matplotlib-devel

[matplotlib-devel] picking bug in SVN with old masked array

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

I just ran into a bug with picking of lines. I changed the line style in
figure 1, subplot 1 to 'o-' (from 'o') and ripped out most of everything
else in examples/pick_event_demo.py to create pick_event_demo3.py
(attached). When I run this and I attempt to click on points, I get

Traceback (most recent call last):
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/backends/backend_gtk.py",
line 193, in button_press_event
    FigureCanvasBase.button_press_event(self, x, y, event.button)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/backend_bases.py",
line 915, in button_press_event
    self.callbacks.process(s, mouseevent)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/cbook.py",
line 157, in process
    func(*args, **kwargs)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/backend_bases.py",
line 849, in pick
    self.figure.pick(mouseevent)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/artist.py",
line 220, in pick
    for a in self.get_children(): a.pick(mouseevent)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/axes.py",
line 2155, in pick
    martist.Artist.pick(self,args[0])
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/artist.py",
line 220, in pick
    for a in self.get_children(): a.pick(mouseevent)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/artist.py",
line 214, in pick
    inside,prop = self.contains(mouseevent)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/lines.py",
line 327, in contains
    ind = segment_hits(mouseevent.x,mouseevent.y,xt,yt,pixels)
  File
"/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/lines.py",
line 100, in segment_hits
    candidates = candidates & ~point_hits[:-1] & ~point_hits[1:]
TypeError: bad operand type for unary ~: 'MaskedArray'

Anyhow, I spent a little while tracking this down and came up with the
attached patch. I guess there's a more direct solution to the issue that
this band-aid, but I hope this will jump-start someone to fix this. In
the meantime, this appears to work sufficiently for my purposes...

FWIW, my numpy is SVN from 16 december 2007 (after 1.0.4 and thus on the
way to 1.0.5) and I'm using the old ma module.

BUILDING MATPLOTLIB
            matplotlib: 0.98pre
                python: 2.5.1 (r251:54863, Oct  5 2007, 13:50:07)  [GCC
                        4.1.3 20070929 (prerelease) (Ubuntu
                        4.1.2-16ubuntu2)]
              platform: linux2

REQUIRED DEPENDENCIES
                 numpy: 1.0.5.dev
             freetype2: 9.16.3

Re: [matplotlib-devel] picking bug in SVN with old masked array

[Michael D. <md...@st...>]

Thanks for finding this.  I just committed a slightly less band-aid-like 
fix in SVN r4979.

There were really two bugs here:

1) A masked array is created for a line plot whenever only y values are 
provided, even if there are no masked values in the data.  That would 
only be a performance bug if it weren't for...

2) The picking code for a line assumes non-masked arrays.  Since the 
Line class already keeps around a "compressed" version of the data for 
drawing, it is easy enough to use that instead of the raw data.

By fixing 1), 2) is no longer even an issue in your example.  However, 
for a plot that really does have gaps, 2) needs to be fixed as well.

Cheers,
Mike

Andrew Straw wrote:
> I just ran into a bug with picking of lines. I changed the line style in
> figure 1, subplot 1 to 'o-' (from 'o') and ripped out most of everything
> else in examples/pick_event_demo.py to create pick_event_demo3.py
> (attached). When I run this and I attempt to click on points, I get
> 
> Traceback (most recent call last):
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/backends/backend_gtk.py",
> line 193, in button_press_event
>     FigureCanvasBase.button_press_event(self, x, y, event.button)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/backend_bases.py",
> line 915, in button_press_event
>     self.callbacks.process(s, mouseevent)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/cbook.py",
> line 157, in process
>     func(*args, **kwargs)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/backend_bases.py",
> line 849, in pick
>     self.figure.pick(mouseevent)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/artist.py",
> line 220, in pick
>     for a in self.get_children(): a.pick(mouseevent)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/axes.py",
> line 2155, in pick
>     martist.Artist.pick(self,args[0])
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/artist.py",
> line 220, in pick
>     for a in self.get_children(): a.pick(mouseevent)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/artist.py",
> line 214, in pick
>     inside,prop = self.contains(mouseevent)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/lines.py",
> line 327, in contains
>     ind = segment_hits(mouseevent.x,mouseevent.y,xt,yt,pixels)
>   File
> "/home/astraw/py2.5-linux-x86_64/lib/python2.5/site-packages/matplotlib/lines.py",
> line 100, in segment_hits
>     candidates = candidates & ~point_hits[:-1] & ~point_hits[1:]
> TypeError: bad operand type for unary ~: 'MaskedArray'
> 
> Anyhow, I spent a little while tracking this down and came up with the
> attached patch. I guess there's a more direct solution to the issue that
> this band-aid, but I hope this will jump-start someone to fix this. In
> the meantime, this appears to work sufficiently for my purposes...
> 
> FWIW, my numpy is SVN from 16 december 2007 (after 1.0.4 and thus on the
> way to 1.0.5) and I'm using the old ma module.
> 
> BUILDING MATPLOTLIB
>             matplotlib: 0.98pre
>                 python: 2.5.1 (r251:54863, Oct  5 2007, 13:50:07)  [GCC
>                         4.1.3 20070929 (prerelease) (Ubuntu
>                         4.1.2-16ubuntu2)]
>               platform: linux2
> 
> REQUIRED DEPENDENCIES
>                  numpy: 1.0.5.dev
>              freetype2: 9.16.3
> 
> 
> ------------------------------------------------------------------------
> 
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Re: [matplotlib-devel] picking bug in SVN with old masked array

[Paul K. <pki...@ni...>]

On Tue, Feb 19, 2008 at 10:55:14AM -0500, Michael Droettboom wrote:
> 2) The picking code for a line assumes non-masked arrays.  Since the 
> Line class already keeps around a "compressed" version of the data for 
> drawing, it is easy enough to use that instead of the raw data.

I didn't provide any masked array checks in any of the contains methods
that I wrote.  Do any of these need to be fixed?

I won't have a lot of time over the next few months, and I will be
slow to fix them.

	- Paul

Re: [matplotlib-devel] picking bug in SVN with old masked array

[John H. <jd...@gm...>]

On Feb 19, 2008 5:45 PM, Paul Kienzle <pki...@ni...> wrote:

> I didn't provide any masked array checks in any of the contains methods
> that I wrote.  Do any of these need to be fixed?

They do need to be fixed, but this is not a high priority item.  Let's
wait until the new maskedarray code that is now in a numpy branch goes
live and official before we invest too much energy in getting masked
arrays working properly here.

JDH

Re: [matplotlib-devel] picking bug in SVN with old masked array

[Eric F. <ef...@ha...>]

John Hunter wrote:
> On Feb 19, 2008 5:45 PM, Paul Kienzle <pki...@ni...> wrote:
> 
>> I didn't provide any masked array checks in any of the contains methods
>> that I wrote.  Do any of these need to be fixed?
> 
> They do need to be fixed, but this is not a high priority item.  Let's
> wait until the new maskedarray code that is now in a numpy branch goes
> live and official before we invest too much energy in getting masked
> arrays working properly here.

The maskedarray branch has been merged into the svn trunk and will 
therefore be in the 1.05 release, coming within days.

Eric