// Copyright 2013 The Flutter Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Generate .dart files with 
// protoc --dart_out=. generator/fonts.proto
syntax = "proto2";

package fonts;

// Details required for a checked download
// A Downloadable Font will typically have a hash but no filename.
// A System Font will typically have only a filename.
// Hash is 20 bytes sha1 up to v12, 32 byte sha256 for v13+,
message FileSpec {
  optional string filename = 1;
  optional int64 file_size = 2;
  optional bytes hash = 3;
}

// To allow expression of variation font capability, e.g. weight 300-700
message IntRange {
  optional int32 start = 1;
  optional int32 end = 2 [default = 0];
}

// To allow expression of variation font capability, e.g. weight 300-700
// If end is <= start it's a point (e.g. for a non-variational font).
// Where possible prefer end = 0 for point to save the field in binary proto.
message FloatRange {
  optional float start = 1;
  optional float end = 2 [default = 0];
}

// Describes a single optentype font file, which may be a variation font or a
// single font from a TTC.
message Font {
  optional FileSpec file = 1;

  // numeric weight per https://drafts.csswg.org/css-fonts/#propdef-font-weight
  // if varfont, range of 'wght' per
  // https://www.microsoft.com/typography/otspec/fvar.htm#VAT
  optional IntRange weight = 2;

  // names converted to values per
  // https://www.microsoft.com/typography/otspec/os2.htm#wdc
  // if varfont, range of 'wdth' per
  // https://www.microsoft.com/typography/otspec/fvar.htm#VAT
  optional FloatRange width = 3;

  // 0.0 or 1.0 per https://www.microsoft.com/typography/otspec/os2.htm#fss
  // bit 0. if varfont, range of 'ital' per
  // https://www.microsoft.com/typography/otspec/fvar.htm#VAT
  optional FloatRange italic = 4;

  // We don't use optical size for matching. We could one day.
  // if varfont, range, per 'opsz'
  // https://www.microsoft.com/typography/otspec/fvar.htm#VAT
  reserved 5;

  // We don't use 'slnt'. We could one day.
  reserved 6;

  // Google Fonts doesn't have any [yet?] but Android does
  optional int32 ttc_index = 7;

  // We don't care about custom axes because we don't use them for matching
}

message FontFamily {
  optional string name = 1;
  optional int32 version = 2;

  // Even for a variation font we may have several entries, for example Roboto
  // as a varfont may
  // span two files, one for regular and one for italic
  repeated Font fonts = 4;
}

// A set of potentially available families.
message Directory {
  // sorted by name
  repeated FontFamily family = 1;

  // sorted name lookup info for binary search
  // see go/fonts-gmscore-namelookup for bit packing scheme
  repeated int32 name_lookup = 2;

  // strings for full and postscript names, broken up.
  // see go/fonts-gmscore-namelookup.
  repeated string strings = 3;

  // Name-lookup style family + font indices to prefetch, highest priority
  // first.
  repeated int32 prefetch = 4;

  optional int32 version = 5;

  // Description of current directory version.
  optional string description = 6;
}