Canvas

An allocated buffer suitable for image data. Compared to a Vec of all samples, it restricts the possible data types but on the other hand focusses on a more efficient interface to casting the data or rearranging the contents.

Why

After some discussion it was concluded that there is likely no safe way to reinterpret the allocation of a Vec<T> for a different Vec<U>, except in a very restricted set of cases. This includes grouping samples in logic pixel structs, even if those are annotated #[repr(C)] or alike. This is hardly the fault of Vec<_>, as images and the necessary transmutations of the representated binary data are far from general but Vec must be.

Not

This library is not yet ready for use, and mostly a reservation in crates.io for future use within the image-rs organization managing the image crate.

It is also not intended to provide nd-algebra or other matrix style operations. This firstly keeps the implementation complexity low, allows other implementation details, and separates concerns. If you nevertheless find it useful for such purposes, rest asured that we find this incredibly cool even though we may not accept PRs to introduce additional complexity motivated solely by such use. Rather, use the code and free license to shape it to those other needs.

Todo

• Rec and underlying Buf need realloc
• Canvas should implement resizing to smaller image with guaranteed reuse
• Canvas mutation to differently sized types blocked by ..
• .. Rec logical mutations, keeping len but not byte_len
• Relaxing internal Buf requirements to allow reuse of memory for f32 (only AsBytes but not FromBytes)
• Use alignment for SIMD iteration/transmutation/map-operation