[autofit] Update and improve segment and edge tracing.

* src/autofit/afhints.c (af_glyph_hints_dump_segments): Trace
`delta' also.
Don't show first point of segment as a replacement for `pos'; this
is (a) misleading, since the difference to `pos' can be almost
arbitrarily large in corner cases, and (b) it is better to have all
segment data in font units instead of a single value given in output
space coordinates.
Improve layout.
(af_glyph_hints_dump_edges): Show px->units and units->px conversion
values for convenience.
Improve layout.

ChangeLog

@@ -1,3 +1,19 @@
+2016-07-15  Werner Lemberg  <wl@gnu.org>
+
+	[autofit] Update and improve segment and edge tracing.
+
+	* src/autofit/afhints.c (af_glyph_hints_dump_segments): Trace
+	`delta' also.
+	Don't show first point of segment as a replacement for `pos'; this
+	is (a) misleading, since the difference to `pos' can be almost
+	arbitrarily large in corner cases, and (b) it is better to have all
+	segment data in font units instead of a single value given in output
+	space coordinates.
+	Improve layout.
+	(af_glyph_hints_dump_edges): Show px->units and units->px conversion
+	values for convenience.
+	Improve layout.
+
 2016-07-15  Werner Lemberg  <wl@gnu.org>
 
 	[autofit] For edges, reject segments wider than 1px (#41334).

src/autofit/afhints.c

@@ -420,20 +420,19 @@
                 dimension == AF_DIMENSION_HORZ ? "vertical"
                                                : "horizontal" ));
       if ( axis->num_segments )
-        AF_DUMP(( "  index   pos    dir   from   to"
-                  "   link  serif  edge"
+        AF_DUMP(( "  index   pos   delta   dir   from   to "
+                  "  link  serif  edge"
                   "  height  extra     flags\n" ));
       else
         AF_DUMP(( "  (none)\n" ));
 
       for ( seg = segments; seg < limit; seg++ )
-        AF_DUMP(( "  %5d  %5.2g  %5s  %4d  %4d"
+        AF_DUMP(( "  %5d  %5d  %5d  %5s  %4d  %4d"
                   "  %4s  %5s  %4s"
                   "  %6d  %5d  %11s\n",
                   AF_INDEX_NUM( seg, segments ),
-                  dimension == AF_DIMENSION_HORZ
-                               ? (int)seg->first->ox / 64.0
-                               : (int)seg->first->oy / 64.0,
+                  seg->pos,
+                  seg->delta,
                   af_dir_str( (AF_Direction)seg->dir ),
                   AF_INDEX_NUM( seg->first, points ),
                   AF_INDEX_NUM( seg->last, points ),
@@ -553,18 +552,26 @@
        *  note: AF_DIMENSION_HORZ corresponds to _vertical_ edges
        *        since they have a constant X coordinate.
        */
-      AF_DUMP(( "Table of %s edges:\n",
-                dimension == AF_DIMENSION_HORZ ? "vertical"
-                                               : "horizontal" ));
+      if ( dimension == AF_DIMENSION_HORZ )
+        AF_DUMP(( "Table of %s edges (1px=%.2fu, 10u=%.2fpx):\n",
+                  "vertical",
+                  65536.0 * 64.0 / hints->x_scale,
+                  10.0 * hints->x_scale / 65536.0 / 64.0 ));
+      else
+        AF_DUMP(( "Table of %s edges (1px=%.2fu, 10u=%.2fpx):\n",
+                  "horizontal",
+                  65536.0 * 64.0 / hints->y_scale,
+                  10.0 * hints->y_scale / 65536.0 / 64.0 ));
+
       if ( axis->num_edges )
-        AF_DUMP(( "  index   pos    dir   link  serif"
-                  "  blue  opos    pos      flags\n" ));
+        AF_DUMP(( "  index    pos     dir   link  serif"
+                  "  blue    opos     pos       flags\n" ));
       else
         AF_DUMP(( "  (none)\n" ));
 
       for ( edge = edges; edge < limit; edge++ )
-        AF_DUMP(( "  %5d  %5.2g  %5s  %4s  %5s"
-                  "    %c   %5.2f  %5.2f  %11s\n",
+        AF_DUMP(( "  %5d  %7.2f  %5s  %4s  %5s"
+                  "    %c   %7.2f  %7.2f  %11s\n",
                   AF_INDEX_NUM( edge, edges ),
                   (int)edge->opos / 64.0,
                   af_dir_str( (AF_Direction)edge->dir ),