Disable save button when PCC is changed

Disable the save button until features are extracted again with the new
PCC filtering.

src/napari_psf_extractor/components/pcc.py

@@ -1,10 +1,13 @@
 from napari.utils.notifications import show_error
+from qtpy.QtCore import Signal
 from qtpy.QtWidgets import QLineEdit, QHBoxLayout, QCheckBox, QWidget, QVBoxLayout, QLabel, QPushButton
 
 from napari_psf_extractor.extractor import extract_psf
 
 
 class PCC(QWidget):
+    changed = Signal()
+
     def __init__(self, widget):
         super().__init__()
 
@@ -34,6 +37,11 @@ def __init__(self, widget):
         self.checkbox.stateChanged.connect(self.update_checkbox)
         self.filter_button.clicked.connect(self.filter)
 
+        self.pcc_min.textChanged.connect(self.emit_changed)
+
+    def emit_changed(self):
+        self.changed.emit()
+
     def update_checkbox(self):
         if not self.checkbox.isChecked():
             self.pcc_min.hide()
@@ -48,6 +56,8 @@ def update_checkbox(self):
             self.pcc_min.setText("0.7")
             self.features_pcc_label.setText("Remaining features:")
 
+        self.emit_changed()
+
     def value(self):
         """
         Get the current PCC value. If PCC filtering is not enabled, return None.

src/napari_psf_extractor/widget.py

@@ -125,6 +125,8 @@ def param_setter(
         self.extract_button.clicked.connect(self.extract)
         self.find_features_button.clicked.connect(self.find_features)
 
+        self.pcc.changed.connect(lambda: self.save_button.setEnabled(False))
+
         self.viewer.layers.events.inserted.connect(param_setter.reset_choices)
         self.viewer.layers.events.removed.connect(param_setter.reset_choices)