Optimize Bézier bisections.

* src/raster/ftraster.c (Split_Conic, Split_Cubic): Use shifts and
refactor.
* src/smooth/ftgrays.c (gray_split_conic, gray_split_cubic): Ditto.
* src/base/ftstroke.c (ft_conic_split, ft_cubic_split): Ditto.
* src/base/ftbbox.c (cubic_peak): Use shifts.

1 files changed, 31 insertions, 25 deletions

diff --git a/src/raster/ftraster.c b/src/raster/ftraster.c
index 798a72d02..2859113a3 100644
--- a/src/raster/ftraster.c
+++ b/src/raster/ftraster.c
@@ -914,16 +914,18 @@
 
 
     base[4].x = base[2].x;
-    b = base[1].x;
-    a = base[3].x = ( base[2].x + b ) / 2;
-    b = base[1].x = ( base[0].x + b ) / 2;
-    base[2].x = ( a + b ) / 2;
+    a = base[0].x + base[1].x;
+    b = base[1].x + base[2].x;
+    base[3].x = b >> 1;
+    base[2].x = ( a + b ) >> 2;
+    base[1].x = a >> 1;
 
     base[4].y = base[2].y;
-    b = base[1].y;
-    a = base[3].y = ( base[2].y + b ) / 2;
-    b = base[1].y = ( base[0].y + b ) / 2;
-    base[2].y = ( a + b ) / 2;
+    a = base[0].y + base[1].y;
+    b = base[1].y + base[2].y;
+    base[3].y = b >> 1;
+    base[2].y = ( a + b ) >> 2;
+    base[1].y = a >> 1;
 
     /* hand optimized.  gcc doesn't seem to be too good at common      */
     /* expression substitution and instruction scheduling ;-)          */
@@ -947,28 +949,32 @@
   static void
   Split_Cubic( TPoint*  base )
   {
-    Long  a, b, c, d;
+    Long  a, b, c;
 
 
     base[6].x = base[3].x;
-    c = base[1].x;
-    d = base[2].x;
-    base[1].x = a = ( base[0].x + c + 1 ) >> 1;
-    base[5].x = b = ( base[3].x + d + 1 ) >> 1;
-    c = ( c + d + 1 ) >> 1;
-    base[2].x = a = ( a + c + 1 ) >> 1;
-    base[4].x = b = ( b + c + 1 ) >> 1;
-    base[3].x = ( a + b + 1 ) >> 1;
+    a = base[0].x + base[1].x;
+    b = base[1].x + base[2].x;
+    c = base[2].x + base[3].x;
+    base[5].x = c >> 1;
+    c += b;
+    base[4].x = c >> 2;
+    base[1].x = a >> 1;
+    a += b;
+    base[2].x = a >> 2;
+    base[3].x = ( a + c ) >> 3;
 
     base[6].y = base[3].y;
-    c = base[1].y;
-    d = base[2].y;
-    base[1].y = a = ( base[0].y + c + 1 ) >> 1;
-    base[5].y = b = ( base[3].y + d + 1 ) >> 1;
-    c = ( c + d + 1 ) >> 1;
-    base[2].y = a = ( a + c + 1 ) >> 1;
-    base[4].y = b = ( b + c + 1 ) >> 1;
-    base[3].y = ( a + b + 1 ) >> 1;
+    a = base[0].y + base[1].y;
+    b = base[1].y + base[2].y;
+    c = base[2].y + base[3].y;
+    base[5].y = c >> 1;
+    c += b;
+    base[4].y = c >> 2;
+    base[1].y = a >> 1;
+    a += b;
+    base[2].y = a >> 2;
+    base[3].y = ( a + c ) >> 3;
   }