[MainWindow] Repaint display bars at a reduced frequency

Too high of a frequency can't be easily read and burns up lots of CPU in
redraw events.

Author: kubark42

mainwindow.cpp

@@ -219,6 +219,8 @@ MainWindow::MainWindow(QWidget *parent) :
     mKeyLeft = false;
     mKeyRight = false;
 
+    shouldUpdateDisplayBars = false;
+
     connect(mDebugTimer, SIGNAL(timeout()),
             this, SLOT(timerSlotDebugMsg()));
     connect(mTimer, SIGNAL(timeout()),
@@ -481,6 +483,8 @@ MainWindow::MainWindow(QWidget *parent) :
     mPollImuTimer.start(int(1000.0 / mSettings.value("poll_rate_imu_data", 50).toDouble()));
     mPollBmsTimer.start(int(1000.0 / mSettings.value("poll_rate_bms_data", 10).toDouble()));
 
+    mRepaintDisplayBarTimer.start(1000.0/30); // Set the refresh rate to 30Hz
+
     connect(&mPollRtTimer, &QTimer::timeout, [this]() {
         if (ui->actionRtData->isChecked()) {
             mVesc->commands()->getValues();
@@ -514,6 +518,15 @@ MainWindow::MainWindow(QWidget *parent) :
         }
     });
 
+    connect(&mRepaintDisplayBarTimer, &QTimer::timeout, [this]() {
+        if (shouldUpdateDisplayBars) {
+           ui->dispCurrent->setVal(mMcValues.current_motor);
+           ui->dispDuty->setVal(mMcValues.duty_now * 100.0);
+
+           shouldUpdateDisplayBars = false;
+        }
+    });
+
     // Restore size and position
     if (mSettings.contains("mainwindow/size")) {
         resize(mSettings.value("mainwindow/size").toSize());
@@ -951,8 +964,8 @@ void MainWindow::serialPortNotWritable(const QString &port)
 void MainWindow::valuesReceived(MC_VALUES values, unsigned int mask)
 {
     (void)mask;
-    ui->dispCurrent->setVal(values.current_motor);
-    ui->dispDuty->setVal(values.duty_now * 100.0);
+    mMcValues = values;
+    shouldUpdateDisplayBars = true;
 }
 
 void MainWindow::paramChangedDouble(QObject *src, QString name, double newParam)

mainwindow.h

@@ -166,12 +166,16 @@ private slots:
     bool mKeyRight;
     bool mMcConfRead;
     bool mAppConfRead;
+    bool shouldUpdateDisplayBars;
     QMap<QString, int> mPageNameIdList;
 
     QTimer mPollRtTimer;
     QTimer mPollAppTimer;
     QTimer mPollImuTimer;
     QTimer mPollBmsTimer;
+    QTimer mRepaintDisplayBarTimer;
+
+    MC_VALUES mMcValues;
 
     PageWelcome *mPageWelcome;
     PageConnection *mPageConnection;