Start adding hb-ot-var.h and implementation
Supports enumerating variation axes, normalizing values, etc.
diff --git a/src/hb-ot-var.h b/src/hb-ot-var.h
new file mode 100644
index 0000000..679feb9
--- /dev/null
+++ b/src/hb-ot-var.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright © 2017 Google, Inc.
+ *
+ * This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Red Hat Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_OT_H_IN
+#error "Include <hb-ot.h> instead."
+#endif
+
+#ifndef HB_OT_VAR_H
+#define HB_OT_VAR_H
+
+#include "hb.h"
+
+HB_BEGIN_DECLS
+
+
+#define HB_OT_TAG_fvar HB_TAG('f','v','a','r')
+#define HB_OT_TAG_avar HB_TAG('a','v','a','r')
+
+
+/*
+ * fvar / avar
+ */
+
+/**
+ * hb_ot_var_axis_t:
+ *
+ * Since: 1.4.2
+ */
+typedef struct hb_ot_var_axis_t {
+ hb_tag_t tag;
+ unsigned int name_id;
+ double min_value;
+ double def_value;
+ double max_value;
+} hb_ot_var_axis_t;
+
+HB_EXTERN hb_bool_t
+hb_ot_var_has_data (hb_face_t *face);
+
+#if 0
+
+HB_EXTERN unsigned int
+Xhb_ot_var_get_axes (hb_face_t *face,
+ unsigned int start_offset,
+ unsigned int *axes_count /* IN/OUT */,
+ hb_ot_var_axis_t *axes_array /* OUT */);
+
+/* TODO Add "find_axis", etc API? Are they needed at all? */
+
+HB_EXTERN unsigned int
+Xhb_ot_var_get_named_instances (hb_face_t *face, ... );
+
+#endif
+
+
+HB_END_DECLS
+
+#endif /* HB_OT_VAR_H */
