feat: +njalla module

2026-07-13 23:37:14 +00:00
parent 7e8c6884db
commit ef7d1b29f4
12 changed files with 2825 additions and 0 deletions
@@ -0,0 +1,184 @@
+use crate::geo::Country;
+
+/// Render a zoomed-in ASCII map centered on the target country, showing borders and labels.
+pub fn render_map(
+    countries: &[Country],
+    target_code: &str,
+    width: usize,
+    height: usize,
+) -> String {
+    // Find the target country and compute its bbox
+    let target_idx = countries
+        .iter()
+        .position(|c| c.iso_a2 == target_code)
+        .expect("Target country not found in GeoJSON");
+
+    let (min_lon, min_lat, max_lon, max_lat) = countries[target_idx].bbox;
+
+    // Add generous padding so the surrounding continent is visible
+    let lon_span = (max_lon - min_lon).max(4.0);
+    let lat_span = (max_lat - min_lat).max(4.0);
+    let pad_lon = lon_span * 1.0;
+    let pad_lat = lat_span * 1.0;
+
+    let view_min_lon = (min_lon - pad_lon).max(-180.0);
+    let view_max_lon = (max_lon + pad_lon).min(180.0);
+    let view_min_lat = (min_lat - pad_lat).max(-90.0);
+    let view_max_lat = (max_lat + pad_lat).min(90.0);
+
+    // Adjust aspect ratio: terminal chars are ~2x taller than wide
+    let lon_range = view_max_lon - view_min_lon;
+    let lat_range = view_max_lat - view_min_lat;
+    let char_aspect = 2.0;
+
+    let (final_lon_range, final_lat_range);
+    let desired_lon = lat_range * (width as f64) / (height as f64) / char_aspect;
+    let desired_lat = lon_range * (height as f64) / (width as f64) * char_aspect;
+
+    if desired_lon > lon_range {
+        final_lon_range = desired_lon;
+        final_lat_range = lat_range;
+    } else {
+        final_lon_range = lon_range;
+        final_lat_range = desired_lat;
+    }
+
+    let center_lon = (view_min_lon + view_max_lon) / 2.0;
+    let center_lat = (view_min_lat + view_max_lat) / 2.0;
+
+    let vp_min_lon = (center_lon - final_lon_range / 2.0).max(-180.0);
+    let vp_max_lat = (center_lat + final_lat_range / 2.0).min(90.0);
+
+    let lon_per_col = final_lon_range / width as f64;
+    let lat_per_row = final_lat_range / height as f64;
+
+    // Grid of characters
+    let mut grid = vec![vec![' '; width]; height];
+
+    // Rasterize polygon edges onto the grid
+    for (i, country) in countries.iter().enumerate() {
+        let (c_min_lon, c_min_lat, c_max_lon, c_max_lat) = country.bbox;
+        if c_max_lon < vp_min_lon
+            || c_min_lon > vp_min_lon + final_lon_range
+            || c_max_lat < vp_max_lat - final_lat_range
+            || c_min_lat > vp_max_lat
+        {
+            continue;
+        }
+
+        let border_ch = if i == target_idx { '#' } else { '\u{00b7}' };
+
+        for poly in &country.polygons {
+            for ring in poly {
+                if ring.len() < 2 {
+                    continue;
+                }
+                for edge in ring.windows(2) {
+                    rasterize_edge(
+                        edge[0][0],
+                        edge[0][1],
+                        edge[1][0],
+                        edge[1][1],
+                        vp_min_lon,
+                        vp_max_lat,
+                        lon_per_col,
+                        lat_per_row,
+                        width,
+                        height,
+                        border_ch,
+                        i == target_idx,
+                        &mut grid,
+                    );
+                }
+            }
+        }
+    }
+
+    // Place country code labels at bbox center
+    for (i, country) in countries.iter().enumerate() {
+        if country.iso_a2 == "-99" {
+            continue;
+        }
+
+        let (label_lon, label_lat) = country.label_pos;
+
+        let col = ((label_lon - vp_min_lon) / lon_per_col) as isize;
+        let row = ((vp_max_lat - label_lat) / lat_per_row) as isize;
+
+        let label = &country.iso_a2;
+        let start_col = col - (label.len() as isize / 2);
+
+        for (j, ch) in label.chars().enumerate() {
+            let c = start_col + j as isize;
+            if c >= 0 && (c as usize) < width && row >= 0 && (row as usize) < height {
+                let r = row as usize;
+                let c = c as usize;
+                let existing = grid[r][c];
+                // Target label always writes; neighbor labels only on empty or neighbor border
+                if i == target_idx || existing == ' ' || existing == '\u{00b7}' {
+                    grid[r][c] = ch;
+                }
+            }
+        }
+    }
+
+    // Render grid to string
+    grid.iter()
+        .map(|row| row.iter().collect::<String>())
+        .collect::<Vec<_>>()
+        .join("\n")
+}
+
+/// Rasterize a line segment onto the grid using Bresenham's algorithm.
+fn rasterize_edge(
+    lon0: f64,
+    lat0: f64,
+    lon1: f64,
+    lat1: f64,
+    vp_min_lon: f64,
+    vp_max_lat: f64,
+    lon_per_col: f64,
+    lat_per_row: f64,
+    width: usize,
+    height: usize,
+    ch: char,
+    is_target: bool,
+    grid: &mut [Vec<char>],
+) {
+    let c0 = ((lon0 - vp_min_lon) / lon_per_col) as i32;
+    let r0 = ((vp_max_lat - lat0) / lat_per_row) as i32;
+    let c1 = ((lon1 - vp_min_lon) / lon_per_col) as i32;
+    let r1 = ((vp_max_lat - lat1) / lat_per_row) as i32;
+
+    let mut x = c0;
+    let mut y = r0;
+    let dx = (c1 - c0).abs();
+    let dy = -(r1 - r0).abs();
+    let sx = if c0 < c1 { 1 } else { -1 };
+    let sy = if r0 < r1 { 1 } else { -1 };
+    let mut err = dx + dy;
+
+    loop {
+        if x >= 0 && (x as usize) < width && y >= 0 && (y as usize) < height {
+            let cell = &mut grid[y as usize][x as usize];
+            // Target borders overwrite neighbor borders; neighbor borders only on empty
+            if is_target || *cell == ' ' {
+                *cell = ch;
+            }
+        }
+
+        if x == c1 && y == r1 {
+            break;
+        }
+
+        let e2 = 2 * err;
+        if e2 >= dy {
+            err += dy;
+            x += sx;
+        }
+        if e2 <= dx {
+            err += dx;
+            y += sy;
+        }
+    }
+}