matplotlib
diff --git a/‎src/napari_matplotlib/histogram.py
Copy file name to clipboardExpand all lines: src/napari_matplotlib/histogram.py
+4-1Lines changed: 4 additions & 1 deletion b/‎src/napari_matplotlib/histogram.py
Copy file name to clipboardExpand all lines: src/napari_matplotlib/histogram.py
+4-1Lines changed: 4 additions & 1 deletion
@@ -33,7 +33,6 @@ def draw(self) -> None:
         Clear the axes and histogram the currently selected layer/slice.
         """
         layer = self.layers[0]
-        bins = np.linspace(np.min(layer.data), np.max(layer.data), 100)
 
         if layer.data.ndim - layer.rgb == 3:
             # 3D data, can be single channel or RGB
@@ -42,6 +41,10 @@ def draw(self) -> None:
         else:
             data = layer.data
 
+        # Important to calculate bins after slicing 3D data, to avoid reading
+        # whole cube into memory.
+        bins = np.linspace(np.min(layer.data), np.max(layer.data), 100)
+
         if layer.rgb:
             # Histogram RGB channels independently
             for i, c in enumerate("rgb"):