[instance] update post.italicAngle

Add tests for instancing glyf/hmtx

src/hb-ot-post-table.hh

@@ -102,6 +102,14 @@ struct post
     if (!serialize (c->serializer, glyph_names))
       return_trace (false);
 
+    if (c->plan->user_axes_location->has (HB_TAG ('s','l','n','t')) &&
+        !c->plan->pinned_at_default)
+    {
+      float italic_angle = c->plan->user_axes_location->get (HB_TAG ('s','l','n','t'));
+      italic_angle = hb_max (-90.f, hb_min (italic_angle, 90.f));
+      post_prime->italicAngle.set_float (italic_angle);
+    }
+
     if (glyph_names && version.major == 2)
       return_trace (v2X.subset (c));
 

test/subset/data/tests/instantiate_glyf.tests

@@ -0,0 +1,13 @@
+FONTS:
+Roboto-Variable.ABC.ttf
+Roboto-Variable.composite.ttf
+
+PROFILES:
+default.txt
+
+SUBSETS:
+*
+
+INSTANCES:
+wght=650,wdth=85
+wght=200,wdth=90

test/subset/meson.build

@@ -50,6 +50,9 @@ tests = [
   'glyph_names',
   'post',
   '32bit_var_store',
+# instacing tests, enable when --instance is not experimental
+# 'pin_all_at_default',
+# 'instantiate_glyf',
 ]
 
 repack_tests = [