matplotlib-devel

[matplotlib-devel] SpanSelector with gtk3cairo backend

[Arnaud G. <ar...@os...>]

SpanSelector is a powerful widget that allows to define a particular
region in a Figure. Some time ago I switched to python3 and needed to
use gtk3cairo instead of gtkagg; to my knowledge there is still a
message preventing using agg backend with python3. Unfortunately since
then I am not able to use SpanSelector widget with gtk3cairo. For
instance with the example [1], an error message appears:
  File "/usr/lib/python3/dist-packages/matplotlib/widgets.py", line
1197, in update_background
    self.background = self.canvas.copy_from_bbox(self.ax.bbox)
AttributeError: 'FigureCanvasGTK3Cairo' object has no attribute
'copy_from_bbox'
This using version 1.4.2 of matplotlib.

Does exists a way to have SpanSelector operating with gtk3cairo
backend ? I tried to look down to the code of gtkagg but it refers to
the C implementation of the library (_RendererAgg), is there an
equivalent in Cairo ?

Arnaud.

[1] http://matplotlib.org/examples/widgets/span_selector.html

Re: [matplotlib-devel] SpanSelector with gtk3cairo backend

[Thomas C. <tca...@gm...>]

Not sure what you mean about agg + py3k, it should work fine (as we test
it).

The issue is that the cairo backend is a vector backend, which does not
have a notion of blitting, which is something that span selector uses to
make it nice and snappy.  Should be able to get it to work by passing the
kwarg `useblit=False` to the constructor.

Tom

Re: [matplotlib-devel] SpanSelector with gtk3cairo backend

[Jens N. <jen...@gm...>]

There was an issue with the GTK3Agg backend on Python 3 due to a missing
feature in the python 3 port of PyCairo but this has been fixed in
Matplotlib 1.4.0 by making it possible to use cairocffi as an alternative to
PyCairo. CairoCFFI implements the missing feature. (While the Agg backends
doesn't use Cairo to render the figures it still needs python binding for
Cairo AFAIK)


/Jens

On Mon, Nov 10, 2014 at 11:26 PM, Thomas Caswell <tca...@gm...> wrote:

> Not sure what you mean about agg + py3k, it should work fine (as we test
> it).
>
> The issue is that the cairo backend is a vector backend, which does not
> have a notion of blitting, which is something that span selector uses to
> make it nice and snappy.  Should be able to get it to work by passing the
> kwarg `useblit=False` to the constructor.
>
> Tom
>
>
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Re: [matplotlib-devel] SpanSelector with gtk3cairo backend

[Arnaud G. <ar...@os...>]

Le mardi 11 novembre 2014 à 08:56 +0000, Jens Nielsen a écrit :
> There was an issue with the GTK3Agg backend on Python 3 due to a
> missing feature in the python 3 port of PyCairo but this has been
> fixed in Matplotlib 1.4.0 by making it possible to use cairocffi as an
> alternative to PyCairo.
This is exactly the issue I meant.

(...)

> On Mon, Nov 10, 2014 at 11:26 PM, Thomas Caswell <tca...@gm...>
> wrote:
(...) 
>         The issue is that the cairo backend is a vector backend, which
>         does not have a notion of blitting, which is something that
>         span selector uses to make it nice and snappy.  Should be able
>         to get it to work by passing the kwarg `useblit=False` to the
>         constructor.
>         
>         Tom

In fact I stupidly copied the example [1], missing completely this
argument in the constructor. Setting useblit=False makes it working
nicely. Thanks.

Arnaud.

[1] http://matplotlib.org/examples/widgets/span_selector.html

PS: For the records, here is the full message that appears when setting
useblit=True in [1] and matplotlibrc contains "backend : GTK3Cairo",
matplotlib version 1.4.2 (debian):

$ ./testspan.py
Traceback (most recent call last):
  File
"/usr/lib/python3/dist-packages/matplotlib/backends/backend_gtk3cairo.py", line 45, in on_draw_event
    self._render_figure(w, h)
  File
"/usr/lib/python3/dist-packages/matplotlib/backends/backend_gtk3cairo.py", line 34, in _render_figure
    self.figure.draw (self._renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 59,
in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/figure.py", line 1085,
in draw
    self.canvas.draw_event(renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/backend_bases.py",
line 1778, in draw_event
    self.callbacks.process(s, event)
  File "/usr/lib/python3/dist-packages/matplotlib/cbook.py", line 540,
in process
    proxy(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/cbook.py", line 415,
in __call__
    return mtd(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/widgets.py", line
1197, in update_background
    self.background = self.canvas.copy_from_bbox(self.ax.bbox)
AttributeError: 'FigureCanvasGTK3Cairo' object has no attribute
'copy_from_bbox'

Re: [matplotlib-devel] SpanSelector with gtk3cairo backend

[Benjamin R. <ben...@ou...>]

I should point out that the animation module tries to determine if the
canvas can blit if the user sets it to True. If it can't blit, then it
simply ignores the True setting. Maybe we should do something similar like
here as well?

On Tue, Nov 11, 2014 at 4:50 PM, Arnaud Gardelein <ar...@os...> wrote:

> Le mardi 11 novembre 2014 à 08:56 +0000, Jens Nielsen a écrit :
> > There was an issue with the GTK3Agg backend on Python 3 due to a
> > missing feature in the python 3 port of PyCairo but this has been
> > fixed in Matplotlib 1.4.0 by making it possible to use cairocffi as an
> > alternative to PyCairo.
> This is exactly the issue I meant.
>
> (...)
>
> > On Mon, Nov 10, 2014 at 11:26 PM, Thomas Caswell <tca...@gm...>
> > wrote:
> (...)
> >         The issue is that the cairo backend is a vector backend, which
> >         does not have a notion of blitting, which is something that
> >         span selector uses to make it nice and snappy.  Should be able
> >         to get it to work by passing the kwarg `useblit=False` to the
> >         constructor.
> >
> >         Tom
>
> In fact I stupidly copied the example [1], missing completely this
> argument in the constructor. Setting useblit=False makes it working
> nicely. Thanks.
>
> Arnaud.
>
> [1] http://matplotlib.org/examples/widgets/span_selector.html
>
> PS: For the records, here is the full message that appears when setting
> useblit=True in [1] and matplotlibrc contains "backend : GTK3Cairo",
> matplotlib version 1.4.2 (debian):
>
> $ ./testspan.py
> Traceback (most recent call last):
>   File
> "/usr/lib/python3/dist-packages/matplotlib/backends/backend_gtk3cairo.py",
> line 45, in on_draw_event
>     self._render_figure(w, h)
>   File
> "/usr/lib/python3/dist-packages/matplotlib/backends/backend_gtk3cairo.py",
> line 34, in _render_figure
>     self.figure.draw (self._renderer)
>   File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 59,
> in draw_wrapper
>     draw(artist, renderer, *args, **kwargs)
>   File "/usr/lib/python3/dist-packages/matplotlib/figure.py", line 1085,
> in draw
>     self.canvas.draw_event(renderer)
>   File "/usr/lib/python3/dist-packages/matplotlib/backend_bases.py",
> line 1778, in draw_event
>     self.callbacks.process(s, event)
>   File "/usr/lib/python3/dist-packages/matplotlib/cbook.py", line 540,
> in process
>     proxy(*args, **kwargs)
>   File "/usr/lib/python3/dist-packages/matplotlib/cbook.py", line 415,
> in __call__
>     return mtd(*args, **kwargs)
>   File "/usr/lib/python3/dist-packages/matplotlib/widgets.py", line
> 1197, in update_background
>     self.background = self.canvas.copy_from_bbox(self.ax.bbox)
> AttributeError: 'FigureCanvasGTK3Cairo' object has no attribute
> 'copy_from_bbox'
>
>
>
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