[truetype] Provide HVAR advance width variation as a service.

Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.

* src/truetype/ttdriver.c (tt_service_metrics_variations): Updated.

* src/truetype/ttgxvar.c (TT_Vary_Apply_Glyph_Deltas): Prevent
double adjustment of advance width.

* src/sfnt/ttmtx.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(tt_face_get_metrics): Apply metrics variations.

ChangeLog

@@ -1,8 +1,25 @@
+2016-12-15  Werner Lemberg  <wl@gnu.org>
+	    Dave Arnold  <darnold@adobe.com>
+
+	[truetype] Provide HVAR advance width variation as a service.
+
+	Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
+
+	* src/truetype/ttdriver.c (tt_service_metrics_variations): Updated.
+
+	* src/truetype/ttgxvar.c (TT_Vary_Apply_Glyph_Deltas): Prevent
+	double adjustment of advance width.
+
+	* src/sfnt/ttmtx.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
+	(tt_face_get_metrics): Apply metrics variations.
+
 2016-12-15  Dave Arnold  <darnold@adobe.com>
 	    Werner Lemberg  <wl@gnu.org>
 
 	[truetype] Provide function to apply `HVAR' advance width variation.
 
+	Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
+
 	* src/truetype/ttgxvar.c (tt_hadvance_adjust): New function.
 	* src/truetype/ttgxvar.h: Updated.
 
@@ -16,6 +33,8 @@
 
 	Activation of the code follows in another commit.
 
+	Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
+
 	* include/freetype/ftmm.h (FT_Var_Named_Style): Add `psid' member.
 
 	* src/truetype/ttgxvar.h (GX_HVarData, GX_AxisCoords, GX_HVarRegion,

src/sfnt/ttmtx.c

@@ -20,6 +20,11 @@
 #include FT_INTERNAL_DEBUG_H
 #include FT_INTERNAL_STREAM_H
 #include FT_TRUETYPE_TAGS_H
+
+#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
+#include FT_SERVICE_METRICS_VARIATIONS_H
+#endif
+
 #include "ttmtx.h"
 
 #include "sferrors.h"
@@ -214,6 +219,11 @@
     FT_ULong        table_pos, table_size, table_end;
     FT_UShort       k;
 
+#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
+    FT_Service_MetricsVariations  var =
+      (FT_Service_MetricsVariations)face->var;
+#endif
+
 
     if ( vertical )
     {
@@ -274,6 +284,34 @@
       *abearing = 0;
       *aadvance = 0;
     }
+
+#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
+    if ( var )
+    {
+      FT_Face  f = FT_FACE( face );
+      FT_Int   a = (FT_Int)*aadvance;
+      FT_Int   b = (FT_Int)*abearing;
+
+
+      if ( vertical )
+      {
+        if ( var->vadvance_adjust )
+          var->vadvance_adjust( f, gindex, &a );
+        if ( var->tsb_adjust )
+          var->tsb_adjust( f, gindex, &b );
+      }
+      else
+      {
+        if ( var->hadvance_adjust )
+          var->hadvance_adjust( f, gindex, &a );
+        if ( var->lsb_adjust )
+          var->lsb_adjust( f, gindex, &b );
+      }
+
+      *aadvance = (FT_Short)a;
+      *abearing = (FT_UShort)b;
+    }
+#endif
   }
 
 

src/truetype/ttdriver.c

@@ -484,7 +484,7 @@
   FT_DEFINE_SERVICE_METRICSVARIATIONSREC(
     tt_service_metrics_variations,
 
-    (FT_HAdvance_Adjust_Func)NULL,                   /* hadvance_adjust */
+    (FT_HAdvance_Adjust_Func)tt_hadvance_adjust,     /* hadvance_adjust */
     (FT_LSB_Adjust_Func)     NULL,                   /* lsb_adjust      */
     (FT_RSB_Adjust_Func)     NULL,                   /* rsb_adjust      */
 

src/truetype/ttgxvar.c

@@ -2629,7 +2629,13 @@
           FT_Pos  delta_y = FT_MulFix( deltas_y[j], apply );
 
 
-          outline->points[j].x += delta_x;
+          /* Experimental fix for double adjustment of advance width: */
+          /* adjust phantom point 2 only if there's no HVAR.          */
+          /*                                                          */
+          /* TODO: handle LSB (pp1) and VVAR (pp3, pp4) too           */
+          if ( j != ( n_points - 3 ) || blend->hvar_checked == FALSE )
+            outline->points[j].x += delta_x;
+
           outline->points[j].y += delta_y;
 
 #ifdef FT_DEBUG_LEVEL_TRACE