Add polished macOS location plotter experience

src/MapWidget.cpp

@@ -4,6 +4,7 @@
 #include <QLabel>
 #include <QLineF>
 #include <QMouseEvent>
+#include <QNativeGestureEvent>
 #include <QNetworkAccessManager>
 #include <QNetworkDiskCache>
 #include <QNetworkRequest>
@@ -58,7 +59,7 @@ MapWidget::MapWidget(QWidget *parent)
     : QWidget(parent)
     , m_network(new QNetworkAccessManager(this))
 {
-    setMinimumSize(640, 420);
+    setMinimumSize(480, 320);
     setMouseTracking(true);
 
     const QString cacheRoot = QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
@@ -115,23 +116,55 @@ void MapWidget::fitToPoints()
     }
     double minimumLatitude = m_points.first().latitude;
     double maximumLatitude = minimumLatitude;
-    double minimumLongitude = m_points.first().longitude;
-    double maximumLongitude = minimumLongitude;
+    QVector<double> longitudes;
+    longitudes.reserve(m_points.size());
     for (const TelemetryPoint &point : m_points) {
         minimumLatitude = std::min(minimumLatitude, point.latitude);
         maximumLatitude = std::max(maximumLatitude, point.latitude);
-        minimumLongitude = std::min(minimumLongitude, point.longitude);
-        maximumLongitude = std::max(maximumLongitude, point.longitude);
+        double normalizedLongitude = std::fmod(point.longitude + 360.0, 360.0);
+        if (normalizedLongitude < 0.0) {
+            normalizedLongitude += 360.0;
+        }
+        longitudes.push_back(normalizedLongitude);
+    }
+    std::sort(longitudes.begin(), longitudes.end());
+
+    // Fit the shortest circular longitude interval. A plain min/max makes
+    // points around +180/-180 look almost a full world apart.
+    double arcStart = longitudes.first();
+    double longitudeSpan = 0.0;
+    if (longitudes.size() > 1) {
+        double largestGap = -1.0;
+        int largestGapIndex = 0;
+        for (int i = 0; i < longitudes.size(); ++i) {
+            const double current = longitudes[i];
+            const double next = i + 1 < longitudes.size()
+                ? longitudes[i + 1] : longitudes.first() + 360.0;
+            const double gap = next - current;
+            if (gap > largestGap) {
+                largestGap = gap;
+                largestGapIndex = i;
+            }
+        }
+        arcStart = largestGapIndex + 1 < longitudes.size()
+            ? longitudes[largestGapIndex + 1] : longitudes.first();
+        longitudeSpan = 360.0 - largestGap;
     }
     m_centerLat = 0.5 * (minimumLatitude + maximumLatitude);
-    m_centerLon = 0.5 * (minimumLongitude + maximumLongitude);
+    m_centerLon = std::fmod(arcStart + longitudeSpan * 0.5 + 180.0, 360.0);
+    if (m_centerLon < 0.0) {
+        m_centerLon += 360.0;
+    }
+    m_centerLon -= 180.0;
     const double availableWidth = std::max(100.0, width() * 0.82);
     const double availableHeight = std::max(100.0, height() * 0.82);
     for (int zoom = MaxZoom; zoom >= MinZoom; --zoom) {
-        const QPointF topLeft = coordinateToWorld(maximumLatitude, minimumLongitude, zoom);
-        const QPointF bottomRight = coordinateToWorld(minimumLatitude, maximumLongitude, zoom);
-        if (std::fabs(bottomRight.x() - topLeft.x()) <= availableWidth
-            && std::fabs(bottomRight.y() - topLeft.y()) <= availableHeight) {
+        const double worldWidth = static_cast<double>(TileSize) * static_cast<double>(1 << zoom);
+        const double longitudeWidth = longitudeSpan / 360.0 * worldWidth;
+        const double top = coordinateToWorld(maximumLatitude, m_centerLon, zoom).y();
+        const double bottom = coordinateToWorld(minimumLatitude, m_centerLon, zoom).y();
+        if (longitudeWidth <= availableWidth
+            && std::fabs(bottom - top) <= availableHeight) {
             m_zoom = zoom;
             break;
         }
@@ -260,16 +293,52 @@ void MapWidget::paintEvent(QPaintEvent *)
 
 void MapWidget::wheelEvent(QWheelEvent *event)
 {
-    const int delta = event->angleDelta().y();
-    if (delta == 0) {
+    const QPoint pixelDelta = event->pixelDelta();
+    const QPoint angleDelta = event->angleDelta();
+    const double delta = !pixelDelta.isNull()
+        ? pixelDelta.y() / 36.0
+        : angleDelta.y() / 120.0;
+    if (qFuzzyIsNull(delta)) {
         return;
     }
 
     disableAutoFollowFromUserAction();
-    setZoomKeepingPoint(m_zoom + (delta > 0 ? 1 : -1), event->position());
+    m_wheelZoomAccumulator += delta;
+    while (std::abs(m_wheelZoomAccumulator) >= 1.0) {
+        const int direction = m_wheelZoomAccumulator > 0.0 ? 1 : -1;
+        setZoomKeepingPoint(m_zoom + direction, event->position());
+        m_wheelZoomAccumulator -= direction;
+    }
+    if (event->phase() == Qt::ScrollEnd) {
+        m_wheelZoomAccumulator = 0.0;
+    }
     event->accept();
 }
 
+bool MapWidget::event(QEvent *event)
+{
+    if (event->type() == QEvent::NativeGesture) {
+        auto *gesture = static_cast<QNativeGestureEvent *>(event);
+        if (gesture->gestureType() == Qt::ZoomNativeGesture) {
+            disableAutoFollowFromUserAction();
+            // macOS reports pinch magnification as small deltas. Accumulate
+            // them so map-tile zoom remains stable instead of flickering.
+            m_wheelZoomAccumulator += gesture->value() * 5.0;
+            while (std::abs(m_wheelZoomAccumulator) >= 1.0) {
+                const int direction = m_wheelZoomAccumulator > 0.0 ? 1 : -1;
+                setZoomKeepingPoint(m_zoom + direction, gesture->position());
+                m_wheelZoomAccumulator -= direction;
+            }
+            gesture->accept();
+            return true;
+        }
+        if (gesture->gestureType() == Qt::EndNativeGesture) {
+            m_wheelZoomAccumulator = 0.0;
+        }
+    }
+    return QWidget::event(event);
+}
+
 void MapWidget::mousePressEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::RightButton) {