Attaching a Legend

In GraphMaster we have seen how to associate a legend with a curve visualization using PoItemLegend node. Other legend nodes derived from PoLegend are very useful in 3DdataMaster. These legends will allow you to visualize the data-color mapping and to “explain” your results.

3DdataMaster provides two main types of legends: automatic and non-automatic. Automatic legends will specify the geometry of inside “items” on their own, unlike non-automatic legends where your application must specify the geometry of each item.

"Note" to build a legend, using data mapping and an isovalues list:

Example : Use of value legend

// tutorialMesh02.cxx
 
#include <Inventor/Xt/SoXt.h>
#include <Inventor/Xt/viewers/SoXtPlaneViewer.h>
#include <Inventor/nodes/SoAnnotation.h>
#include <MeshViz/graph/PoLinearValueLegend.h>
#include <MeshViz/nodes/PoIsovaluesList.h>
#include <MeshViz/nodes/PoLinearDataMapping.h>
 
int
main( int, char** argv )
{
  // Initialize Inventor and Xt
  Widget myWindow = SoXt::init( argv[0] );
  if ( myWindow == NULL )
    exit( 1 );
 
  // Initialize MeshViz
  PoMeshViz::init();
 
  // Define the data-color mapping
  PoLinearDataMapping* myDataMapping = new PoLinearDataMapping;
  myDataMapping->color1 = SbColor( 0, 0, 1 );
  myDataMapping->value1 = 0;
  myDataMapping->color2 = SbColor( 1, 0, 0 );
  myDataMapping->value1 = 10;
 
  // Define list of values
  PoIsovaluesList* myList = new PoIsovaluesList;
  myList->setRegularIsoList( 0., 9., 10 );
 
  // Create the legend node
  PoLinearValueLegend* legend = new PoLinearValueLegend( SbVec2f( 0., 0. ), SbVec2f( 0.3, 1.0 ) );
  legend->set( "backgroundApp.material", "diffuseColor .4 .4 .4" );
 
  // Create the root of our scene graph
  SoAnnotation* root = new SoAnnotation;
  root->ref();
  root->addChild( myDataMapping );
  root->addChild( myList );
  root->addChild( legend );
 
  SoXtPlaneViewer* viewer = new SoXtPlaneViewer( myWindow );
  viewer->setBackgroundColor( SbColor( 1., 1., 1. ) );
  viewer->setSceneGraph( root );
  viewer->show();
 
  SoXt::show( myWindow );
  SoXt::mainLoop();
  return 0;
}