Potential Bug with SpanSelector

Aman_Thakral · July 21, 2010, 5:58pm

Hi all,

I’m getting the following exception when I use the Span Selector. It happens when I try and select the entire region.

Exception in Tkinter callback

Traceback (most recent call last):
File “C:\Python26\lib\lib-tk\Tkinter.py”, line 1410, in call

return self.func(*args)

File “C:\Python26\Lib\site-packages\matplotlib\backends\backend_tkagg.py”, line 246, in motion_notify_event
FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=event)

File “C:\Python26\Lib\site-packages\matplotlib\backend_bases.py”, line 1245, in motion_notify_event
self.callbacks.process(s, event)
File “C:\Python26\Lib\site-packages\matplotlib\cbook.py”, line 165, in process

func(*args, **kwargs)

File “C:\Python26\Lib\site-packages\matplotlib\widgets.py”, line 952, in onmove
self.rect.set_width(maxv-minv)
TypeError: unsupported operand type(s) for -: ‘float’ and ‘NoneType’

My sample code is shown here (its also attached):

import matplotlib.pyplot as plt
from matplotlib.widgets import SpanSelector

import numpy as np
import datetime

class TimeSelector(SpanSelector):
“”"

SpanSelector that is only activated by the left mouse button
"""

def ignore(self,event):
    if event.button == 2 or event.button == 3: return True

def onselect(xmin,xmax):
print xmin,xmax

fig = plt.figure()

ax = fig.add_subplot(111)
span = TimeSelector(ax, onselect, ‘horizontal’, useblit=True, rectprops=dict(alpha=0.5, facecolor=‘yellow’) )

y = np.random.rand(100,1)
start = datetime.datetime(2010,7,15,0,0)

x = []
for i in range(len(y)):

x.append(start + datetime.timedelta(hours=i))

ax.plot_date(x,y,‘b-’)
plt.show()

Any help on this issue would be greatly appreciated.

Thanks,
Aman

spanselector_issue.py (734 Bytes)

Aman_Thakral · July 21, 2010, 6:44pm

Update on the error.

It occurs in the following cases:

User clicks and drags from left to right and approaches the edge of the right side of the axes
User clicks and drags from right to left and approaches the edge of the left side of the axes

I’m working on this bug now, I’ll see if I can fix it. I’ll welcome any input you guys can provide though.

Thanks,
Aman

···

On Wed, Jul 21, 2010 at 1:58 PM, Aman Thakral <aman.thakral@…287…> wrote:

Hi all,

I’m getting the following exception when I use the Span Selector. It happens when I try and select the entire region.

Exception in Tkinter callback

Traceback (most recent call last):
File “C:\Python26\lib\lib-tk\Tkinter.py”, line 1410, in call
return self.func(*args)
File “C:\Python26\Lib\site-packages\matplotlib\backends\backend_tkagg.py”, line 246, in motion_notify_event
FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=event)

File “C:\Python26\Lib\site-packages\matplotlib\backend_bases.py”, line 1245, in motion_notify_event
self.callbacks.process(s, event)
File “C:\Python26\Lib\site-packages\matplotlib\cbook.py”, line 165, in process
func(*args, **kwargs)
File “C:\Python26\Lib\site-packages\matplotlib\widgets.py”, line 952, in onmove
self.rect.set_width(maxv-minv)
TypeError: unsupported operand type(s) for -: ‘float’ and ‘NoneType’

My sample code is shown here (its also attached):

import matplotlib.pyplot as plt
from matplotlib.widgets import SpanSelector

import numpy as np
import datetime

class TimeSelector(SpanSelector):
“”"
SpanSelector that is only activated by the left mouse button
"""



def ignore(self,event):
    if event.button == 2 or event.button == 3: return True
def onselect(xmin,xmax):
print xmin,xmax

fig = plt.figure()

ax = fig.add_subplot(111)
span = TimeSelector(ax, onselect, ‘horizontal’, useblit=True, rectprops=dict(alpha=0.5, facecolor=‘yellow’) )

y = np.random.rand(100,1)
start = datetime.datetime(2010,7,15,0,0)

x =
for i in range(len(y)):
x.append(start + datetime.timedelta(hours=i))
ax.plot_date(x,y,‘b-’)
plt.show()

Any help on this issue would be greatly appreciated.

Thanks,
Aman

–
Aman Thakral
B.Eng & Biosci, M.Eng Design

Aman_Thakral · July 21, 2010, 7:11pm

Ok, so I’ve fixed it. Its just because the mouse goes outside the axes. How do I make the change in the code?

Error: line 924 in widgets.py

old code:

x,y = event.xdata, event.ydata

fixed code:

if not event.xdata is None:
x = event.xdata
else:
x = self.prev[0]

if not event.ydata is None:
y = event.ydata
else:
y = self.prev[1]

I know it’s a bit verbose, but it works.

Thanks,
Aman

···

On Wed, Jul 21, 2010 at 2:44 PM, Aman Thakral <aman.thakral@…287…> wrote:

Update on the error.

It occurs in the following cases:

User clicks and drags from left to right and approaches the edge of the right side of the axes

User clicks and drags from right to left and approaches the edge of the left side of the axes

I’m working on this bug now, I’ll see if I can fix it. I’ll welcome any input you guys can provide though.

Thanks,
Aman

On Wed, Jul 21, 2010 at 1:58 PM, Aman Thakral <aman.thakral@…287…> wrote:
Hi all,

I’m getting the following exception when I use the Span Selector. It happens when I try and select the entire region.

Exception in Tkinter callback

Traceback (most recent call last):
File “C:\Python26\lib\lib-tk\Tkinter.py”, line 1410, in call
return self.func(*args)
File “C:\Python26\Lib\site-packages\matplotlib\backends\backend_tkagg.py”, line 246, in motion_notify_event
FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=event)

File “C:\Python26\Lib\site-packages\matplotlib\backend_bases.py”, line 1245, in motion_notify_event
self.callbacks.process(s, event)
File “C:\Python26\Lib\site-packages\matplotlib\cbook.py”, line 165, in process
func(*args, **kwargs)
File “C:\Python26\Lib\site-packages\matplotlib\widgets.py”, line 952, in onmove
self.rect.set_width(maxv-minv)
TypeError: unsupported operand type(s) for -: ‘float’ and ‘NoneType’

My sample code is shown here (its also attached):

import matplotlib.pyplot as plt
from matplotlib.widgets import SpanSelector

import numpy as np
import datetime

class TimeSelector(SpanSelector):
“”"
SpanSelector that is only activated by the left mouse button
"""




def ignore(self,event):
    if event.button == 2 or event.button == 3: return True
def onselect(xmin,xmax):
print xmin,xmax

fig = plt.figure()

ax = fig.add_subplot(111)
span = TimeSelector(ax, onselect, ‘horizontal’, useblit=True, rectprops=dict(alpha=0.5, facecolor=‘yellow’) )

y = np.random.rand(100,1)
start = datetime.datetime(2010,7,15,0,0)

x =
for i in range(len(y)):
x.append(start + datetime.timedelta(hours=i))
ax.plot_date(x,y,‘b-’)
plt.show()

Any help on this issue would be greatly appreciated.

Thanks,
Aman

–
Aman Thakral
B.Eng & Biosci, M.Eng Design

–
Aman Thakral
B.Eng & Biosci, M.Eng Design

_John_Hunter1 · July 22, 2010, 2:56am

Hey Aman, thanks for the fix. Could you create an svn diff, as described at:

http://matplotlib.sourceforge.net/faq/howto_faq.html#contributing-howto

JDH

···

On Wed, Jul 21, 2010 at 2:11 PM, Aman Thakral <aman.thakral@...287...> wrote:

Ok, so I've fixed it. Its just because the mouse goes outside the axes. How
do I make the change in the code?

Error: line 924 in widgets.py

old code:

x,y = event.xdata, event.ydata

fixed code:

if not event.xdata is None:
x = event.xdata
else:
x = self.prev[0]

if not event.ydata is None:
y = event.ydata
else:
y = self.prev[1]

I know it's a bit verbose, but it works.

Eric_Firing1 · July 22, 2010, 5:47am

Ok, so I've fixed it. Its just because the mouse goes outside the axes.
How do I make the change in the code?

Error: line 924 in widgets.py

old code:

x,y = event.xdata, event.ydata

fixed code:

if not event.xdata is None:
x = event.xdata
else:
x = self.prev[0]

Good! When you make the svn diff, as requested by John, you might change to a more typical idiom--easier to read, to my eye at least:

if event.xdata is None:
x = self.prev[0]
else:
x = event.xdata

Eric

···

On 07/21/2010 09:11 AM, Aman Thakral wrote:

if not event.ydata is None:
     y = event.ydata
else:
     y = self.prev[1]

I know it's a bit verbose, but it works.

Thanks,
Aman

On Wed, Jul 21, 2010 at 2:44 PM, Aman Thakral <aman.thakral@...287... > <mailto:aman.thakral@…287…>> wrote:

    Update on the error.

    It occurs in the following cases:
    - User clicks and drags from left to right and approaches the edge
    of the right side of the axes
    - User clicks and drags from right to left and approaches the edge
    of the left side of the axes

    I'm working on this bug now, I'll see if I can fix it. I'll welcome
    any input you guys can provide though.

    Thanks,
    Aman

    On Wed, Jul 21, 2010 at 1:58 PM, Aman Thakral > <aman.thakral@...287... <mailto:aman.thakral@…287…>> wrote:

        Hi all,

        I'm getting the following exception when I use the Span
        Selector. It happens when I try and select the entire region.

        Exception in Tkinter callback

        Traceback (most recent call last):
           File "C:\Python26\lib\lib-tk\Tkinter.py", line 1410, in __call__
             return self.func(*args)
           File
        "C:\Python26\Lib\site-packages\matplotlib\backends\backend_tkagg.py",
        line 246, in motion_notify_event
             FigureCanvasBase.motion_notify_event(self, x, y,
        guiEvent=event)
           File
        "C:\Python26\Lib\site-packages\matplotlib\backend_bases.py",
        line 1245, in motion_notify_event
             self.callbacks.process(s, event)
           File "C:\Python26\Lib\site-packages\matplotlib\cbook.py",
        line 165, in process
             func(*args, **kwargs)
           File "C:\Python26\Lib\site-packages\matplotlib\widgets.py",
        line 952, in onmove
             self.rect.set_width(maxv-minv)
        TypeError: unsupported operand type(s) for -: 'float' and 'NoneType'

        My sample code is shown here (its also attached):

        import matplotlib.pyplot as plt
        from matplotlib.widgets import SpanSelector
        import numpy as np
        import datetime

        class TimeSelector(SpanSelector):
        """
             SpanSelector that is only activated by the left mouse button
        """
             def ignore(self,event):
                 if event.button == 2 or event.button == 3: return True

        def onselect(xmin,xmax):
             print xmin,xmax

        fig = plt.figure()
        ax = fig.add_subplot(111)
        span = TimeSelector(ax, onselect, 'horizontal', useblit=True,
        rectprops=dict(alpha=0.5, facecolor='yellow') )

        y = np.random.rand(100,1)
        start = datetime.datetime(2010,7,15,0,0)
        x =
        for i in range(len(y)):
             x.append(start + datetime.timedelta(hours=i))

        ax.plot_date(x,y,'b-')
        plt.show()

        Any help on this issue would be greatly appreciated.

        Thanks,
        Aman

    --
    Aman Thakral
    B.Eng & Biosci, M.Eng Design

--
Aman Thakral
B.Eng & Biosci, M.Eng Design

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