Re: [matplotlib-devel] Transparent backgrounds for savefig

[Eric F. <ef...@ha...>]

Michael Droettboom wrote:

>>    get_frame and get_patch deprecated - just use "patch" and "frame",
>> formerly "axesPatch" and "axesFrame".  We'll add a deprecation warning
>> to get_frame and keep axesPatch and axesFrame around as aliases.
>>
>> Michael -- IIRC you added the axesFrame.  Was this to support to
>> separate drawing of the edge and face since our patches don't
>> (currently) have support for separate alpha channels for edge and
>> face.  Or are there additional motivations for the projection
>> backends?

I did it two years ago, r2415.

> It was so that the zorder could be something like:
> 
>    axesPatch
>    ... data ...
>    ... grids ...
>    axesFrame
> 

This was the main motivation, but the secondary thought was that it 
would facilitate doing something that people ask for now and then, which 
is allow one to specify only some axes boundaries instead of the whole 
rectangle.  A common plot style is to have axes lines on the left and 
bottom, for example; but sometimes people want only a line on the 
bottom, and I am sure that sooner or later someone will want top and 
right, or top and bottom, or whatever.  Obviously, I never got around to 
putting that option in place.

> It prevents data from overlapping the axes frame.  This was most crucial 
> in the PDF and Cairo backends where the clipping rectangle is 
> pixel-aligned but the axes frame and background are not necessarily.  In 
> the Agg backend, where we have more fine control, it actually doesn't 
> really matter.

No, I think it matters on all backends, especially if the frame is 
thick.  Whether the zorder above is what one wants may be a matter of 
taste, but on any backend it will make a difference in the way the plot 
looks.

Eric

> 
> Cheers,
> Mike
>