Add a real-time Plot tab to brewpi_gui, mirroring demo_sud figure 1

Embeds a dark-themed matplotlib canvas (3 stacked strip charts: theta
ist/soll, heatrate ist/soll, heater power_set/power_eff) in a new Plot
tab, sampled once per second from the latest websocket-received values.

HeaterTask now also emits a PowerSet message (the pre-discretization
target power) alongside the existing Power (effective) message, since
the GUI had no way to see the set-point side of figure 1's bottom plot
otherwise.

client/brewpi.ui

@@ -708,8 +708,20 @@
     </widget>
     <widget class="QWidget" name="tab_2">
      <attribute name="title">
-      <string>Seite</string>
+      <string>Plot</string>
      </attribute>
+     <layout class="QVBoxLayout" name="verticalLayout_plot">
+      <item>
+       <widget class="QWidget" name="widget_plot" native="true">
+        <property name="minimumSize">
+         <size>
+          <width>0</width>
+          <height>400</height>
+         </size>
+        </property>
+       </widget>
+      </item>
+     </layout>
     </widget>
    </widget>
    <widget class="QWidget" name="gridLayoutWidget">

client/brewpi_gui.py

@@ -1,14 +1,87 @@
 #!/usr/bin/env python3
 from main_window import Ui_MainWindow
-from PyQt5 import QtWidgets, QtGui
+from PyQt5 import QtWidgets, QtGui, QtCore
 import json
 import sys
+import time
+import matplotlib
+matplotlib.use("Qt5Agg")
+import matplotlib.style
+matplotlib.style.use("dark_background")
+from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
+from matplotlib.figure import Figure
 from ws.client.ws_client import WsClient
 from ws.message import MessageDispatcherSync
 from queue import Queue
 import asyncio
 
 
+class RealtimePlot(FigureCanvasQTAgg):
+	"""Live theta/heatrate/heater-power strip charts, mirroring figure 1 of
+	scripts/demos/sud/demo_sud.py but fed from the websocket connection
+	instead of an offline simulation run."""
+
+	def __init__(self):
+		figure = Figure()
+		FigureCanvasQTAgg.__init__(self, figure)
+
+		self.ax_temp, self.ax_rate, self.ax_power = figure.subplots(3, 1, sharex=True)
+
+		self.line_temp_ist, = self.ax_temp.plot([], [], '-c', linewidth=1, label="theta_ist")
+		self.line_temp_soll, = self.ax_temp.plot([], [], '-m', linewidth=1, label="theta_soll")
+		self.ax_temp.set_ylabel("Temp [°C]")
+		self.ax_temp.legend(loc='upper left', fontsize='small')
+		self.ax_temp.grid(True)
+
+		self.line_rate_ist, = self.ax_rate.plot([], [], '-c', linewidth=1, label="heatrate_ist")
+		self.line_rate_soll, = self.ax_rate.plot([], [], '-m', linewidth=1, label="heatrate_soll")
+		self.ax_rate.set_ylabel("Rate [K/min]")
+		self.ax_rate.legend(loc='upper left', fontsize='small')
+		self.ax_rate.grid(True)
+
+		self.line_power_set, = self.ax_power.plot([], [], '-m', linewidth=1, label="power_set")
+		self.line_power_eff, = self.ax_power.plot([], [], '-c', linewidth=1, label="power_eff")
+		self.ax_power.set_ylabel("Power [W]")
+		self.ax_power.set_xlabel("t [s]")
+		self.ax_power.legend(loc='upper left', fontsize='small')
+		self.ax_power.grid(True)
+
+		figure.tight_layout()
+		self.reset()
+
+	def reset(self):
+		self.t0 = time.monotonic()
+		self.t = []
+		self.temp_ist = []
+		self.temp_soll = []
+		self.rate_ist = []
+		self.rate_soll = []
+		self.power_set = []
+		self.power_eff = []
+
+	def sample(self, temp_ist, temp_soll, rate_ist, rate_soll, power_set, power_eff):
+		self.t.append(time.monotonic() - self.t0)
+		self.temp_ist.append(temp_ist)
+		self.temp_soll.append(temp_soll)
+		self.rate_ist.append(rate_ist)
+		self.rate_soll.append(rate_soll)
+		self.power_set.append(power_set)
+		self.power_eff.append(power_eff)
+
+		self.line_temp_ist.set_data(self.t, self.temp_ist)
+		self.line_temp_soll.set_data(self.t, self.temp_soll)
+		self.line_rate_ist.set_data(self.t, self.rate_ist)
+		self.line_rate_soll.set_data(self.t, self.rate_soll)
+		self.line_power_set.set_data(self.t, self.power_set)
+		self.line_power_eff.set_data(self.t, self.power_eff)
+
+		for ax in (self.ax_temp, self.ax_rate, self.ax_power):
+			ax.relim()
+			ax.autoscale_view()
+
+		self.draw_idle()
+
+
 class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 	def __init__(self):
 		QtWidgets.QMainWindow.__init__(self)
@@ -55,6 +128,25 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.heatrate_soll_initial_update = True
 		self.sud_download_path = None
 
+		# Latest values sampled by the plot timer - written from the
+		# websocket recv thread, read from the GUI thread; plain floats so
+		# no locking, consistent with how the rest of the GUI is wired.
+		self.plot_temp_ist = 0.0
+		self.plot_temp_soll = 0.0
+		self.plot_rate_ist = 0.0
+		self.plot_rate_soll = 0.0
+		self.plot_power_set = 0.0
+		self.plot_power_eff = 0.0
+
+		self.plot = RealtimePlot()
+		plot_layout = QtWidgets.QVBoxLayout(self.widget_plot)
+		plot_layout.setContentsMargins(0, 0, 0, 0)
+		plot_layout.addWidget(self.plot)
+
+		self.plot_timer = QtCore.QTimer(self)
+		self.plot_timer.timeout.connect(self.on_plot_timer)
+		self.plot_timer.start(1000)
+
 	def connect(self):
 		self.slider_pwr_initial_update = True
 		self.slider_temp_soll_initial_update = True
@@ -62,8 +154,15 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.checkbox_heater_activate_initial_update = True
 		self.checkbox_stirrer_activate_initial_update = True
 		self.heatrate_soll_initial_update = True
+		self.plot.reset()
 		self.ws_client.connect(uri=self.plainTextUri.toPlainText())
 
+	def on_plot_timer(self):
+		self.plot.sample(
+			self.plot_temp_ist, self.plot_temp_soll,
+			self.plot_rate_ist, self.plot_rate_soll,
+			self.plot_power_set, self.plot_power_eff)
+
 	def disconnect(self):
 		self.ws_client.disconnect()
 
@@ -127,6 +226,7 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			elif "Soll" in key:
 				submsg = msg['Soll']
 				if 'Temp' in submsg:
+					self.plot_temp_soll = submsg['Temp']
 					self.lcdNumber_temp_soll.display(str(submsg['Temp']))
 					if self.slider_temp_soll_initial_update:
 						self.Slider_temp_soll.setValue(int(round(submsg['Temp'])))
@@ -135,6 +235,7 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 					subsubmsg = submsg['Rate']
 					for subkey in subsubmsg:
 						if "Current" in subkey:
+							self.plot_rate_soll = subsubmsg['Current']
 							self.lcdNumber_heatrate_soll.display(str(subsubmsg['Current']))
 						if "Set" in subkey:
 							if self.heatrate_soll_initial_update:
@@ -143,8 +244,10 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			if "Ist" in key:
 				submsg = msg['Ist']
 				if 'Temp' in submsg:
+					self.plot_temp_ist = submsg['Temp']
 					self.lcdNumber_temp_ist.display(str(submsg['Temp']))
 				if 'Rate' in submsg:
+					self.plot_rate_ist = submsg['Rate']
 					self.lcdNumber_heatrate_ist.display(str(submsg['Rate']))
 
 	def on_heater_changed(self, msg):
@@ -154,7 +257,10 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 				if self.checkbox_heater_activate_initial_update:
 					self.checkbox_heater_activate.setCheckState(2 if msg['Activate'] == 1 else 0)
 					self.checkbox_heater_activate_initial_update = False
+			elif "PowerSet" in key:
+				self.plot_power_set = msg['PowerSet']
 			elif "Power" in key:
+				self.plot_power_eff = msg['Power']
 				self.lcdNumber_power_heater.display(msg['Power'])
 				if self.slider_pwr_initial_update:
 					self.Slider_pwr_soll.setValue(int(round(msg['Power'])))

client/main_window.py

@@ -249,6 +249,12 @@ class Ui_MainWindow(object):
         self.horizontalTabWidget.addTab(self.tab, "")
         self.tab_2 = QtWidgets.QWidget()
         self.tab_2.setObjectName("tab_2")
+        self.verticalLayout_plot = QtWidgets.QVBoxLayout(self.tab_2)
+        self.verticalLayout_plot.setObjectName("verticalLayout_plot")
+        self.widget_plot = QtWidgets.QWidget(self.tab_2)
+        self.widget_plot.setMinimumSize(QtCore.QSize(0, 400))
+        self.widget_plot.setObjectName("widget_plot")
+        self.verticalLayout_plot.addWidget(self.widget_plot)
         self.horizontalTabWidget.addTab(self.tab_2, "")
         self.gridLayoutWidget = QtWidgets.QWidget(self.centralwidget)
         self.gridLayoutWidget.setGeometry(QtCore.QRect(480, 70, 481, 374))
@@ -1270,7 +1276,7 @@ class Ui_MainWindow(object):
         self.label_11.setText(_translate("MainWindow", "Speed [%]"))
         self.horizontalTabWidget.setTabText(self.horizontalTabWidget.indexOf(self.horizontalTabWidgetPage1), _translate("MainWindow", "Manual"))
         self.horizontalTabWidget.setTabText(self.horizontalTabWidget.indexOf(self.tab), _translate("MainWindow", "Automatic"))
-        self.horizontalTabWidget.setTabText(self.horizontalTabWidget.indexOf(self.tab_2), _translate("MainWindow", "Seite"))
+        self.horizontalTabWidget.setTabText(self.horizontalTabWidget.indexOf(self.tab_2), _translate("MainWindow", "Plot"))
         self.label.setText(_translate("MainWindow", "Ist"))
         self.label_2.setText(_translate("MainWindow", "Soll"))
         self.label_3.setText(_translate("MainWindow", "Temperature [°C]"))

client/requirements.txt

@@ -1,2 +1,3 @@
 pyqt5
+matplotlib
 websockets==10.4

tasks/heater.py

@@ -26,6 +26,9 @@ class HeaterTask(ATask):
 	def on_changed_power(self, power):
 		asyncio.create_task(self.send({'Power': power}))
 
+	def on_changed_power_set(self, power):
+		asyncio.create_task(self.send({'PowerSet': power}))
+
 	async def recv(self, data):
 		for pair in data.items():
 			if 'Power' in pair[0]:
@@ -53,6 +56,7 @@ class HeaterTask(ATask):
 		await self.send({'Capabilities': {'Power': {'Min': 0, 'Max': self.device.get_power_max()}}})
 
 		self.device.set_on_changed('power_eff', ChangedInteger(self.on_changed_power).set)
+		power_set_changed = ChangedInteger(self.on_changed_power_set).set
 
 		pulse_period_s = 10
 		pulse_period_count = pulse_period_s/self.interval
@@ -61,6 +65,7 @@ class HeaterTask(ATask):
 			while True:
 				# Combine power set from different sources
 				power_soll = max(self.power_soll, self.power_actor)
+				power_set_changed(power_soll)
 
 				# Calculate duty cycle
 				power_low = self.get_next_smaller_power(power_soll)