Centering Text with axes_divider

Greetings,

Let me begin by saying that I’ve fallen in love with ImageGrid. I love the control it gives me in setting up plots, and I really like the control it offers for setting up a colorbar. Unfortunately, like all relationships, ImageGrid and I have hit a rough patch.

I like to manually place titles and other boxes of texts on plots that I make using ImageGrid. However, to center things I have to know what the axes bounds are so I can do the centering calculations. Unfortunately, when using ImageGrid, or axes_divider, I have yet to find a way to get the axes bounds that are actually used to do the plotting. When I try to use

ax.get_position().bounds

I get the pre-adjusted bounds, even if I use plt.draw() before requesting the axes_positions. This means the only way I can center the text is by guessing what the final axes bounds will be. Is there any way of getting the final bounds? It appears anchored text is able to do it, but I haven’t been able to…

Here’s a self-contained example script that demonstrates the problem. I don’t use ImageGrid, instead using axes_divider, however this is the same problem that AxesGrid has. (I’m guessing this is because ImageGrid ultimately does what I did here behind the scenes.)

https://gist.github.com/2004869

Thanks for any help!

Patrick

···

Patrick Marsh
Ph.D. Student / Liaison to the HWT
School of Meteorology / University of Oklahoma
Cooperative Institute for Mesoscale Meteorological Studies

National Severe Storms Laboratory

http://www.patricktmarsh.com

Hi, All,

Here’s an update to the problem I submitted last night.

I was able to utilize anchored text to work for centering a title, which is ultimately what I’m wanting to do now. (Although, I’d still like to know the proper way to get the axes bounds when using axes_divider). The new problem lies how to horizontally align the text inside the anchored box. When the horizontal alignment is “left”, the text lines up in the anchored box. However, as the updated example below shows, then you use “center” or “right”, the text is now positioned outside the anchored box. Is this a bug in how the text is aligned? If so, how might I go about tracking it down?

https://gist.github.com/2004869 (rev: b984ca)

Cheers,

Patrick

···

Patrick Marsh

Ph.D. Student / Liaison to the HWT
School of Meteorology / University of Oklahoma
Cooperative Institute for Mesoscale Meteorological Studies
National Severe Storms Laboratory
http://www.patricktmarsh.com

On Fri, Mar 9, 2012 at 12:12 AM, Patrick Marsh <patrickmarshwx@…287…> wrote:

Greetings,

Let me begin by saying that I’ve fallen in love with ImageGrid. I love the control it gives me in setting up plots, and I really like the control it offers for setting up a colorbar. Unfortunately, like all relationships, ImageGrid and I have hit a rough patch.

I like to manually place titles and other boxes of texts on plots that I make using ImageGrid. However, to center things I have to know what the axes bounds are so I can do the centering calculations. Unfortunately, when using ImageGrid, or axes_divider, I have yet to find a way to get the axes bounds that are actually used to do the plotting. When I try to use

ax.get_position().bounds

I get the pre-adjusted bounds, even if I use plt.draw() before requesting the axes_positions. This means the only way I can center the text is by guessing what the final axes bounds will be. Is there any way of getting the final bounds? It appears anchored text is able to do it, but I haven’t been able to…

Here’s a self-contained example script that demonstrates the problem. I don’t use ImageGrid, instead using axes_divider, however this is the same problem that AxesGrid has. (I’m guessing this is because ImageGrid ultimately does what I did here behind the scenes.)

https://gist.github.com/2004869

Thanks for any help!

Patrick

Patrick Marsh
Ph.D. Student / Liaison to the HWT
School of Meteorology / University of Oklahoma

Cooperative Institute for Mesoscale Meteorological Studies

National Severe Storms Laboratory

http://www.patricktmarsh.com

I wonder why the simple text command does not work for you? e.g.,

def add_center_text(ax):
    ax.text(0.5, 0.9075, "Centered Title", ha='center', va='center',
fontsize=18,
            bbox=dict(boxstyle='round, pad=0.5, rounding_size=0.25', fc="white",
                      ec="k", lw=2),
            transform=ax.transAxes)

Also, annotate command gives you more flexibility in text positioning.

The axes location is supposed to be known during the drawing time. To
get the axes position, you may do something like

   ax1._axes_locator(ax1, fig._cachedRenderer)

Of course, this need to be done after the figure is properly drawn
(e.g., after calling draw()) or during the drawing time.

Regards,

-JJ

···

On Sat, Mar 10, 2012 at 1:00 PM, Patrick Marsh <patrickmarshwx@...287...> wrote:

Hi, All,

Here's an update to the problem I submitted last night.

I was able to utilize anchored text to work for centering a title, which is
ultimately what I'm wanting to do now. (Although, I'd still like to know the
proper way to get the axes bounds when using axes_divider). The new problem
lies how to horizontally align the text inside the anchored box. When the
horizontal alignment is "left", the text lines up in the anchored box.
However, as the updated example below shows, then you use "center" or
"right", the text is now positioned outside the anchored box. Is this a bug
in how the text is aligned? If so, how might I go about tracking it down?

https://gist.github.com/2004869 (rev: b984ca)

Cheers,
Patrick
---
Patrick Marsh
Ph.D. Student / Liaison to the HWT
School of Meteorology / University of Oklahoma
Cooperative Institute for Mesoscale Meteorological Studies
National Severe Storms Laboratory
http://www.patricktmarsh.com

On Fri, Mar 9, 2012 at 12:12 AM, Patrick Marsh <patrickmarshwx@...287...> > wrote:

Greetings,

Let me begin by saying that I've fallen in love with ImageGrid. I love the
control it gives me in setting up plots, and I really like the control it
offers for setting up a colorbar. Unfortunately, like all relationships,
ImageGrid and I have hit a rough patch.

I like to manually place titles and other boxes of texts on plots that I
make using ImageGrid. However, to center things I have to know what the axes
bounds are so I can do the centering calculations. Unfortunately, when using
ImageGrid, or axes_divider, I have yet to find a way to get the axes bounds
that are actually used to do the plotting. When I try to use

ax.get_position().bounds

I get the pre-adjusted bounds, even if I use plt.draw() before requesting
the axes_positions. This means the only way I can center the text is by
guessing what the final axes bounds will be. Is there any way of getting
the final bounds? It appears anchored text is able to do it, but I haven't
been able to...

Here's a self-contained example script that demonstrates the problem. I
don't use ImageGrid, instead using axes_divider, however this is the same
problem that AxesGrid has. (I'm guessing this is because ImageGrid
ultimately does what I did here behind the scenes.)

https://gist.github.com/2004869

Thanks for any help!

Patrick
---
Patrick Marsh
Ph.D. Student / Liaison to the HWT
School of Meteorology / University of Oklahoma
Cooperative Institute for Mesoscale Meteorological Studies
National Severe Storms Laboratory
http://www.patricktmarsh.com

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Hi, JJ,

I wonder why the simple text command does not work for you? e.g.,

def add_center_text(ax):

ax.text(0.5, 0.9075, "Centered Title", ha='center', va='center',

fontsize=18,

        bbox=dict(boxstyle='round, pad=0.5, rounding_size=0.25', fc="white",

                  ec="k", lw=2),

        transform=ax.transAxes)

The simple answer here is that I didn’t understand what the transform keyword argument was doing. I’m not entirely sure, still, but I gather it has something to do with handling the changing of the axes coordinates. Man, I still have so much to learn about MPL…

Also, annotate command gives you more flexibility in text positioning.

The axes location is supposed to be known during the drawing time. To

get the axes position, you may do something like

ax1._axes_locator(ax1, fig._cachedRenderer)

Of course, this need to be done after the figure is properly drawn

(e.g., after calling draw()) or during the drawing time.

Excellent. Thank you fot taking the time to explain how this works. Although your first suggestion is what I need for the moment, I’m glad to know how to get the axes positions, should I ever need them.

Thanks again!

Patrick