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author | Daniel Schadt <kingdread@gmx.de> | 2025-06-26 22:10:31 +0200 |
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committer | Daniel Schadt <kingdread@gmx.de> | 2025-06-26 22:10:31 +0200 |
commit | 99150875308e0cac89f4de2996cfd1954305dcfe (patch) | |
tree | f19224064543aed367522b05778a992d7385c712 /src/renderer/heatmap.rs | |
parent | 6adcd94a6747fe7ec6f1ad1073453636847a0bff (diff) | |
download | hittekaart-99150875308e0cac89f4de2996cfd1954305dcfe.tar.gz hittekaart-99150875308e0cac89f4de2996cfd1954305dcfe.tar.bz2 hittekaart-99150875308e0cac89f4de2996cfd1954305dcfe.zip |
split crate into core and clipy
Diffstat (limited to 'src/renderer/heatmap.rs')
-rw-r--r-- | src/renderer/heatmap.rs | 214 |
1 files changed, 0 insertions, 214 deletions
diff --git a/src/renderer/heatmap.rs b/src/renderer/heatmap.rs deleted file mode 100644 index 0c4f93f..0000000 --- a/src/renderer/heatmap.rs +++ /dev/null @@ -1,214 +0,0 @@ -//! 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()) - } -} |