Difference between revisions of "Projects/Marble/MarbleMarbleWidget"

Revision as of 21:30, 5 July 2010

Editing Projects/Marble/MarbleCPlusPlus

MarbleWidget: Changing basic map properties

Tutorial Series	Marble C++ Tutorial
Previous	C++, Qt
What's Next	Tutorial 3 - Marble's GeoPainter
Further Reading	n/a

Making changes to the map

Now we want to modify the map:

Again MarbleWidget provides a convenient way to make changes to the overall look and feel:

We'd like to display a small weather map. So we switch on the satellite view, enable the clouds and enable the border lines.


include <QtGui/QApplication>

include <marble/global.h>
include <marble/MarbleWidget.h>
include <marble/AbstractFloatItem.h>

using namespace Marble;
int main(int argc, char** argv)
{

   QApplication app(argc,argv);

   // Create a Marble QWidget without a parent
   MarbleWidget *mapWidget = new MarbleWidget();

   // Load the OpenStreetMap map
   mapWidget->setMapThemeId("earth/bluemarble/bluemarble.dgml");

   mapWidget->setProjection( Mercator ); 
   
   // Enable the cloud cover and enable the country borders
   mapWidget->setShowClouds( true );
   mapWidget->setShowBorders( true );
   
   // Hide the FloatItems: Compass and StatusBar
   mapWidget->setShowOverviewMap(false);
   mapWidget->setShowScaleBar(false);
   
   foreach ( AbstractFloatItem * floatItem, mapWidget->floatItems() )
       if ( floatItem && floatItem->nameId() == "compass" ) {
           
           // Put the compass onto the left hand side
           floatItem->setPosition( QPoint( 10, 10 ) );
           // Make the content size of the compass smaller
           floatItem->setContentSize( QSize( 50, 50 ) );
       }
       
   mapWidget->show();

   return app.exec();

}

Save the code above as my_marble.cpp and compile it:


g++ -I /usr/include/qt4/ -o my_marble my_marble.cpp -lmarblewidget -lQtGui

If things go fine, execute ./my_marble and you end up with a fully usable OpenStreetMap application:

Here's a little checklist to tackle some problems that might arise when compiling the code above:

You need Qt and Marble development packages (or comparable SVN installations)
If Qt headers are not installed in /usr/include/qt4 on your system, change the path in the g++ call above accordingly.
Likewise, add -I /path/to/marble/headers if they're not to be found in /usr/include

@@ Line 12: / Line 12: @@
-== Hello Marble! ==
+== Making changes to the map ==
-The Marble API allows for a very easy integration of a map widget into your application.
+Now we want to modify the map:
+Again [http://api.kde.org/4.x-api/kdeedu/marble/classMarble_1_1MarbleWidget.html MarbleWidget] provides a convenient way to make changes to the overall look and feel:
+We'd like to display a small weather map. So we switch on the satellite view, enable the clouds and enable the border lines.
-Let's prove that with a tiny "Hello world"-like example. We just create a [http://api.kde.org/4.x-api/kdeedu/marble/classMarble_1_1MarbleWidget.html MarbleWidget] object and show it:
 <code cppqt>
@@ Line 21: / Line 24: @@
 #include <QtGui/QApplication>
+#include <marble/global.h>
 #include <marble/MarbleWidget.h>
 #include <marble/AbstractFloatItem.h>
@@ Line 36: / Line 40: @@
      mapWidget->setMapThemeId("earth/bluemarble/bluemarble.dgml");
+    mapWidget->setProjection( Mercator );
      // Enable the cloud cover and enable the country borders
      mapWidget->setShowClouds( true );