Pending release of 0.3

[Chris Colbert]

So while i havent yet been able to get the pyos_inputhook thing sorted
out, I did time a couple loops.

For a decent sized image, we can easily get 60fps update rates, and
thats including the time for the numpy operations:

In [5]: img = io.imread('/home/brucewayne/Pictures/failboat_4.jpg')

In [6]: img.shape
Out[6]: (503, 790, 3)

In [7]: win = io.imshow(img, updateable=True)

In [8]: def test(img, win):
   ...:     for i in range(30):
   ...:         img[:] += 1
   ...:         win.update()
   ...:
   ...:

In [9]: %timeit test(img, win)
1 loops, best of 3: 564 ms per loop


one thing to note, I bypassed the prepare_for_display() method that we
usually call to make sure an array is contiguous, of the right dtype,
etc...
I assume if someone wants video, they can prepare the arrays themselves.

This behavior can also be changed by the plugin writer. For this
example, i simply took the easy route and subclassed ImageWindow

Cheers,

Chris


On Thu, Nov 5, 2009 at 4:24 PM, Chris Colbert <sccolbert at gmail.com> wrote:
> I was just testing out something along these lines, but I run into the
> problem of the the python interpreter not considering time.sleep() as
> idle time, thus, it never calls PyOS_InputHook inside of for-loops. So
> i'm not quite sure how to get video  feed to run interactively without
> hacking out something like ipython -whatever thread.
>
> Mind you, this is not a problem with the plugin architecture, its a
> problem with the python interpreter...
>
> but maybe i can ctypes into the os_hook and call it at the end of a
> loop.... <evil grin>
>
> 2009/11/5 Stéfan van der Walt <stefan at sun.ac.za>:
>>
>> 2009/11/5 Chris Colbert <sccolbert at gmail.com>:
>>> Further, these imshow() type widgets are primarily meant to be used
>>> from the interactive interpreter, an environment not best suited for
>>> real time image acquisition and display. that said, the plugin
>>> archiceture can most certainly be used in the method you speak of. You
>>> just simply have your imshow() function return the window object, and
>>> implement an update() or similar method that the consumer can call to
>>> update the image.
>>
>> This could even be accomplished using 'imshow' only.  The
>> WindowManager keeps track of the single window produced, and 'imshow'
>> simply grabs that window and updates its current content.  I'd be
>> surprised if we couldn't pump out a large number of frames-per-second
>> that way.
>>
>> Stéfan
>>
>