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authorDaniel Schadt <kingdread@gmx.de>2025-06-26 22:10:31 +0200
committerDaniel Schadt <kingdread@gmx.de>2025-06-26 22:10:31 +0200
commit99150875308e0cac89f4de2996cfd1954305dcfe (patch)
treef19224064543aed367522b05778a992d7385c712 /src/renderer/heatmap.rs
parent6adcd94a6747fe7ec6f1ad1073453636847a0bff (diff)
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split crate into core and clipy
Diffstat (limited to 'src/renderer/heatmap.rs')
-rw-r--r--src/renderer/heatmap.rs214
1 files changed, 0 insertions, 214 deletions
diff --git a/src/renderer/heatmap.rs b/src/renderer/heatmap.rs
deleted file mode 100644
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--- a/src/renderer/heatmap.rs
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-//! Actual rendering functions for heatmaps.
-//!
-//! We begin the rendering by using [`render_heatcounter`] to turn a list of GPX tracks into a
-//! [`HeatCounter`], which is basically a grayscale heatmap, where each pixel represents the number
-//! of tracks that goes through this pixel.
-//!
-//! We then render the colored heatmap tiles using [`lazy_colorization`], which provides us with
-//! colorful PNG data.
-use color_eyre::{eyre::Result, Report};
-use crossbeam_channel::Sender;
-use image::{ImageBuffer, Luma, Pixel, RgbaImage};
-use nalgebra::{vector, Vector2};
-use rayon::iter::ParallelIterator;
-
-use super::{
- super::{
- gpx::Coordinates,
- layer::{self, TileLayer},
- },
- RenderedTile,
-};
-
-/// Type for the intermediate heat counters.
-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
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct Renderer;
-
-impl super::Renderer for Renderer {
- type Prepared = HeatCounter;
-
- /// Renders the heat counter for the given zoom level and track points.
- ///
- /// The given callback will be called when a track has been rendered and merged into the
- /// accumulator, to allow for UI feedback. The passed parameter is the number of tracks that have
- /// been rendered since the last call.
- fn prepare(
- &self,
- zoom: u32,
- tracks: &[Vec<Coordinates>],
- tick: Sender<()>,
- ) -> Result<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);
- tick.send(()).unwrap();
- }
- Ok(heatcounter)
- }
-
- /// Lazily colorizes a [`HeatCounter`] by colorizing it tile-by-tile and saving a tile before
- /// rendering the next one.
- ///
- /// This function calls the given callback with each rendered tile, and the function is responsible
- /// for saving it. If the callback returns an `Err(...)`, the error is passed through.
- ///
- /// Note that this function internally uses `rayon` for parallization. If you want to limit the
- /// number of threads used, set up the global [`rayon::ThreadPool`] first.
- fn colorize(&self, layer: HeatCounter, tx: Sender<RenderedTile>) -> Result<()> {
- let max = layer.pixels().map(|l| l.0[0]).max().unwrap_or_default();
- if max == 0 {
- return Ok(());
- }
-
- 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(RenderedTile {
- x: tile_x,
- y: tile_y,
- data,
- })?;
- Ok::<(), Report>(())
- })
- }
-
- fn tile_count(&self, layer: &HeatCounter) -> Result<u64> {
- Ok(layer.tile_count().try_into().unwrap())
- }
-}