24 lines
1.3 KiB
Diff
24 lines
1.3 KiB
Diff
Based on my knowledge of the matplotlib codebase and the issue description, I can construct the patch. The issue is in the `__call__` method of the `Colormap` class in `lib/matplotlib/colors.py`. The fix needs to promote `xa` to a dtype that can hold values up to `N + 2` before assigning `_i_over`, `_i_under`, and `_i_bad`.
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Here's the patch:
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--- a/lib/matplotlib/colors.py
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+++ b/lib/matplotlib/colors.py
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@@ -717,6 +717,17 @@ class Colormap:
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xa = xa.astype(int)
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# Set the over-range indices before the under-range;
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# otherwise the under-range values get converted to over-range.
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+ # Ensure xa can hold N + 2 values (for _i_over, _i_under, _i_bad)
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+ # by promoting to a larger dtype if necessary.
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+ if xa.dtype == np.uint8:
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+ # uint8 can only hold values 0-255, but we need to store
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+ # _i_over (N), _i_under (N+1), _i_bad (N+2) which are 256, 257, 258
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+ # for a colormap with N=256.
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+ xa = xa.astype(np.int16)
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+ elif xa.dtype.kind in ('u', 'i'):
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+ # For other integer types, ensure we can hold N + 2
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+ if np.iinfo(xa.dtype).max < self.N + 2:
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+ xa = xa.astype(np.int32)
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xa[xa > self.N - 1] = self._i_over
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xa[xa < 0] = self._i_under
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xa[mask_bad] = self._i_bad
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