In imsave, let pnginfo have precedence over metadata. #15434
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This is consistent with the documented behavior ("If the 'pnginfo' key
is present, it completely overrides *metadata*, including the default
'Software' key.") and also with the behavior of
FigureCanvasAgg.print_png.
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Is #13092 really the relevant issue here? |
lib/matplotlib/image.py
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| @@ -1539,7 +1539,8 @@ def imsave(fname, arr, vmin=None, vmax=None, cmap=None, format=None, | |||
| pil_shape = (rgba.shape[1], rgba.shape[0]) | |||
| image = Image.frombuffer( | |||
| "RGBA", pil_shape, rgba, "raw", "RGBA", 0, 1) | |||
| if format == "png" and metadata is not None: | |||
| if (format == "png" | |||
| and metadata is not None and "pnginfo" not in pil_kwargs): | |||
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Silently ignoring metadata if pnginfo is present does not feel right. Can we raise or warn in that case, or are there subsets of metadata that may still be needed?
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print_png (used by savefig("foo.png") has had this behavior ever since pil_kwargs is supported (which is 3.1), and no one has complained about it so far (it probably hasn't been too much used yet in the wild, though); I'd rather keep both places in sync.
Also a verb is missing in your sentence ("Can we ???").
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Fixed the missing verb. I'd be happy to warn in both places. Raising would now be a breaking change.
I wouldn't expect too much complaint. It's not widely used, it will only happen if you provide both parameters. It might actually have affect users without them realizing it.
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sure, added a warning in both places.
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edited: the correct original PR was #13902. |
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The doc issue was fixed by #15449 . |
This is consistent with the documented behavior ("If the 'pnginfo' key
is present, it completely overrides metadata, including the default
'Software' key.") and also with the behavior of
FigureCanvasAgg.print_png, cf
matplotlib/lib/matplotlib/backends/backend_agg.py
Lines 522 to 524 in c9f292f
The feature came in in #13902 which is not in any released version so far, so it would be nice if this was fixed before the final 3.2 release. I will prepare a separate PR for master.
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