beer

diff --git a/src/render.rs b/src/render.rsindex 4da46a7..3f7c336 100644--- a/src/render.rs+++ b/src/render.rs@@ -442,35 +442,93 @@ fn is_braille(c: char) -> bool {     ('\u{2800}'..='\u{28ff}').contains(&c) } -/// Draw a braille pattern as a 2×4 grid of dots filling the cell. The low eight-/// bits of the codepoint select dots, numbered down each column then across:-/// `0x01 0x08 / 0x02 0x10 / 0x04 0x20 / 0x40 0x80` for (col0,col1) rows 0-3.+/// Braille dot geometry for a `width`×`height` cell: the square dot side `w`,+/// the two column origins, and the four row origins. Ported verbatim from+/// foot's `box-drawing.c` `draw_braille` - base size and spacing from the cell,+/// then leftover pixels distributed (dot → margin → spacing → margin → dot) so+/// dots land on exact pixels with no rounding drift.+fn braille_geometry(width: i32, height: i32) -> (u32, [i32; 2], [i32; 4]) {+    let mut w = (width / 4).min(height / 8);+    let mut x_spacing = width / 4;+    let mut y_spacing = height / 8;+    let mut x_margin = x_spacing / 2;+    let mut y_margin = y_spacing / 2;++    let mut x_left = width - 2 * x_margin - x_spacing - 2 * w;+    let mut y_left = height - 2 * y_margin - 3 * y_spacing - 4 * w;++    // First, try hard to ensure a non-zero dot width.+    if x_left >= 2 && y_left >= 4 && w == 0 {+        w += 1;+        x_left -= 2;+        y_left -= 4;+    }+    // Second, prefer a non-zero margin.+    if x_left >= 2 && x_margin == 0 {+        x_margin = 1;+        x_left -= 2;+    }+    if y_left >= 2 && y_margin == 0 {+        y_margin = 1;+        y_left -= 2;+    }+    // Third, increase spacing.+    if x_left >= 1 {+        x_spacing += 1;+        x_left -= 1;+    }+    if y_left >= 3 {+        y_spacing += 1;+        y_left -= 3;+    }+    // Fourth, the side margins.+    if x_left >= 2 {+        x_margin += 1;+        x_left -= 2;+    }+    if y_left >= 2 {+        y_margin += 1;+        y_left -= 2;+    }+    // Last, increase the dot width.+    if x_left >= 2 && y_left >= 4 {+        w += 1;+    }++    let xs = [x_margin, x_margin + w + x_spacing];+    let ys = [+        y_margin,+        y_margin + w + y_spacing,+        y_margin + 2 * (w + y_spacing),+        y_margin + 3 * (w + y_spacing),+    ];+    (w.max(0) as u32, xs, ys)+}++/// Draw a braille pattern as a 2×4 grid of `w`×`w` square dots. Geometry ported+/// from foot's `box-drawing.c` `draw_braille`: a dot size and base spacing are+/// derived from the cell, then leftover pixels are distributed (dot width →+/// margins → spacing → …) so dots land on exact pixels with no rounding drift.+/// The low eight bits of the codepoint select dots: bits 0-2 are the left+/// column rows 0-2, bits 3-5 the right column rows 0-2, bits 6-7 the bottom row. fn draw_braille(canvas: &mut Canvas, c: char, x0: i32, top: i32, m: CellMetrics, fg: Rgb) {-    let bits = (c as u32).wrapping_sub(0x2800) as u8;-    let (w, h) = (m.width as i32, m.height as i32);-    // Each dot owns a 1/2-width by 1/4-height sub-cell; the dot itself fills-    // most of it and is kept square so columns and rows look even.-    let sub_w = w / 2;-    let sub_h = h / 4;-    let dot = ((sub_w.min(sub_h) * 7) / 10).max(1);-    // (mask, column, row) for the eight dots.-    const DOTS: [(u8, i32, i32); 8] = [+    let (w, xs, ys) = braille_geometry(m.width as i32, m.height as i32);+    let sym = ((c as u32) - 0x2800) as u8;+    // (bit mask, column index, row index).+    const DOTS: [(u8, usize, usize); 8] = [         (0x01, 0, 0),         (0x02, 0, 1),         (0x04, 0, 2),-        (0x40, 0, 3),         (0x08, 1, 0),         (0x10, 1, 1),         (0x20, 1, 2),+        (0x40, 0, 3),         (0x80, 1, 3),     ];     for (mask, col, row) in DOTS {-        if bits & mask == 0 {-            continue;+        if sym & mask != 0 {+            canvas.fill_rect(x0 + xs[col], top + ys[row], w, w, fg);         }-        let cx = x0 + col * sub_w + sub_w / 2;-        let cy = top + row * sub_h + sub_h / 2;-        canvas.fill_rect(cx - dot / 2, cy - dot / 2, dot as u32, dot as u32, fg);     } } @@ -525,3 +583,18 @@ fn draw_decorations(         canvas.hline(x0, top + m.ascent as i32 * 2 / 3, w, fg);     } }++#[cfg(test)]+mod tests {+    use super::braille_geometry;++    // Pinned to foot box-drawing.c draw_braille output (cross-checked numerically+    // identical across cell sizes 4..30 x 6..48); guards against drift.+    #[test]+    fn braille_geometry_matches_foot() {+        assert_eq!(braille_geometry(8, 18), (2, [1, 5], [2, 6, 10, 14]));+        assert_eq!(braille_geometry(10, 20), (2, [1, 6], [1, 6, 11, 16]));+        assert_eq!(braille_geometry(12, 27), (3, [1, 8], [1, 8, 15, 22]));+        assert_eq!(braille_geometry(7, 15), (1, [1, 4], [2, 5, 8, 11]));+    }+}