diff --git a/graphics/nxbe/nxbe_filltrapezoid.c b/graphics/nxbe/nxbe_filltrapezoid.c
index 82adbd5190e..31593e71e6f 100644
--- a/graphics/nxbe/nxbe_filltrapezoid.c
+++ b/graphics/nxbe/nxbe_filltrapezoid.c
@@ -285,9 +285,10 @@ void nxbe_filltrapezoid(FAR struct nxbe_window_s *wnd,
                         nxgl_mxpixel_t color[CONFIG_NX_NPLANES])
 {
   struct nxgl_rect_s remaining;
+  struct nxgl_rect_s absclip;
   struct nxgl_trapezoid_s devtrap;
 
-  DEBUGASSERT(wnd != NULL && trap != NULL);
+  DEBUGASSERT(wnd != NULL && clip != NULL && trap != NULL);
 
   /* Offset the trapezoid by the window origin to position it within
    * the device graphics coordinate system.
@@ -304,12 +305,8 @@ void nxbe_filltrapezoid(FAR struct nxbe_window_s *wnd,
 
   /* Clip to any user specified clipping window */
 
-  if (clip != NULL)
-    {
-      struct nxgl_rect_s tmp;
-      nxgl_rectoffset(&tmp, clip, wnd->bounds.pt1.x, wnd->bounds.pt1.y);
-      nxgl_rectintersect(&remaining, &remaining, &tmp);
-    }
+  nxgl_rectoffset(&absclip, clip, wnd->bounds.pt1.x, wnd->bounds.pt1.y);
+  nxgl_rectintersect(&remaining, &remaining, &absclip);
 
   /* Clip to the limits of the window and of the background screen */
 
diff --git a/libs/libnx/nx/nx_drawline.c b/libs/libnx/nx/nx_drawline.c
index 762957e3e7e..f142db954f1 100644
--- a/libs/libnx/nx/nx_drawline.c
+++ b/libs/libnx/nx/nx_drawline.c
@@ -80,7 +80,7 @@ int nx_drawline(NXWINDOW hwnd, FAR struct nxgl_vector_s *vector,
   int ret;
 
 #ifdef CONFIG_DEBUG_FEATURES
-  if (!hwnd || !vector || width < 1 || !color)
+  if (hwnd == NULL || vector == NULL || width < 1 || color == NULL)
     {
       set_errno(EINVAL);
       return ERROR;
diff --git a/libs/libnx/nxglib/nxglib_trapoffset.c b/libs/libnx/nxglib/nxglib_trapoffset.c
index 51ec4922358..9222f43d59e 100644
--- a/libs/libnx/nxglib/nxglib_trapoffset.c
+++ b/libs/libnx/nxglib/nxglib_trapoffset.c
@@ -60,4 +60,3 @@ void nxgl_trapoffset(FAR struct nxgl_trapezoid_s *dest,
   nxgl_runoffset(&dest->top, &src->top, dx, dy);
   nxgl_runoffset(&dest->bot, &src->bot, dx, dy);
 }
-
diff --git a/libs/libnx/nxmu/nx_filltrapezoid.c b/libs/libnx/nxmu/nx_filltrapezoid.c
index 49327a9d106..b6069257f6c 100644
--- a/libs/libnx/nxmu/nx_filltrapezoid.c
+++ b/libs/libnx/nxmu/nx_filltrapezoid.c
@@ -77,10 +77,10 @@ int nx_filltrapezoid(NXWINDOW hwnd, FAR const struct nxgl_rect_s *clip,
   struct nxsvrmsg_filltrapezoid_s outmsg;
   int i;
 
+#ifdef CONFIG_DEBUG_FEATURES
   /* Some debug-only sanity checks */
 
-#ifdef CONFIG_DEBUG_FEATURES
-  if (!wnd || !trap || !color)
+  if (wnd == NULL || trap == NULL || color == NULL)
     {
       set_errno(EINVAL);
       return ERROR;
@@ -94,13 +94,22 @@ int nx_filltrapezoid(NXWINDOW hwnd, FAR const struct nxgl_rect_s *clip,
 
   /* If no clipping window was provided, then use the size of the entire window */
 
-  if (clip)
+  if (clip != NULL)
     {
       nxgl_rectcopy(&outmsg.clip, clip);
     }
   else
     {
-      nxgl_rectcopy(&outmsg.clip, &wnd->bounds);
+      struct nxgl_rect_s tmpclip;
+
+      /* Convert the window bounds to window relative coordinates */
+
+      nxgl_rectoffset(&tmpclip, &wnd->bounds,
+                     -wnd->bounds.pt1.x, -wnd->bounds.pt1.y);
+
+      /* And use that for the clipping winding */
+
+      nxgl_rectcopy(&outmsg.clip, &tmpclip);
     }
 
   /* Copy the trapezod and the color into the message */