fast image operations
Diffstat (limited to 'src/affine.rs')
| -rw-r--r-- | src/affine.rs | 37 |
1 files changed, 25 insertions, 12 deletions
diff --git a/src/affine.rs b/src/affine.rs index eae511b..b0152a5 100644 --- a/src/affine.rs +++ b/src/affine.rs @@ -105,18 +105,11 @@ impl<const CHANNELS: usize> ImageCloner<'_, CHANNELS> { /// UB if the image is not square #[must_use = "function does not modify the original image"] pub unsafe fn rot_90(&self) -> Image<Vec<u8>, CHANNELS> { - let mut o = self.alloc(); - for y in 0..self.height() { - for x in 0..self.width() { - // SAFETY: x and y in bounds, slice is okay - unsafe { - let px = self.buffer.get_unchecked(self.slice(x, y)); - let out = o.pixel_mut(self.height() - y - 1, x); - out.copy_from_slice(px); - } - } - } - o + // SAFETY: yep + let mut out = unsafe { transpose_out(self) }; + // SAFETY: sqar + unsafe { crev(out.as_mut()) }; + out } /// Rotate an image 270 degrees clockwise, or 90 degrees anti clockwise. @@ -163,6 +156,26 @@ impl<const CHANNELS: usize, T: AsMut<[u8]> + AsRef<[u8]>> Image<T, CHANNELS> { } } +/// Reverse columns of square image +/// # Safety +/// +/// UB if supplied image not square +unsafe fn crev<const CHANNELS: usize, T: AsMut<[u8]> + AsRef<[u8]>>(mut img: Image<T, CHANNELS>) { + debug_assert_eq!(img.width(), img.height()); + let size = img.width() as usize; + let b = img.flatten_mut(); + for i in 0..size { + let mut start = 0; + let mut end = size - 1; + while start < end { + // SAFETY: hmm + unsafe { b.swap_unchecked(i * size + start, i * size + end) }; + start += 1; + end -= 1; + } + } +} + /// Transpose a square image out of place /// # Safety /// |