Add new shaper method postprocess_glyphs()

Unused currently.  To be used for Syriac stretch implementation.

https://github.com/behdad/harfbuzz/issues/141

src/hb-ot-shape-complex-arabic.cc

@@ -379,7 +379,8 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
   NULL, /* override_features */
   data_create_arabic,
   data_destroy_arabic,
-  NULL, /* preprocess_text_arabic */
+  NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */

src/hb-ot-shape-complex-default.cc

@@ -35,6 +35,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default =
   NULL, /* data_create */
   NULL, /* data_destroy */
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */

src/hb-ot-shape-complex-hangul.cc

@@ -411,13 +411,14 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hangul =
   "hangul",
   collect_features_hangul,
   override_features_hangul,
-  data_create_hangul, /* data_create */
-  data_destroy_hangul, /* data_destroy */
+  data_create_hangul,
+  data_destroy_hangul,
   preprocess_text_hangul,
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
   NULL, /* decompose */
   NULL, /* compose */
-  setup_masks_hangul, /* setup_masks */
+  setup_masks_hangul,
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };

src/hb-ot-shape-complex-hebrew.cc

@@ -163,6 +163,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hebrew =
   NULL, /* data_create */
   NULL, /* data_destroy */
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   compose_hebrew,

src/hb-ot-shape-complex-indic.cc

@@ -1834,6 +1834,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
   data_create_indic,
   data_destroy_indic,
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
   decompose_indic,
   compose_indic,

src/hb-ot-shape-complex-myanmar.cc

@@ -507,6 +507,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar_old =
   NULL, /* data_create */
   NULL, /* data_destroy */
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */
@@ -523,6 +524,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar =
   NULL, /* data_create */
   NULL, /* data_destroy */
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
   NULL, /* decompose */
   NULL, /* compose */

src/hb-ot-shape-complex-private.hh

@@ -110,6 +110,15 @@ struct hb_ot_complex_shaper_t
 			   hb_buffer_t              *buffer,
 			   hb_font_t                *font);
 
+  /* postprocess_glyphs()
+   * Called during shape().
+   * Shapers can use to modify glyphs after shaping ends.
+   * May be NULL.
+   */
+  void (*postprocess_glyphs) (const hb_ot_shape_plan_t *plan,
+			      hb_buffer_t              *buffer,
+			      hb_font_t                *font);
+
 
   hb_ot_shape_normalization_mode_t normalization_preference;
 

src/hb-ot-shape-complex-thai.cc

@@ -372,6 +372,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
   NULL, /* data_create */
   NULL, /* data_destroy */
   preprocess_text_thai,
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */

src/hb-ot-shape-complex-tibetan.cc

@@ -52,6 +52,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_tibetan =
   NULL, /* data_create */
   NULL, /* data_destroy */
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */

src/hb-ot-shape-complex-use.cc

@@ -576,6 +576,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_use =
   data_create_use,
   data_destroy_use,
   NULL, /* preprocess_text */
+  NULL, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
   NULL, /* decompose */
   compose_use,

src/hb-ot-shape.cc

@@ -553,9 +553,6 @@ hb_ot_substitute_default (hb_ot_shape_context_t *c)
 {
   hb_buffer_t *buffer = c->buffer;
 
-  if (c->plan->shaper->preprocess_text)
-    c->plan->shaper->preprocess_text (c->plan, buffer, c->font);
-
   hb_ot_shape_initialize_masks (c);
 
   hb_ot_mirror_chars (c);
@@ -815,11 +812,17 @@ hb_ot_shape_internal (hb_ot_shape_context_t *c)
 
   hb_ensure_native_direction (c->buffer);
 
+  if (c->plan->shaper->preprocess_text)
+    c->plan->shaper->preprocess_text (c->plan, c->buffer, c->font);
+
   hb_ot_substitute (c);
   hb_ot_position (c);
 
   hb_ot_hide_default_ignorables (c);
 
+  if (c->plan->shaper->postprocess_glyphs)
+    c->plan->shaper->postprocess_glyphs (c->plan, c->buffer, c->font);
+
   _hb_buffer_deallocate_unicode_vars (c->buffer);
 
   c->buffer->props.direction = c->target_direction;