[freetype2] slot-inflate 1d977536d: * src/base/ftsynth.c (FT_GlyphSlot_Inflate): New API to adjust weight.

[Werner Lemberg]

branch: slot-inflate
commit 1d977536d197380da2cb0ecbb0b3eb38cd89512d
Author: Alexei Podtelezhnikov <apodtele@gmail.com>
Commit: Alexei Podtelezhnikov <apodtele@gmail.com>

    * src/base/ftsynth.c (FT_GlyphSlot_Inflate): New API to adjust weight.
    * include/freetype/ftsynth.h (FT_GlyphSlot_Inflate): Document it.
---
 include/freetype/ftsynth.h | 12 ++++++++++++
 src/base/ftsynth.c         | 16 ++++++++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/freetype/ftsynth.h b/include/freetype/ftsynth.h
index 5d1969765..2aae4220c 100644
--- a/include/freetype/ftsynth.h
+++ b/include/freetype/ftsynth.h
@@ -68,6 +68,18 @@ FT_BEGIN_HEADER
   FT_EXPORT( void )
   FT_GlyphSlot_Embolden( FT_GlyphSlot  slot );
 
+  /* Change the glyph weight either horizontally or vertically precisely.  */
+  /* The `xdelta` and `ydelta` values are fractions of the face Em size    */
+  /* (in fixed-point format).  Considering that a regular face would have  */
+  /* stem widths on the order of 0.1 Em, a delta of 0.05 (0x0666) might be */
+  /* noticeable.  To increase or decrease the weight, use positive or      */
+  /* negative values, respectively.                                        */
+  FT_EXPORT( void )
+  FT_GlyphSlot_Inflate( FT_GlyphSlot  slot,
+                        FT_Fixed      xdelta,
+                        FT_Fixed      ydelta );
+
+
   /* Slant an outline glyph to the right by about 12 degrees.              */
   FT_EXPORT( void )
   FT_GlyphSlot_Oblique( FT_GlyphSlot  slot );
diff --git a/src/base/ftsynth.c b/src/base/ftsynth.c
index 6ec25e13e..c587fdcc8 100644
--- a/src/base/ftsynth.c
+++ b/src/base/ftsynth.c
@@ -97,6 +97,15 @@
 
   FT_EXPORT_DEF( void )
   FT_GlyphSlot_Embolden( FT_GlyphSlot  slot )
+  {
+    FT_GlyphSlot_Inflate( slot, 0x0555, 0x0555 );
+  }
+
+
+  FT_EXPORT_DEF( void )
+  FT_GlyphSlot_Inflate( FT_GlyphSlot  slot,
+                        FT_Fixed      xdelta,
+                        FT_Fixed      ydelta )
   {
     FT_Library  library;
     FT_Face     face;
@@ -114,10 +123,9 @@
          slot->format != FT_GLYPH_FORMAT_BITMAP  )
       return;
 
-    /* some reasonable strength */
-    xstr = FT_MulFix( face->units_per_EM,
-                      face->size->metrics.y_scale ) / 24;
-    ystr = xstr;
+    /* express deltas in pixels in 26.6 format */
+    xstr = FT_MulFix( (FT_Pos)face->size->metrics.x_ppem << 6, xdelta );
+    ystr = FT_MulFix( (FT_Pos)face->size->metrics.y_ppem << 6, ydelta );
 
     if ( slot->format == FT_GLYPH_FORMAT_OUTLINE )
       FT_Outline_EmboldenXY( &slot->outline, xstr, ystr );