From 4882c717b5bc6f2cfe45c5c84bb5ddc060f8ee2e Mon Sep 17 00:00:00 2001
From: Qunxin Liu <qxliu@google.com>
Date: Wed, 27 Jul 2022 12:54:33 -0700
Subject: [PATCH] [instance] update OS/2.usWeightClass and OS/2.usWidthClass

---
 src/hb-ot-os2-table.hh | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/src/hb-ot-os2-table.hh b/src/hb-ot-os2-table.hh
index 3473afef5..780d9627c 100644
--- a/src/hb-ot-os2-table.hh
+++ b/src/hb-ot-os2-table.hh
@@ -166,6 +166,21 @@ struct OS2
     }
   }
 
+  float map_wdth_to_widthclass(float width) const
+  {
+    if (width < 50) return 1.0f;
+    if (width > 200) return 9.0f;
+
+    float ratio = (width - 50) / 12.5f;
+    int a = (int) floorf (ratio);
+    int b = (int) ceilf (ratio);
+
+    float va = 50 + a * 12.5f;
+    float vb = 50 + b * 12.5f;
+
+    return a + 1.0f + (float) (b - a) * (width - va) / (vb - va);
+  }
+
   bool subset (hb_subset_context_t *c) const
   {
     TRACE_SUBSET (this);
@@ -183,6 +198,26 @@ struct OS2
 
     _update_unicode_ranges (c->plan->unicodes, os2_prime->ulUnicodeRange);
 
+    if (c->plan->user_axes_location->has (HB_TAG ('w','g','h','t')) &&
+        !c->plan->pinned_at_default)
+    {
+      float weight_class = c->plan->user_axes_location->get (HB_TAG ('w','g','h','t'));
+      if (!c->serializer->check_assign (os2_prime->usWeightClass,
+                                        roundf (hb_clamp (weight_class, 1.0f, 1000.0f)),
+                                        HB_SERIALIZE_ERROR_INT_OVERFLOW))
+        return_trace (false);
+    }
+
+    if (c->plan->user_axes_location->has (HB_TAG ('w','d','t','h')) &&
+        !c->plan->pinned_at_default)
+    {
+      float width = c->plan->user_axes_location->get (HB_TAG ('w','d','t','h'));
+      if (!c->serializer->check_assign (os2_prime->usWidthClass,
+                                        roundf (map_wdth_to_widthclass (width)),
+                                        HB_SERIALIZE_ERROR_INT_OVERFLOW))
+        return_trace (false);
+    }
+
     return_trace (true);
   }