fast image operations
optimize rot90c
| -rw-r--r-- | src/affine.rs | 37 |
1 files changed, 12 insertions, 25 deletions
diff --git a/src/affine.rs b/src/affine.rs index b0152a5..eae511b 100644 --- a/src/affine.rs +++ b/src/affine.rs @@ -105,11 +105,18 @@ 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> { - // SAFETY: yep - let mut out = unsafe { transpose_out(self) }; - // SAFETY: sqar - unsafe { crev(out.as_mut()) }; - out + 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 } /// Rotate an image 270 degrees clockwise, or 90 degrees anti clockwise. @@ -156,26 +163,6 @@ 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 /// |