diff --git a/scanslicer/canvas_state.py b/scanslicer/canvas_state.py
new file mode 100644
index 0000000..87e5d97
--- /dev/null
+++ b/scanslicer/canvas_state.py
@@ -0,0 +1,7 @@
+import numpy as np
+from PySide6.QtCore import QPointF, QRectF
+
+from .slices import PhotoSlice, polys_iou
+
+
+# CanvasStateMixin: class definition for ScanSlicer behavior.