diff --git a/scanslicer/canvas.py b/scanslicer/canvas.py
index c6a5a44..60a736d 100644
--- a/scanslicer/canvas.py
+++ b/scanslicer/canvas.py
@@ -8,3 +8,32 @@ from .canvas_state import CanvasStateMixin
 
 
 # QtSlicingCanvas: class definition for ScanSlicer behavior.
+class QtSlicingCanvas(CanvasInteractionMixin, CanvasRenderMixin, CanvasStateMixin, QWidget):
+    AUTO_FIT_SCALE = 0.95
+    OFF_CANVAS_COLOR = QColor(38, 38, 38)
+    CORNER_HANDLE_HIT_RADIUS = 12.0
+    SIDE_HANDLE_HIT_RADIUS = 14.0
+    SIDE_HANDLE_SIZE_ACTIVE = 11.0
+    SIDE_HANDLE_SIZE_INACTIVE = 9.0
+    active_slice_changed = Signal(int)
+
+    # __init__: function definition for ScanSlicer behavior.
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self.setMouseTracking(True)
+        self.setMinimumSize(640, 480)
+
+        self.zoom = 1.0
+        self.image = None
+        self.pan_offset = QPointF(0.0, 0.0)
+        self.slices = []
+        self.active_slice_index = None
+
+        self.corner_dragging = None
+        self.side_dragging = None
+        self.rotation_dragging = None
+        self.box_dragging = None
+        self.rotate_handles_mode = False
+        self.panning = False
+        self.last_mouse_pos = QPointF(0.0, 0.0)
+        self.user_transformed_view = False