fast image operations
Diffstat (limited to 'src/overlay.rs')
| -rw-r--r-- | src/overlay.rs | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/src/overlay.rs b/src/overlay.rs index f28d820..1a059e1 100644 --- a/src/overlay.rs +++ b/src/overlay.rs @@ -1,3 +1,4 @@ +//! Handles image overlay use super::{assert_unchecked, really_unsafe_index, Image}; use std::simd::SimdInt; use std::simd::SimdPartialOrd; @@ -22,11 +23,10 @@ pub trait Overlay<W> { } #[inline] +/// SIMD accelerated rgba => rgb overlay. +/// +/// See [blit](https://en.wikipedia.org/wiki/Bit_blit) unsafe fn blit(rgb: &mut [u8], rgba: &[u8]) { - const LAST4: Simd<u8, 16> = Simd::from_array([ - 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, - ]); - let mut srci = 0; let mut dsti = 0; while dsti + 16 <= rgb.len() { @@ -38,7 +38,9 @@ unsafe fn blit(rgb: &mut [u8], rgba: &[u8]) { threshold, [3, 3, 3, 7, 7, 7, 11, 11, 11, 15, 15, 15, 0, 0, 0, 0] ); - mask &= LAST4; + mask &= Simd::from_array([ + 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, + ]); let new_rgb = simd_swizzle!(new, [0, 1, 2, 4, 5, 6, 8, 9, 10, 12, 13, 14, 0, 0, 0, 0]); let blended = (new_rgb & mask) | (old & !mask); @@ -106,8 +108,16 @@ impl OverlayAt<Image<&[u8], 4>> for Image<&mut [u8], 3> { } impl OverlayAt<Image<&[u8], 3>> for Image<&mut [u8], 3> { + /// Overlay a RGB image(with) => self at coordinates x, y. + /// As this is a `RGBxRGB` operation, blending is unnecessary, + /// and this is simply a copy. + /// + /// # Safety + /// + /// UB if x, y is out of bounds #[inline] unsafe fn overlay_at(&mut self, with: &Image<&[u8], 3>, x: u32, y: u32) -> &mut Self { + /// helper macro for defining rgb=>rgb overlays. allows unrolling macro_rules! o3x3 { ($n:expr) => {{ for j in 0..($n as usize) { |