Expose ascender/descender metadata properties in protobuf

fontnik.js

@@ -0,0 +1,3 @@
+"use strict";
+
+module.exports = require('./index.js');

proto/glyphs.proto

@@ -10,7 +10,7 @@ option optimize_for = LITE_RUNTIME;
 message glyph {
     required uint32 id = 1;
 
-    // A signed distance field of the glyph with a border of 3 pixels.
+    // A signed distance field of a glyph with buffer documented in metadata.
     optional bytes bitmap = 2;
 
     // Glyph metrics.
@@ -21,11 +21,14 @@ message glyph {
     required uint32 advance = 7;
 }
 
-// Stores fontstack information and a list of faces.
+// Stores a face with glyphs and metadata.
 message fontstack {
     required string name = 1;
     required string range = 2;
     repeated glyph glyphs = 3;
+
+    optional sint32 ascender = 4;
+    optional sint32 descender = 5;
 }
 
 message glyphs {

src/glyphs.cpp

@@ -547,6 +547,10 @@ void RangeAsync(uv_work_t* req) {
                 double size = 24 * scale_factor;
                 FT_Set_Char_Size(ft_face, 0, static_cast<FT_F26Dot6>(size * (1 << 6)), 0, 0);
 
+                // Set ascender and descender in 26.6 fractional pixels.
+                fontstack_writer.add_sint32(4, static_cast<std::int32_t>(ft_face->size->metrics.ascender / 64));
+                fontstack_writer.add_sint32(5, static_cast<std::int32_t>(ft_face->size->metrics.descender / 64));
+
                 for (std::vector<uint32_t>::size_type x = 0; x != baton->chars.size(); x++) {
                     FT_ULong char_code = baton->chars[x];
                     sdf_glyph_foundry::glyph_info glyph;

test/fontnik.test.js

@@ -241,6 +241,8 @@ test('range', function(t) {
             var vt = new Glyphs(new Protobuf(new Uint8Array(data)));
             t.equal(vt.stacks.hasOwnProperty('?'), true);
             t.equal(vt.stacks['?'].hasOwnProperty('name'), true);
+            t.equal(vt.stacks['?'].hasOwnProperty('ascender'), true);
+            t.equal(vt.stacks['?'].hasOwnProperty('descender'), true);
             t.equal(vt.stacks['?'].name, '?');
             t.end();
         });
@@ -251,6 +253,12 @@ test('range', function(t) {
             t.error(err);
             var vt = new Glyphs(new Protobuf(new Uint8Array(data)));
             var glyphs = vt.stacks['Osaka Regular'].glyphs;
+            var stack = vt.stacks['Osaka Regular'];
+
+            t.equal(stack.name, 'Osaka Regular');
+            t.equal(stack.ascender, 24);
+            t.equal(stack.descender, -6);
+
             var keys = Object.keys(glyphs);
 
             var glyph;

test/format/glyphs.js

@@ -41,6 +41,12 @@ Glyphs.prototype.readFontstack = function() {
         } else if (tag == 3) {
             var glyph = this.readGlyph();
             fontstack.glyphs[glyph.id] = glyph;
+        } else if (tag == 4) {
+            var ascender = buffer.readSVarint();
+            fontstack.ascender = ascender;
+        } else if (tag == 5) {
+            var descender = buffer.readSVarint();
+            fontstack.descender = descender;
         } else {
             buffer.skip(val);
         }