yes

mainwindow.cpp

@@ -42,6 +42,10 @@ MainWindow::MainWindow(QWidget *parent) :
     for (const auto framerate : {15, 30, 50, 60})
         m_ui->comboBoxFps->addItem(tr("%0 FPS").arg(framerate), framerate);
 
+    connect(m_ui->comboBoxFps, qOverload<int>(&QComboBox::currentIndexChanged), m_ui->widget, [this](){
+        m_ui->widget->setFps(m_ui->comboBoxFps->currentData().toInt());
+    });
+
     m_ui->spinBoxBlend->setValue(m_ui->widget->blend());
 
     connect(m_ui->spinBoxBlend, qOverload<int>(&QSpinBox::valueChanged), m_ui->widget, &OsciWidget::setBlend);
@@ -51,7 +55,7 @@ MainWindow::MainWindow(QWidget *parent) :
     connect(m_ui->spinBoxGlow, qOverload<int>(&QSpinBox::valueChanged), m_ui->widget, &OsciWidget::setGlow);
 
     auto buttonGroup = new QButtonGroup;
-    buttonGroup->setExclusive(true);    
+    buttonGroup->setExclusive(true);
     for (auto factor : { .5f, 1.f, 2.f, 4.f, 8.f })
     {
         auto radioButton = new QRadioButton(QString::number(factor));
@@ -78,20 +82,18 @@ void MainWindow::toggle()
         m_input->stop();
         m_ui->comboBoxDevices->setEnabled(true);
         m_ui->comboBoxSamplerate->setEnabled(true);
-        m_ui->comboBoxFps->setEnabled(true);
         m_ui->pushButtonToggle->setText("▶");
     }
     else
     {
         m_input->setSamplerate(m_ui->comboBoxSamplerate->currentData().toInt());
-        m_input->setFramerate(m_ui->comboBoxFps->currentData().toInt());
+        m_input->setFramerate(60);
         if (auto audioDevice = dynamic_cast<AudioDevice*>(m_input.get()))
             audioDevice->setDevice(m_audioDevices.at(m_ui->comboBoxDevices->currentIndex()));
         m_input->start();
 
         m_ui->comboBoxDevices->setEnabled(false);
         m_ui->comboBoxSamplerate->setEnabled(false);
-        m_ui->comboBoxFps->setEnabled(false);
         m_ui->pushButtonToggle->setText("▮▮");
     }
 }

oscilloscope.pro

@@ -1,6 +1,6 @@
 QT = core gui widgets multimedia
 
-CONFIG += c++17
+CONFIG += c++14
 DEFINES += QT_DEPRECATED_WARNINGS QT_DISABLE_DEPRECATED_BEFORE=0x060000
 
 SOURCES += \

osciwidget.cpp

@@ -2,12 +2,17 @@
 
 #include <cmath>
 
-#include <QLine>
+#include <QLineF>
+#include <QDebug>
+#include <QPainter>
+#include <QTimerEvent>
 
 OsciWidget::OsciWidget(QWidget *parent) :
-    QOpenGLWidget{parent}
+    QWidget{parent},
+    m_redrawTimerId(startTimer(1000/m_fps))
 {
     resizePixmap();
+    m_fpsTimer.start();
 }
 
 int OsciWidget::blend() const
@@ -25,6 +30,11 @@ float OsciWidget::glow() const
     return m_glow;
 }
 
+int OsciWidget::fps() const
+{
+    return m_fps;
+}
+
 void OsciWidget::setBlend(int blend)
 {
     if (blend == m_blend)
@@ -47,6 +57,14 @@ void OsciWidget::setGlow(float glow)
     m_glow = glow;
 }
 
+void OsciWidget::setFps(int fps)
+{
+    qDebug() << fps;
+    killTimer(m_redrawTimerId);
+    m_fps = fps;
+    m_redrawTimerId = startTimer(1000/m_fps);
+}
+
 void OsciWidget::renderSamples(const SamplePair *begin, const SamplePair *end)
 {
     QPainter painter;
@@ -59,35 +77,32 @@ void OsciWidget::renderSamples(const SamplePair *begin, const SamplePair *end)
     painter.setPen(pen);
 
     // Paint from center
-    painter.translate(width()/2, height()/2);
+    painter.translate(m_pixmap.width()/2, m_pixmap.height()/2);
+
+    const auto pointToCoordinates = [width=m_pixmap.width()/2,height=m_pixmap.height()/2,factor=m_factor](const QPointF &point)
+    {
+        return QPoint{
+            int(point.x() * factor * width),
+            int(point.y() * factor * height)
+        };
+    };
 
     for (auto i = begin; i < end; i++)
     {
         const QPointF p{
-            float(i->x) / std::numeric_limits<qint16>::max() / 2,
+            float(i->x) / std::numeric_limits<qint16>::max(),
-            float(-i->y) / std::numeric_limits<qint16>::max() / 2
+            float(-i->y) / std::numeric_limits<qint16>::max()
         };
 
-        if (Q_LIKELY(m_lastPoint.has_value()))
+        const QLineF line(m_lastPoint, p);
-        {
-            const QLineF line(*m_lastPoint, p);
-            
-            auto brightness = 1.f / line.length() / m_glow;
-            if (line.length() == 0.f || brightness > 255.f)
-                brightness = 255.f;
 
-            painter.setOpacity(brightness);
+        auto brightness = 1.f / line.length() / m_glow;
+        if (line.length() == 0.f || brightness > 255.f)
+            brightness = 255.f;
 
-            const auto pointToCoordinates = [this](const QPointF &point)
+        painter.setOpacity(brightness);
-            {
-                return QPoint{
-                    int((point.x() * width() / 2 * m_factor)),
-                    int((point.y() * height() / 2 * m_factor))
-                };
-            };
 
-            painter.drawLine(pointToCoordinates(*m_lastPoint), pointToCoordinates(p));
+        painter.drawLine(pointToCoordinates(m_lastPoint), pointToCoordinates(p));
-        }
 
         m_lastPoint = p;
     }
@@ -97,29 +112,51 @@ void OsciWidget::renderSamples(const SamplePair *begin, const SamplePair *end)
     painter.fillRect(m_pixmap.rect(), QColor(m_blend,m_blend,m_blend));
 
     painter.end();
-
-    repaint();
 }
 
 void OsciWidget::paintEvent(QPaintEvent *event)
 {
-    Q_UNUSED(event)
+    QWidget::paintEvent(event);
+
+    m_frameCounter++;
+    if (m_fpsTimer.hasExpired(1000))
+    {
+        m_displayFrameCounter = m_frameCounter;
+        m_frameCounter = 0;
+        m_fpsTimer.restart();
+    }
 
     QPainter painter;
     painter.begin(this);
     painter.drawPixmap(0, 0, m_pixmap);
+
+    painter.setPen(Qt::white);
+    painter.setBrush(Qt::white);
+    QFont font;
+    font.setPixelSize(24);
+    painter.drawText(20, 20, QString("%0FPS").arg(m_displayFrameCounter));
+
     painter.end();
+
+    if (m_pixmap.rect() != rect())
+        qDebug() << m_pixmap.rect() << rect();
+}
+
+void OsciWidget::timerEvent(QTimerEvent *event)
+{
+    QWidget::timerEvent(event);
+    if (event->timerId() == m_redrawTimerId)
+        repaint();
 }
 
 void OsciWidget::resizeEvent(QResizeEvent *event)
 {
-    Q_UNUSED(event)
+    QWidget::resizeEvent(event);
-
     resizePixmap();
 }
 
 void OsciWidget::resizePixmap()
 {
     m_pixmap = QPixmap(size());
-    m_pixmap.fill(QColor());
+    m_pixmap.fill(QColor{});
 }

osciwidget.h

@@ -1,20 +1,13 @@
 #pragma once
 
 #include <QWidget>
-
-#include <QOpenGLWidget>
-#include <QDebug>
-#include <QPainter>
 #include <QPixmap>
-#include <QTimerEvent>
+#include <QPointF>
-#include <QPoint>
 #include <QElapsedTimer>
 
-#include <optional>
-
 #include "audiodevice.h"
 
-class OsciWidget : public QOpenGLWidget
+class OsciWidget : public QWidget
 {
     Q_OBJECT
 
@@ -24,17 +17,20 @@ public:
     int blend() const;
     float factor() const;
     float glow() const;
+    int fps() const;
 
 public slots:
     void setBlend(int blend);
     void setFactor(float factor);
     void setGlow(float glow);
+    void setFps(int fps);
 
     void renderSamples(const SamplePair *begin, const SamplePair *end);
 
 protected:
     void paintEvent(QPaintEvent *event) override;
     void resizeEvent(QResizeEvent *event) override;
+    void timerEvent(QTimerEvent *event) override;
 
 private:
     void resizePixmap();
@@ -46,5 +42,11 @@ private:
 
     QPixmap m_pixmap;
 
-    std::optional<QPointF> m_lastPoint;
+    QPointF m_lastPoint;
+
+    int m_frameCounter{0}, m_displayFrameCounter{0};
+    QElapsedTimer m_fpsTimer;
+
+    int m_fps{15};
+    int m_redrawTimerId;
 };