New design

negstation/image_pipeline.py

@@ -0,0 +1,18 @@
+import numpy as np
+
+from .event_bus import EventBus
+
+
+class ImagePipeline:
+    def __init__(self, bus: EventBus):
+        self.bus = bus
+        self.stages = {}
+
+    def add_stage(self, name: str, img: np.ndarray):
+        self.stages[name] = img.astype(np.float32)
+        # notify widgets of updated stage list and data
+        self.bus.publish_deferred("pipeline_stages", list(self.stages.keys()))
+        self.bus.publish_deferred("pipeline_stage", (name, self.stages[name]))
+
+    def get_stage(self, name: str):
+        return self.stages.get(name)