tiny.filigree.describeAtAlloc

1pub fn describeAtAlloc(allocator: std.mem.Allocator, data: []const u8, face_index: u32) (model.FontError || error{OutOfMemory})!Description {2    const offset = try directory.fontDirectoryOffset(data, face_index);3    const os2 = try directory.tableAt(data, offset, "OS/2");4    if (os2.len < 64) return error.InvalidFont;5    const head = try directory.tableAt(data, offset, "head");6    const hhea = try directory.tableAt(data, offset, "hhea");7    if (head.len < 54 or hhea.len < 10) return error.InvalidFont;8    const units_per_em = try binary.readU16(data, head.offset + 18);9    if (units_per_em == 0) return error.InvalidFont;10    const selection = try binary.readU16(data, os2.offset + 62);11    const metric_source = if (selection & 0x80 != 0) os2 else hhea;12    if (selection & 0x80 != 0 and os2.len < 78) return error.InvalidFont;13    const metric_offset: usize = if (selection & 0x80 != 0) 68 else 4;14    const scale = @as(f32, @floatFromInt(units_per_em));15    const cmap_table = try directory.tableAt(data, offset, "cmap");16    const cmap = try cmap_owner.Cmap.init(data, cmap_table);17    var coverage: [8]u32 = @splat(0);18    inline for (0..4) |word| {19        coverage[word] = try binary.readU32(data, os2.offset + 42 + word * 4);20    }21    if (try hasEmoji(data, cmap)) coverage[extended_emoji_word] |= @as(u32, 1) << extended_emoji_bit;22    const post = directory.tableAt(data, offset, "post") catch |err| switch (err) {23        error.MissingTable => null,24        else => return err,25    };26    const name_table = try directory.tableAt(data, offset, "name");27    const record = (try names.bestNameRecord(data, name_table, 16)) orelse28        (try names.bestNameRecord(data, name_table, 1)) orelse return error.InvalidFont;29    const family = names.utf16BeToUtf8Alloc(allocator, record.bytes) catch |err| switch (err) {30        error.OutOfMemory => return error.OutOfMemory,31        else => return error.InvalidFont,32    };33    errdefer allocator.free(family);34    return .{35        .family = family,36        .weight_class = try binary.readU16(data, os2.offset + 4),37        .width_class = try binary.readU16(data, os2.offset + 6),38        .selection = selection,39        .units_per_em = units_per_em,40        .ascent = @as(f32, @floatFromInt(try binary.readI16(data, metric_source.offset + metric_offset))) / scale,41        .descent = @as(f32, @floatFromInt(try binary.readI16(data, metric_source.offset + metric_offset + 2))) / scale,42        .line_gap = @as(f32, @floatFromInt(try binary.readI16(data, metric_source.offset + metric_offset + 4))) / scale,43        .coverage = coverage,44        .fixed_pitch = if (post) |table| try readFixedPitch(data, table) else false,45        .color = directory.optionalAt(data, offset, "COLR") != null or46            directory.optionalAt(data, offset, "CBDT") != null or47            directory.optionalAt(data, offset, "sbix") != null or48            directory.optionalAt(data, offset, "SVG ") != null,49        .face_index = face_index,50    };51}

1pub const describeAtAlloc = font.describeAtAlloc;