[sfnt] PaintRotate/PaintRotateAroundCenter spec updates

* src/sfnt/ttcolr.c (read_paint): Implement spec change where
PaintRotate and PaintRotateAroundCenter were split for a more
compact format definition.  Update parsing to read shorter values
as changed in the spec.
* include/freetype/ftcolor.h (FT_PaintRotate): Update documentation.

include/freetype/ftcolor.h

@@ -1173,7 +1173,9 @@ FT_BEGIN_HEADER
    *     rotated.
    *
    *   angle ::
-   *     The rotation angle that is to be applied.
+   *     The rotation angle that is to be applied in degrees divided by
+   *     180.0 (as in the spec).  Multiply by 180.0f to receive degrees
+   *     value.
    *
    *   center_x ::
    *     The x~coordinate of the pivot point of the rotation (in font

src/sfnt/ttcolr.c

@@ -619,15 +619,32 @@
       return 1;
     }
 
-    else if ( apaint->format == FT_COLR_PAINTFORMAT_ROTATE )
+    else if ( apaint->format == FT_COLR_PAINTFORMAT_ROTATE  ||
+              (FT_PaintFormat_Internal)apaint->format ==
+                FT_COLR_PAINTFORMAT_INTERNAL_ROTATE_CENTER  )
     {
       apaint->u.rotate.paint.p                     = child_table_p;
       apaint->u.rotate.paint.insert_root_transform = 0;
 
-      apaint->u.rotate.angle = FT_NEXT_LONG( p );
+      /* The angle is specified as F2DOT14 and our output type is an FT_Fixed,
+       * shift by 2 positions. */
+      apaint->u.rotate.angle = FT_NEXT_SHORT( p ) << 2;
+
+      if ( (FT_PaintFormat_Internal)apaint->format ==
+           FT_COLR_PAINTFORMAT_INTERNAL_ROTATE_CENTER )
+      {
+        /* The center is specified as Int16 in font units, shift by 16 bits to
+         * convert to our FT_Fixed output type. */
+        apaint->u.rotate.center_x = FT_NEXT_SHORT( p ) << 16;
+        apaint->u.rotate.center_y = FT_NEXT_SHORT( p ) << 16;
+      }
+      else
+      {
+        apaint->u.rotate.center_x = 0;
+        apaint->u.rotate.center_y = 0;
+      }
 
-      apaint->u.rotate.center_x = FT_NEXT_LONG( p );
-      apaint->u.rotate.center_y = FT_NEXT_LONG( p );
+      apaint->format = FT_COLR_PAINTFORMAT_ROTATE;
 
       return 1;
     }