A fast linear-time gaussian blur based on
<http://blog.ivank.net/fastest-gaussian-blur.html>.
This implementation was based on <https://github.com/fschutt/fastblur>.
These functions in-place blur a given slice of (presumably) image data, with any number of
channels and the given blur radius. Performance is roughly linear time, and uses a single
allocation for a backing store, of the same size as the input slice.
# Example
Blur an [`RgbImage`](<https://docs.rs/image/latest/image/type.RgbImage.html>)
```rust
fn blur_fast(rgb_image: &mut image::RgbImage, radius: f32) -> Result<(), blurslice::SliceSizeError> {
let width = rgb_image.width() as usize;
let height = rgb_image.width() as usize;
let samples = rgb_image.as_flat_samples_mut();
blurslice::gaussian_blur_bytes::<3>(samples.samples, width, height, radius)
}
```
# Changes:
- Support any number of channels via const generics
- No allocation for passes list generation, uses const generic stack array
## TODO:
- [ ] Support arbitrary stride, for over-aligned data or vertical image sub-slices
- [ ] Allow providing a backing store, to allow for zero-allocation execution