Camera crosshair

Author: etet100

src/astrocore/modules/camera/camera.cpp

@@ -8,6 +8,7 @@
 #include <QMessageBox>
 #include <QtWidgets>
 #include <QImageCapture>
+#include "utils/cache.h"
 
 Camera::Camera(QWidget* parent) : QVideoWidget(parent), m_frameProcessor(this)
 {
@@ -28,6 +29,9 @@ Camera::Camera(QWidget* parent) : QVideoWidget(parent), m_frameProcessor(this)
         findBestResolution(this->width(), this->height());
     });
 
+    buildCrosshairMenu();
+    loadCrosshairStyle();
+
     init();
 }
 
@@ -227,6 +231,11 @@ void Camera::updateCameras()
         m_menu.addAction(videoDeviceAction);
         m_camerasCount++;
     }
+
+    if (m_crosshairMenu != nullptr) {
+        m_menu.addSeparator();
+        m_menu.addMenu(m_crosshairMenu);
+    }
 }
 
 void Camera::findBestResolution(int w, int h)
@@ -262,3 +271,57 @@ void Camera::findBestResolution(int w, int h)
     }
 }
 
+void Camera::buildCrosshairMenu()
+{
+    using Style = CameraFrameProcessor::CrosshairStyle;
+
+    m_crosshairMenu = new QMenu(tr("Crosshair"), this);
+    m_crosshairGroup = new QActionGroup(this);
+    m_crosshairGroup->setExclusive(true);
+
+    const QList<QPair<QString, Style>> styles = {
+        { tr("None"), Style::None },
+        { tr("Cross"), Style::Cross },
+        { tr("Cross with gap"), Style::CrossGap },
+        { tr("Dot"), Style::Dot },
+        { tr("Circle with ticks"), Style::CircleTicks }
+    };
+
+    for (const auto &[label, style] : styles) {
+        QAction *action = new QAction(label, m_crosshairGroup);
+        action->setCheckable(true);
+        action->setData(static_cast<int>(style));
+        m_crosshairMenu->addAction(action);
+    }
+
+    connect(m_crosshairGroup, &QActionGroup::triggered, this, &Camera::updateCrosshairStyle);
+}
+
+void Camera::loadCrosshairStyle()
+{
+    using Style = CameraFrameProcessor::CrosshairStyle;
+
+    const int stored = Cache::instance().getInt("camera/crosshairStyle", static_cast<int>(Style::CrossGap));
+
+    m_frameProcessor.setCrosshairStyle(static_cast<Style>(stored));
+
+    for (QAction *action : m_crosshairGroup->actions()) {
+        if (action->data().toInt() == stored) {
+            action->setChecked(true);
+            break;
+        }
+    }
+}
+
+void Camera::updateCrosshairStyle(QAction *action)
+{
+    using Style = CameraFrameProcessor::CrosshairStyle;
+
+    const int value = action->data().toInt();
+
+    m_frameProcessor.setCrosshairStyle(static_cast<Style>(value));
+
+    Cache::instance().set("camera/crosshairStyle", value);
+    Cache::instance().flush();
+}
+

src/astrocore/modules/camera/camera.h

@@ -31,6 +31,7 @@ private slots:
     void displayCameraError();
     void updateCameraDevice(QAction *action);
     void updateCameraActive(bool active);
+    void updateCrosshairStyle(QAction *action);
 
 protected:
     void resizeEvent(QResizeEvent *event) override;
@@ -39,12 +40,14 @@ private slots:
 
 private:
     QActionGroup *videoDevicesGroup = nullptr;
+    QActionGroup *m_crosshairGroup = nullptr;
     QMediaDevices m_devices;
     QVideoSink m_videoSink;
     QScopedPointer<QCamera> m_camera;
     QMediaCaptureSession m_captureSession;
     QTimer m_resizeTimer;
     QMenu m_menu;
+    QMenu *m_crosshairMenu = nullptr;
     CameraFrameProcessor m_frameProcessor;
     int m_camerasCount = 0;
 
@@ -53,6 +56,8 @@ private slots:
     void findBestResolution(int, int);
     void showCameraDisabled();
     void disableCamera();
+    void buildCrosshairMenu();
+    void loadCrosshairStyle();
 };
 
 #endif

src/astrocore/modules/camera/cameraframeprocessor.cpp

@@ -27,7 +27,7 @@ void CameraFrameProcessor::setVideoSinks(QVideoSink *inputSink, QVideoSink *outp
 
 void CameraFrameProcessor::processFrame(const QVideoFrame &frame)
 {
-    if (!m_overlay) {
+    if (m_style == CrosshairStyle::None) {
         m_outputSink->setVideoFrame(frame);
 
         return;
@@ -40,19 +40,70 @@ void CameraFrameProcessor::processFrame(const QVideoFrame &frame)
         return;
     }
 
-    QFont font = painter.font();
-    font.setPixelSize(100);
-    font.setBold(true);
-    painter.setFont(font);
-
-    painter.drawText(50, 50, "Example text");
+    drawCrosshair(painter, image.size());
 
     QVideoFrame frameCopy(image);
 
     m_outputSink->setVideoFrame(frameCopy);
-    m_outputSink->setSubtitleText("abc");
 }
-void CameraFrameProcessor::setOverlay(bool overlay)
+
+void CameraFrameProcessor::drawCrosshair(QPainter &painter, const QSize &size)
+{
+    const int cx = size.width() / 2;
+    const int cy = size.height() / 2;
+
+    // scale line width and center gap to the frame size so the crosshair
+    // stays visible on both low- and high-resolution cameras
+    const int penWidth = qMax(2, size.height() / 300);
+    const int gap = qMax(6, size.height() / 40);
+
+    painter.setRenderHint(QPainter::Antialiasing, true);
+
+    QPen pen(Qt::red);
+    pen.setWidth(penWidth);
+    painter.setPen(pen);
+    painter.setBrush(Qt::NoBrush);
+
+    switch (m_style) {
+        case CrosshairStyle::Cross:
+            // full lines crossing the whole frame
+            painter.drawLine(0, cy, size.width(), cy);
+            painter.drawLine(cx, 0, cx, size.height());
+            break;
+
+        case CrosshairStyle::CrossGap:
+            // lines with a gap in the middle and a circle at the center
+            painter.drawLine(0, cy, cx - gap, cy);
+            painter.drawLine(cx + gap, cy, size.width(), cy);
+            painter.drawLine(cx, 0, cx, cy - gap);
+            painter.drawLine(cx, cy + gap, cx, size.height());
+            painter.drawEllipse(QPoint(cx, cy), gap, gap);
+            break;
+
+        case CrosshairStyle::Dot:
+            // single filled dot marking the target point
+            painter.setBrush(Qt::red);
+            painter.drawEllipse(QPoint(cx, cy), penWidth * 2, penWidth * 2);
+            break;
+
+        case CrosshairStyle::CircleTicks: {
+            // center circle with short ticks pointing inward
+            const int radius = gap * 2;
+            const int tick = gap;
+            painter.drawEllipse(QPoint(cx, cy), radius, radius);
+            painter.drawLine(cx, cy - radius - tick, cx, cy - radius);
+            painter.drawLine(cx, cy + radius, cx, cy + radius + tick);
+            painter.drawLine(cx - radius - tick, cy, cx - radius, cy);
+            painter.drawLine(cx + radius, cy, cx + radius + tick, cy);
+            break;
+        }
+
+        case CrosshairStyle::None:
+            break;
+    }
+}
+
+void CameraFrameProcessor::setCrosshairStyle(CrosshairStyle style)
 {
-    m_overlay = overlay;
+    m_style = style;
 }

src/astrocore/modules/camera/cameraframeprocessor.h

@@ -8,14 +8,26 @@
 #include <QVideoSink>
 #include <QVideoFrame>
 
+class QPainter;
+
 class CameraFrameProcessor : public QObject
 {
     Q_OBJECT
 
     public:
+        enum class CrosshairStyle {
+            None,
+            Cross,
+            CrossGap,
+            Dot,
+            CircleTicks
+        };
+        Q_ENUM(CrosshairStyle)
+
         CameraFrameProcessor(QObject *parent);
         void setVideoSinks(QVideoSink *inputSink, QVideoSink *outputSink);
-        void setOverlay(bool overlay);
+        void setCrosshairStyle(CrosshairStyle style);
+        CrosshairStyle crosshairStyle() const { return m_style; }
 
     signals:
         void videoSinkChanged();
@@ -24,9 +36,11 @@ class CameraFrameProcessor : public QObject
         void processFrame(const QVideoFrame &frame);
 
     private:
+        void drawCrosshair(QPainter &painter, const QSize &size);
+
         QVideoSink *m_inputSink = nullptr;
         QVideoSink *m_outputSink = nullptr;
-        bool m_overlay = false;
+        CrosshairStyle m_style = CrosshairStyle::CrossGap;
 };
 
 #endif // CAMERAFRAMEPROCESSOR_H