FIX macos: Use the agg buffer_rgba rather than private attribute #28964
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The _renderer attribute has changed with the pybind11 update and we aren't able to access it as a buffer anymore. We can use the buffer_rgba method to get the direct memoryview of the buffer instead.
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(Seems close enough to #18993 which did the same for tk.) |
| @@ -1236,7 +1236,7 @@ -(void)drawRect:(NSRect)rect | |||
| CGContextRef cr = [[NSGraphicsContext currentContext] CGContext]; | |||
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| if (!(renderer = PyObject_CallMethod(canvas, "get_renderer", "")) | |||
| || !(renderer_buffer = PyObject_GetAttrString(renderer, "_renderer"))) { | |||
| || !(renderer_buffer = PyObject_CallMethod(renderer, "buffer_rgba", ""))) { | |||
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Looking at the implementation of RendererAgg, it's:
def buffer_rgba(self):
return memoryview(self._renderer)
so this looks like a reasonable change. I'm a bit uncertain why PyObject_GetBuffer is not sufficient with pybind11's version of buffers, but we can investigate that for later.
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So in the original implementation: matplotlib/src/_backend_agg_wrapper.cpp Lines 415 to 437 in ac268ec we always filled out all fields regardless of flags. The macosx backend asks for a contiguous read-only buffer:Line 1167 in fbf1611 which is an alias for PyBUF_ND.
In pybind11 however, it does attempt to respect Line 1172 in fbf1611 I've opened pybind/pybind11#5407 to fix pybind11. |
PR summary
I'm getting
copy_agg_buffer failedand no plots to show up with the macosx backend.The
_rendererattribute has changed with the pybind11 update and we aren't able to access it as a buffer anymore. We can use the buffer_rgba method to get the direct memoryview of the buffer instead.git bisect shows me it is this commit: 96dd843
ping @QuLogic