Add hb_ot_layout_position_finish()

We expect buffer to be setup with default positions before GPOS.

src/hb-buffer-private.h

@@ -51,11 +51,7 @@ typedef struct _hb_internal_glyph_position_t {
   hb_position_t  y_advance;
   hb_position_t  x_offset;
   hb_position_t  y_offset;
-  uint32_t       new_advance :1;	/* if set, the advance width values are
+  uint32_t       back : 16;		/* number of glyphs to go back
-					   absolute, i.e., they won't be
-					   added to the original glyph's value
-					   but rather replace them */
-  uint32_t       back : 15;		/* number of glyphs to go back
 					   for drawing current glyph */
   int32_t        cursive_chain : 16;	/* character to which this connects,
 					   may be positive or negative; used

src/hb-buffer.h

@@ -56,16 +56,7 @@ typedef struct _hb_glyph_position_t {
   hb_position_t  y_advance;
   hb_position_t  x_offset;
   hb_position_t  y_offset;
-  /* XXX these should all be replaced by "uint32_t internal" */
+  uint32_t       internal;
-  uint32_t       new_advance :1;	/* if set, the advance width values are
-					   absolute, i.e., they won't be
-					   added to the original glyph's value
-					   but rather replace them */
-  uint32_t       back : 15;		/* number of glyphs to go back
-					   for drawing current glyph */
-  int32_t        cursive_chain : 16;	/* character to which this connects,
-					   may be positive or negative; used
-					   only internally */
 } hb_glyph_position_t;
 
 

src/hb-ot-layout-gpos-private.hh

@@ -840,13 +840,13 @@ struct CursivePosFormat1
 
     if (buffer->direction == HB_DIRECTION_RTL)
     {
-      POSITION (buffer->in_pos)->x_advance   = entry_x - gpi->anchor_x;
+      /* advance is absolute, not relative */
-      POSITION (buffer->in_pos)->new_advance = true;
+      POSITION (buffer->in_pos)->x_advance = entry_x - gpi->anchor_x;
     }
     else
     {
-      POSITION (last_pos)->x_advance   = gpi->anchor_x - entry_x;
+      /* advance is absolute, not relative */
-      POSITION (last_pos)->new_advance = true;
+      POSITION (last_pos)->x_advance = gpi->anchor_x - entry_x;
     }
 
     if  (lookup_flag & LookupFlag::RightToLeft)

src/hb-ot-layout.cc

@@ -564,3 +564,55 @@ hb_ot_layout_position_lookup   (hb_face_t    *face,
   context.face = face;
   return _get_gpos (face).position_lookup (&context, buffer, lookup_index, mask);
 }
+
+#include <stdio.h>
+void
+hb_ot_layout_position_finish (hb_face_t    *face,
+			      hb_font_t    *font,
+			      hb_buffer_t  *buffer)
+{
+  unsigned int i, j;
+  unsigned int len = hb_buffer_get_length (buffer);
+  hb_internal_glyph_position_t *positions = (hb_internal_glyph_position_t *) hb_buffer_get_glyph_positions (buffer);
+
+  /* TODO: Vertical */
+
+  /* Handle cursive connections */
+  /* First handle all left-to-right connections */
+  for (j = 0; j < len; j++) {
+    if (positions[j].cursive_chain > 0) {
+  printf ("0000000000000\n");
+      positions[j].y_offset += positions[j - positions[j].cursive_chain].y_offset;
+      positions[j].cursive_chain = 0;
+    }
+  }
+  /* Then handle all right-to-left connections */
+  for (i = len; i > 0; i--) {
+    j = i - 1;
+    if (positions[j].cursive_chain < 0) {
+      positions[j].y_offset += positions[j - positions[j].cursive_chain].y_offset;
+      positions[j].cursive_chain = 0;
+    }
+  }
+
+  /* Handle attachments */
+  for (i = 0; i < len; i++)
+    if (positions[i].back)
+      {
+	unsigned int back = i - positions[i].back;
+	positions[i].back = 0;
+	positions[i].x_offset += positions[back].x_offset;
+	positions[i].y_offset += positions[back].y_offset;
+
+	if (buffer->direction == HB_DIRECTION_RTL)
+	  for (j = back + 1; j < i + 1; j++) {
+	    positions[i].x_offset += positions[j].x_advance;
+	    positions[i].y_offset += positions[j].y_advance;
+	  }
+	else
+	  for (j = back; j < i; j++) {
+	    positions[i].x_offset -= positions[j].x_advance;
+	    positions[i].y_offset -= positions[j].y_advance;
+	  }
+      }
+}

src/hb-ot-layout.h

@@ -198,11 +198,17 @@ hb_bool_t
 hb_ot_layout_has_positioning (hb_face_t *face);
 
 hb_bool_t
-hb_ot_layout_position_lookup   (hb_face_t    *face,
+hb_ot_layout_position_lookup (hb_face_t    *face,
-				hb_font_t    *font,
+			      hb_font_t    *font,
-				hb_buffer_t  *buffer,
+			      hb_buffer_t  *buffer,
-				unsigned int  lookup_index,
+			      unsigned int  lookup_index,
-				hb_mask_t     mask);
+			      hb_mask_t     mask);
+
+/* Should be called after all the position_lookup's are done */
+void
+hb_ot_layout_position_finish (hb_face_t    *face,
+			      hb_font_t    *font,
+			      hb_buffer_t  *buffer);
 
 
 HB_END_DECLS