fast image operations
Diffstat (limited to 'src/pixels/blending.rs')
| -rw-r--r-- | src/pixels/blending.rs | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/src/pixels/blending.rs b/src/pixels/blending.rs index 20d312e..33beecf 100644 --- a/src/pixels/blending.rs +++ b/src/pixels/blending.rs @@ -1,6 +1,6 @@ //! module for pixel blending ops #![allow(redundant_semicolons)] -use super::{Floatify, Unfloatify, convert::PFrom, unfloat}; +use super::{Floatify, Unfloatify, convert::PFrom, float, unfloat}; use atools::prelude::*; /// Trait for blending pixels together. @@ -9,6 +9,29 @@ pub trait Blend<const W: usize> { fn blend(&mut self, with: [u8; W]); } +pub(crate) fn blend_alpha_and_color(a: u8, color: [u8; 3], onto: &mut [u8; 3]) { + if a == 0 { + return; + } + if a == 255 { + *onto = color; + return; + } + + let [br, bg, bb] = *onto; + let [fr, fg, fb] = color; + + onto[0] = lerp(br, fr, a); + onto[1] = lerp(bg, fg, a); + onto[2] = lerp(bb, fb, a); + + // onto.copy_from_slice(&fg.zip(bg).map(|(f, b)| a * (f - b) + b)); +} + +fn lerp(ba: u8, fo: u8, a: u8) -> u8 { + ((fo as i32 - ba as i32) * a as i32 / 256 + ba as i32) as u8 +} + impl Blend<4> for [u8; 4] { #[lower::apply(algebraic)] fn blend(&mut self, fg: [u8; 4]) { |