[paint] Minor skew

src/hb-paint.hh

diff --git a/src/hb-paint.hh b/src/hb-paint.hh
index 007e899..f7b71aa 100644
--- a/src/hb-paint.hh
+++ b/src/hb-paint.hh
@@ -216,8 +216,8 @@
     if (!sx && !sy)
       return false;
 
-    float x = -tanf (sx * (float) M_PI);
-    float y = +tanf (sy * (float) M_PI);
+    float x = tanf (-sx * (float) M_PI);
+    float y = tanf (+sy * (float) M_PI);
     push_transform (paint_data, 1.f, y, x, 1.f, 0.f, 0.f);
     return true;
   }