15 #ifndef QGSMAPCANVASTRACER_H    16 #define QGSMAPCANVASTRACER_H    79     void reportError( 
PathError err, 
bool addingVertex );
    86     void onCurrentLayerChanged();
    93     QAction *mActionEnableTracing = 
nullptr;
    94     QAction *mActionEnableSnapping = 
nullptr;
    96     static QHash<QgsMapCanvas *, QgsMapCanvasTracer *> sTracers;
    99 #endif // QGSMAPCANVASTRACER_H virtual void configure()
Allows derived classes to setup the settings just before the tracer is initialized. 
Utility class that construct a planar graph from the input vector layers and provides shortest path s...
A bar for displaying non-blocking messages to the user. 
Map canvas is a class for displaying all GIS data types on a canvas. 
void setActionEnableTracing(QAction *action)
Assign "enable tracing" checkable action to the tracer. 
Extension of QgsTracer that provides extra functionality: 
void setActionEnableSnapping(QAction *action)
Assign "enable snapping" checkable action to the tracer. 
PathError
Possible errors that may happen when calling findShortestPath() 
QAction * actionEnableSnapping() const 
Access to action that user may use to toggle snapping on/off. 
QAction * actionEnableTracing() const 
Access to action that user may use to toggle tracing on/off. May be null if no action was associated...