fast image operations
| -rw-r--r-- | src/affine.rs | 22 | ||||
| -rw-r--r-- | src/lib.rs | 1 |
2 files changed, 11 insertions, 12 deletions
diff --git a/src/affine.rs b/src/affine.rs index 18f19ee..393b571 100644 --- a/src/affine.rs +++ b/src/affine.rs @@ -104,35 +104,33 @@ impl<const CHANNELS: usize> Rotations for Image<&mut [u8], CHANNELS> { // This is done by first flipping self.flip_v(); // Then transposing the image, to save allocations. - // SAFETY: caller ensures rectangularity + // SAFETY: caller ensures square unsafe { transpose(self) }; } #[inline] unsafe fn rot_270(&mut self) { self.flip_h(); - // SAFETY: caller ensures rectangularity + // SAFETY: caller ensures squareness unsafe { transpose(self) }; } } +/// Transpose a square image /// # Safety /// /// UB if supplied image rectangular unsafe fn transpose<const CHANNELS: usize>(img: &mut Image<&mut [u8], CHANNELS>) { debug_assert_eq!(img.width(), img.height()); - let size = img.width(); + let size = img.width() as usize; + // SAFETY: no half pixels + let b = unsafe { img.buffer.as_chunks_unchecked_mut::<CHANNELS>() }; for i in 0..size { for j in i..size { - for c in 0..CHANNELS { - // SAFETY: caller gurantees rectangularity - unsafe { - img.buffer.swap_unchecked( - (i * size + j) as usize * CHANNELS + c, - (j * size + i) as usize * CHANNELS + c, - ); - }; - } + // SAFETY: caller ensures squarity + unsafe { + b.swap_unchecked(i * size + j, j * size + i); + }; } } } @@ -1,5 +1,6 @@ #![feature( slice_swap_unchecked, + slice_as_chunks, unchecked_math, portable_simd, array_chunks, |