Re: [Matplotlib-users] Get contourf image as array
Thanks Ben. I'll take a look through the archive. On 10/16/14, 9:43 AM, Benjamin Root wrote: > What you are looking for is called "rasterization". Matplotlib does this > deep within the codebase and is not accessible (believe me, I tried). > However, there have been other discussions in this mailing list about > how to use GDAL to rasterize a set of polygons (represented as paths), > including some links to stack-overflow questions. It isn't a complete > end-to-end solution, but the pieces are there. > > Cheers! > Ben Root > > > On Wed, Oct 15, 2014 at 2:09 PM, David Hoese <mailto:dho...@gmail.com>> wrote: > > For the first question, if I save the figure (as a PNG I'm guessing, > unless you can save into a more array-like format), I'd have to make > sure that there were no labels or ticks and that the axes fit the whole > figure. I'd also have to get the dpi and size information correct, but I > suppose it would be possible that way. I was hoping for something a > little easier and in-memory. This might be the simplest answer the more > I think about it. > > If I'm starting from the paths, I'd still have to write them to the > "grid" array. I thought maybe the backend could do that and I magically > get the image. > > I'll look in to using savefig and getting the data out. > > -Dave > > On 10/15/14, 12:42 PM, Joy merwin monteiro wrote: > > pardon the query if it seems dumb, but why don't you do a savefig() > > after plotting the data and then convert it to any format you like? > > > > alternatively, contour() and contourf() both create paths that can > > be accessed: > > > > cf = contourf(.) > > > > output = cf.collections.pop() > > paths = output.get_paths()[i] # for the various contours > > > > the x,y coordinates can then be accessed as > > > > xcoords = paths.vertices.transpose()[0] > > ycoords = paths.vertices.transpose()[1] > > > > you can then do whatever you wish with them. > > > > Joy > > > > > > On Wed, Oct 15, 2014 at 9:11 PM, David Hoese <mailto:dho...@gmail.com> > > <mailto:dho...@gmail.com <mailto:dho...@gmail.com>>> wrote: > > > > I've been searching and reading through source code and > google searches > > to see if this is possible, but no luck so far. I'm basically > trying to > > map some data using Basemap, use contourf to map it to an > image, and > > then put that image in a geotiff (or other format) for use in > other GIS > > programs. I have other tools for remapping data and creating > geotiffs, > > but the contour image looks better. All I would need to get > this to work > > would be an array representing the image inside the axes of a > contourf > > plot. I found a lot of geotiff -> Basemap png results, but I > would like > > the reverse. > > > > Since the plots are made using paths/patches I'm guessing I > would have > > to have a backend render the image and then extract the image > somehow. > > Does anyone have some tips or tricks to do something like > this? Or am I > > thinking about this completely wrong? > > > > Thanks for any help and if you could CC me in any replies it > would be > > much appreciated. > > > > -Dave > > > > > > -- > > Comprehensive Server Monitoring with Site24x7. > > Monitor 10 servers for $9/Month. > > Get alerted through email, SMS, voice calls or mobile push > > notifications. > > Take corrective actions from your mobile device. > > http://p.sf.net/sfu/Zoho > > ___ > > Matplotlib-users mailing list > > Matplotlib-users@lists.sourceforge.net > <mailto:Matplotlib-users@lists.sourceforge.net> > > <mailto:Matplotlib-users@lists.sourceforge.net > <mailto:Matplotlib-users@lists.sourceforge.net>> > > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > > > > > > > > > -- > > The best ruler, wh
Re: [Matplotlib-users] Get contourf image as array
For the first question, if I save the figure (as a PNG I'm guessing, unless you can save into a more array-like format), I'd have to make sure that there were no labels or ticks and that the axes fit the whole figure. I'd also have to get the dpi and size information correct, but I suppose it would be possible that way. I was hoping for something a little easier and in-memory. This might be the simplest answer the more I think about it. If I'm starting from the paths, I'd still have to write them to the "grid" array. I thought maybe the backend could do that and I magically get the image. I'll look in to using savefig and getting the data out. -Dave On 10/15/14, 12:42 PM, Joy merwin monteiro wrote: > pardon the query if it seems dumb, but why don't you do a savefig() > after plotting the data and then convert it to any format you like? > > alternatively, contour() and contourf() both create paths that can > be accessed: > > cf = contourf(.) > > output = cf.collections.pop() > paths = output.get_paths()[i] # for the various contours > > the x,y coordinates can then be accessed as > > xcoords = paths.vertices.transpose()[0] > ycoords = paths.vertices.transpose()[1] > > you can then do whatever you wish with them. > > Joy > > > On Wed, Oct 15, 2014 at 9:11 PM, David Hoese <mailto:dho...@gmail.com>> wrote: > > I've been searching and reading through source code and google searches > to see if this is possible, but no luck so far. I'm basically trying to > map some data using Basemap, use contourf to map it to an image, and > then put that image in a geotiff (or other format) for use in other GIS > programs. I have other tools for remapping data and creating geotiffs, > but the contour image looks better. All I would need to get this to work > would be an array representing the image inside the axes of a contourf > plot. I found a lot of geotiff -> Basemap png results, but I would like > the reverse. > > Since the plots are made using paths/patches I'm guessing I would have > to have a backend render the image and then extract the image somehow. > Does anyone have some tips or tricks to do something like this? Or am I > thinking about this completely wrong? > > Thanks for any help and if you could CC me in any replies it would be > much appreciated. > > -Dave > > > -- > Comprehensive Server Monitoring with Site24x7. > Monitor 10 servers for $9/Month. > Get alerted through email, SMS, voice calls or mobile push > notifications. > Take corrective actions from your mobile device. > http://p.sf.net/sfu/Zoho > ___ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > <mailto:Matplotlib-users@lists.sourceforge.net> > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > > > > -- > The best ruler, when he finishes his > tasks and completes his affairs, > the people say > “It all happened naturally” > > - Te Tao Ch'ing -- Comprehensive Server Monitoring with Site24x7. Monitor 10 servers for $9/Month. Get alerted through email, SMS, voice calls or mobile push notifications. Take corrective actions from your mobile device. http://p.sf.net/sfu/Zoho ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
[Matplotlib-users] Get contourf image as array
I've been searching and reading through source code and google searches to see if this is possible, but no luck so far. I'm basically trying to map some data using Basemap, use contourf to map it to an image, and then put that image in a geotiff (or other format) for use in other GIS programs. I have other tools for remapping data and creating geotiffs, but the contour image looks better. All I would need to get this to work would be an array representing the image inside the axes of a contourf plot. I found a lot of geotiff -> Basemap png results, but I would like the reverse. Since the plots are made using paths/patches I'm guessing I would have to have a backend render the image and then extract the image somehow. Does anyone have some tips or tricks to do something like this? Or am I thinking about this completely wrong? Thanks for any help and if you could CC me in any replies it would be much appreciated. -Dave -- Comprehensive Server Monitoring with Site24x7. Monitor 10 servers for $9/Month. Get alerted through email, SMS, voice calls or mobile push notifications. Take corrective actions from your mobile device. http://p.sf.net/sfu/Zoho ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] real time plotting
I agree, I don't think that will work with mpl's animation stuff or at
least I wouldn't want to do it that way. I've created GUIs that received
data from a weather instrument in real-time. I did method 3 that I
mentioned before because I knew the scientists using it were going to
want more and more features.
...I FOUND A WAY FOR YOU TO CHEAT:
You can use the Qt "processEvents()" method to have it process
drawing/painting operation between the event loop iterations. This
method is frowned upon when doing real Qt GUIs, but eh go for it. If you
aren't doing anything more serious than watching the output of your
processing as it goes then try this:
import matplotlib
matplotlib.use('qt4agg')
import matplotlib as mpl
import matplotlib.pyplot as plt
plt.ion()
import numpy as np
from time import sleep
from PyQt4 import QtGui,QtCore
fig=plt.figure()
plt.axis([0,1000,0,1])
i=0
x=list()
y=list()
while i <1000:
temp_y=np.random.random()
x.append(i)
y.append(temp_y)
plt.scatter(i,temp_y)
i+=1
plt.draw()
sleep(1)
QtGui.qApp.processEvents()
Good luck,
Dave
On 3/11/13 12:59 PM, Neal Becker wrote:
I go through a compute loop that takes maybe a few seconds per pass,
then plot a new point on the graph. Do I have to? No - I thought mpl
was supposed to do this and wanted to learn how. If it really doesn't
work I'll do something else.
I don't think animation is correct here - I had the impression
animation is where my update would be run as a callback, with a main
loop that calls me periodically. Could that fit the model I
described, where a lengthy computation produces a new value every
few/10s of seconds?
On Mon, Mar 11, 2013 at 1:55 PM, David Hoese <mailto:dho...@gmail.com>> wrote:
Someone may have to correct me, but I think this has to do with
the Qt4 event loop and it not being run properly. When you get
into real time plotting it can get kind of tricky. In your case (I
got the same results). I have made real-time PyQt4 GUIs before and
have always used separate QThreads and Qt signals/slots to update
the plot. I've never used GTK so I'm not sure why that worked vs
Qt, I would think they would use similar principles but matplotlib
does some magic behind the scenes sometimes. You can see different
results if you comment out the while loop and import the module
into your python/ipython interpreter. After doing this you'll see
the figure pop up (you don't even need the fig.canvas.show() for
this part if interactive mode is on. I went one step further and
turned the while loop into a function:
def one_iter(i):
# Contents of while loop
Calling this in the interpreter shows the figure updating after
each call, but running in a loop (even with sleep) won't show any
updates until the loop is done. In my opinion you have a few
choices that really depend on your programming comfort level:
1. Don't make a real-time plot.
Do you really need a real-time plot that updates from some
external source?
2. Maybe you should look at the matplotlib animation functionality
(http://matplotlib.org/api/animation_api.html). I like this
tutorial:
http://jakevdp.github.com/blog/2012/08/18/matplotlib-animation-tutorial/.
This won't get you a real-time GUI exactly, but it can help if
what you're doing isn't too complicated. It can also be nice for
making videos of plot animations.
3. If you need a GUI with multiple plots and you need for future
feature creep, I would research making PyQt4 GUIs, QThreads, Qt
signals and slots, and putting matplotlib figures into a PyQt4
GUI. This is complex if you are not familiar with GUI programming
and will take a while.
Sorry I couldn't be of more help, but it really depends on what
exactly you are doing. Mainly, what do you mean by real-time? Do
you really mean animation? Let me know what you come up with, I'm
interested.
-Dave
P.S. Why use a while loop? You can do the same thing with:
for i in range(1000):
# Do stuff
On 3/11/13 10:34 AM, Neal Becker wrote:
I added fig.canvas.show(). It still does nothing.
If I add
mpl.use ('GTK'), now it seems to be doing realtime plotting.
import matplotlib as mpl
import matplotlib.pyplot as plt
plt.ion()
import numpy as np
fig=plt.figure()
plt.axis([0,1000,0,1])
i=0
x=list()
y=list()
fig.canvas.show()
while i <1000:
temp_y=np.random.random()
x.append(i)
y.append(temp_y)
plt.scatter(i,temp_y)
i+=1
plt.draw()
On Mon, Mar 11, 2013 at 10:35 AM, David Hoese mailto:dho...@gmail.com>> wrote:
Oops forgot to change the subject line.
On
Re: [Matplotlib-users] real time plotting
Someone may have to correct me, but I think this has to do with the Qt4
event loop and it not being run properly. When you get into real time
plotting it can get kind of tricky. In your case (I got the same
results). I have made real-time PyQt4 GUIs before and have always used
separate QThreads and Qt signals/slots to update the plot. I've never
used GTK so I'm not sure why that worked vs Qt, I would think they would
use similar principles but matplotlib does some magic behind the scenes
sometimes. You can see different results if you comment out the while
loop and import the module into your python/ipython interpreter. After
doing this you'll see the figure pop up (you don't even need the
fig.canvas.show() for this part if interactive mode is on. I went one
step further and turned the while loop into a function:
def one_iter(i):
# Contents of while loop
Calling this in the interpreter shows the figure updating after each
call, but running in a loop (even with sleep) won't show any updates
until the loop is done. In my opinion you have a few choices that really
depend on your programming comfort level:
1. Don't make a real-time plot.
Do you really need a real-time plot that updates from some
external source?
2. Maybe you should look at the matplotlib animation functionality
(http://matplotlib.org/api/animation_api.html). I like this tutorial:
http://jakevdp.github.com/blog/2012/08/18/matplotlib-animation-tutorial/. This
won't get you a real-time GUI exactly, but it can help if what you're
doing isn't too complicated. It can also be nice for making videos of
plot animations.
3. If you need a GUI with multiple plots and you need for future feature
creep, I would research making PyQt4 GUIs, QThreads, Qt signals and
slots, and putting matplotlib figures into a PyQt4 GUI. This is complex
if you are not familiar with GUI programming and will take a while.
Sorry I couldn't be of more help, but it really depends on what exactly
you are doing. Mainly, what do you mean by real-time? Do you really
mean animation? Let me know what you come up with, I'm interested.
-Dave
P.S. Why use a while loop? You can do the same thing with:
for i in range(1000):
# Do stuff
On 3/11/13 10:34 AM, Neal Becker wrote:
I added fig.canvas.show(). It still does nothing.
If I add
mpl.use ('GTK'), now it seems to be doing realtime plotting.
import matplotlib as mpl
import matplotlib.pyplot as plt
plt.ion()
import numpy as np
fig=plt.figure()
plt.axis([0,1000,0,1])
i=0
x=list()
y=list()
fig.canvas.show()
while i <1000:
temp_y=np.random.random()
x.append(i)
y.append(temp_y)
plt.scatter(i,temp_y)
i+=1
plt.draw()
On Mon, Mar 11, 2013 at 10:35 AM, David Hoese <mailto:dho...@gmail.com>> wrote:
Oops forgot to change the subject line.
On 3/11/13 9:34 AM, David Hoese wrote:
You likely need to "show()" the canvas. I usually do this by
calling "fig.canvas.show()" before the for loop.
Since you are using a Qt4 backend the canvas used by the
figure is a QWidget, the basic component of a Qt4 GUI. I don't
know if there is a more matplotlib specific way of doing this,
but when dealing with a larger system this is how I do it.
I would also add a sleep ("from time import sleep") of a
couple seconds for testing to make sure you are getting
through the entire for loop before you can see it.
Please CC in any replies, thanks.
-Dave
On 3/11/13 8:58 AM, ndbeck...@gmail.com
<mailto:ndbeck...@gmail.com> wrote:
I want to update a plot in real time. I did some goog
search, and saw various
answers. Trouble is, they aren't working.
Here's a typical example:
import matplotlib.pyplot as plt
import numpy as np
fig=plt.figure()
plt.axis([0,1000,0,1])
i=0
x=list()
y=list()
while i <1000:
temp_y=np.random.random()
x.append(i)
y.append(temp_y)
plt.scatter(i,temp_y)
i+=1
plt.draw()
If I run this, it draws nothing.
This is my matplotlibrc:
backend : Qt4Agg
mathtext.fontset: stix
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Re: [Matplotlib-users] real time plotting
Oops forgot to change the subject line.
On 3/11/13 9:34 AM, David Hoese wrote:
> You likely need to "show()" the canvas. I usually do this by calling
> "fig.canvas.show()" before the for loop.
> Since you are using a Qt4 backend the canvas used by the figure is a
> QWidget, the basic component of a Qt4 GUI. I don't know if there is a
> more matplotlib specific way of doing this, but when dealing with a
> larger system this is how I do it.
>
> I would also add a sleep ("from time import sleep") of a couple
> seconds for testing to make sure you are getting through the entire
> for loop before you can see it.
>
> Please CC in any replies, thanks.
>
> -Dave
>
> On 3/11/13 8:58 AM, ndbeck...@gmail.com wrote:
>> I want to update a plot in real time. I did some goog search, and
>> saw various
>> answers. Trouble is, they aren't working.
>>
>> Here's a typical example:
>>
>> import matplotlib.pyplot as plt
>> import numpy as np
>> fig=plt.figure()
>> plt.axis([0,1000,0,1])
>>
>> i=0
>> x=list()
>> y=list()
>>
>> while i <1000:
>> temp_y=np.random.random()
>> x.append(i)
>> y.append(temp_y)
>> plt.scatter(i,temp_y)
>> i+=1
>> plt.draw()
>>
>> If I run this, it draws nothing.
>>
>> This is my matplotlibrc:
>> backend : Qt4Agg
>> mathtext.fontset: stix
>
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Re: [Matplotlib-users] Matplotlib-users Digest, Vol 82, Issue 16
You likely need to "show()" the canvas. I usually do this by calling
"fig.canvas.show()" before the for loop.
Since you are using a Qt4 backend the canvas used by the figure is a
QWidget, the basic component of a Qt4 GUI. I don't know if there is a
more matplotlib specific way of doing this, but when dealing with a
larger system this is how I do it.
I would also add a sleep ("from time import sleep") of a couple seconds
for testing to make sure you are getting through the entire for loop
before you can see it.
Please CC in any replies, thanks.
-Dave
On 3/11/13 8:58 AM, ndbeck...@gmail.com wrote:
> I want to update a plot in real time. I did some goog search, and saw various
> answers. Trouble is, they aren't working.
>
> Here's a typical example:
>
> import matplotlib.pyplot as plt
> import numpy as np
> fig=plt.figure()
> plt.axis([0,1000,0,1])
>
> i=0
> x=list()
> y=list()
>
> while i <1000:
> temp_y=np.random.random()
> x.append(i)
> y.append(temp_y)
> plt.scatter(i,temp_y)
> i+=1
> plt.draw()
>
> If I run this, it draws nothing.
>
> This is my matplotlibrc:
> backend : Qt4Agg
> mathtext.fontset: stix
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[Matplotlib-users] importing basemap then shapely causes error
I've asked this question on GIS stack exchange site, but thought it
would be good to post here too. The SE question is here:
http://gis.stackexchange.com/questions/50394/importing-matplotlib-basemap-and-shapely
I have a python script that uses matplotlib's basemap and another part
that uses shapely to do an intersection of 2 polygons. If basemap is
imported before shapely and I run the intersection I get this exception:
| intersect_poly= grid_poly.intersection(data_poly)
File "/sw/lib/python2.7/site-packages/shapely/geometry/base.py", line334, in
intersection
return geom_factory(self.impl['intersection'](self, other))
File "/sw/lib/python2.7/site-packages/shapely/topology.py", line53, in
__call__
"This operation produced a null geometry. Reason: unknown")
shapely.geos.TopologicalError: This operation produced a null geometry.
Reason: unknown|
If I import shapely first, everything works fine. I would assume this is
because of some "funkiness" in the way they are accessing the GEOS
library. I've checked that in both situations the same library file is
loaded in shapely ("print shapely.geos._lgeos").
Does anyone have an idea as to why this is happening and if there is a
right way of doing this? Does this happen for anyone else? In the mean
time I can just make sure to import shapely first (not sure if that
affects basemap yet). Otherwise maybe I'll skim through the basemap source.
I'm using OSX(10.7) with a fink install that has "libgeos3.3.3-shlibs",
"libgeos3.3.1-shlibs", "libgeos3.3.1", "libgeos3.3.0-shlibs",
"libgeos3.3.0", and "shapely-py27 (1.2.16-1)" installed. The current
basemap version in fink is 1.0.2.
And here's a simple test script that reproduces the problem (flip the
imports and it works):
|from mpl_toolkitsimport basemap
from shapelyimport geometry
g_ring= [(-88.462425, 26.992203), (-57.847187, 26.992203), (-57.847187,
17.599869), (-88.462425, 17.599869), (-88.462425, 26.992203)]
grid_g_ring= [(-123.044, 59.8440001), (-49.3849998,
57.2890001), (-65.0909994, 14.3350001), (-113.133,
16.369), (-123.044, 59.8440001)]
data_poly= geometry.Polygon(g_ring)
grid_poly= geometry.Polygon(grid_g_ring)
print grid_poly.intersection(data_poly).area|
Thanks again. Please CC me in any replies.
-Dave
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Re: [Matplotlib-users] matplotlib 1.1 "TypeError: a float is required" problem
Hi Ken,
You're getting that error because you probably don't have Qt4 installed
on your Mac (I do). I'm not sure what backends come with matplotlib and
will work for you (maybe someone here knows). You can use any of the
following:
GTK GTKAgg GTKCairo CocoaAgg FltkAgg
MacOSX QtAgg Qt4Agg TkAgg WX WXAgg Agg Cairo GDK PS PDF SVG Template
Like Qt4, some of those may need to be installed. I also have Gtk
installed (never used it before) and "GTKAgg" works for me, but not
"GTK". It's also important to know that not all of those backends are
interactive (they don't all show a window) and the figure must be saved
to a file.
Also make sure that the 2 lines I provided need to be BEFORE any other
matplotlib/pyplot imports. Hope you find something that works for you,
at least until the macosx bug is fixed. I'm not an expert, sorry.
-Dave
On 1/6/12 10:35 AM, Mingkui Li wrote:
Hi, Dave,
I tried the two lines of code you posted, but when I ran the example I
mentioned above I got such error:
ImportError: No module named sip
Seems I can't import any other libs from matplotlib after
"matplotlib.use("Qt4Agg")"
I'm kind of a newbie, sorry.
Ken
On Sat, Jan 7, 2012 at 12:22 AM, David Hoese <mailto:dho...@gmail.com>> wrote:
I experienced the same problem on the macosx backend, switched to
Qt4Agg
and no problems.
import matplotlib
matplotlib.use("Qt4Agg")
-Dave
On 1/6/12 10:08 AM, md...@stsci.edu <mailto:md...@stsci.edu> wrote:
> I suspect this bug is specific to the macosx backend. Can you
switch to
> another backend and confirm it doesn't happen there? (I can't
reproduce
> it on Linux).
>
> Mike
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Re: [Matplotlib-users] matplotlib 1.1 "TypeError: a float is required" problem
I experienced the same problem on the macosx backend, switched to Qt4Agg
and no problems.
import matplotlib
matplotlib.use("Qt4Agg")
-Dave
On 1/6/12 10:08 AM, md...@stsci.edu wrote:
> I suspect this bug is specific to the macosx backend. Can you switch to
> another backend and confirm it doesn't happen there? (I can't reproduce
> it on Linux).
>
> Mike
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Re: [Matplotlib-users] Blitting with qt4
Eric,
Good news I think I got it to work. So using the same code I sent you
originally, I applied the following changes:
1. Install matplotlib from git (this did fix things that I wasn't noticing)
2. Add c.draw() before "c.copy_from_bbox"
3. Copy "f.bbox" instead of "a.bbox" (I think this makes sense since I
want it to hold on to the title,ticks, and labels, a.bbox is only the
content inside the axis rectangle)
4. Restore f_bbox, blit f.bbox.
...and it seems to work. The git version of mpl did fix this, although
restoring just the a.bbox was only keeping the axis rectangle so it made
it look like even worse of a bug. Using the new version I noticed this
and then started using f.bbox which seems to work the way I want it.
Now, my final question is: Is this actually doing what I want
performance-wise. When I blit just f.bbox, is it really only repainting
the updated line or is it redrawing most of the figure? If you need a
copy of the new version of my test code let me know. Thanks for any
more clarity/help you can give.
-Dave
P.S. Is there a book or tutorial or website where I can learn more about
how the rendering/painting of stuff like this works. For example, if I
could better understand why your bug fix was needed.
On 12/15/11 10:04 AM, David Hoese wrote:
> Oops forgot to change subject.
>
> On 12/15/11 10:02 AM, David Hoese wrote:
>> Eric,
>>
>> I installed mpl from git ("git clone
>> git://github.com/matplotlib/matplotlib.git", unless I was suppose to
>> use one of the branches) and same problem. I looked at my code again
>> and thought there should be a canvas.draw() before calling
>> "c.copy_from_bbox(a.bbox)", but still the same problem. However, I
>> did have it work the first time I added "c.draw()" and used the git
>> mpl, and by work I mean that everything stayed visible on the figure.
>>
>> When people start coming in to my work I'll ask them to run my sample
>> code and see what happens. It almost seems like mpl is handling the
>> window activation event funny, is there an easy way to print out the
>> callbacks being used by a mpl figure? For now, I will subclass
>> QApplication, and implement "notify()" to print out events as they
>> come in, but still...this is just weird. Thanks.
>>
>> -Dave
>>
>> On 12/14/11 10:30 PM, Eric Firing wrote:
>>> David,
>>>
>>> It works for me on linux with mpl from git. I haven't tried to figure
>>> it out, but it is conceivable that the problem you are seeing was fixed
>>> with this:
>>>
>>> commit b624546ae60dc5878e75a32f41a160d383548b8f
>>> Author: Eric Firing
>>> Date: Tue Oct 18 08:06:21 2011 -1000
>>>
>>> backend_qt4agg: draw() immediately calls FigureCanvasAgg.draw()
>>>
>>> This is the latest in a series of modifications to the Qt4Agg
>>> drawing strategy going back several years. It simplifies the
>>> code and should solve the problem introduced in 6938b0025; that
>>> is, delaying the Agg draw operation until the paintEvent breaks
>>> code expecting that draw operation to have occurred immediately.
>>> The problem was reported here:
>>> http://sourceforge.net/mailarchive/message.php?msg_id=28245744
>>>
>>> Eric
>>
>
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Re: [Matplotlib-users] Blitting with qt4
Oops forgot to change subject.
On 12/15/11 10:02 AM, David Hoese wrote:
> Eric,
>
> I installed mpl from git ("git clone
> git://github.com/matplotlib/matplotlib.git", unless I was suppose to
> use one of the branches) and same problem. I looked at my code again
> and thought there should be a canvas.draw() before calling
> "c.copy_from_bbox(a.bbox)", but still the same problem. However, I
> did have it work the first time I added "c.draw()" and used the git
> mpl, and by work I mean that everything stayed visible on the figure.
>
> When people start coming in to my work I'll ask them to run my sample
> code and see what happens. It almost seems like mpl is handling the
> window activation event funny, is there an easy way to print out the
> callbacks being used by a mpl figure? For now, I will subclass
> QApplication, and implement "notify()" to print out events as they
> come in, but still...this is just weird. Thanks.
>
> -Dave
>
> On 12/14/11 10:30 PM, Eric Firing wrote:
>> David,
>>
>> It works for me on linux with mpl from git. I haven't tried to figure
>> it out, but it is conceivable that the problem you are seeing was fixed
>> with this:
>>
>> commit b624546ae60dc5878e75a32f41a160d383548b8f
>> Author: Eric Firing
>> Date: Tue Oct 18 08:06:21 2011 -1000
>>
>> backend_qt4agg: draw() immediately calls FigureCanvasAgg.draw()
>>
>> This is the latest in a series of modifications to the Qt4Agg
>> drawing strategy going back several years. It simplifies the
>> code and should solve the problem introduced in 6938b0025; that
>> is, delaying the Agg draw operation until the paintEvent breaks
>> code expecting that draw operation to have occurred immediately.
>> The problem was reported here:
>> http://sourceforge.net/mailarchive/message.php?msg_id=28245744
>>
>> Eric
>
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Re: [Matplotlib-users] Matplotlib-users Digest, Vol 67, Issue 23
Eric,
I installed mpl from git ("git clone
git://github.com/matplotlib/matplotlib.git", unless I was suppose to use
one of the branches) and same problem. I looked at my code again and
thought there should be a canvas.draw() before calling
"c.copy_from_bbox(a.bbox)", but still the same problem. However, I did
have it work the first time I added "c.draw()" and used the git mpl, and
by work I mean that everything stayed visible on the figure.
When people start coming in to my work I'll ask them to run my sample
code and see what happens. It almost seems like mpl is handling the
window activation event funny, is there an easy way to print out the
callbacks being used by a mpl figure? For now, I will subclass
QApplication, and implement "notify()" to print out events as they come
in, but still...this is just weird. Thanks.
-Dave
On 12/14/11 10:30 PM, Eric Firing wrote:
> David,
>
> It works for me on linux with mpl from git. I haven't tried to figure
> it out, but it is conceivable that the problem you are seeing was fixed
> with this:
>
> commit b624546ae60dc5878e75a32f41a160d383548b8f
> Author: Eric Firing
> Date: Tue Oct 18 08:06:21 2011 -1000
>
> backend_qt4agg: draw() immediately calls FigureCanvasAgg.draw()
>
> This is the latest in a series of modifications to the Qt4Agg
> drawing strategy going back several years. It simplifies the
> code and should solve the problem introduced in 6938b0025; that
> is, delaying the Agg draw operation until the paintEvent breaks
> code expecting that draw operation to have occurred immediately.
> The problem was reported here:
> http://sourceforge.net/mailarchive/message.php?msg_id=28245744
>
> Eric
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[Matplotlib-users] Blitting with qt4
Does anyone know if using the blit method from FigureCanvasQTAgg is not
fully supported? I'm having a problem where I'm animating a plot using
the blit method and I click on/activate the window the background of the
figure disappears (axes and line stay visible). I'm not sure if this is
just me (Mac OS X Lion, Qt4 4.8.6, Matplotlib 1.1.0), but the following
code reproduces the error:
###
from PyQt4 import QtGui,QtCore
from matplotlib.figure import Figure
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg
from time import sleep
app = QtGui.QApplication([" "])
f = Figure()
c = FigureCanvasQTAgg(f)
a = f.add_subplot(111)
a.set_title("A Title")
bbox = c.copy_from_bbox(a.bbox)
lines = a.plot([1,2,3],[1,2,3])
c.draw()
c.show()
wait = raw_input("Press a key to continue...")
def update(i):
a.lines[0].set_ydata([i,1,i])
print a.bbox.bounds
c.restore_region(bbox, bbox=a.bbox)
a.draw_artist(a.lines[0])
c.blit(a.bbox)
sleep(1)
app.processEvents()
for i in range(20):
update(i)
wait = raw_input("Press a key to continue...")
###
To see the problem, run the code, watch the plot to make sure its
updating properly, then click on the window to put it in focus/activate
it. I'm hoping that I'm just doing something stupid and its an easy
fix. It seems to work until I click on the window (in Mac OS X Lion
Terminal the window is opened in the background and the Terminal window
stays in focus). Thanks for any help.
-Dave
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Re: [Matplotlib-users] [ploting data] Live data
I don't know what you mean by "ApplicationWindow", is that a class or just a name for the main GUI window. I also don't really know what calling the graphical application means, but I'm sure the book can help you more than I can. Again, good luck. -Dave On 12/14/11 10:17 AM, Fabien Lafont wrote: > Thanks David, I start to read the Mark summerfield' book about PyQt > programming. > > In fact I realized I don't need multi-threading because I can remove > the Timer and just need to call the graphical application from the > while loop. > > How can I call the "ApplicationWindow" class from my while loop? I'll > try to read a bit more about PyQt to understand how it works :) > > thanks again! > > Fabien > > 2011/12/14 David Hoese: >> I'm not sure how experienced you are with multithreaded programs, but here >> is some sample code (I mentioned it can get complicated). I suggest you >> research Qt4 QThreads and also Qt4 Signals and slots to better understand >> the code below. It is a working sample so you should be able to run it in a >> terminal and notice that the GUI is responsive and that you have messages >> being printed out on the terminal. The code I provided below is more >> complicated than you may need for a proof-of-concept kind of program, but if >> you will be communicating with physical devices I suggest something like >> this. I am by no means and expert, but I have been doing something similar >> to what you are doing. I also suggest maybe separating the device >> communication into another module/class, especially if others are going to >> (re)use your code. >> >> Good Luck, >> Dave >> >> P.S. There are a lot of Qt4/PyQt4 threading examples online, but not all of >> them correct. What I posted below is what I have found to be considered >> "correct" by most people. >> >> # >> ### Sample Code ### >> # >> >> import time >> from PyQt4 import QtGui,QtCore >> >> class MyWindow(QtGui.QWidget): >> def __init__(self): >> QtGui.QWidget.__init__(self) >> >> # Sample GUI elements to test responsiveness >> the_choices = ["item"]*20 >> self.choices = QtGui.QComboBox() >> self.choices.addItems(the_choices) >> self.layout = QtGui.QVBoxLayout(self) >> self.layout.addWidget(self.choices) >> self.setLayout(self.layout) >> >> def handle_new_data(self): >> # This is where you could redraw any matplotlib plots >> # Maybe send data through the signal/slot connection >> print "Updating data" >> >> class MyInstrument(QtCore.QObject): >> signal_new_data = QtCore.pyqtSignal(name="signal_new_data") >> signal_closing = QtCore.pyqtSignal(name="signal_closing") >> def run(self): >> self._timer = QtCore.QTimer() >> self._timer.timeout.connect(self._run) >> self._timer.start(0) >> >> def _run(self): >> time.sleep(1) >> print "Running the instrument function" >> time.sleep(1) >> self.signal_new_data.emit() >> >> def close(self): >> print "Closing instrument thread" >> self._timer.stop() >> # Redundant timer stop >> self._timer.timeout.disconnect() >> self.signal_closing.emit() >> >> if __name__ == "__main__": >> app = QtGui.QApplication([" "]) >> w = MyWindow() >> w.show() >> instrument = MyInstrument() >> instrument_thread = QtCore.QThread() >> instrument.moveToThread(instrument_thread) >> >> instrument_thread.started.connect(instrument.run) >> instrument.signal_new_data.connect(w.handle_new_data) >> >> # Make the close function run in the main thread so you can "interrupt" >> the sleeps >> app.lastWindowClosed.connect(instrument.close, >> QtCore.Qt.DirectConnection) >> # You could also call quit "manually" after exec_() returns >> instrument.signal_closing.connect(instrument_thread.quit) >> >> instrument_thread.start() >> app.exec_() >> #instrument_thread.quit() >> >> print "Waiting for instrument thread..." >> instrument_thread.wait() >> print "SUCCESS" >> >> ## >> ### End of Sample Code ### >> #
Re: [Matplotlib-users] [ploting data] Live data
I'm not sure how experienced you are with multithreaded programs, but here is some sample code (I mentioned it can get complicated). I suggest you research Qt4 QThreads and also Qt4 Signals and slots to better understand the code below. It is a working sample so you should be able to run it in a terminal and notice that the GUI is responsive and that you have messages being printed out on the terminal. The code I provided below is more complicated than you may need for a proof-of-concept kind of program, but if you will be communicating with physical devices I suggest something like this. I am by no means and expert, but I have been doing something similar to what you are doing. I also suggest maybe separating the device communication into another module/class, especially if others are going to (re)use your code. Good Luck, Dave P.S. There are a lot of Qt4/PyQt4 threading examples online, but not all of them correct. What I posted below is what I have found to be considered "correct" by most people. # ### Sample Code ### # import time from PyQt4 import QtGui,QtCore class MyWindow(QtGui.QWidget): def __init__(self): QtGui.QWidget.__init__(self) # Sample GUI elements to test responsiveness the_choices = ["item"]*20 self.choices = QtGui.QComboBox() self.choices.addItems(the_choices) self.layout = QtGui.QVBoxLayout(self) self.layout.addWidget(self.choices) self.setLayout(self.layout) def handle_new_data(self): # This is where you could redraw any matplotlib plots # Maybe send data through the signal/slot connection print "Updating data" class MyInstrument(QtCore.QObject): signal_new_data = QtCore.pyqtSignal(name="signal_new_data") signal_closing = QtCore.pyqtSignal(name="signal_closing") def run(self): self._timer = QtCore.QTimer() self._timer.timeout.connect(self._run) self._timer.start(0) def _run(self): time.sleep(1) print "Running the instrument function" time.sleep(1) self.signal_new_data.emit() def close(self): print "Closing instrument thread" self._timer.stop() # Redundant timer stop self._timer.timeout.disconnect() self.signal_closing.emit() if __name__ == "__main__": app = QtGui.QApplication([" "]) w = MyWindow() w.show() instrument = MyInstrument() instrument_thread = QtCore.QThread() instrument.moveToThread(instrument_thread) instrument_thread.started.connect(instrument.run) instrument.signal_new_data.connect(w.handle_new_data) # Make the close function run in the main thread so you can "interrupt" the sleeps app.lastWindowClosed.connect(instrument.close, QtCore.Qt.DirectConnection) # You could also call quit "manually" after exec_() returns instrument.signal_closing.connect(instrument_thread.quit) instrument_thread.start() app.exec_() #instrument_thread.quit() print "Waiting for instrument thread..." instrument_thread.wait() print "SUCCESS" ## ### End of Sample Code ### ## On 12/14/11 3:51 AM, Fabien Lafont wrote: > I prefer to use the multi-thread method beacause it's easier for me > and my colaborators to have the entire acquisition process at the same > place. Until then I use a simple one but I hope to use a more complex > one in few weeks ( put different voltages on different devices then > measure many voltages or current). If I use the "domino" technique > (call the next operation by the end of the previous) it can be complex > to read and to edit. Thank you very much anyway! > > How can I write a multi-thread process? I've just tried to add > qApp.processEvents() at the end of my while loop but it doesn't change > anything... > > Thanks again, > > Fabien > > 2011/12/13 David Hoese: >> Yeah I didn't think about suggesting that, but I think it might get >> complicated. I think he would have to start a one shot timer to call a >> function to set the voltage. Then that function would also start another >> one shot timer to call another function that would read from the sample. >> That function then would start a one shot timer to call the first function >> again. This way he can be sure that things are called in order and that >> timing is consistent, just in case the GUI gets complicated or something >> makes the event loop slow down. >> >> He could also use multiple threads. Whatever works for Fabien I guess. >> >> -Dave >> >> On 12/13/11 1:00 PM, ma
Re: [Matplotlib-users] [ploting data] Live data
Yeah I didn't think about suggesting that, but I think it might get complicated. I think he would have to start a one shot timer to call a function to set the voltage. Then that function would also start another one shot timer to call another function that would read from the sample. That function then would start a one shot timer to call the first function again. This way he can be sure that things are called in order and that timing is consistent, just in case the GUI gets complicated or something makes the event loop slow down. He could also use multiple threads. Whatever works for Fabien I guess. -Dave On 12/13/11 1:00 PM, matplotlib-users-requ...@lists.sourceforge.net wrote: > From: "Drain, Theodore R (343P)" > Subject: Re: [Matplotlib-users] [ploting data] Live data > > Perhaps I'm missing something, but why not use QTimer? You can't really > every call sleep in a single threaded gui (for reasons you've encountered). > If you need to poll something, create a QTimer for 2 seconds and have it call > a measurement function to update the data. You shouldn't need any > processEvents calls or sleep. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] [ploting data] Live data
Fabien,
The GUI not being responsive might be my fault, I've never used a timer
of 0 and processEvents(). I think what might be happening is that when
you call processEvents, the timer of 0 calls your principal function
again, which calls processEvents again, and so on. Try a timer of 2
again, that "should" stop the timer from being constantly triggered.
Later today, once I get to work, I'll run some tests of my own and
figure out if that's really the problem. Email me if you make any progress.
-Dave
On 12/13/2011 2:30 AM, Fabien Lafont wrote:
> Hey David,
>
> I'm doing this program to control an experiment, so I want to put the
> voltage on the sample, then wait two seconds to be sure there is no
> current fluctuations then measure the curent with multimeters and
> finally plot the datas. That's why I need the "sleep"... In fact I
> wanted to use in parallel the timer to "refresh" the graph and a while
> loop to "extract" the datas.
>
> If I use startTimer(0) it works but the GUI is almost unresponsive.
> I'm trying to use qApp.processEvents() but up to now I don't manage to
> see the window appears...
>
> Thanks again for your help
>
> Fabien
>
>
>
> 2011/12/12 David Hoese:
>> Hey Fabien,
>>
>> So you made your principal function run on a timer every 2 seconds? And by
>> "lag" do you mean that the GUI is unresponsive? I'm still not seeing when
>> the loop stops, but what you can do is set the timer at a 0 interval so it
>> will call the principal function as fast as it can (but with no loop). The
>> problem with this is that you have those 2 sleep calls in the function. I'm
>> not sure why you have the sleeps, but if you need them you have two choices:
>>
>> 1. Make you GUI multi-threaded and you could emit a Qt signal from the data
>> thread when the GUI thread needs to update the GUI. Yes this could get
>> complicated, but if the sleeps are required then its probably the best way.
>>
>> 2. (From what I've been told, the Qt experts don't approve this) You can use
>> app.processEvents() in your loop (after each sleep maybe) and this will
>> pause your function and tell the main event loop to process any queued
>> events (like GUI actions/events) which will make your GUI more responsive.
>>
>> If that doesn't make sense let me know.
>>
>> -Dave
>>
>>
>> On 12/12/11 9:16 AM, Fabien Lafont wrote:
>>>
>>> Hi David! Sorry about the delay I was abroad and without any way to
>>> connect to the internet.
>>>
>>> Thank you very much. I've tried to put the principal inside the
>>> timerEvent. It work but it lags. In fact I've set the interval of the
>>> Timer to 2 seconds because the principal loop takes roughly 2seconds
>>> but it's not very accurate...
>>>
>>> Is there a way to do the principal loop, show it on the screen, then
>>> redo the loop?
>>>
>>> Thanks again!
>>>
>>> Fabien
>>>
>>> 2011/12/5 David Hoese:
>>>>
>>>> If I'm understanding your question correctly and reading your code
>>>> correctly, you're asking why the timer method of doing things works, but
>>>> the
>>>> principal() while loop method does not.
>>>>
>>>> I had a couple solutions that involved the main event loop, but I just
>>>> noticed 2 main things that are probably wrong with your code:
>>>> 1. You are calling 'principal' from inside __init__ so you never actually
>>>> return from __init__ which means that you never call "window.show()" and
>>>> therefore never call "qApp.exec_()". If you really want to use the
>>>> 'principal' method you would have to connect it to a one shot timer anyway
>>>> to have it run after you have started the application ('qApp.exec_()'). I
>>>> think the recommended way would be to use the timer the way you did in your
>>>> latest email.
>>>>
>>>> 2. At least in the way my email client reads your original code, your
>>>> calls to the matplotlib drawing functions aren't inside the while loop and
>>>> the while loop never ends...although this doesn't matter if you don't fix
>>>> #1
>>>> above.
>>>>
>>>> Hope that made sense.
>>>>
>>>> -Dave
>>>>
>>>>
>>>&
Re: [Matplotlib-users] [ploting data] Live data
Hey Fabien,
So you made your principal function run on a timer every 2 seconds? And
by "lag" do you mean that the GUI is unresponsive? I'm still not seeing
when the loop stops, but what you can do is set the timer at a 0
interval so it will call the principal function as fast as it can (but
with no loop). The problem with this is that you have those 2 sleep
calls in the function. I'm not sure why you have the sleeps, but if you
need them you have two choices:
1. Make you GUI multi-threaded and you could emit a Qt signal from the
data thread when the GUI thread needs to update the GUI. Yes this could
get complicated, but if the sleeps are required then its probably the
best way.
2. (From what I've been told, the Qt experts don't approve this) You can
use app.processEvents() in your loop (after each sleep maybe) and this
will pause your function and tell the main event loop to process any
queued events (like GUI actions/events) which will make your GUI more
responsive.
If that doesn't make sense let me know.
-Dave
On 12/12/11 9:16 AM, Fabien Lafont wrote:
> Hi David! Sorry about the delay I was abroad and without any way to
> connect to the internet.
>
> Thank you very much. I've tried to put the principal inside the
> timerEvent. It work but it lags. In fact I've set the interval of the
> Timer to 2 seconds because the principal loop takes roughly 2seconds
> but it's not very accurate...
>
> Is there a way to do the principal loop, show it on the screen, then
> redo the loop?
>
> Thanks again!
>
> Fabien
>
> 2011/12/5 David Hoese:
>> If I'm understanding your question correctly and reading your code
>> correctly, you're asking why the timer method of doing things works, but the
>> principal() while loop method does not.
>>
>> I had a couple solutions that involved the main event loop, but I just
>> noticed 2 main things that are probably wrong with your code:
>> 1. You are calling 'principal' from inside __init__ so you never actually
>> return from __init__ which means that you never call "window.show()" and
>> therefore never call "qApp.exec_()". If you really want to use the
>> 'principal' method you would have to connect it to a one shot timer anyway
>> to have it run after you have started the application ('qApp.exec_()'). I
>> think the recommended way would be to use the timer the way you did in your
>> latest email.
>>
>> 2. At least in the way my email client reads your original code, your calls
>> to the matplotlib drawing functions aren't inside the while loop and the
>> while loop never ends...although this doesn't matter if you don't fix #1
>> above.
>>
>> Hope that made sense.
>>
>> -Dave
>>
>>
>> On 12/5/11 1:44 PM, matplotlib-users-requ...@lists.sourceforge.net wrote:
>>> Message: 3
>>> Date: Mon, 5 Dec 2011 15:46:02 +0100
>>> From: Fabien Lafont
>>> Subject: Re: [Matplotlib-users] [ploting data] Live data
>>> Cc:matplotlib-users@lists.sourceforge.net
>>> Message-ID:
>>>
>>> Content-Type: text/plain; charset=ISO-8859-1
>>>
>>> Thx all for your remarks,
>>>
>>> I can't understand why this code works (when I use the timer method):
>>
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Re: [Matplotlib-users] [ploting data] Live data
If I'm understanding your question correctly and reading your code correctly,
you're asking why the timer method of doing things works, but the principal()
while loop method does not.
I had a couple solutions that involved the main event loop, but I just noticed
2 main things that are probably wrong with your code:
1. You are calling 'principal' from inside __init__ so you never actually
return from __init__ which means that you never call "window.show()" and
therefore never call "qApp.exec_()". If you really want to use the 'principal'
method you would have to connect it to a one shot timer anyway to have it run
after you have started the application ('qApp.exec_()'). I think the
recommended way would be to use the timer the way you did in your latest email.
2. At least in the way my email client reads your original code, your calls to
the matplotlib drawing functions aren't inside the while loop and the while
loop never ends...although this doesn't matter if you don't fix #1 above.
Hope that made sense.
-Dave
On 12/5/11 1:44 PM, matplotlib-users-requ...@lists.sourceforge.net wrote:
> Message: 3
> Date: Mon, 5 Dec 2011 15:46:02 +0100
> From: Fabien Lafont
> Subject: Re: [Matplotlib-users] [ploting data] Live data
> Cc:matplotlib-users@lists.sourceforge.net
> Message-ID:
>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Thx all for your remarks,
>
> I can't understand why this code works (when I use the timer method):
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Re: [Matplotlib-users] [ploting data] Live data
I think you forget to set the layout on your central widget. self.main_widget.setLayout(vbl) # in your case -Dave On 12/4/2011 9:57 AM, matplotlib-users-requ...@lists.sourceforge.net wrote: > 2011/12/2 Daniel Hyams: >> > I don't have PyQt installed, so I couldn't test the code, but don't you >> > want >> > to be using "extend" and not "append", if you are returning a list from >> > your >> > two get_info() functions? >> > >> > On Fri, Dec 2, 2011 at 8:13 AM, Fabien Lafont >> > wrote: >>> >> >>> >> Hello everyone, I'm trying to plot live data extracting from remote >>> >> devices (here it's simulated by get_info1 and 2 the result is always >>> >> 0.8 or 0.9 >>> >> >>> >> I can't understand why it doesnt plot the graph at the end of the >>> >> while loop. Does somebody has an idea? -- All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] how would you do this (animated bargraph) (Neal Becker)
Neal, I do something similar to this where data that I'm plotting in a 2D line plot comes from a UDP socket and some memory mapped files. To accomplish the live updating I have a mix of your #2 and #3. I have a main GUI thread that displays the plots, then I have a second thread that gets data from a python generator and signals the GUI thread when that new data has arrived. Inside the generator is where I have socket communications and select calls. Hope this helps. -Dave On 9/30/11 9:10 AM, matplotlib-users-requ...@lists.sourceforge.net wrote: > Message: 4 > Date: Fri, 30 Sep 2011 07:37:49 -0400 > From: Neal Becker > Subject: [Matplotlib-users] how would you do this (animated bargraph) > To:matplotlib-users@lists.sourceforge.net > Message-ID: > Content-Type: text/plain; charset="ISO-8859-1" > > I just put together an animated bargraph to show results from a realtime > process. > > I used this as an example: > http://matplotlib.sourceforge.net/examples/animation/animation_blit_qt4.html > > The tricky part for me was that in the original design, there was a realtime > process running. I have to write some information to my hardware (at a rate > of > about 1/360ms). To do this, I have a kernel driver that uses 'read' to tell > the > user space when an interrupt has occurred, which is when the user space should > write new information to the hardware. > > So I don't know how or if this could be hooked into qt event processing. Just > for a quick-and-dirty demo, I just removed the realtime processing from the > user-space and put it in the kernel driver, so now my bargraph display can > simply update on a periodic timer, and the userspace code has no realtime > requirement. But this is just a kludge. > > So I wonder how other's would solve this? I'm thinking it would be either: > > 1) multi-process > 2) multi-thread > 3) 1 process, but somehow hook my realtime events into qt's event loop. > > For #3, my device driver has a filedescriptor, that could use select to detect > the interrupt (rather than blocking read call). > > #1 and #2 seem complicated. -- All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
