tiny.filigree.glyphBitmapAlloc

1/// Rasterizes one glyph. Scratch allocations end before return; `alpha` belongs to2/// `output_allocator` and must be released with `GlyphBitmap.deinit` and the same allocator.3pub fn glyphBitmapAlloc(4    output_allocator: std.mem.Allocator,5    scratch_allocator: std.mem.Allocator,6    face: face_table.Face,7    glyph_id: u32,8    pixel_size: i32,9) Error!GlyphBitmap {10    if (pixel_size <= 0) return error.InvalidPixelSize;11    const scale = fontScale(face, pixel_size);12    const advance_x = scaleMetric(face.advanceWidth(glyph_id), scale);13    var glyph = try outline.glyphAlloc(scratch_allocator, face, glyph_id);14    defer glyph.deinit(scratch_allocator);1516    if (glyph.points.len == 0 or glyph.bounds.x_max <= glyph.bounds.x_min or glyph.bounds.y_max <= glyph.bounds.y_min) {17        return blankGlyph(glyph_id, advance_x);18    }1920    const pixel_bounds = glyphPixelBounds(glyph.bounds, face.ascender, scale);21    const width = pixel_bounds.width();22    const height = pixel_bounds.height();23    if (width <= 0 or height <= 0) return blankGlyph(glyph_id, advance_x);2425    var points = std.ArrayListUnmanaged(FloatPoint).empty;26    defer points.deinit(scratch_allocator);27    var contours = std.ArrayListUnmanaged(ContourRange).empty;28    defer contours.deinit(scratch_allocator);29    try flattenGlyph(scratch_allocator, glyph, face.ascender, pixel_bounds, scale, &points, &contours);3031    const alpha = try output_allocator.alloc(u8, try pixelCount(width, height));32    errdefer output_allocator.free(alpha);33    @memset(alpha, 0);34    if (points.items.len > 0) {35        try coverage.rasterizeAlloc(scratch_allocator, alpha, width, height, points.items, contours.items);36    }3738    return .{39        .glyph_id = glyph_id,40        .width = width,41        .height = height,42        .offset_x = pixel_bounds.left,43        .offset_y = pixel_bounds.top,44        .advance_x = advance_x,45        .alpha = alpha,46    };47}

1pub const glyphBitmapAlloc = font.glyphBitmapAlloc;