Improve camera config loading UX and improve Basler backend

dlclivegui/config.py

@@ -85,10 +85,20 @@ def _coerce_gain(cls, v):
     def _validate_crop(self):
         for f in ("crop_x0", "crop_y0", "crop_x1", "crop_y1"):
             setattr(self, f, max(0, int(getattr(self, f))))
-        # Optional: if any crop is set, enforce x1>x0 and y1>y0
-        if any([self.crop_x0, self.crop_y0, self.crop_x1, self.crop_y1]):
-            if not (self.crop_x1 > self.crop_x0 and self.crop_y1 > self.crop_y0):
-                raise ValueError("Invalid crop rectangle: require x1>x0 and y1>y0 when cropping is enabled.")
+
+        # No crop
+        if self.crop_x0 == self.crop_y0 == self.crop_x1 == self.crop_y1 == 0:
+            return self
+
+        # Allow x1/y1 == 0 to mean "to edge"
+        # If x1 is explicitly set (>0), it must be > x0
+        if self.crop_x1 > 0 and self.crop_x1 <= self.crop_x0:
+            raise ValueError("Invalid crop rectangle: require x1 > x0 (or x1=0 for 'to edge').")
+
+        # If y1 is explicitly set (>0), it must be > y0
+        if self.crop_y1 > 0 and self.crop_y1 <= self.crop_y0:
+            raise ValueError("Invalid crop rectangle: require y1 > y0 (or y1=0 for 'to edge').")
+
         return self
 
     def get_crop_region(self) -> tuple[int, int, int, int] | None:

dlclivegui/gui/main_window.py

@@ -1454,7 +1454,11 @@ def _start_preview(self) -> None:
         # Store active settings for single camera mode (for DLC, recording frame rate, etc.)
         self._active_camera_settings = active_cams[0] if active_cams else None
         for cam in active_cams:
-            cam.properties.setdefault("fast_start", True)
+            if not isinstance(cam.properties, dict):
+                cam.properties = {}
+            ns = cam.properties.setdefault((cam.backend or "").lower(), {})
+            if isinstance(ns, dict):
+                ns["fast_start"] = False
 
         self.multi_camera_controller.start(active_cams)
         self._update_inference_buttons()