From 875a5cbc9c37f4264241c43b80afad2628eab749 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Tue, 11 Dec 2012 14:17:01 -0500
Subject: [PATCH] [OTLayout] Change hb_ot_layout_get_params() API

And add implementation for StylisticSet UINameID.  No API yet.
---
 src/hb-ot-layout-common-private.hh | 85 ++++++++++++++++++++++++++++--
 src/hb-ot-layout.cc                | 28 +++++++---
 src/hb-ot-layout.h                 |  8 ++-
 src/test-size-params.cc            |  9 +++-
 4 files changed, 115 insertions(+), 15 deletions(-)

diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index 0b753b833..4a8116e5b 100644
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -248,6 +248,8 @@ struct Script
 
 typedef RecordListOf<Script> ScriptList;
 
+
+/* http://www.microsoft.com/typography/otspec/features_pt.htm#size */
 struct FeatureParamsSize
 {
   inline bool sanitize (hb_sanitize_context_t *c) {
@@ -255,15 +257,89 @@ struct FeatureParamsSize
     return TRACE_RETURN (c->check_struct (this));
   }
 
-  USHORT params[5];
+  USHORT	designSize;	/* Represents the design size in 720/inch
+				 * units (decipoints).  The design size entry
+				 * must be non-zero.  When there is a design
+				 * size but no recommended size range, the
+				 * rest of the array will consist of zeros. */
+  USHORT	subfamilyID;	/* Has no independent meaning, but serves
+				 * as an identifier that associates fonts
+				 * in a subfamily. All fonts which share a
+				 * Preferred or Font Family name and which
+				 * differ only by size range shall have the
+				 * same subfamily value, and no fonts which
+				 * differ in weight or style shall have the
+				 * same subfamily value. If this value is
+				 * zero, the remaining fields in the array
+				 * will be ignored. */
+  USHORT	subfamilyNameID;/* If the preceding value is non-zero, this
+				 * value must be set in the range 256 - 32767
+				 * (inclusive). It records the value of a
+				 * field in the name table, which must
+				 * contain English-language strings encoded
+				 * in Windows Unicode and Macintosh Roman,
+				 * and may contain additional strings
+				 * localized to other scripts and languages.
+				 * Each of these strings is the name an
+				 * application should use, in combination
+				 * with the family name, to represent the
+				 * subfamily in a menu.  Applications will
+				 * choose the appropriate version based on
+				 * their selection criteria. */
+  USHORT	rangeStart;	/* Large end of the recommended usage range
+				 * (inclusive), stored in 720/inch units
+				 * (decipoints). */
+  USHORT	rangeEnd;	/* Small end of the recommended usage range
+				   (exclusive), stored in 720/inch units
+				 * (decipoints). */
   public:
   DEFINE_SIZE_STATIC (10);
 };
 
+/* http://www.microsoft.com/typography/otspec/features_pt.htm#ssxx */
+struct FeatureParamsStylisticSet
+{
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    /* Right now minorVersion is at zero.  Which means, any table supports
+     * the uiNameID field. */
+    return TRACE_RETURN (c->check_struct (this));
+  }
+
+  USHORT	minorVersion;	/* (set to 0): This corresponds to a “minor”
+				 * version number. Additional data may be
+				 * added to the end of this Feature Parameters
+				 * table in the future. */
+
+  USHORT	uiNameID;	/* The 'name' table name ID that specifies a
+				 * string (or strings, for multiple languages)
+				 * for a user-interface label for this
+				 * feature.  The values of uiLabelNameId and
+				 * sampleTextNameId are expected to be in the
+				 * font-specific name ID range (256-32767),
+				 * though that is not a requirement in this
+				 * Feature Parameters specification. The
+				 * user-interface label for the feature can
+				 * be provided in multiple languages. An
+				 * English string should be included as a
+				 * fallback. The string should be kept to a
+				 * minimal length to fit comfortably with
+				 * different application interfaces. */
+  public:
+  DEFINE_SIZE_STATIC (4);
+};
+
 struct FeatureParams
 {
-  /* Note: currently the only feature with params is 'size', so we hardcode
-   * the length of the table to that of the FeatureParamsSize. */
+  /* Note:
+   *
+   * FeatureParams structures unfortunately don't have a generic length argument,
+   * so their length depends on the feature name / requested use.  We don't have
+   * that information at sanitize time.  As such, we sanitize for the longest
+   * subtable possible.  This may nuke a possibly valid subtable if it's unfortunate
+   * enough to happen at the very end of the GSUB/GPOS table.  But that's very
+   * unlikely (I hope!).
+   */
 
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
@@ -271,7 +347,8 @@ struct FeatureParams
   }
 
   union {
-  FeatureParamsSize size;
+  FeatureParamsSize		size;
+  FeatureParamsStylisticSet	stylisticSet;
   } u;
   DEFINE_SIZE_STATIC (10);
 };
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 441b3ea9b..cf485bd30 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -640,8 +640,12 @@ hb_ot_layout_position_finish (hb_font_t *font, hb_buffer_t *buffer, hb_bool_t ze
 }
 
 hb_bool_t
-hb_ot_layout_get_size_params (hb_face_t *face,
-			      uint16_t  *data /* OUT, 5 items */)
+hb_ot_layout_get_size_params (hb_face_t    *face,
+			      unsigned int *design_size,       /* OUT.  May be NULL */
+			      unsigned int *subfamily_id,      /* OUT.  May be NULL */
+			      unsigned int *subfamily_name_id, /* OUT.  May be NULL */
+			      unsigned int *range_start,       /* OUT.  May be NULL */
+			      unsigned int *range_end          /* OUT.  May be NULL */)
 {
   const OT::GPOS &gpos = _get_gpos (face);
 
@@ -651,17 +655,27 @@ hb_ot_layout_get_size_params (hb_face_t *face,
     if (HB_TAG ('s','i','z','e') == gpos.get_feature_tag (i))
     {
       const OT::Feature &f = gpos.get_feature (i);
-      const OT::FeatureParams &params = f.get_feature_params ();
+      const OT::FeatureParamsSize &params = f.get_feature_params ().u.size;
 
-      for (unsigned int i = 0; i < 5; i++)
-	data[i] = params.u.size.params[i];
+#define PARAM(a, A) if (a) *a = params.A
+      PARAM (design_size, designSize);
+      PARAM (subfamily_id, subfamilyID);
+      PARAM (subfamily_name_id, subfamilyNameID);
+      PARAM (range_start, rangeStart);
+      PARAM (range_end, rangeEnd);
+#undef PARAM
 
       return true;
     }
   }
 
-  for (unsigned int i = 0; i < 5; i++)
-    data[i] = 0;
+#define PARAM(a, A) if (a) *a = 0
+  PARAM (design_size, designSize);
+  PARAM (subfamily_id, subfamilyID);
+  PARAM (subfamily_name_id, subfamilyNameID);
+  PARAM (range_start, rangeStart);
+  PARAM (range_end, rangeEnd);
+#undef PARAM
 
   return false;
 }
diff --git a/src/hb-ot-layout.h b/src/hb-ot-layout.h
index f8fab24bc..134f1a6c1 100644
--- a/src/hb-ot-layout.h
+++ b/src/hb-ot-layout.h
@@ -280,8 +280,12 @@ Xhb_ot_layout_lookup_position (hb_font_t            *font,
 /* Optical 'size' feature info.  Returns true if found.
  * http://www.microsoft.com/typography/otspec/features_pt.htm#size */
 hb_bool_t
-hb_ot_layout_get_size_params (hb_face_t *face,
-			      uint16_t  *data /* OUT, 5 items */);
+hb_ot_layout_get_size_params (hb_face_t    *face,
+			      unsigned int *design_size,       /* OUT.  May be NULL */
+			      unsigned int *subfamily_id,      /* OUT.  May be NULL */
+			      unsigned int *subfamily_name_id, /* OUT.  May be NULL */
+			      unsigned int *range_start,       /* OUT.  May be NULL */
+			      unsigned int *range_end          /* OUT.  May be NULL */);
 
 
 HB_END_DECLS
diff --git a/src/test-size-params.cc b/src/test-size-params.cc
index a60aa10e1..0caef9740 100644
--- a/src/test-size-params.cc
+++ b/src/test-size-params.cc
@@ -84,8 +84,13 @@ main (int argc, char **argv)
   hb_blob_destroy (blob);
   blob = NULL;
 
-  uint16_t params[5];
-  if (!hb_ot_layout_get_size_params (face, params))
+  unsigned int params[5];
+  if (!hb_ot_layout_get_size_params (face,
+				     params,
+				     params+1,
+				     params+2,
+				     params+3,
+				     params+4))
     return 1;
 
   for (unsigned int i = 0; i < 5; i++) {