotwystron examples $ python embedding_in_wx.py
Could not import mathtext (build with ft2font)

GThread-ERROR **: GThread system may only be initialized once.
aborting...
Aborted
wohlbier@gyrotwystron examples $


If running from the command line, does .matplotlibrc make a difference?
I did set the default backend in this file to WX.

I am on gentoo linux, python 2.3.3, wxPython 2.4.1.2, matplotlib 0.51,
executing from the command line as above, from the directory
/usr/lib/python2.3/site-packages/matplotlib-0.51/examples/

Let me know if you need something more about my setup.

jgw


>     John> I get the error even using 0.51. Maybe my wxPython is
>     John> broken. Do you know of a way I can test it?
>
> The example runs fine on my systm.
>
> Something funny is going on.  wx does not attempt to load mathtext,
> either in 0.51 or in CVS.  That, and the fact that you are getting a
> gthread error, make me suspect you are actually loading the gtk
> backend.
>
> Are you trying to run embedding_in_wx from the prompt or from a
> development environment such as pycrust?  If you run from the prompt,
> you shouldn't see that error.  If not, you may be loading the default
> backend (GTK) first in your development environment and then trying to
> run embedding_in_wx.
>
> For example, if you first import matplotlib and later try to run
> embedding_in_wx in the same python/pycrust session, you will get
> yourself into a world of trouble, since the default import loads GTK and
> the second one WX.  These two cannot peacefully coexist.
>
> Try running the examples from the linux shell or DOS prompt first. Have
> you read the information about how to select the various backends on
> http://matplotlib.sourceforge.net/backends.html?
>
> You can change your default backend (eg to WX) in you .matplotlibrc
> file.
>
>   http://matplotlib.sourceforge.net/faq.html#MATPLOTLIBRC
>   http://matplotlib.sourceforge.net/.matplotlibrc
>
> If you still encounter problems, please tell me exactly what you are
> doing: what platform, how you are trying to run the example etc...
>
> Hope this helps,
> JDH

Re: [Matplotlib-users] error with embedding_in_wx.py

[John H. <jdh...@ac...>]

>>>>> "John" == John Wohlbier <jd...@go...> writes:

    John> I get the error even using 0.51. Maybe my wxPython is
    John> broken. Do you know of a way I can test it?

The example runs fine on my systm.

Something funny is going on.  wx does not attempt to load mathtext,
either in 0.51 or in CVS.  That, and the fact that you are getting a
gthread error, make me suspect you are actually loading the gtk
backend.  

Are you trying to run embedding_in_wx from the prompt or from a
development environment such as pycrust?  If you run from the prompt,
you shouldn't see that error.  If not, you may be loading the default
backend (GTK) first in your development environment and then trying to
run embedding_in_wx.  

For example, if you first import matplotlib and later try to run
embedding_in_wx in the same python/pycrust session, you will get
yourself into a world of trouble, since the default import loads GTK
and the second one WX.  These two cannot peacefully coexist.

Try running the examples from the linux shell or DOS prompt first.
Have you read the information about how to select the various backends
on http://matplotlib.sourceforge.net/backends.html?

You can change your default backend (eg to WX) in you .matplotlibrc
file.

  http://matplotlib.sourceforge.net/faq.html#MATPLOTLIBRC
  http://matplotlib.sourceforge.net/.matplotlibrc

If you still encounter problems, please tell me exactly what you are
doing: what platform, how you are trying to run the example etc...

Hope this helps,
JDH

Re: [Matplotlib-users] error with embedding_in_wx.py

[John W. <jd...@go...>]

I get the error even using 0.51. Maybe my wxPython is
broken. Do you know of a way I can test it?

Thanks.
jgw


>John> I am using the latest CVS release of matplotlib from
>John> sourceforge, and when I try to run the wx backend example I
>John> get
>
>John> gyrotwystron examples # python embedding_in_wx.py Could not
>John> import mathtext (build with ft2font)
>
>John> GThread-ERROR **: GThread system may only be initialized John>
> once.  aborting...  Aborted
>
>John> The gtk backend examples work fine (although I still get the
>John> mathtext warning). I have python 2.3 and wxPython 2.4.2.4 on
>John> a gentoo linux system.
>
> Not sure why you get this - Jeremy may be working on porting mathtext to
> WX.  The 0.51 release is quite current, so unless you are looking for a
> specific feature from CVS I suggest you use that distribution since
> there are extra problems you'll encounter trying to build from CVS (see
> my last response to Andrew for details).
>
> If you want to clear up the cannot import mathtext problem, set
> BUILD_FT2FONT to True in setup.py before building.
>
> JDH

Re: [Matplotlib-users] multiple plots in matplotlib

[John H. <jdh...@ac...>]

>>>>> "Jim" == Jim Benson <jb...@se...> writes:


    Jim> ...it worked great. I closed the plot...and tried it again.
    Jim> Here is what happened:

    .... snip ....
    Jim> line 121, in show self.window.deiconify() File
    Jim> "/usr/local/lib/python2.3/lib-tk/Tkinter.py", line 1412, in
    Jim> wm_deiconify return self.tk.call('wm', 'deiconify', self._w)
    Jim> _tkinter.TclError: can't invoke "wm" command: application has
    Jim> been destroyed
    >>>>

    Jim> Should i be doing something different if i want to make
    Jim> multiple plots in interactive mode? I also tried using a
    Jim> figure(i) command before the plot command...this works
    Jim> fine...unless i try to reuse a previously closed i-th figure.

Several people have experienced problems along these lines, and we're
working on a fix.  This was the first release of the Tk backend so
please keep us up to date on other problems you find.  Using the "close"
command instead of clicking the x to close the window should work

>>> from matplotlib.matlab import *
>>> plot([1,2,3])
>>> close()
>>> plot([1,2,3])

Or you can use multiple figures at the same time with the figure
command

>>> from matplotlib.matlab import *
>>> figure(1)
>>> plot([1,2,3])
>>> figure(2)
>>> plot([1,2,3])
>>> close(2)
>>> xlabel('time')  # figure 1 is active


Thanks,
JDH

[Matplotlib-users] multiple plots in matplotlib

[Jim B. <jb...@se...>]

Hi,

  I'm a matplotlib (great package!) newbie. I decided to give the 
new TkAgg interactive mode a try. I did the setup
then tried the example:

>>> from matplotlib.matlab import *
>>> plot([1,2,3])
>>> xlabel('hi mom')

...it worked great. I closed the plot...and tried it again.
Here is what happened:

floyd:/home/jbenson/python>python
Python 2.3.3 (#1, Dec 21 2003, 15:13:18)
[GCC 3.3.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from matplotlib.matlab import *
>>> plot([1,2,3]) # This plot looked fine
Could not find requested font Times
Please set environment var TTFPATH to point to your true type fonts 
(*.ttf)
Could not find Times; falling back on Vera
[<matplotlib.lines.Line2D instance at 0x42c2b20c>]
>>> plot([1,2,3])
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/local/lib/python2.3/site-packages/matplotlib/matlab.py", line 
788, in plot
    draw_if_interactive()
  File 
"/usr/local/lib/python2.3/site-packages/matplotlib/backends/backend_tkagg.py", 
line 46, in draw_if_interactive
    figManager.show()
  File 
"/usr/local/lib/python2.3/site-packages/matplotlib/backends/backend_tkagg.py", 
line 121, in show
    self.window.deiconify()
  File "/usr/local/lib/python2.3/lib-tk/Tkinter.py", line 1412, in 
wm_deiconify
    return self.tk.call('wm', 'deiconify', self._w)
_tkinter.TclError: can't invoke "wm" command:  application has been 
destroyed
>>>

Should i be doing something different if i want to make multiple
plots in interactive mode? I also tried using a figure(i) command
before the plot command...this works fine...unless i try to reuse
a previously closed i-th figure.

Thanks,

Jim
     

Re: [Matplotlib-users] creating shaded areas

[Andrew S. <str...@as...>]

John Hunter wrote:

>     Andrew> Also, this is
>     Andrew> using the version of matplotlib I checked out with CVS.
>     Andrew> This version fails to build the agg backend with:
>
>     Andrew> running build_py package init file 'ttfquery/__init__.py'
>     Andrew> not found (or not a regular file) package init file
>     Andrew> 'FontTools/__init__.py' not found (or not a regular file)
>     Andrew> package init file 'FontTools/fontTools/__init__.py' not
>     Andrew> found (or not a regular file) package init file
>     Andrew> 'FontTools/fontTools/encodings/__init__.py' not found (or
>     Andrew> not a regular file) error: package directory
>     Andrew> 'FontTools/fontTools/misc' does not exist
>
> I won't get a chance to look at your fill code til Monday (which BTW
> is something I've been wanting to add for a while), but the main
> problem here is that CVS doesn't have a complete version of the
> FontTools* and ttf* that are needed to build from src.  The 0.51
> release is actually quite up to date and you would probably be best
> off just working in that tree for now.  vis-a-vis FontTools and
> ttfquery - an increasing number of matplotlib backends need ttf font
> finding capabilitlities which FontTools and ttfquery provide.
> However, they are big and a pain to install and Paul Barrett has been
> working on a replacement.  At one point I added them to CVS since I
> was distributing them with matplotlib but thought twice about it and
> tried to remove them.  However despite multiple attempts I have not
> been able to get them out of CVS (a free beer to anyone with commit
> privs who can purge these bastards).  No in a nutshell there is an
> incomplete version of FontTools and ttfquery in CVS.

This is one of the downsides of CVS; it doesn't deal with directories 
very well (or at all).  A SourceForge support request would be required 
for one of their admins to go into CVSROOT and manually do this.

What's wrong with distributing them via CVS, at least while they're 
distributed in the officially released matplotlib sources?  It would 
made things a bit cleaner for those willing to live on the bleeding 
edge.  (Then again, I suppose those willing to live on the bleeding 
edge are probably also be happy copy a few directories around, too. At 
least as long as we know what to do.)

> If you want to build from CVS, copy the agg, FontTools* and ttfquery
> dirs/files from the 0.51 src distro into the CVS tree and build from
> there.

Works like a charm!

Cheers!
Andrew

Re: [Matplotlib-users] error with embedding_in_wx.py

[John H. <jdh...@ac...>]

>>>>> "John" == John Wohlbier <jd...@go...> writes:

    John> I am using the latest CVS release of matplotlib from
    John> sourceforge, and when I try to run the wx backend example I
    John> get

    John> gyrotwystron examples # python embedding_in_wx.py Could not
    John> import mathtext (build with ft2font)

    John> GThread-ERROR **: GThread system may only be initialized
    John> once.  aborting...  Aborted

    John> The gtk backend examples work fine (although I still get the
    John> mathtext warning). I have python 2.3 and wxPython 2.4.2.4 on
    John> a gentoo linux system.

Not sure why you get this - Jeremy may be working on porting mathtext
to WX.  The 0.51 release is quite current, so unless you are looking
for a specific feature from CVS I suggest you use that distribution
since there are extra problems you'll encounter trying to build from
CVS (see my last response to Andrew for details).

If you want to clear up the cannot import mathtext problem, set
BUILD_FT2FONT to True in setup.py before building.

JDH

Re: [Matplotlib-users] creating shaded areas

[John H. <jdh...@ac...>]

>>>>> "Andrew" == Andrew Straw <str...@as...> writes:

    Andrew> G'day all!  I'm back to using matplotlib after a few
    Andrew> months away. I'm very impressed with the recent progress!

Thanks.  It's good to see you back around in these parts :-)

    Andrew> I often plot the instantaneous variance of repeated
    Andrew> recordings made under the same conditions using a shaded
    Andrew> area to surround the mean. I'm trying to find a way to do
    Andrew> this with matplotlib.  Included below is a "filly" (fill
    Andrew> y) function I wrote to attempt to do this.  It doesn't
    Andrew> quite work yet, and I'd like some help.  (BTW, I don't
    Andrew> know of how this would be done in Matlab, so if there's a
    Andrew> more compatible way, I'd be happy to change the approach.)

    Andrew> 1) How do I make the data fill the axes automatically,
    Andrew> such as the "plot" function?

    Andrew> 2) Is it a bug that the polygon is not filled, or am I
    Andrew> missing something?

    Andrew> I've only tried this in the PS backend -- I'm having
    Andrew> troubles with the others at the moment.  Also, this is
    Andrew> using the version of matplotlib I checked out with CVS.
    Andrew> This version fails to build the agg backend with:

    Andrew> running build_py package init file 'ttfquery/__init__.py'
    Andrew> not found (or not a regular file) package init file
    Andrew> 'FontTools/__init__.py' not found (or not a regular file)
    Andrew> package init file 'FontTools/fontTools/__init__.py' not
    Andrew> found (or not a regular file) package init file
    Andrew> 'FontTools/fontTools/encodings/__init__.py' not found (or
    Andrew> not a regular file) error: package directory
    Andrew> 'FontTools/fontTools/misc' does not exist

I won't get a chance to look at your fill code til Monday (which BTW
is something I've been wanting to add for a while), but the main
problem here is that CVS doesn't have a complete version of the
FontTools* and ttf* that are needed to build from src.  The 0.51
release is actually quite up to date and you would probably be best
off just working in that tree for now.  vis-a-vis FontTools and
ttfquery - an increasing number of matplotlib backends need ttf font
finding capabilitlities which FontTools and ttfquery provide.
However, they are big and a pain to install and Paul Barrett has been
working on a replacement.  At one point I added them to CVS since I
was distributing them with matplotlib but thought twice about it and
tried to remove them.  However despite multiple attempts I have not
been able to get them out of CVS (a free beer to anyone with commit
privs who can purge these bastards).  No in a nutshell there is an
incomplete version of FontTools and ttfquery in CVS.

If you want to build from CVS, copy the agg, FontTools* and ttfquery
dirs/files from the 0.51 src distro into the CVS tree and build from
there.  This will all be cleared up in a few weeks time.

JDH

[Matplotlib-users] Bug in PS output with multi-line ticklabels

[Al S. <a.d...@wo...>]

I am generating a plot with multi-line ticklabels.
Although the plot displays normally, clicking on the SAVE icon fails
(after selecting the target file name).

I tracked this down as far as afm.get_str_bbox(), line 307 in afm.py

It appears to me that the '\n' character in my multi-line label is
causing the following error:

   File "/usr/local/lib/python2.3/site-packages/matplotlib/afm.py", line
307, in get_str_bbox
    wx, name, bbox = self._metrics[ord(c)]
KeyError: 10

Note that '\n' == 10.  I confirmed the failure with a tiny example:
Run the following and click on the SAVE icon, enter a file name, and
observe the failure.

################################
from matplotlib.matlab import *

plot([1,2,3,4], [1,4,9,16])
set(gca(), 'xticks', [1,2,3,4])

t = set(gca(), 'xticklabels', ['Frogs\nOKAY 1', 'Hogs\nFine 2',
'Bogs\nGOOD 3', 'Slogs'])

show()
################################

Although I realize that computing the bounding box of a multi-line text
is a bit more complex, I would really like to see this supported.

Also, I don't know in how many other places the embedded '\n' will cause
problems.

Thanks.

-- 
Al Schapira <a.d...@wo...>

[Matplotlib-users] error with embedding_in_wx.py

[John W. <jd...@go...>]

I am using the latest CVS release of matplotlib
from sourceforge, and when I try to run the
wx backend example I get

gyrotwystron examples # python embedding_in_wx.py
Could not import mathtext (build with ft2font)

GThread-ERROR **: GThread system may only be initialized once.
aborting...
Aborted


The gtk backend examples work fine (although I still get
the mathtext warning). I have python 2.3 and wxPython 2.4.2.4
on a gentoo linux system.

Thanks!

jgw

[Matplotlib-users] error with multi-line vertical ticklabels

[Al S. <a.d...@wo...>]

I found that multi-line ticklabels work fine in normal (hortizontal) 
mode.  However, after a  set(t, 'rotation', 'vertical')   the plot fails 
as shown below. The plot window pops up, then disappears.
System is RH linux 9, matplotlib 0.51, pygtk 2.0.0,

Are multi-line labels supported?  In vertical mode too?

Thanks for your help.

	-Al Schapira, a.d...@wo...


### This is based upon the "vertical_ticklabels.py" in /examples.

[ads@ADS1 py]$ cat vertical_ticklabels.py
from matplotlib.matlab import *

plot([1,2,3,4], [1,4,9,16])
set(gca(), 'xticks', [1,2,3,4])

t = set(gca(), 'xticklabels', ['Frogs\nOKAY 1', 'Hogs\nFine 2', 
Bogs\nGOOD 3', 'Slogs'])

set(t, 'rotation', 'vertical')  # UNCOMMENT THIS to make the above fail

show()

[ads@ADS1 py]$ python vertical_ticklabels.py

The program 'vertical_ticklabels.py' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadMatch (invalid parameter attributes)'.
   (Details: serial 1083 error_code 8 request_code 73 minor_code 0)
   (Note to programmers: normally, X errors are reported asynchronously;
    that is, you will receive the error a while after causing it.
    To debug your program, run it with the --sync command line
    option to change this behavior. You can then get a meaningful
    backtrace from your debugger if you break on the gdk_x_error() 
function.)

[Matplotlib-users] creating shaded areas

[Andrew S. <str...@as...>]

G'day all!

I'm back to using matplotlib after a few months away. I'm very 
impressed with the recent progress!

I often plot the instantaneous variance of repeated recordings made 
under the same conditions using a shaded area to surround the mean. I'm 
trying to find a way to do this with matplotlib.  Included below is a 
"filly" (fill y) function I wrote to attempt to do this.  It doesn't 
quite work yet, and I'd like some help.  (BTW, I don't know of how this 
would be done in Matlab, so if there's a more compatible way, I'd be 
happy to change the approach.)

1) How do I make the data fill the axes automatically, such as the 
"plot" function?

2) Is it a bug that the polygon is not filled, or am I missing 
something?

I've only tried this in the PS backend -- I'm having troubles with the 
others at the moment.  Also, this is using the version of matplotlib I 
checked out with CVS.  This version fails to build the agg backend with:

running build_py
package init file 'ttfquery/__init__.py' not found (or not a regular 
file)
package init file 'FontTools/__init__.py' not found (or not a regular 
file)
package init file 'FontTools/fontTools/__init__.py' not found (or not a 
regular file)
package init file 'FontTools/fontTools/encodings/__init__.py' not found 
(or not a regular file)
error: package directory 'FontTools/fontTools/misc' does not exist

Cheers!
Andrew

-=-=-=-=-=-=-= filly.py -=-=-=-=-=-=-=-=
from matplotlib.matlab import *
from matplotlib.patches import Rectangle, Polygon

def filly(x,y1,y2,**kwargs):
     ax = gca()
     xy = []
     for xi, yi in zip(x,y1):
         xy.append( (xi,yi) )
     for xi, yi in zip(x[::-1],y2[::-1]):
         xy.append( (xi,yi) )
     xy.append( xy[0] )

     polygon = Polygon(
         ax.dpi, ax.bbox,
         xy,
         transx = ax.xaxis.transData, # what does this do?
         transy = ax.yaxis.transData, # and this??
         **kwargs)

     ax.add_patch(polygon)
     return polygon

figure(1)
t = arange(0.0, 1.0, 0.01)
s_mean = 0.5*sin(2*2*pi*t)
s_lo = s_mean-0.1
s_hi = s_mean+0.1
#plot(t,s_mean,'k')
filly(t,s_lo,s_hi,fill=1,facecolor='g')
gca().xaxis.autoscale_view() # why doesn't this help?
gca().yaxis.autoscale_view()
savefig('filly')
#show()