matplotlib-users

[Matplotlib-users] Axes on top of graphs

[Christian D. O. <chr...@gm...>]

Hi,

using the PS Backend and matplotlib 0.82 with python 2.3.5 I have the
problem that my graphs typically show up on top of the axes lines (the
figure frame) and tick marks. However, for a journal quality figure, I
need the axes and the tick marks to be on top of the graph(s).

I looked through the archives and found below e-mail. Has there been
any progress in fixing this? Has Michael Brady submitted a patch?

Thanks.

 - Christian


*****************************************************************
 >>>>> "Michael" =3D=3D Michael Brady <mbrady@jp...> writes:

     Michael> I tried setting the z-order of the tick objects, but it
     Michael> looks to me like the ticks are hard-coded to always draw
     Michael> before (underneath) any lines or patches.

 That"s right, they are.  This is a bug and not a feature :-(

 The ticks are drawn as part of the Axis.  See
 matplotlib.axes.Axes.draw, eg

         if self.axison:
             self.xaxis.draw(renderer)
             self.yaxis.draw(renderer)

 The Axis instances (XAxis and YAxis) are comprised of Line2D (the
 ticks) and Text (the labels) instances.

     Michael> Is there a way to tell the Axes to draw the ticks on top
     Michael> of any Polygons instead of underneath?

 As noted above, before any of the zorder sorting is done, the xaxis
 and yaxis are drawn.  One possible solution is to move the axis
 drawing commands to the
 end of the Axes.draw function.  Off the top of
 my head, I don"t see any problem with this approach.  Typically, you
 want the ticks visible.  We"ve talked in the past on the dev list
 about the desirability in supporting ticking inside, center or outside
 the axes box, but it hasn"t been implemented yet.

 Vis-a-vis zorder sorting, a more general solution would be to have a
 method which extracts the Artist primitives (Line2D and Text) from the
 XAxis and YAxis and adds them to the sort, but I"m not sure if this is
 actually better.  In real life, I think you always want them on top.
 Right?

     Michael> If not, it doesn"t look like it would be too hard to
     Michael> modify Axes.draw() to respect the z-order of ticks.  I"m
     Michael> happy to do this, although I"m nervous that it might
     Michael> break stuff that assumes that ticks are always drawn
     Michael> before everything else.  John, do you recommend that I
     Michael> create such a mod?

 Yes, if you can find something that works, and behaves sanely over the
 poorman"s unit tests in examples/backend_driver.py.

 JDH

[Matplotlib-users] Re: Axes on top of graphs

[Christian D. O. <chr...@gm...>]

Hi,

sorry about my previous e-mail. I have now tried the same with 0.85.
The tick marks are now by default on top of the data graphs while the
axes lines (please correct my vocabulary usage here, axes lines =3D
figure frame?) are still below.

To get the figure frame drawn on top of everything, one
has to modify axes.draw. Namely, one adds to

         if not self._axisbelow:
            if self.axison and not inframe:
                self.xaxis.draw(renderer)
                self.yaxis.draw(renderer)

these 4 lines:

            if self.axison:
                if self._frameon:
                    self.axesPatch.set_fill(False)
                    self.axesPatch.draw(renderer)

. Also, one has to set gca.set_axisbelow(False) for the if block
to be executed.

The additional code draws another figure frame, this time without
filling, on top of the previous one and the data graphs.

- Christian


On 11/19/05, Christian David Ott  wrote:
> Hi,
>
> using the PS Backend and matplotlib 0.82 with python 2.3.5 I have the
> problem that my graphs typically show up on top of the axes lines (the
> figure frame) and tick marks. However, for a journal quality figure, I
> need the axes and the tick marks to be on top of the graph(s).
>
> I looked through the archives and found below e-mail. Has there been
> any progress in fixing this? Has Michael Brady submitted a patch?
>
> Thanks.
>
>  - Christian
>
>

Re: [Matplotlib-users] Re: Axes on top of graphs

[John H. <jdh...@ac...>]

>>>>> "Christian" == Christian David Ott <chr...@gm...> writes:

    Christian> Hi, sorry about my previous e-mail. I have now tried
    Christian> the same with 0.85.  The tick marks are now by default

Yep, the axisbelow property was just added in 0.85 and this controls
whether the ticks and grid lines are drawn above or below your data
lines.

    Christian> on top of the data graphs while the axes lines (please
    Christian> correct my vocabulary usage here, axes lines = figure
    Christian> frame?) are still below.

I see the source of our previous confusion -- matplotlib has a figure
patch and an axes patch. The figure patch controls the backgroud of
the entire figure canvas and the frame of this borders your window or
paper.  The axes patch is the thing surrounding the subplot/axes (eg
the white area where your data are).  I think in your previous emails
when you referred to the "figure frame" you meant the axes frame.  In
which case you would use subplot(111, frameon=False)

    Christian> To get the figure frame drawn on top of everything, one
    Christian> has to modify axes.draw. Namely, one adds to


    Christian> these 4 lines:

    Christian>             if self.axison: if self._frameon:
    Christian> self.axesPatch.set_fill(False)
    Christian> self.axesPatch.draw(renderer)

So basically, you want a second draw of the axespatch edge over the
ticks. Could you post a script w/o these changes that shows the
undesirable effect, so I can see better what the problem is.  I worry
that doing two draws of the axes patch, one w/ the fill first and one
w/o the fill later will screw up the alpha channel of the edgecolor of
the axes patch.  Albeit a corner case.

JDH