diff --git a/piker/ui/_curve.py b/piker/ui/_curve.py
index cb696257..065887af 100644
--- a/piker/ui/_curve.py
+++ b/piker/ui/_curve.py
@@ -360,7 +360,6 @@ class Curve(pg.GraphicsObject):
         self,
         path: QPainterPath,
         src_data: np.ndarray,
-        render_data: np.ndarray,
         reset: bool,
         array_key: str,
         index_field: str,
@@ -368,8 +367,8 @@ class Curve(pg.GraphicsObject):
     ) -> None:
         # default line draw last call
         # with self.reset_cache():
-        x = render_data[index_field]
-        y = render_data[array_key]
+        x = src_data[index_field]
+        y = src_data[array_key]
 
         # draw the "current" step graphic segment so it
         # lines up with the "middle" of the current
@@ -392,7 +391,6 @@ class FlattenedOHLC(Curve):
         self,
         path: QPainterPath,
         src_data: np.ndarray,
-        render_data: np.ndarray,
         reset: bool,
         array_key: str,
         index_field: str,
@@ -423,7 +421,6 @@ class StepCurve(Curve):
         self,
         path: QPainterPath,
         src_data: np.ndarray,
-        render_data: np.ndarray,
         reset: bool,
         array_key: str,
         index_field: str,
diff --git a/piker/ui/_ohlc.py b/piker/ui/_ohlc.py
index a7e36146..d935bd5c 100644
--- a/piker/ui/_ohlc.py
+++ b/piker/ui/_ohlc.py
@@ -221,7 +221,6 @@ class BarItems(pg.GraphicsObject):
         self,
         path: QPainterPath,
         src_data: np.ndarray,
-        render_data: np.ndarray,
         reset: bool,
         array_key: str,
         index_field: str,
diff --git a/piker/ui/_render.py b/piker/ui/_render.py
index 1e77ce03..9f03c189 100644
--- a/piker/ui/_render.py
+++ b/piker/ui/_render.py
@@ -733,7 +733,6 @@ class Viz(msgspec.Struct):  # , frozen=True):
         #         # graphics.draw_last_datum(
         #         #     path,
         #         #     src_array,
-        #         #     data,
         #         #     reset,
         #         #     array_key,
         #         # )
@@ -747,7 +746,6 @@ class Viz(msgspec.Struct):  # , frozen=True):
         graphics.draw_last_datum(
             path,
             src_array,
-            data,
             reset,
             array_key,
             index_field=self.index_field,
@@ -785,7 +783,6 @@ class Viz(msgspec.Struct):  # , frozen=True):
         x, y = g.draw_last_datum(
             g.path,
             src_array,
-            src_array,
             False,  # never reset path
             array_key,
             self.index_field,