add zoom control

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