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|
use std::{fs, path::Path, thread};
use color_eyre::{
eyre::{bail, Result},
Report,
};
use image::{ImageBuffer, Luma, Pixel, RgbaImage};
use nalgebra::{vector, Vector2};
use rayon::iter::ParallelIterator;
use super::{
gpx::Coordinates,
layer::{self, TileLayer},
};
pub type HeatCounter = TileLayer<Luma<u8>>;
fn render_circle<P: Pixel>(layer: &mut TileLayer<P>, center: (u64, u64), radius: u64, pixel: P) {
let topleft = (center.0 - radius, center.1 - radius);
let rad_32: u32 = radius.try_into().unwrap();
let mut circle = ImageBuffer::<P, Vec<P::Subpixel>>::new(rad_32 * 2 + 1, rad_32 * 2 + 1);
imageproc::drawing::draw_filled_circle_mut(
&mut circle,
(
i32::try_from(radius).unwrap(),
i32::try_from(radius).unwrap(),
),
radius.try_into().unwrap(),
pixel,
);
layer.blit_nonzero(topleft.0, topleft.1, &circle);
}
fn direction_vector(a: (u64, u64), b: (u64, u64)) -> Vector2<f64> {
let dx = if b.0 > a.0 {
(b.0 - a.0) as f64
} else {
-((a.0 - b.0) as f64)
};
let dy = if b.1 > a.1 {
(b.1 - a.1) as f64
} else {
-((a.1 - b.1) as f64)
};
vector![dx, dy]
}
fn render_line<P: Pixel>(
layer: &mut TileLayer<P>,
start: (u64, u64),
end: (u64, u64),
thickness: u64,
pixel: P,
) {
use imageproc::point::Point;
if start == end {
return;
}
fn unsigned_add(a: Vector2<u64>, b: Vector2<i32>) -> Vector2<u64> {
let x = if b[0] < 0 {
a[0] - u64::from(b[0].unsigned_abs())
} else {
a[0] + u64::try_from(b[0]).unwrap()
};
let y = if b[1] < 0 {
a[1] - u64::from(b[1].unsigned_abs())
} else {
a[1] + u64::try_from(b[1]).unwrap()
};
vector![x, y]
}
let r = direction_vector(start, end);
let normal = vector![r[1], -r[0]].normalize();
let start = vector![start.0, start.1];
let end = vector![end.0, end.1];
let displacement = normal * thickness as f64;
let displacement = displacement.map(|x| x as i32);
if displacement == vector![0, 0] {
return;
}
let polygon = [
unsigned_add(start, displacement),
unsigned_add(end, displacement),
unsigned_add(end, -displacement),
unsigned_add(start, -displacement),
];
let min_x = polygon.iter().map(|p| p[0]).min().unwrap();
let min_y = polygon.iter().map(|p| p[1]).min().unwrap();
let max_x = polygon.iter().map(|p| p[0]).max().unwrap();
let max_y = polygon.iter().map(|p| p[1]).max().unwrap();
let mut overlay = ImageBuffer::<P, Vec<P::Subpixel>>::new(
(max_x - min_x).try_into().unwrap(),
(max_y - min_y).try_into().unwrap(),
);
let adjusted_poly = polygon
.into_iter()
.map(|p| Point::new((p[0] - min_x) as i32, (p[1] - min_y) as i32))
.collect::<Vec<_>>();
imageproc::drawing::draw_polygon_mut(&mut overlay, &adjusted_poly, pixel);
layer.blit_nonzero(min_x, min_y, &overlay);
}
fn merge_heat_counter(base: &mut HeatCounter, overlay: &HeatCounter) {
for (tx, ty, source) in overlay.enumerate_tiles() {
let target = base.tile_mut(tx, ty);
for (x, y, source) in source.enumerate_pixels() {
let target = target.get_pixel_mut(x, y);
target[0] += source[0];
}
}
}
fn colorize_tile(tile: &ImageBuffer<Luma<u8>, Vec<u8>>, max: u32) -> RgbaImage {
let gradient = colorgrad::yl_or_rd();
let mut result = ImageBuffer::from_pixel(tile.width(), tile.height(), [0, 0, 0, 0].into());
for (x, y, pixel) in tile.enumerate_pixels() {
if pixel[0] > 0 {
let alpha = pixel[0] as f64 / max as f64;
let color = gradient.at(1.0 - alpha);
let target = result.get_pixel_mut(x, y);
*target = color.to_rgba8().into();
}
}
result
}
/// Lazily colorizes a [`HeatCounter`] by colorizing it tile-by-tile and saving a tile before
/// rendering the next one.
///
/// This has a way lower memory usage than [`colorize_heatcounter`].
pub fn lazy_colorization<P: AsRef<Path>, F: Fn(usize) + Send + Sync>(
layer: HeatCounter,
base_dir: P,
progress_callback: F,
) -> Result<()> {
let base_dir = base_dir.as_ref();
let max = layer.pixels().map(|l| l.0[0]).max().unwrap_or_default();
if max == 0 {
return Ok(());
}
type Job = (u64, u64, Vec<u8>);
let (tx, rx) = crossbeam_channel::bounded::<Job>(30);
thread::scope(|s| {
let saver = s.spawn(move || loop {
let Ok((tile_x, tile_y, data)) = rx.recv() else { return Ok(()) };
let folder = base_dir.join(tile_x.to_string());
let metadata = folder.metadata();
match metadata {
Err(_) => fs::create_dir(&folder)?,
Ok(m) if !m.is_dir() => bail!("Output path is not a directory"),
_ => {}
}
let file = folder.join(format!("{tile_y}.png"));
fs::write(file, data)?;
});
layer
.into_parallel_tiles()
.try_for_each_with(tx, |tx, (tile_x, tile_y, tile)| {
let colorized = colorize_tile(&tile, max.into());
let data = layer::compress_png_as_bytes(&colorized)?;
tx.send((tile_x, tile_y, data))?;
progress_callback(1);
Ok::<(), Report>(())
})?;
saver.join().unwrap()?;
Ok::<_, Report>(())
})?;
Ok(())
}
/// Renders the heat counter for the given zoom level and track points.
pub fn render_heatcounter<F: Fn(usize) + Send + Sync>(
zoom: u32,
tracks: &[Vec<Coordinates>],
progress_callback: F,
) -> HeatCounter {
let mut heatcounter = TileLayer::from_pixel([0].into());
for track in tracks {
let mut layer = TileLayer::from_pixel([0].into());
let points = track
.iter()
.map(|coords| coords.web_mercator(zoom))
.collect::<Vec<_>>();
for point in points.iter() {
render_circle(&mut layer, *point, (zoom as u64 / 4).max(2) - 1, [1].into());
}
for (a, b) in points.iter().zip(points.iter().skip(1)) {
render_line(&mut layer, *a, *b, (zoom as u64 / 4).max(1), [1].into());
}
merge_heat_counter(&mut heatcounter, &layer);
progress_callback(1);
}
heatcounter
}
|
