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|
//! Mean selection frontier.
use super::{neighbors, Frontier, RcPixel, Target};
use crate::color::{ColorSpace, Rgb8};
use crate::soft::SoftKdForest;
use acap::NearestNeighbors;
use std::iter;
/// A pixel on a mean frontier.
#[derive(Debug)]
enum MeanPixel<C> {
Empty,
Fillable(RcPixel<C>),
Filled(C),
}
impl<C: ColorSpace> MeanPixel<C>
where
C::Value: PartialOrd<C::Distance>,
{
fn filled_color(&self) -> Option<C> {
match self {
Self::Filled(color) => Some(*color),
_ => None,
}
}
}
/// A [Frontier] that looks at the average color of each pixel's neighbors.
#[derive(Debug)]
pub struct MeanFrontier<C> {
pixels: Vec<MeanPixel<C>>,
forest: SoftKdForest<RcPixel<C>>,
width: u32,
height: u32,
len: usize,
deleted: usize,
}
impl<C: ColorSpace> MeanFrontier<C>
where
C::Value: PartialOrd<C::Distance>,
{
/// Create a MeanFrontier with the given dimensions and initial pixel location.
pub fn new(width: u32, height: u32, x0: u32, y0: u32) -> Self {
let size = (width as usize) * (height as usize);
let mut pixels = Vec::with_capacity(size);
for _ in 0..size {
pixels.push(MeanPixel::Empty);
}
let pixel0 = RcPixel::new(x0, y0, C::from(Rgb8::from([0, 0, 0])));
let i = (x0 + y0 * width) as usize;
pixels[i] = MeanPixel::Fillable(pixel0.clone());
Self {
pixels,
forest: iter::once(pixel0).collect(),
width,
height,
len: 1,
deleted: 0,
}
}
fn pixel_index(&self, x: u32, y: u32) -> usize {
debug_assert!(x < self.width);
debug_assert!(y < self.height);
(x + y * self.width) as usize
}
fn fill(&mut self, x: u32, y: u32, color: C) {
let i = self.pixel_index(x, y);
match &self.pixels[i] {
MeanPixel::Empty => {}
MeanPixel::Fillable(pixel) => {
pixel.delete();
self.deleted += 1;
}
_ => unreachable!(),
}
self.pixels[i] = MeanPixel::Filled(color);
let mut pixels = Vec::new();
for &(x, y) in &neighbors(x, y) {
if x < self.width && y < self.height {
let i = self.pixel_index(x, y);
match &self.pixels[i] {
MeanPixel::Empty => {}
MeanPixel::Fillable(pixel) => {
pixel.delete();
self.deleted += 1;
}
MeanPixel::Filled(_) => continue,
}
let color = C::average(
neighbors(x, y)
.iter()
.filter(|(x, y)| *x < self.width && *y < self.height)
.map(|(x, y)| self.pixel_index(*x, *y))
.map(|i| &self.pixels[i])
.map(MeanPixel::filled_color)
.flatten(),
);
let pixel = RcPixel::new(x, y, color);
self.pixels[i] = MeanPixel::Fillable(pixel.clone());
pixels.push(pixel);
}
}
self.len += pixels.len();
self.forest.extend(pixels);
if 2 * self.deleted >= self.len {
self.forest.rebuild();
self.len -= self.deleted;
self.deleted = 0;
}
}
}
impl<C: ColorSpace> Frontier for MeanFrontier<C>
where
C::Value: PartialOrd<C::Distance>,
{
fn width(&self) -> u32 {
self.width
}
fn height(&self) -> u32 {
self.height
}
fn len(&self) -> usize {
self.len - self.deleted
}
fn is_empty(&self) -> bool {
self.len() == 0
}
fn place(&mut self, rgb8: Rgb8) -> Option<(u32, u32)> {
let color = C::from(rgb8);
let (x, y) = self.forest.nearest(&Target(color)).map(|n| n.item.pos)?;
self.fill(x, y, color);
Some((x, y))
}
}
|
