multichannel support + colormap inherit

backend/execution.py

@@ -50,6 +50,7 @@ class ExecutionEngine:
         on_table: Callable[[str, list], None] | None = None,
         on_mesh: Callable[[str, dict], None] | None = None,
         on_overlay: Callable[[str, str], None] | None = None,
+        on_warning: Callable[[str, str], None] | None = None,
     ) -> dict[str, tuple]:
         """
         Execute the workflow described by `prompt`.
@@ -62,6 +63,7 @@ class ExecutionEngine:
         on_preview      : called with (node_id, data_uri) when a display node runs
         on_table        : called with (node_id, table_list) when PrintTable runs
         on_overlay      : called with (node_id, data_uri) for interactive overlays
+        on_warning      : called with (node_id, message) for node warnings
 
         Returns
         -------
@@ -71,7 +73,7 @@ class ExecutionEngine:
         node_outputs: dict[str, tuple] = {}
 
         # Inject display callbacks before execution
-        self._inject_display_callbacks(on_preview, on_table, on_mesh, on_overlay)
+        self._inject_display_callbacks(on_preview, on_table, on_mesh, on_overlay, on_warning)
 
         for node_id in order:
             node_def = prompt[node_id]
@@ -174,12 +176,13 @@ class ExecutionEngine:
         on_table: Callable | None,
         on_mesh: Callable | None = None,
         on_overlay: Callable | None = None,
+        on_warning: Callable | None = None,
     ) -> None:
         """Wire up broadcast callbacks on display node classes."""
         from backend.nodes.display import PreviewImage, PrintTable, View3D
         from backend.nodes.analysis import CrossSection, LineCursors
         from backend.nodes.mask import ThresholdMask, MaskMorphology, MaskInvert, MaskCombine
-        from backend.nodes.io import SaveImage
+        from backend.nodes.io import SaveImage, LoadFile
 
         PreviewImage._broadcast_fn = on_preview
         ThresholdMask._broadcast_fn = on_preview
@@ -190,6 +193,7 @@ class ExecutionEngine:
         PrintTable._broadcast_table_fn = on_table
         CrossSection._broadcast_overlay_fn = on_overlay
         LineCursors._broadcast_overlay_fn = on_overlay
+        LoadFile._broadcast_warning_fn = on_warning
         SaveImage._broadcast_preview = (
             (lambda data_uri: on_preview("save", data_uri)) if on_preview else None
         )
@@ -199,8 +203,9 @@ class ExecutionEngine:
         from backend.nodes.display import PreviewImage, PrintTable, View3D
         from backend.nodes.analysis import CrossSection, LineCursors
         from backend.nodes.mask import ThresholdMask, MaskMorphology, MaskInvert, MaskCombine
+        from backend.nodes.io import LoadFile
         if cls in (PreviewImage, PrintTable, View3D, CrossSection, LineCursors,
-                   ThresholdMask, MaskMorphology, MaskInvert, MaskCombine):
+                   ThresholdMask, MaskMorphology, MaskInvert, MaskCombine, LoadFile):
             cls._current_node_id = node_id
 
     def _auto_preview(
@@ -232,7 +237,7 @@ class ExecutionEngine:
             value = result[slot]
 
             if type_name == "DATA_FIELD" and isinstance(value, DataField) and on_preview:
-                arr = datafield_to_uint8(value, "viridis")
+                arr = datafield_to_uint8(value, value.colormap)
                 on_preview(node_id, encode_preview(arr))
                 return  # one preview per node is enough