add zoom control

videoviewerwidget.cpp

@@ -9,7 +9,7 @@
 
 VideoViewerWidget::VideoViewerWidget(QWidget *parent)
     : QWidget(parent), m_pipeline(nullptr), m_appSink(nullptr),
-      m_busWatchId(0)
+      m_busWatchId(0), m_zoomFactor(1.0)
 {
     // Register QImage as meta type for signal/slot across threads
     qRegisterMetaType<QImage>("QImage");
@@ -38,12 +38,37 @@ void VideoViewerWidget::setupUI()
     mainLayout->setContentsMargins(0, 0, 0, 0);
     mainLayout->setSpacing(5);
 
-    // Video display - no GroupBox for maximum space
+    // Video display in scroll area for zoom support
-    m_videoDisplay = new QLabel(this);
+    m_scrollArea = new QScrollArea(this);
-    m_videoDisplay->setMinimumSize(640, 480);
+    m_scrollArea->setWidgetResizable(false);
-    m_videoDisplay->setStyleSheet("background-color: black; border: 1px solid #666;");
+    m_scrollArea->setAlignment(Qt::AlignCenter);
+    m_scrollArea->setStyleSheet("QScrollArea { background-color: black; border: 1px solid #666; }");
+
+    m_videoDisplay = new QLabel();
+    m_videoDisplay->setMinimumSize(320, 240);
+    m_videoDisplay->setStyleSheet("background-color: black;");
     m_videoDisplay->setAlignment(Qt::AlignCenter);
-    m_videoDisplay->setScaledContents(false); // Disable for better aspect ratio control
+    m_videoDisplay->setScaledContents(false);
+
+    m_scrollArea->setWidget(m_videoDisplay);
+
+    // Zoom control
+    QHBoxLayout* zoomLayout = new QHBoxLayout();
+    zoomLayout->addWidget(new QLabel("Zoom:", this));
+
+    m_zoomSlider = new QSlider(Qt::Horizontal, this);
+    m_zoomSlider->setMinimum(50);  // 50%
+    m_zoomSlider->setMaximum(200); // 200%
+    m_zoomSlider->setValue(100);   // 100% default
+    m_zoomSlider->setTickPosition(QSlider::TicksBelow);
+    m_zoomSlider->setTickInterval(25);
+    connect(m_zoomSlider, &QSlider::valueChanged, this, &VideoViewerWidget::onZoomChanged);
+
+    m_zoomLabel = new QLabel("100%", this);
+    m_zoomLabel->setMinimumWidth(50);
+
+    zoomLayout->addWidget(m_zoomSlider);
+    zoomLayout->addWidget(m_zoomLabel);
 
     // Controls
     QGroupBox* controlGroup = new QGroupBox("Viewer Controls", this);
@@ -91,8 +116,9 @@ void VideoViewerWidget::setupUI()
     controlLayout->addWidget(m_statusLabel);
     controlGroup->setLayout(controlLayout);
 
-    // Add to main layout: video takes most space, controls at bottom
+    // Add to main layout: video takes most space, zoom control, then viewer controls at bottom
-    mainLayout->addWidget(m_videoDisplay, 1);
+    mainLayout->addWidget(m_scrollArea, 1);
+    mainLayout->addLayout(zoomLayout);
     mainLayout->addWidget(controlGroup);
 
     setLayout(mainLayout);
@@ -220,9 +246,10 @@ void VideoViewerWidget::stopPipeline()
         m_busWatchId = 0;
     }
 
-    // Clear video display
+    // Clear video display and current frame
     m_videoDisplay->clear();
     m_videoDisplay->setText("");
+    m_currentFrame = QImage();
 
     m_statusLabel->setText("Status: Stopped");
     m_statusLabel->setStyleSheet("QLabel { background-color: #f0f0f0; padding: 5px; border-radius: 3px; }");
@@ -322,8 +349,28 @@ void VideoViewerWidget::onSourceTypeChanged(int index)
     m_portEdit->setEnabled(needsNetwork);
 }
 
+void VideoViewerWidget::onZoomChanged(int value)
+{
+    m_zoomFactor = value / 100.0;
+    m_zoomLabel->setText(QString("%1%").arg(value));
+
+    // Re-display the current frame with new zoom factor
+    if (!m_currentFrame.isNull()) {
+        displayFrame(m_currentFrame);
+    }
+}
+
 GstFlowReturn VideoViewerWidget::newSampleCallback(GstAppSink* appsink, gpointer user_data)
 {
+    static int callbackCount = 0;
+    callbackCount++;
+
+    if (callbackCount == 1) {
+        qDebug() << "[VideoViewer] Callback: First sample callback!";
+    } else if (callbackCount % 30 == 0) {
+        qDebug() << "[VideoViewer] Callback: Samples received:" << callbackCount;
+    }
+
     VideoViewerWidget* viewer = static_cast<VideoViewerWidget*>(user_data);
     if (!viewer) {
         qDebug() << "[VideoViewer] Callback: viewer is null";
@@ -405,15 +452,44 @@ void VideoViewerWidget::displayFrame(const QImage& frame)
     }
 
     static bool firstFrame = true;
+    static int frameCount = 0;
+    frameCount++;
+
+    bool debugThisFrame = firstFrame || (frameCount % 30 == 0);
+
     if (firstFrame) {
-        qDebug() << "[VideoViewer] First frame received! Size:" << frame.width() << "x" << frame.height();
+        qDebug() << "[VideoViewer] First frame received! Size:" << frame.width() << "x" << frame.height()
+                 << "Format:" << frame.format();
         firstFrame = false;
+    } else if (frameCount % 30 == 0) {
+        qDebug() << "[VideoViewer] Frames received:" << frameCount;
     }
 
-    // Convert QImage to QPixmap and scale to fit label while keeping aspect ratio
+    // Store current frame for zoom changes
+    m_currentFrame = frame;
+
+    // Convert QImage to QPixmap
     QPixmap pixmap = QPixmap::fromImage(frame);
-    QPixmap scaledPixmap = pixmap.scaled(m_videoDisplay->size(),
+    if (pixmap.isNull()) {
+        qDebug() << "[VideoViewer] ERROR: Pixmap conversion failed!";
+        return;
+    }
+
+    // Calculate target size with zoom factor
+    QSize targetSize = frame.size() * m_zoomFactor;
+
+    // Scale pixmap with zoom factor
+    QPixmap scaledPixmap = pixmap.scaled(targetSize,
                                          Qt::KeepAspectRatio,
                                          Qt::SmoothTransformation);
-    m_videoDisplay->setPixmap(scaledPixmap);
+
+    if (debugThisFrame) {
+        qDebug() << "[VideoViewer] Target size:" << targetSize << "Zoom:" << m_zoomFactor
+                 << "Scaled pixmap:" << scaledPixmap.size();
+    }
+
+    // Update the label size to match the scaled pixmap
+    m_videoDisplay->setPixmap(scaledPixmap);
+    m_videoDisplay->resize(scaledPixmap.size());
+    m_videoDisplay->update();
 }

videoviewerwidget.h

@@ -7,6 +7,8 @@
 #include <QLineEdit>
 #include <QLabel>
 #include <QImage>
+#include <QSlider>
+#include <QScrollArea>
 #include <gst/gst.h>
 #include <gst/app/gstappsink.h>
 
@@ -25,6 +27,7 @@ private slots:
     void onStartViewer();
     void onStopViewer();
     void onSourceTypeChanged(int index);
+    void onZoomChanged(int value);
     void displayFrame(const QImage& frame);
 
 private:
@@ -39,6 +42,7 @@ private:
     static GstFlowReturn newSampleCallback(GstAppSink* appsink, gpointer user_data);
 
     // UI elements
+    QScrollArea* m_scrollArea;
     QLabel* m_videoDisplay;
     QPushButton* m_startBtn;
     QPushButton* m_stopBtn;
@@ -46,11 +50,17 @@ private:
     QLineEdit* m_hostEdit;
     QLineEdit* m_portEdit;
     QLabel* m_statusLabel;
+    QSlider* m_zoomSlider;
+    QLabel* m_zoomLabel;
 
     // GStreamer elements
     GstElement* m_pipeline;
     GstElement* m_appSink;
     guint m_busWatchId;
+
+    // Video state
+    QImage m_currentFrame;
+    double m_zoomFactor;
 };
 
 #endif // VIDEOVIEWERWIDGET_H