matplotlib-devel Mailing List for matplotlib

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

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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> 
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

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