Resolve 'auto' trigger source in GenTL backend

Add resolution logic for trigger source: implement _resolve_trigger_source to map the model-level default 'auto' to the first supported camera line (Line0/Line1/Line2/Any), return whether the resolved value is supported, and log/warn or raise depending on strict mode. Integrate this into _configure_pixel_format/_configure trigger flow so TriggerSource is only set if resolution succeeded. Change CameraTriggerSettings default source to 'auto' and add a field validator to coerce common aliases (e.g. 'default', 'automatic', 'device', 'camera') to 'auto'. Update tests and fixtures: adjust fake node default TriggerSource to Line1, update expectations, and add unit tests for auto-selection behavior and strict-mode error. This makes trigger configuration more robust across cameras with differing GenICam enum symbolics.

Author: C-Achard

dlclivegui/cameras/backends/gentl_backend.py

@@ -1056,6 +1056,51 @@ def _trigger_to_dict(trigger) -> dict[str, Any]:
                 pass
         return {}
 
+    def _resolve_trigger_source(self, node_map, requested: str, *, strict: bool) -> tuple[str, bool]:
+        """Resolve TriggerSource against the camera-supported GenICam enum values.
+
+        Model-level default is "auto"; this backend maps it to the first preferred
+        source supported by the actual camera.
+        """
+        requested = str(requested or "auto").strip()
+        node = self._node(node_map, "TriggerSource")
+        available = self._node_symbolics(node)
+
+        if not available:
+            if strict:
+                raise RuntimeError("GenICam node 'TriggerSource' is not available or has no symbolics")
+            LOG.warning("GenICam node 'TriggerSource' is not available; disabling trigger input.")
+            return requested, False
+
+        if requested in available:
+            return requested, True
+
+        if requested.lower() == "auto":
+            for candidate in ("Line0", "Line1", "Line2", "Any"):
+                if candidate in available:
+                    LOG.info(
+                        "GenTL TriggerSource auto-selected '%s'. Available: %s",
+                        candidate,
+                        available,
+                    )
+                    return candidate, True
+
+            LOG.warning(
+                "Could not auto-select a GenTL TriggerSource. Available: %s",
+                available,
+            )
+            return requested, False
+
+        if strict:
+            raise RuntimeError(f"GenICam node 'TriggerSource' does not support '{requested}'. Available: {available}")
+
+        LOG.warning(
+            "GenTL TriggerSource '%s' is not available. Available: %s",
+            requested,
+            available,
+        )
+        return requested, False
+
     def _configure_pixel_format(self, node_map) -> None:
         try:
             pixel_format_node = getattr(node_map, "PixelFormat", None)
@@ -1145,7 +1190,8 @@ def _configure_trigger_input(self, node_map, cfg, *, strict: bool = False) -> No
         self._set_enum_node(node_map, "TriggerMode", "Off", strict=False)
 
         selector_ok = self._set_enum_node(node_map, "TriggerSelector", selector, strict=strict)
-        source_ok = self._set_enum_node(node_map, "TriggerSource", source, strict=strict)
+        source, source_resolved = self._resolve_trigger_source(node_map, source, strict=strict)
+        source_ok = source_resolved and self._set_enum_node(node_map, "TriggerSource", source, strict=strict)
         activation_ok = self._set_enum_node(node_map, "TriggerActivation", activation, strict=strict)
 
         # TriggerSelector and TriggerSource are required routing nodes.

dlclivegui/config.py

@@ -224,7 +224,7 @@ class CameraTriggerSettings(BaseModel):
 
     # Input trigger config: external/follower
     selector: str = "FrameStart"
-    source: str = "Line0"
+    source: str = "auto"
     activation: TriggerActivation | str = "RisingEdge"
 
     # Output config: master
@@ -272,6 +272,24 @@ def _coerce_timeout(cls, v):
             return None
         return fv if fv > 0 else None
 
+    @field_validator("source", mode="before")
+    @classmethod
+    def _coerce_source(cls, v):
+        if v is None:
+            return "auto"
+
+        s = str(v).strip()
+        if not s:
+            return "auto"
+
+        aliases = {
+            "default": "auto",
+            "automatic": "auto",
+            "device": "auto",
+            "camera": "auto",
+        }
+        return aliases.get(s.lower(), s)
+
     @classmethod
     def from_any(cls, value) -> CameraTriggerSettings:
         if isinstance(value, cls):

tests/cameras/backends/conftest.py

@@ -603,7 +603,7 @@ def __init__(
         self.AcquisitionMode = _FakeNode("Continuous", symbolics=["Continuous", "SingleFrame"])
         self.TriggerSelector = _FakeNode("FrameStart", symbolics=["FrameStart"])
         self.TriggerMode = _FakeNode("Off", symbolics=["Off", "On"])
-        self.TriggerSource = _FakeNode("Line0", symbolics=["Line0", "Line1", "Software"])
+        self.TriggerSource = _FakeNode("Line1", symbolics=["Line0", "Line1", "Software"])
         self.TriggerActivation = _FakeNode("RisingEdge", symbolics=["RisingEdge", "FallingEdge"])
 
         # GPIO output nodes for master/follower setups

tests/cameras/backends/test_gentl_trigger.py

@@ -158,7 +158,7 @@ def test_trigger_invalid_source_non_strict_disables_trigger(patch_gentl_sdk, gen
     nm = be._acquirer.remote_device.node_map
 
     # Source was unsupported, so the fake node should retain its default.
-    assert nm.TriggerSource.value == "Line0"
+    assert nm.TriggerSource.value == "Line1"
 
     # Safety behavior: do not arm TriggerMode on the previous/default source.
     assert nm.TriggerMode.value == "Off"
@@ -422,3 +422,39 @@ def test_trigger_timeout_not_capped_for_master_mode(patch_gentl_sdk, gentl_setti
 
     finally:
         be.close()
+
+
+def test_resolve_trigger_source_auto_selects_supported_line(
+    patch_gentl_sdk,
+    gentl_settings_factory,
+):
+    gb = patch_gentl_sdk
+    be = gb.GenTLCameraBackend(gentl_settings_factory())
+
+    class Node:
+        symbolics = ["Line1", "Software", "Any"]
+
+    class NodeMap:
+        TriggerSource = Node()
+
+    source, ok = be._resolve_trigger_source(NodeMap(), "auto", strict=False)
+
+    assert ok is True
+    assert source == "Line1"
+
+
+def test_resolve_trigger_source_strict_raises_for_unsupported_explicit_line(
+    patch_gentl_sdk,
+    gentl_settings_factory,
+):
+    gb = patch_gentl_sdk
+    be = gb.GenTLCameraBackend(gentl_settings_factory())
+
+    class Node:
+        symbolics = ["Line1", "Software", "Any"]
+
+    class NodeMap:
+        TriggerSource = Node()
+
+    with pytest.raises(RuntimeError, match="TriggerSource.*Line0"):
+        be._resolve_trigger_source(NodeMap(), "Line0", strict=True)

tests/test_config.py

@@ -1,6 +1,6 @@
 import pytest
 
-from dlclivegui.config import ApplicationSettings, CameraSettings, MultiCameraSettings
+from dlclivegui.config import ApplicationSettings, CameraSettings, CameraTriggerSettings, MultiCameraSettings
 
 
 @pytest.mark.unit
@@ -34,3 +34,10 @@ def test_save_applies_gentl_trigger_defaults_to_multi_camera():
     data = settings.to_dict()
 
     assert "trigger" in data["multi_camera"]["cameras"][0]["properties"]["gentl"]
+
+
+@pytest.mark.unit
+def test_trigger_source_defaults_to_auto():
+    trigger = CameraTriggerSettings()
+
+    assert trigger.source == "auto"