diff options
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()) -    } -}  | 
