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optimize rot90c

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bendn 2023-11-06 19:34:32 +07:00
parent dd74d73361
commit e2002f18b4
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1 changed files with 12 additions and 25 deletions
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37
src/affine.rs
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@ -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
///