ENH: Support visualize beam envelope when any quad is changed.

src/myApp/app.py

 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
-
 """Template Python module generated based on 'app_template', 'phantasy-ui'
 is required to make it executable as a PyQt5 app.
 
@@ -15,14 +14,20 @@ Show the available templates:
 >>> makeBasePyQtApp -l
 """
 
+from PyQt5.QtCore import pyqtSlot
 from PyQt5.QtWidgets import QMainWindow
+
+from phantasy import MachinePortal
 from phantasy_ui import BaseAppForm
 
 from .ui.ui_app import Ui_MainWindow
 
+MACH, SEGM = "ARIS", "F1"
+ARIS_MP = MachinePortal(MACH, SEGM)
+ARIS_LAT = ARIS_MP.work_lattice_conf
 
-class MyAppWindow(BaseAppForm, Ui_MainWindow):
 
+class MyAppWindow(BaseAppForm, Ui_MainWindow):
     def __init__(self, version, **kws):
         super(self.__class__, self).__init__()
 
@@ -37,6 +42,85 @@ class MyAppWindow(BaseAppForm, Ui_MainWindow):
         self.setupUi(self)
         self.postInitUi()
 
+        # post init
+        self._post_init()
+
+    def _post_init(self):
+        """Initialize UI, user customized code put here.
+        """
+        # Fill comboBox quad1_name_cbb with all quad names.
+        quad_name_list = [i.name for i in ARIS_MP.get_elements(type='QUAD')]
+        self.quad1_name_cbb.addItems(quad_name_list)
+        # connect currentTextChanged signal to slot: on_quad1_name_changed()
+        self.quad1_name_cbb.currentTextChanged.connect(
+            self.on_quad1_name_changed)
+        # connect valueChanged signal of quad1_grad_dsbox to on_quad1_grad_changed()
+        self.quad1_grad_dsbox.valueChanged.connect(self.on_quad1_grad_changed)
+        # initialize quad1_name_cbb
+        self.quad1_name_cbb.currentTextChanged.emit(quad_name_list[0])
+
+    @pyqtSlot('QString')
+    def on_quad1_name_changed(self, name: str) -> None:
+        """When the current selected quad name is changed, do:
+        show the current setting of the selected quad on quad1_grad_dsbox.
+        when set value to quad1_grad_dsbox, disconnect valueChanged and
+        reconnect, to avoid unnecessary trigging.
+        """
+        self.quad_selected = ARIS_MP.get_elements(name=name)[0]
+        self.quad1_grad_dsbox.valueChanged.disconnect()
+        self.quad1_grad_dsbox.setValue(
+            self.quad_selected.current_setting('B2'))
+        self.quad1_grad_dsbox.valueChanged.connect(self.on_quad1_grad_changed)
+
+    @pyqtSlot(float)
+    def on_quad1_grad_changed(self, grad: float) -> None:
+        """When the setting of the selected quad is changed, do:
+        1. print the setting of selected quad
+        2. update drawing with online simulated results
+        """
+        q = self.quad_selected.name
+        print(f"'{q}' setting is: {grad} T/m")
+        # draw ellipse
+        self.update_drawing()
+
+    def update_drawing(self):
+        """This is the routine to update the figure with the updated drawing.
+        Here I'm drawing the beam envelop along the entire beamline, try to
+        replace with your routine for beam ellipse drawing.
+        """
+        try:
+            self.draw_ellipse()
+        except NotImplementedError:
+            self.draw_envelope()
+
+    def draw_envelope(self):
+        """Draw beam envelop onto the figure area.
+        """
+        # online simulation
+        ARIS_LAT.sync_settings()
+        _, fm = ARIS_LAT.run()
+        r, _ = fm.run(monitor='all')
+        results_dict = fm.collect_data(r, 'pos', 'xrms', 'yrms')
+        pos = results_dict['pos']
+        xrms = results_dict['xrms']
+        yrms = results_dict['yrms']
+        # update drawing
+        # Note: matplotlibbaseWidget is used here for generic drawing,
+        # for curve visualization, matplotlibCurveWidget is a better choice.
+        self.matplotlibbaseWidget.clear_figure()
+        self.matplotlibbaseWidget.axes.plot(
+            pos,
+            xrms,
+            'b-',
+            pos,
+            yrms,
+            'r-',
+        )
+        self.matplotlibbaseWidget.update_figure()
+
+    def draw_ellipse(self):
+        raise NotImplementedError
+
 
 if __name__ == "__main__":
     from PyQt5.QtWidgets import QApplication