Revert "qgrayraster: Speed up rendering of small cubic splines."

This reverts commit a9c0fbd5e946ae6e90b6db6dd4aea64c824a4066.

The subdivision code in the above commit messed up subdivision of
cubic beziers, so we have to revert it.

Task-number: QTBUG-15660
Reviewed-by: Andreas Kling

1 files changed, 20 insertions, 16 deletions

diff --git a/src/gui/painting/qgrayraster.c b/src/gui/painting/qgrayraster.c
index ec9ebeb..5d665cd 100644
--- a/src/gui/painting/qgrayraster.c
+++ b/src/gui/painting/qgrayraster.c
@@ -963,49 +963,53 @@
                               const QT_FT_Vector*  control2,
                               const QT_FT_Vector*  to )
   {
+    TPos        dx, dy, da, db;
     int         top, level;
     int*        levels;
     QT_FT_Vector*  arc;
-    int         mid_x = ( DOWNSCALE( ras.x ) + to->x +
-                          3 * (control1->x + control2->x ) ) / 8;
-    int         mid_y = ( DOWNSCALE( ras.y ) + to->y +
-                          3 * (control1->y + control2->y ) ) / 8;
-    TPos        dx = DOWNSCALE( ras.x ) + to->x - ( mid_x << 1 );
-    TPos        dy = DOWNSCALE( ras.y ) + to->y - ( mid_y << 1 );
 
 
+    dx = DOWNSCALE( ras.x ) + to->x - ( control1->x << 1 );
     if ( dx < 0 )
       dx = -dx;
+    dy = DOWNSCALE( ras.y ) + to->y - ( control1->y << 1 );
     if ( dy < 0 )
       dy = -dy;
     if ( dx < dy )
       dx = dy;
+    da = dx;
+
+    dx = DOWNSCALE( ras.x ) + to->x - 3 * ( control1->x + control2->x );
+    if ( dx < 0 )
+      dx = -dx;
+    dy = DOWNSCALE( ras.y ) + to->y - 3 * ( control1->x + control2->y );
+    if ( dy < 0 )
+      dy = -dy;
+    if ( dx < dy )
+      dx = dy;
+    db = dx;
 
     level = 1;
-    dx /= ras.cubic_level;
-    while ( dx > 0 )
+    da    = da / ras.cubic_level;
+    db    = db / ras.conic_level;
+    while ( da > 0 || db > 0 )
     {
-      dx >>= 2;
+      da >>= 2;
+      db >>= 3;
       level++;
     }
 
     if ( level <= 1 )
     {
-      TPos   to_x, to_y;
+      TPos   to_x, to_y, mid_x, mid_y;
 
 
       to_x  = UPSCALE( to->x );
       to_y  = UPSCALE( to->y );
-
-      /* Recalculation of midpoint is needed only if */
-      /* UPSCALE and DOWNSCALE have any effect.      */
-
-#if ( PIXEL_BITS != 6 )
       mid_x = ( ras.x + to_x +
                 3 * UPSCALE( control1->x + control2->x ) ) / 8;
       mid_y = ( ras.y + to_y +
                 3 * UPSCALE( control1->y + control2->y ) ) / 8;
-#endif
 
       gray_render_line( RAS_VAR_ mid_x, mid_y );
       gray_render_line( RAS_VAR_ to_x, to_y );