New distance units

lib/include/QGeoView/QGVGlobal.h

@@ -54,6 +54,14 @@ enum class MapState
     SelectionRect,
 };
 
+enum class DistanceUnits
+{
+    Meters,
+    Kilometers,
+    NauticalMiles,
+    Miles,
+};
+
 enum class MouseAction : int
 {
     Move = 0x1,

lib/include/QGeoView/QGVUtils.h

@@ -0,0 +1,28 @@
+/***************************************************************************
+ * QGeoView is a Qt / C ++ widget for visualizing geographic data.
+ * Copyright (C) 2018-2020 Andrey Yaroshenko.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, see https://www.gnu.org/licenses.
+ ****************************************************************************/
+
+#pragma once
+
+#include <QGVGlobal.h>
+
+namespace QGV {
+
+QGV_LIB_DECL double metersToDistance(const double meters, const DistanceUnits unit);
+QGV_LIB_DECL QString unitToString(const DistanceUnits unit);
+
+} // namespace QGV

lib/include/QGeoView/QGVWidgetScale.h

@@ -33,9 +33,15 @@ class QGV_LIB_DECL QGVWidgetScale : public QGVWidget
     void setOrientation(Qt::Orientation orientation);
     Qt::Orientation getOrientation() const;
 
-    QString getDistanceLabel(int meters, int accuracy = 0) const;
+    void setDistanceUnits(QGV::DistanceUnits distanceUnits);
+    QGV::DistanceUnits getDistanceUnits() const;
+
+    void setUseMetersForSmallDistance(bool useMetersForSmallDistance);
+    bool getUseMetersForSmallDistance() const;
+
+protected:
+    QString getDistanceLabel(int meters) const;
 
-private:
     void onCamera(const QGVCameraState& oldState, const QGVCameraState& newState) override;
     void paintEvent(QPaintEvent* event) override;
 
@@ -44,4 +50,6 @@ class QGV_LIB_DECL QGVWidgetScale : public QGVWidget
     bool mAutoAdjust;
     int mScaleMeters;
     int mScalePixels;
+    QGV::DistanceUnits mDistanceUnits;
+    bool mUseMetersForSmallDistance;
 };

lib/lib.pri

@@ -6,6 +6,7 @@ SOURCES += \
     $$PWD/src/QGVCamera.cpp \
     $$PWD/src/QGVDrawItem.cpp \
     $$PWD/src/QGVGlobal.cpp \
+    $$PWD/src/QGVUtils.cpp \
     $$PWD/src/QGVImage.cpp \
     $$PWD/src/QGVItem.cpp \
     $$PWD/src/QGVLayer.cpp \
@@ -30,6 +31,7 @@ HEADERS += \
     $$PWD/include/QGeoView/QGVCamera.h \
     $$PWD/include/QGeoView/QGVDrawItem.h \
     $$PWD/include/QGeoView/QGVGlobal.h \
+    $$PWD/include/QGeoView/QGVUtils.h \
     $$PWD/include/QGeoView/QGVImage.h \
     $$PWD/include/QGeoView/QGVItem.h \
     $$PWD/include/QGeoView/QGVLayer.h \

lib/src/QGVUtils.cpp

@@ -0,0 +1,50 @@
+/***************************************************************************
+ * QGeoView is a Qt / C ++ widget for visualizing geographic data.
+ * Copyright (C) 2018-2020 Andrey Yaroshenko.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, see https://www.gnu.org/licenses.
+ ****************************************************************************/
+
+#include "QGVUtils.h"
+#include <QtGlobal>
+
+namespace QGV {
+
+double metersToDistance(const double meters, const DistanceUnits unit)
+{
+    if (unit == DistanceUnits::Kilometers) {
+        return meters / 1000;
+    } else if (unit == DistanceUnits::NauticalMiles) {
+        return meters / 1852.0;
+    } else if (unit == DistanceUnits::Miles) {
+        return meters / 1609.0;
+    }
+    return meters;
+}
+
+QString unitToString(const DistanceUnits unit)
+{
+    if (unit == DistanceUnits::Meters) {
+        return QT_TRANSLATE_NOOP("QGV", "m");
+    } else if (unit == DistanceUnits::Kilometers) {
+        return QT_TRANSLATE_NOOP("QGV", "km");
+    } else if (unit == DistanceUnits::NauticalMiles) {
+        return QT_TRANSLATE_NOOP("QGV", "nm");
+    } else if (unit == DistanceUnits::Miles) {
+        return QT_TRANSLATE_NOOP("QGV", "mi");
+    }
+    return "";
+}
+
+} // namespace QGV

lib/src/QGVWidgetScale.cpp

@@ -18,6 +18,7 @@
 
 #include "QGVWidgetScale.h"
 #include "QGVMapQGView.h"
+#include "QGVUtils.h"
 
 #include <QPaintEvent>
 #include <QPainter>
@@ -30,6 +31,9 @@ const int minLengthPixel = 130;
 
 QGVWidgetScale::QGVWidgetScale(Qt::Orientation orientation)
 {
+    mDistanceUnits = QGV::DistanceUnits::Kilometers;
+    mUseMetersForSmallDistance = true;
+
     mAutoAdjust = true;
     mScaleMeters = 0;
     mScalePixels = 0;
@@ -75,12 +79,38 @@ Qt::Orientation QGVWidgetScale::getOrientation() const
     return mOrientation;
 }
 
-QString QGVWidgetScale::getDistanceLabel(int meters, int accuracy) const
+void QGVWidgetScale::setDistanceUnits(QGV::DistanceUnits distanceUnits)
+{
+    mDistanceUnits = distanceUnits;
+}
+
+QGV::DistanceUnits QGVWidgetScale::getDistanceUnits() const
+{
+    return mDistanceUnits;
+}
+
+void QGVWidgetScale::setUseMetersForSmallDistance(bool useMetersForSmallDistance)
+{
+    mUseMetersForSmallDistance = useMetersForSmallDistance;
+}
+
+bool QGVWidgetScale::getUseMetersForSmallDistance() const
+{
+    return mUseMetersForSmallDistance;
+}
+
+QString QGVWidgetScale::getDistanceLabel(int meters) const
 {
-    if (meters > 1000) {
-        return tr("%1 km").arg(QString::number(static_cast<double>(meters) / 1000, 'f', accuracy));
+    const double distanceValue = QGV::metersToDistance(meters, mDistanceUnits);
+    if (distanceValue >= 1 || (distanceValue < 1 && !mUseMetersForSmallDistance)) {
+        const int accuracy = distanceValue >= 1 ? 0 : 2;
+        return tr("%1 %2")
+                .arg(QString::number(static_cast<double>(distanceValue), 'f', accuracy))
+                .arg(QGV::unitToString(mDistanceUnits));
     } else {
-        return tr("%1 m").arg(QString::number(static_cast<double>(meters), 'f', accuracy));
+        return tr("%1 %2")
+                .arg(QString::number(static_cast<double>(meters), 'f', 0))
+                .arg(QGV::unitToString(QGV::DistanceUnits::Meters));
     }
 }