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From: Damon M. <dam...@gm...> - 2012-08-27 17:05:19
|
My cherubs,
With my new found free time, I may have discovered a sneaky bug to which
you are not aware. Unless, of course, my example code is incorrect.
I do normal setup:
from matplotlib.backends.backend_pdf import FigureCanvasPdf as FigureCanvas
from matplotlib.figure import Figure
from matplotlib.patches import Rectangle
from matplotlib.transforms import Affine2D
fig = Figure()
canvas = FigureCanvas(fig)
ax = fig.add_subplot(1, 1, 1)
# Make a sexy rectangle at the origin
r = Rectangle((0.0, 0.0), 0.6, 0.4)
# Construct a mind-blowing transformation: rotation by 30 degrees
t = Affine2D().rotate_deg(30.0)
# Make sure to add in the already-known axes data transformation
t += ax.transData
# Rotate that shizzle
r.set_transform(t)
# Plottify
ax.add_patch(r)
fig.savefig('my_awesome_TRAPEZIUM.pdf')
Or you can look at my output here: http://i.imgur.com/2l439.png
Rotation by 30 degrees is an angle-preserving linear transformation. So
this shouldn't happen.
Here's what's messing shiz up: the figure dimensions are not square.
Look what happens when I use a square figure and make the axes fit
exactly to the figure dimensions:
...
fig = Figure((4, 4))
...
ax = fig.add_axes([0, 0, 1, 1])
...
...
fig.savefig('my_awesome_RECTANGLE.pdf')
You can see the output here: http://i.imgur.com/baXiH.png
Boom.
I have no idea how to fix it. I came across it while trying to address
https://github.com/matplotlib/matplotlib/issues/987 but it may or may
not also be related to
https://github.com/matplotlib/matplotlib/issues/1113
Let me know if it's worth putting in github issue. I'm dont want to
create a duplicate ticket should it transpire that this problem is
actually #1113 in disguise.
Best,
Damon
--
Damon McDougall
http://www.damon-is-a-geek.com
B2.39
Mathematics Institute
University of Warwick
Coventry
West Midlands
CV4 7AL
United Kingdom
|
|
From: Michael D. <md...@st...> - 2012-08-27 17:26:59
|
I'm not sure this is a bug. The transformation is being applied in data
space, and then the mapping to physical space is not square in the x and
y dimensions.
I think calling set_aspect('equal') on the axes should fix this -- if it
doesn't, that's indeed a bug.
Mike
On 08/27/2012 01:05 PM, Damon McDougall wrote:
> My cherubs,
>
> With my new found free time, I may have discovered a sneaky bug to which
> you are not aware. Unless, of course, my example code is incorrect.
>
> I do normal setup:
>
> from matplotlib.backends.backend_pdf import FigureCanvasPdf as FigureCanvas
> from matplotlib.figure import Figure
> from matplotlib.patches import Rectangle
> from matplotlib.transforms import Affine2D
>
> fig = Figure()
> canvas = FigureCanvas(fig)
> ax = fig.add_subplot(1, 1, 1)
>
> # Make a sexy rectangle at the origin
> r = Rectangle((0.0, 0.0), 0.6, 0.4)
>
> # Construct a mind-blowing transformation: rotation by 30 degrees
> t = Affine2D().rotate_deg(30.0)
>
> # Make sure to add in the already-known axes data transformation
> t += ax.transData
>
> # Rotate that shizzle
> r.set_transform(t)
>
> # Plottify
> ax.add_patch(r)
>
> fig.savefig('my_awesome_TRAPEZIUM.pdf')
>
> Or you can look at my output here: http://i.imgur.com/2l439.png
>
> Rotation by 30 degrees is an angle-preserving linear transformation. So
> this shouldn't happen.
>
> Here's what's messing shiz up: the figure dimensions are not square.
> Look what happens when I use a square figure and make the axes fit
> exactly to the figure dimensions:
>
> ...
> fig = Figure((4, 4))
> ...
> ax = fig.add_axes([0, 0, 1, 1])
> ...
> ...
> fig.savefig('my_awesome_RECTANGLE.pdf')
>
> You can see the output here: http://i.imgur.com/baXiH.png
>
> Boom.
>
> I have no idea how to fix it. I came across it while trying to address
> https://github.com/matplotlib/matplotlib/issues/987 but it may or may
> not also be related to
> https://github.com/matplotlib/matplotlib/issues/1113
>
> Let me know if it's worth putting in github issue. I'm dont want to
> create a duplicate ticket should it transpire that this problem is
> actually #1113 in disguise.
>
> Best,
> Damon
>
|
|
From: Damon M. <dam...@gm...> - 2012-08-27 17:35:02
|
On Mon, Aug 27, 2012 at 01:26:49PM -0400, Michael Droettboom wrote:
> I'm not sure this is a bug. The transformation is being applied in data
> space, and then the mapping to physical space is not square in the x and
> y dimensions.
>
> I think calling set_aspect('equal') on the axes should fix this -- if it
> doesn't, that's indeed a bug.
>
Awesome, it worked. Honestly, I probably should have realised that when
you don't have square axes, right angles are no longer right angles:
noob error. Apologies.
>
> Mike
>
> On 08/27/2012 01:05 PM, Damon McDougall wrote:
> > My cherubs,
> >
> > With my new found free time, I may have discovered a sneaky bug to which
> > you are not aware. Unless, of course, my example code is incorrect.
> >
> > I do normal setup:
> >
> > from matplotlib.backends.backend_pdf import FigureCanvasPdf as FigureCanvas
> > from matplotlib.figure import Figure
> > from matplotlib.patches import Rectangle
> > from matplotlib.transforms import Affine2D
> >
> > fig = Figure()
> > canvas = FigureCanvas(fig)
> > ax = fig.add_subplot(1, 1, 1)
> >
> > # Make a sexy rectangle at the origin
> > r = Rectangle((0.0, 0.0), 0.6, 0.4)
> >
> > # Construct a mind-blowing transformation: rotation by 30 degrees
> > t = Affine2D().rotate_deg(30.0)
> >
> > # Make sure to add in the already-known axes data transformation
> > t += ax.transData
> >
> > # Rotate that shizzle
> > r.set_transform(t)
> >
> > # Plottify
> > ax.add_patch(r)
> >
> > fig.savefig('my_awesome_TRAPEZIUM.pdf')
> >
> > Or you can look at my output here: http://i.imgur.com/2l439.png
> >
> > Rotation by 30 degrees is an angle-preserving linear transformation. So
> > this shouldn't happen.
> >
> > Here's what's messing shiz up: the figure dimensions are not square.
> > Look what happens when I use a square figure and make the axes fit
> > exactly to the figure dimensions:
> >
> > ...
> > fig = Figure((4, 4))
> > ...
> > ax = fig.add_axes([0, 0, 1, 1])
> > ...
> > ...
> > fig.savefig('my_awesome_RECTANGLE.pdf')
> >
> > You can see the output here: http://i.imgur.com/baXiH.png
> >
> > Boom.
> >
> > I have no idea how to fix it. I came across it while trying to address
> > https://github.com/matplotlib/matplotlib/issues/987 but it may or may
> > not also be related to
> > https://github.com/matplotlib/matplotlib/issues/1113
> >
> > Let me know if it's worth putting in github issue. I'm dont want to
> > create a duplicate ticket should it transpire that this problem is
> > actually #1113 in disguise.
> >
> > Best,
> > Damon
> >
>
>
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--
Damon McDougall
http://www.damon-is-a-geek.com
B2.39
Mathematics Institute
University of Warwick
Coventry
West Midlands
CV4 7AL
United Kingdom
|
|
From: Phil E. <pel...@gm...> - 2012-08-27 18:48:26
|
>>> right angles are no longer right angles: noob error. Apologies. Forgiven; on the basis that you provided such an entertainingly colourful initial report! :-) |
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