From 2119eab69f5e8c5323fa23ab6c7dc26c2ab5aab3 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Wed, 1 Feb 2023 17:37:10 -0700
Subject: [PATCH] [embolden] Adjust advance values

---
 src/hb-ft.cc      | 16 +++++++++++++++-
 src/hb-ot-font.cc | 29 +++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/src/hb-ft.cc b/src/hb-ft.cc
index 35313569d..064fff15d 100644
--- a/src/hb-ft.cc
+++ b/src/hb-ft.cc
@@ -448,6 +448,7 @@ hb_ft_get_glyph_h_advances (hb_font_t* font, void* font_data,
 			    void *user_data HB_UNUSED)
 {
   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
+  hb_position_t *orig_first_advance = first_advance;
   hb_lock_t lock (ft_font->lock);
   FT_Face ft_face = ft_font->ft_face;
   int load_flags = ft_font->load_flags;
@@ -488,6 +489,18 @@ hb_ft_get_glyph_h_advances (hb_font_t* font, void* font_data,
     first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride);
     first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
   }
+
+  if (font->x_shift)
+  {
+    /* Emboldening. */
+    hb_position_t x_shift = font->x_scale >= 0 ? font->x_shift : -font->x_shift;
+    first_advance = orig_first_advance;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      *first_advance += *first_advance ? x_shift : 0;
+      first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
+    }
+  }
 }
 
 #ifndef HB_NO_VERTICAL
@@ -523,7 +536,8 @@ hb_ft_get_glyph_v_advance (hb_font_t *font,
   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
    * have a Y growing upward.  Hence the extra negation. */
 
-  return (-v + (1<<9)) >> 10;
+  hb_position_t y_shift = font->y_scale >= 0 ? font->y_shift : -font->y_shift;
+  return ((-v + (1<<9)) >> 10) + y_shift;
 }
 #endif
 
diff --git a/src/hb-ot-font.cc b/src/hb-ot-font.cc
index 43ec4227d..6cfe8cf56 100644
--- a/src/hb-ot-font.cc
+++ b/src/hb-ot-font.cc
@@ -181,10 +181,13 @@ hb_ot_get_glyph_h_advances (hb_font_t* font, void* font_data,
 			    unsigned advance_stride,
 			    void *user_data HB_UNUSED)
 {
+
   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
   const hb_ot_face_t *ot_face = ot_font->ot_face;
   const OT::hmtx_accelerator_t &hmtx = *ot_face->hmtx;
 
+  hb_position_t *orig_first_advance = first_advance;
+
 #ifndef HB_NO_VAR
   const OT::HVAR &HVAR = *hmtx.var_table;
   const OT::VariationStore &varStore = &HVAR + HVAR.varStore;
@@ -258,6 +261,18 @@ hb_ot_get_glyph_h_advances (hb_font_t* font, void* font_data,
 #ifndef HB_NO_VAR
   OT::VariationStore::destroy_cache (varStore_cache);
 #endif
+
+  if (font->x_shift)
+  {
+    /* Emboldening. */
+    hb_position_t x_shift = font->x_scale >= 0 ? font->x_shift : -font->x_shift;
+    first_advance = orig_first_advance;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      *first_advance += *first_advance ? x_shift : 0;
+      first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
+    }
+  }
 }
 
 #ifndef HB_NO_VERTICAL
@@ -274,6 +289,8 @@ hb_ot_get_glyph_v_advances (hb_font_t* font, void* font_data,
   const hb_ot_face_t *ot_face = ot_font->ot_face;
   const OT::vmtx_accelerator_t &vmtx = *ot_face->vmtx;
 
+  hb_position_t *orig_first_advance = first_advance;
+
   if (vmtx.has_data ())
   {
 #ifndef HB_NO_VAR
@@ -308,6 +325,18 @@ hb_ot_get_glyph_v_advances (hb_font_t* font, void* font_data,
       first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
     }
   }
+
+  if (font->y_shift)
+  {
+    /* Emboldening. */
+    hb_position_t y_shift = font->y_scale >= 0 ? font->y_shift : -font->y_shift;
+    first_advance = orig_first_advance;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      *first_advance += *first_advance ? y_shift : 0;
+      first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
+    }
+  }
 }
 #endif