I have added a bbox support for "restore_region", but I'm afraid that
this feature is not well tested. And I guess what you find is,
unfortunately, a bug. While I'll try to push the changes to the svn
tomorrow, you may try to monkey-patch with following code.
from matplotlib.transforms import Bbox, BboxBase
from matplotlib.backends.backend_agg import RendererAgg
def restore_region(self, region, bbox=None, xy=None):
if bbox is not None or xy is not None:
rx, ry, width, height = region.get_extents()
if bbox is None:
x1, y1, x2, y2 = region.get_extents()
elif isinstance(bbox, BboxBase):
x1, y1, x2, y2 = bbox.extents
else:
x1, y1, x2, y2 = bbox
if xy is None:
ox, oy = rx, ry
else:
ox, oy = xy
self._renderer.restore_region2(region, x1, height-y2+ry, x2,
height-y1+ry,
ox, oy)
else:
self._renderer.restore_region(region)
RendererAgg.restore_region = restore_region
But, again, the code is not well tested and there could be another bug
(or even this patch may introduce a new bug). So, see how it works and
let know of any problem.
However, while matplotlib does support some animation, I think you 'd
better turn to another tool if you need an efficiency,
Regards,
-JJ
On Sun, Feb 14, 2010 at 2:18 PM, Brendan Barnwell <brenb...@brenbarn.net> wrote:
> Brendan Barnwell wrote:
>> I'm trying to find the quickest way to erase a rectangular area of
>> the figure canvas. I tried using canvas.restore_region with the
>> optional bbox argument, but there seems to be some mismatch between
>> the measurement units of the saved buffer object and the currently
>> shown data. For instance, if I have a Text object on my plot, I tried
>> this:
>>
>> bbox = g.text.get_window_extent()
>> canvas.restore_region(background, bbox)
>>
>> . . . but it does not correctly block out the text. (The restored
>> rectangle from the background appears elsewhere on the axes.) How can
>> I convert the buffer coordinates to the coordinates of the the
>> displayed plot?
>
> I'm sorry to bump my own post, but I would really appreciate some
> help with this. I've been wrestling with it for a couple days now,
> and I cannot figure out how the coordinate system of the saved canvas
> is related to the axes coordinates. I have found that with
> bbox.transformed(ax.transData) I can at least get the coordinates
> scaled to fit on the axes, but they are still offset in position from
> where the box actually appears on the canvas. I can't figure out how
> to compute this offset.
>
> By playing around with the coordinates manually, for instance, I've
> found that adjusting x by -52 and y by 21 appears to line up the
> canvas with the axes, but I can't see where these numbers -52 and 21
> would come from. My saved canvas buffer's get_extents() method
> returns (65, 50, 586, 443), so I thought that the appropriate offsets
> would be 65 and 50, but that doesn't work.
>
> So, what coordinates (x1, y1, x2, y2) do I need to use in
> canvas.restore_region(savedBuffer, (x1, y1, x2, y2)) in order to
> restore precisely the area of canvas occupied by a patch drawn at axis
> coordinates (a1, b1, a2, b2)?
>
> Thanks?
> --
> Brendan Barnwell
> "Do not follow where the path may lead. Go, instead, where there is
> no path, and leave a trail."
> --author unknown
>
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