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This has been a long standing issue. The lack of generalization in Rust makes it generally hard to provide specialized implementations of `copy_from` that can make full use of the layout information to improve code generation. Since the argument is generic we stay with the default implementation even for the very strict targets (and source) of `ImageBuffer`. We sidestep a large part of the problem by speeding up only the copy from a well-described layout: `View` (a strided matrix). Then an optional method on `GenericImageView` lets us query if the source is equivalent to such a copy. We wont reap the benefits for user defined trait impls but importantly the crate's own `ImageBuffer` and `SubImage` can provide it The latter also has a generic impl for SubImage<D> were <D as Deref>::Target: GenericImageView Due to this we do not use a double-dispatch approach (adding a `copy_into_buffer`) but this which composes purely at runtime. Also note that DynamicImage can not provide it but the goal is to replace this, too. Backport-Of: e7d1ea2
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Backport-Of: 392a587
This also speeds up copies from them as well as copies from sub images of sample views. Backport-Of: 903d448
Backport-Of: 225e597
The pattern was caught in review, went ahead and generalized it to the other occasion where a rectangular placement is built from an image. Backport-Of: 2861fb8
Since conversion is fallible, using `to_*` is more appropriate. Backport-Of: 41046d3
Backport-Of: cf4dbaf
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Backport of: #2766 , #2768 to
0.25*