[freetype2] master bc3b528: [smooth] Faster fractions.

[Alexei Podtelezhnikov]

branch: master
commit bc3b5281ed08d1cae3a2d881d2c72d0e98e57c05
Author: Alexei Podtelezhnikov <address@hidden>
Commit: Alexei Podtelezhnikov <address@hidden>

    [smooth] Faster fractions.
    
    * src/smooth/ftgrays.c (SUBPIXELS): Replace with...
    (FRACT): A fractional coordinate macro to use in...
    (gray_render_line, gray_render_scanline): ... here.
---
 ChangeLog            |  8 ++++++++
 src/smooth/ftgrays.c | 43 ++++++++++++++++++++++---------------------
 2 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d68323a..ab6d302 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-05-08  Alexei Podtelezhnikov  <address@hidden>
+
+       [smooth] Faster fractions.
+
+       * src/smooth/ftgrays.c (SUBPIXELS): Replace with...
+       (FRACT): A fractional coordinate macro to use in...
+       (gray_render_line, gray_render_scanline): ... here.
+
 2019-05-07  Alexei Podtelezhnikov  <address@hidden>
 
        * src/raster/ftraster.c (Draw_Sweep): Unbreak.
diff --git a/src/smooth/ftgrays.c b/src/smooth/ftgrays.c
index b09bcce..8f87f84 100644
--- a/src/smooth/ftgrays.c
+++ b/src/smooth/ftgrays.c
@@ -328,8 +328,8 @@ typedef ptrdiff_t  FT_PtrDist;
 #define PIXEL_BITS  8
 
 #define ONE_PIXEL       ( 1 << PIXEL_BITS )
-#define TRUNC( x )      ( (TCoord)( (x) >> PIXEL_BITS ) )
-#define SUBPIXELS( x )  ( (TPos)(x) * ONE_PIXEL )
+#define TRUNC( x )      (TCoord)( (x) >> PIXEL_BITS )
+#define FRACT( x )      (TCoord)( (x) & ( ONE_PIXEL - 1 ) )
 
 #if PIXEL_BITS >= 6
 #define UPSCALE( x )    ( (x) * ( ONE_PIXEL >> 6 ) )
@@ -380,9 +380,9 @@ typedef ptrdiff_t  FT_PtrDist;
 #define FT_UDIVPREP( c, b )                                        \
   long  b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \
                     : 0
-#define FT_UDIV( a, b )                                        \
-  ( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >>   \
-    ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
+#define FT_UDIV( a, b )                                                \
+  (TCoord)( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >>   \
+            ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
 
 
   /**************************************************************************
@@ -610,8 +610,8 @@ typedef ptrdiff_t  FT_PtrDist;
       return;
     }
 
-    fx1   = (TCoord)( x1 - SUBPIXELS( ex1 ) );
-    fx2   = (TCoord)( x2 - SUBPIXELS( ex2 ) );
+    fx1   = FRACT( x1 );
+    fx2   = FRACT( x2 );
 
     /* everything is located in a single cell.  That is easy! */
     /*                                                        */
@@ -703,8 +703,8 @@ typedef ptrdiff_t  FT_PtrDist;
          ( ey1 <  ras.min_ey && ey2 <  ras.min_ey ) )
       goto End;
 
-    fy1 = (TCoord)( ras.y - SUBPIXELS( ey1 ) );
-    fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
+    fy1 = FRACT( ras.y );
+    fy2 = FRACT( to_y );
 
     /* everything is on a single scanline */
     if ( ey1 == ey2 )
@@ -720,7 +720,7 @@ typedef ptrdiff_t  FT_PtrDist;
     if ( dx == 0 )
     {
       TCoord  ex     = TRUNC( ras.x );
-      TCoord  two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
+      TCoord  two_fx = FRACT( ras.x ) << 1;
       TArea   area;
 
 
@@ -831,8 +831,9 @@ typedef ptrdiff_t  FT_PtrDist;
   gray_render_line( RAS_ARG_ TPos  to_x,
                              TPos  to_y )
   {
-    TPos    dx, dy, fx1, fy1, fx2, fy2;
-    TCoord  ex1, ex2, ey1, ey2;
+    TPos    dx, dy;
+    TCoord  fx1, fy1, fx2, fy2;
+    TCoord  ex1, ey1, ex2, ey2;
 
 
     ey1 = TRUNC( ras.y );
@@ -846,8 +847,8 @@ typedef ptrdiff_t  FT_PtrDist;
     ex1 = TRUNC( ras.x );
     ex2 = TRUNC( to_x );
 
-    fx1 = ras.x - SUBPIXELS( ex1 );
-    fy1 = ras.y - SUBPIXELS( ey1 );
+    fx1 = FRACT( ras.x );
+    fy1 = FRACT( ras.y );
 
     dx = to_x - ras.x;
     dy = to_y - ras.y;
@@ -884,7 +885,7 @@ typedef ptrdiff_t  FT_PtrDist;
     }
     else                                  /* any other line */
     {
-      TPos  prod = dx * fy1 - dy * fx1;
+      TPos  prod = dx * (TPos)fy1 - dy * (TPos)fx1;
       FT_UDIVPREP( ex1 != ex2, dx );
       FT_UDIVPREP( ey1 != ey2, dy );
 
@@ -898,7 +899,7 @@ typedef ptrdiff_t  FT_PtrDist;
                   prod - dx * ONE_PIXEL                  >  0 ) /* left */
         {
           fx2 = 0;
-          fy2 = (TPos)FT_UDIV( -prod, -dx );
+          fy2 = FT_UDIV( -prod, -dx );
           prod -= dy * ONE_PIXEL;
           ras.cover += ( fy2 - fy1 );
           ras.area  += ( fy2 - fy1 ) * ( fx1 + fx2 );
@@ -910,7 +911,7 @@ typedef ptrdiff_t  FT_PtrDist;
                   prod - dx * ONE_PIXEL + dy * ONE_PIXEL >  0 ) /* up */
         {
           prod -= dx * ONE_PIXEL;
-          fx2 = (TPos)FT_UDIV( -prod, dy );
+          fx2 = FT_UDIV( -prod, dy );
           fy2 = ONE_PIXEL;
           ras.cover += ( fy2 - fy1 );
           ras.area  += ( fy2 - fy1 ) * ( fx1 + fx2 );
@@ -923,7 +924,7 @@ typedef ptrdiff_t  FT_PtrDist;
         {
           prod += dy * ONE_PIXEL;
           fx2 = ONE_PIXEL;
-          fy2 = (TPos)FT_UDIV( prod, dx );
+          fy2 = FT_UDIV( prod, dx );
           ras.cover += ( fy2 - fy1 );
           ras.area  += ( fy2 - fy1 ) * ( fx1 + fx2 );
           fx1 = 0;
@@ -933,7 +934,7 @@ typedef ptrdiff_t  FT_PtrDist;
         else /* ( prod                  + dy * ONE_PIXEL <  0 &&
                   prod                                   >  0 )    down */
         {
-          fx2 = (TPos)FT_UDIV( prod, -dy );
+          fx2 = FT_UDIV( prod, -dy );
           fy2 = 0;
           prod += dx * ONE_PIXEL;
           ras.cover += ( fy2 - fy1 );
@@ -947,8 +948,8 @@ typedef ptrdiff_t  FT_PtrDist;
       } while ( ex1 != ex2 || ey1 != ey2 );
     }
 
-    fx2 = to_x - SUBPIXELS( ex2 );
-    fy2 = to_y - SUBPIXELS( ey2 );
+    fx2 = FRACT( to_x );
+    fy2 = FRACT( to_y );
 
     ras.cover += ( fy2 - fy1 );
     ras.area  += ( fy2 - fy1 ) * ( fx1 + fx2 );