• QML地图Map中使用QPainterPath,并显示任意点经纬度位置

            QML地图Map中提供了供绘制图形的组件，例如MapPolyline，MapCircle等，但是这些组件在绘制复杂轨迹时就显得功能不够全面，因此我将QPainterPath在Map中进行使用并进行绘制，并使用C++和Qml中的函数进行相互调用计算获取点屏幕坐标和经纬度坐标。例子中使用了QPainterPath的QPainterPath::pointAtPercent获取绘制的轨迹全过程中的各个位置的经纬度。效果如图：

     

            QML主要功能为地图显示,其中Plugin中定义的路径为我地图瓦片存放路径，你们需要修改为自己的或者直接使用在线地图。我们自定义了一个类 MapPainter，该类继承至QQuickPaintedItem,并通过元对象系统注册至QML中，覆盖到Map上方作为画布使用。

    Demo项目地址：

    https://download.csdn.net/download/zjgo007/87259998icon-default.png?t=M85Bhttps://download.csdn.net/download/zjgo007/87259998https://github.com/zjgo007/QmlDemo/tree/master/MapPainterhttps://github.com/zjgo007/QmlDemo/tree/master/MapPainter

     

    main.qml

    1. import QtQuick 2.9
    2. import QtQuick.Window 2.2
    3. import QtLocation 5.9
    4. import QtPositioning 5.9
    5. import QtQuick.Controls 2.9
    6.  
    7. import MapPainter 1.0
    8.  
    9. Window {
    10.     id:window
    11.     width: 640
    12.     height: 480
    13.     visible: true
    14.     title: qsTr("Map Painter Path")
    15.  
    16.     Plugin {
    17.         id: mapPlugin
    18.         name: "osm" // "mapboxgl", "esri", ...
    19.  
    20.         PluginParameter{//自定义地图瓦片路径
    21.             name:"osm.mapping.offline.directory"
    22.             value: "G:/Map/"
    23.         }
    24.  
    25.         PluginParameter{
    26.             name:"osm.mapping.offline.maptiledir"
    27.             value:true
    28.         }
    29.  
    30.     }
    31.  
    32.     Map {
    33.         id: myMap
    34.         center: QtPositioning.coordinate(24,104)
    35.         anchors.fill: parent
    36.         plugin: mapPlugin
    37.  
    38.         zoomLevel: 8
    39.         color: "#00000000"
    40.         copyrightsVisible: false
    41.         activeMapType: supportedMapTypes[2]
    42.  
    43. //        onVisibleRegionChanged: {//Qt 5.15以上使用
    44. //            mapPainter.mapRegionChanged()
    45. //        }
    46.  
    47.         onCenterChanged: {//Qt 5.15以下使用
    48.             mapPainter.mapRegionChanged()
    49.         }
    50.  
    51.         onZoomLevelChanged: {//Qt 5.15以下使用
    52.             mapPainter.mapRegionChanged()
    53.         }
    54.  
    55.         MapPainter{
    56.             id:mapPainter
    57.             anchors.fill: parent
    58.         }
    59.  
    60.         MapQuickItem{
    61.             id: anchorMarker
    62.             width: 50
    63.             height: 36
    64.             anchorPoint.x: image.width/2
    65.             anchorPoint.y: image.height
    66.             coordinate: myMap.center
    67.  
    68.             sourceItem: Item{
    69.                 Image {
    70.                     id:image
    71.                     source: "qrc:/anchor.png"
    72.                     sourceSize.height: 36
    73.                     sourceSize.width: 50
    74.                 }
    75.                 Text {
    76.                     id: label
    77.                     y:-15
    78.                     color: "#00ffff"
    79.                     text: qsTr("")
    80.                     font.bold: true
    81.                     font.pointSize: 11
    82.                     font.family: "微软雅黑"
    83.                 }
    84.             }
    85.         }
    86.         MouseArea {
    87.             id: mouseArea_measure
    88.             anchors.fill: parent
    89.             onClicked: {
    90.                 var coordinate = myMap.toCoordinate(Qt.point(mouse.x, mouse.y))
    91.                 mapPainter.addPathPoint(mouse.x, mouse.y,coordinate)
    92.                 anchorMarker.coordinate = coordinate
    93.             }
    94.         }
    95.     }
    96.  
    97.     Slider {
    98.         id: slider
    99.         x: 430
    100.         y: 10
    101.         stepSize: 0.01
    102.         value: 1
    103.         onValueChanged: {
    104.             var coordinate = mapPainter.mapPathData(value)
    105.             anchorMarker.coordinate = coordinate
    106.             label.text = "("+coordinate.latitude.toFixed(4)+","+coordinate.longitude.toFixed(4)+")"
    107.         }
    108.     }
    109.     Component.onCompleted: {
    110.         mapPainter.setQmlObject(window)
    111.     }
    112.  
    113.     function transGeoToPoint(coordinate){
    114.         return myMap.fromCoordinate(coordinate,false)
    115.     }
    116.  
    117.     function transPointToGeo(pointf){
    118.         return myMap.toCoordinate(pointf,false)
    119.     }
    120. }

            其中需要注意的是，在QML的Component.onCompleted信号发出后，需要该QML的QObject传递至MapPainter中，便于在C++中调用qml里定义的函数，这两个函数用于经纬度坐标和屏幕坐标转换。

    1. Component.onCompleted: {
    2.         mapPainter.setQmlObject(window)
    3.     }
    4.  
    5.     function transGeoToPoint(coordinate){
    6.         return myMap.fromCoordinate(coordinate,false)
    7.     }
    8.  
    9.     function transPointToGeo(pointf){
    10.         return myMap.toCoordinate(pointf,false)
    11.     }

            在C++中，addPathPoint(qreal x,qreal y,QGeoCoordinate coordinate)函数用于传入鼠标点击位置的屏幕坐标和经纬度坐标。mapRegionChanged()用于标记当前地图已被平移或者缩放，需要重新绘制轨迹。

            同时自定义了类GeoPainterPath，该类记录了鼠标绘制轨迹的点位置和绘制方式，我只简单的放了MoveTo和LineTo，其他绘制方式可自行添加。

    mappainter.h

    1. #ifndef MAPPAINTER_H
    2. #define MAPPAINTER_H
    3.  
    4. #include 
    5. #include 
    6. #include 
    7. #include 
    8. #include 
    9.  
    10. class GeoPainterPath
    11. {
    12. public:
    13.     GeoPainterPath() {}
    14.     ~GeoPainterPath(){}
    15.  
    16.     enum PainterType{
    17.         None,
    18.         MoveTo,
    19.         LineTo
    20.     };
    21.  
    22.     void addGeoPath(PainterType type,QGeoCoordinate coordinate);
    23.  
    24.     PainterType painterType(int index);
    25.  
    26.     QGeoCoordinate coordinate(int index);
    27.  
    28.     int size();
    29.  
    30.     void clear();
    31.  
    32. private:
    33.     QList typeList;
    34.     QList geoList;
    35. };
    36.  
    37. class MapPainter : public QQuickPaintedItem
    38. {
    39.     Q_OBJECT
    40. public:
    41.     MapPainter(QQuickItem *parent = nullptr);
    42.     ~MapPainter();
    43.     virtual void paint(QPainter *painter) Q_DECL_OVERRIDE;
    44.  
    45.     Q_INVOKABLE void setQmlObject(QObject* object);
    46.  
    47. public slots:
    48.     void addPathPoint(qreal x,qreal y,QGeoCoordinate coordinate);
    49.     void updatePainterPath();
    50.     void mapRegionChanged();
    51.  
    52.     QGeoCoordinate mapPathData(qreal percent);
    53.  
    54. private:
    55.     QPainterPath* testPath;
    56.     bool pathDirty;
    57.     GeoPainterPath mGeoPainterPath;
    58.     QObject* qmlObject;
    59. };
    60.  
    61.  
    62. #endif // MAPPAINTER_H

    mappainter.cpp

    1. #include "mappainter.h"
    2.  
    3. MapPainter::MapPainter(QQuickItem *parent):QQuickPaintedItem(parent),pathDirty(false)
    4. {
    5.     testPath = new QPainterPath();
    6.     connect(this,&QQuickPaintedItem::widthChanged,this,&MapPainter::mapRegionChanged);
    7.     connect(this,&QQuickPaintedItem::heightChanged,this,&MapPainter::mapRegionChanged);
    8. }
    9.  
    10. MapPainter::~MapPainter()
    11. {
    12.     delete testPath;
    13. }
    14.  
    15. void MapPainter::paint(QPainter *painter)
    16. {
    17.     if(pathDirty)
    18.         updatePainterPath();
    19.  
    20.     painter->setPen(QPen(QColor("red"), 2, Qt::SolidLine,
    21.                          Qt::RoundCap, Qt::RoundJoin));
    22.  
    23.     painter->drawPath(*testPath);
    24. }
    25.  
    26. void MapPainter::setQmlObject(QObject *object)
    27. {
    28.     qmlObject = object;
    29. }
    30.  
    31. void MapPainter::addPathPoint(qreal x, qreal y, QGeoCoordinate coordinate)
    32. {
    33.     if(testPath->elementCount()==0){
    34.         testPath->moveTo(x,y);
    35.         mGeoPainterPath.addGeoPath(GeoPainterPath::MoveTo,coordinate);
    36.     }else{
    37.         testPath->lineTo(x,y);
    38.         mGeoPainterPath.addGeoPath(GeoPainterPath::LineTo,coordinate);
    39.     }
    40.     update();
    41. }
    42.  
    43. void MapPainter::updatePainterPath()
    44. {
    45.     if(qmlObject){
    46.         testPath->clear();
    47.         int size = mGeoPainterPath.size();
    48.         for(int i=0;i
    49.             QGeoCoordinate coordinate = mGeoPainterPath.coordinate(i);
    50.             QVariant mapPointVar;
    51.             QMetaObject::invokeMethod(qmlObject,"transGeoToPoint",Qt::DirectConnection,
    52.                                       Q_RETURN_ARG(QVariant,mapPointVar),
    53.                                       Q_ARG(QVariant,QVariant::fromValue(coordinate))
    54.                                       );
    55.             GeoPainterPath::PainterType painterType = mGeoPainterPath.painterType(i);
    56.             QPointF mapPoint = mapPointVar.toPointF();
    57.             switch (painterType) {
    58.             case GeoPainterPath::MoveTo:
    59.                 testPath->moveTo(mapPoint);
    60.                 break;
    61.             case GeoPainterPath::LineTo:
    62.                 testPath->lineTo(mapPoint);
    63.                 break;
    64.             default:
    65.                 break;
    66.             }
    67.         }
    68.         pathDirty = false;
    69.     }
    70. }
    71.  
    72. void MapPainter::mapRegionChanged()
    73. {
    74.     pathDirty = true;
    75.     update();
    76. }
    77.  
    78. QGeoCoordinate MapPainter::mapPathData(qreal percent)
    79. {
    80.     QPointF pointf = testPath->pointAtPercent(percent);
    81.     QVariant coordinateVar;
    82.     QMetaObject::invokeMethod(qmlObject,"transPointToGeo",Qt::DirectConnection,
    83.                               Q_RETURN_ARG(QVariant,coordinateVar),
    84.                               Q_ARG(QVariant,QVariant::fromValue(pointf)));
    85.     return coordinateVar.value();
    86. }
    87.  
    88. void GeoPainterPath::addGeoPath(PainterType type, QGeoCoordinate coordinate)
    89. {
    90.     typeList.append(type);
    91.     geoList.append(coordinate);
    92. }
    93.  
    94. GeoPainterPath::PainterType GeoPainterPath::painterType(int index)
    95. {
    96.     if(index>=typeList.size()){
    97.         return PainterType::None;
    98.     }
    99.     return typeList.at(index);
    100. }
    101.  
    102. QGeoCoordinate GeoPainterPath::coordinate(int index)
    103. {
    104.     if(index>=geoList.size()){
    105.         return QGeoCoordinate();
    106.     }
    107.     return geoList.at(index);
    108. }
    109.  
    110. int GeoPainterPath::size()
    111. {
    112.     return geoList.size();
    113. }
    114.  
    115. void GeoPainterPath::clear()
    116. {
    117.     typeList.clear();
    118.     geoList.clear();
    119. }

     Demo项目地址：https://github.com/zjgo007/QmlDemo/tree/master/MapPainterhttps://github.com/zjgo007/QmlDemo/tree/master/MapPainter

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  • 原文地址：https://blog.csdn.net/zjgo007/article/details/127911714