Marble paint layer example

main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include <marble/MarbleWidget.h>
#include <marble/GeoPainter.h>
#include "mypaintlayer.h"
#include <QMenuBar>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    map_widget = new Marble::MarbleWidget();
    map_widget->setMapThemeId("earth/openstreetmap/openstreetmap.dgml");

    home = new Marble::GeoDataCoordinates(4.75028, 52.09761, 0.0, Marble::GeoDataCoordinates::Degree);
    map_widget->centerOn(*home);
    map_widget->setZoom(3500);

    layerList = new QList<MyPaintLayer*>();

    map_widget->setShowCompass(false);
    map_widget->setShowCrosshairs(false);
    map_widget->setShowGrid(false);
    map_widget->setShowScaleBar(false);
    map_widget->setShowOverviewMap(false);


    setCentralWidget(map_widget);
    mainMenu = menuBar()->addMenu("Main menu");
    addLayer = new QAction("Add Layer", this);
    mainMenu->addAction(addLayer);

    removeLayer = new QAction("Remove Layer", this);
    mainMenu->addAction(removeLayer);

    connect(addLayer, SIGNAL(triggered()), this, SLOT(onLayerAdded()));
    connect(removeLayer, SIGNAL(triggered()), this, SLOT(onLayerRemoved()));
}

void MainWindow::onLayerAdded()
{
    MyPaintLayer *pLayer = new MyPaintLayer(map_widget, *home);
    map_widget->addLayer(pLayer);
    layerList->append(pLayer);
    map_widget->update();
}

void MainWindow::onLayerRemoved()
{
    map_widget->removeLayer(layerList->last());
    layerList->removeLast();
    map_widget->update();
}

MainWindow::~MainWindow()
{

}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <marble/MarbleWidget.h>
#include <QMenu>
#include <QAction>
#include "mypaintlayer.h"
#include <QList>

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    QMenu *mainMenu;
    QAction *addLayer;
    QAction *removeLayer;
    Marble::GeoDataCoordinates *home;
    Marble::MarbleWidget *map_widget;
    QList<MyPaintLayer*> *layerList;

private slots:
    void onLayerAdded();
    void onLayerRemoved();
};

#endif // MAINWINDOW_H

mypaintlayer.cpp

#include "mypaintlayer.h"
#include <marble/GeoDataLinearRing.h>
#include <math.h>

MyPaintLayer::MyPaintLayer(MarbleWidget* widget, GeoDataCoordinates &origin) :
    m_widget(widget),
    m_index(0),
    origin(origin)
{

}

QStringList MyPaintLayer::renderPosition() const
{
    return  QStringList() << "SURFACE";
}

bool MyPaintLayer::render(GeoPainter *painter, ViewportParams *viewport,
    const QString& renderPos, GeoSceneLayer * layer)
{
    qDebug() << "render object: " << this;
    painter->setRenderHint(QPainter::Antialiasing, true);
    painter->setPen(QPen(QBrush(QColor::fromRgb(255,255,255,200)), 3.0, Qt::SolidLine, Qt::RoundCap ));
    painter->setBrush(QBrush(QColor::fromRgb(255,255,255,100)));

    GeoDataLinearRing *ring = new GeoDataLinearRing();
    GeoDataCoordinates one = origin.moveByBearing(0, 0);
    GeoDataCoordinates two = one.moveByBearing(M_PI/2, 0.000004);
    GeoDataCoordinates three = two.moveByBearing(M_PI, 0.000004);
    GeoDataCoordinates four = three.moveByBearing(3*M_PI/2, 0.000004);
    ring->append(one);
    ring->append(two);
    ring->append(three);
    ring->append(four);

    painter->drawPolygon(*ring);

    return true;
}

mypaintlayer.h

#ifndef MYPAINTLAYER_H
#define MYPAINTLAYER_H

#include <marble/MarbleWidget.h>
#include <marble/MarbleMap.h>
#include <marble/MarbleModel.h>
#include <marble/GeoPainter.h>
#include <marble/LayerInterface.h>

using namespace Marble;

class MyPaintLayer : public QObject, public LayerInterface
{
    Q_OBJECT

public:
    MyPaintLayer(MarbleWidget* widget, GeoDataCoordinates &origin);

    virtual QStringList renderPosition() const;

    virtual bool render(GeoPainter *painter, ViewportParams *viewport,
       const QString& renderPos = "NONE", GeoSceneLayer * layer = 0);

private:
    MarbleWidget* m_widget;
    GeoDataCoordinates origin;
    int m_index;
};

#endif // MYPAINTLAYER_H