[freetype2] gsoc-craig-2023-final 984ff8918: Attempted for for tilde flattening

[Werner Lemberg]

branch: gsoc-craig-2023-final
commit 984ff8918571c97ff122f3986646b486ee01ec09
Author: Craig White <gerzytet@gmail.com>
Commit: Craig White <gerzytet@gmail.com>

    Attempted for for tilde flattening
---
 include/freetype/config/ftoption.h |  5 ++--
 src/autofit/aflatin.c              | 50 +++++++++++++++++++++++++++++++++++---
 2 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/include/freetype/config/ftoption.h 
b/include/freetype/config/ftoption.h
index 1976b33af..558fa1872 100644
--- a/include/freetype/config/ftoption.h
+++ b/include/freetype/config/ftoption.h
@@ -430,9 +430,8 @@ FT_BEGIN_HEADER
    *   Do not `#undef` these macros here since the build system might define
    *   them for certain configurations only.
    */
-/* #define FT_DEBUG_LEVEL_ERROR */
-/* #define FT_DEBUG_LEVEL_TRACE */
-
+#define FT_DEBUG_LEVEL_ERROR
+#define FT_DEBUG_LEVEL_TRACE
 
   /**************************************************************************
    *
diff --git a/src/autofit/aflatin.c b/src/autofit/aflatin.c
index 2331eaef1..e9b0ad429 100644
--- a/src/autofit/aflatin.c
+++ b/src/autofit/aflatin.c
@@ -2976,8 +2976,18 @@ af_latin_stretch_tildes( AF_GlyphHints hints,
   }
   while ( p != first_point );
 
-  FT_Pos height = max_y - min_y;
+  //touch all points
+  p = first_point;
+  do
+  {
+    p = p->next;
+    if ( !(p->flags & AF_FLAG_CONTROL) )
+      p->flags |= AF_FLAG_TOUCH_Y;
+  }
+  while ( p != first_point );
+
 
+  FT_Pos height = max_y - min_y;
   FT_Pos target_height = min_measurement + 64;
   if ( height >= target_height )
   {
@@ -2991,8 +3001,6 @@ af_latin_stretch_tildes( AF_GlyphHints hints,
     p->y = ((p->y - min_y) * target_height / height) + min_y;
     p->fy = ((p->fy - min_fy) * target_height / height) + min_fy;
     p->oy = p->y;
-    if ( !(p->flags & AF_FLAG_CONTROL) )
-      p->flags |= AF_FLAG_TOUCH_Y;
   }
   while ( p != first_point );
 
@@ -3160,6 +3168,8 @@ af_glyph_hints_apply_vertical_separation_adjustments( 
AF_GlyphHints hints,
       }
     }
 
+    FT_TRACE4(( "    Calculated adjustment amount %d\n", adjustment_amount ));
+
     if ( adjustment_amount > 64 )
     {
       FT_TRACE4(( "    Calculated adjustment amount %d was more than threshold 
of 64.  Not adjusting\n", adjustment_amount ));
@@ -4066,6 +4076,33 @@ af_glyph_hints_apply_vertical_separation_adjustments( 
AF_GlyphHints hints,
 #endif
   }
 
+  /*Print the height of the topmost contour for debugging purposes.
+  TODO: remove this once the tilde unflattening works.*/
+  static void traceheight(FT_UInt num, AF_GlyphHints hints) {
+    AF_Point p = hints->contours[af_find_highest_contour(hints)];
+    AF_Point first_point = p;
+
+    FT_Pos min_y, max_y;
+    min_y = max_y = p->y;
+
+    do {
+      p = p->next;
+      if ( !(p->flags & AF_FLAG_CONTROL) ) {
+        if ( p->y < min_y ) {
+          min_y = p->y;
+        }
+        if ( p->y > max_y ) {
+          max_y = p->y;
+        }
+      }
+    } while ( p != first_point );
+
+    FT_Pos height = max_y - min_y;
+    FT_TRACE4(( "height %d: %d\n", num, height ));
+  }
+
+
+
 
   /* Apply the complete hinting algorithm to a latin glyph. */
 
@@ -4103,7 +4140,9 @@ af_glyph_hints_apply_vertical_separation_adjustments( 
AF_GlyphHints hints,
     {
       FT_Bool is_tilde = af_lookup_tilde_correction_type( 
metrics->root.reverse_charmap, glyph_index );
       if ( is_tilde ) {
+        traceheight(0, hints);
         af_latin_stretch_tildes( hints, glyph_index );
+        traceheight(1, hints);
       }
       axis  = &metrics->axis[AF_DIMENSION_VERT];
       error = af_latin_hints_detect_features( hints,
@@ -4128,10 +4167,15 @@ af_glyph_hints_apply_vertical_separation_adjustments( 
AF_GlyphHints hints,
            ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) )   )
       {
         af_latin_hint_edges( hints, (AF_Dimension)dim );
+        traceheight(2, hints);
         af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim );
+        traceheight(3, hints);
         af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim );
+        traceheight(4, hints);
         af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim );
+        traceheight(5, hints);
         af_glyph_hints_apply_vertical_separation_adjustments(hints, 
(AF_Dimension) dim, glyph_index, metrics->root.reverse_charmap);
+        traceheight(6, hints);
       }
     }