Fix: Change alpha application for RGBA from overwrite to multiply#30523
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LangQi99 wants to merge 1 commit intomatplotlib:mainfrom
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Fix: Change alpha application for RGBA from overwrite to multiply#30523LangQi99 wants to merge 1 commit intomatplotlib:mainfrom
LangQi99 wants to merge 1 commit intomatplotlib:mainfrom
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Old Behavior pay attention to the bottom right New Behavior |
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rcomer
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Nov 23, 2025
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Thank you for your work on this @LangQi99 and sorry you did not get a response sooner. The fix looks right to me. However, this is a breaking change, as shown by the modified test. I do not think we can reasonably provide a deprecation pathway for this, but it should have an API change note.
| (im_rgb, | ||
| (scalar_alpha * array_alpha).reshape((ny, nx, 1))), | ||
| axis=-1), | ||
| interpolation_stage=intp_stage) |
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This looks like a style-only change. Please revert.
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I'm not working on this currently. Feel free to close it. |
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PR summary
Closes #26092
Per community consensus in #26092, the behavior for RGBA inputs has been changed from overwriting to blending; the image's intrinsic alpha is now multiplied with the passed alpha value. This change unifies alpha handling for 2D, RGB, and RGBA images, making the behavior consistent and predictable.
PR checklist