Geant4 User's Guide for Application Developers - Geant4 - CERN

VisualizationNote that class G4Text also inherits G4VMarker. Size of text is recognized as "font size", i.e., height of the text.All the access functions defined for class G4VMarker mentioned above are available. In addition, the followingaccess functions are available, too://----- Set functions of G4Textvoid G4Text::SetText ( const G4String& text ) ;void G4Text::SetOffset ( double dx, double dy ) ;//----- Get functions of G4TextG4String G4Text::GetText () const;G4double G4Text::GetXOffset () const;G4double G4Text::GetYOffset () const;Method SetText() defines text to be visualized, and GetText() returns the defined text. Method SetOffset()defines x (horizontal) and y (vertical) offsets in the screen coordinates. By default, both offsets are zero, andthe text starts from the 3D position given to the constructor or to the method G4VMarker:SetPosition().Offsets should be given with the same units as the one adopted for the size, i.e., world-size or screen-size units.Example 8.8 shows sample C++ source code to define text with the following properties:• Text: "Welcome to Geant4 Visualization"• Position: (0.,0.,0.) in the world coordinates• Horizontal offset: 10 pixels• Vertical offset: -20 pixels• Colour: blue (default)Example 8.8. An example of defining text.//----- C++ source codes: An example of defining a visualizable text//----- InstantiationG4Text text ;text.SetText ( "Welcome to Geant4 Visualization");text.SetPosition ( G4Point3D(0.,0.,0.) );// These three lines are equivalent to:// G4Text text ( "Welcome to Geant4 Visualization",// G4Point3D(0.,0.,0.) );//----- Size (font size in units of pixels)G4double fontsize = 24.; // Should be 24. * pixels - to be implemented.text.SetScreenSize ( fontsize );//----- OffsetsG4double x_offset = 10.; // Should be 10. * pixels - to be implemented.G4double y_offset = -20.; // Should be -20. * pixels - to be implemented.text.SetOffset( x_offset, y_offset );//----- Color (Blue is the default setting, and so the codes below are omissible)G4Colour blue( 0., 0., 1. );G4VisAttributes att ( blue );text.SetVisAttributes ( att );//----- end of C++ source codes8.10. Making a MovieThese instructions are suggestive only. The following procedures have not been tested on all platforms. Thereare clearly some instructions that apply only to Unix-like systems with an X-Windows based windowing system.However, it should not be difficult to take the ideas presented here and extend them to other platforms and systems.The procedures described here need graphics drivers that can produce picture files that can be converted to a formsuitable for an MPEG encoder. There may be other ways of capturing the screen images and we would be happyto hear about them. Graphics drivers currently capable of producing picture files are: More informations aboutMPEG encoderDriverFile type266