TriState Manual

Table of Contents

• About
• Functionality
• Further Reading

About

In Cinema 4D it is possible to select multiple scene elements at once. The Attribute Manager displays the parameters of all these selected objects. Only the parameters that are part of all selected objects are displayed. If the value of a given parameter is the same for all selected objects, this value is displayed in the Attribute Manager. But if the value of the parameter on the different objects is not the same a tristate is displayed instead, indicating that the values are not the same.

TriState is a utility class to make it easy to handle multiple parameter values and to display them using GeDialog gadgets. The TriState template class can handle Bool, Int32, Float, Vector, BaseTime and String values. Typically the TriState class is only relevant to create CustomGuiData / iCustomGui based custom GUI elements.

Note

TriState elements are only handled with GeDialog gadgets. Parameter descriptions (Description elements) define the parameters of a C4DAtom based element and do not handle any TriState.

    // This example gets the names of all selected objects in a GeDialog::InitValues() function.
    // The object names are stored in a TriState object.
    // This TriState object is used to display the names with a text field element.
 
    BaseDocument*        const doc = GetActiveDocument();
    AutoAlloc<AtomArray>       objects;
 
    // check if both the BaseDocument and the AtomArray are available
    if (doc && objects)
    {
      // get selected objects
      doc->GetActiveObjects(objects, GETACTIVEOBJECTFLAGS::NONE);
 
      // store all names in the TriState object
      TriState<String> triState;
 
      const Int32 count = objects->GetCount();
      for (Int32 i = 0; i < count; ++i)
      {
        // get name
        const BaseList2D* const bl = static_cast<BaseList2D*>(objects->GetIndex(i));
        if (bl)
        {
          const String name = bl->GetName();
          // store
          triState.Add(name);
        }
      }
 
      // the text field should display the value(s) stored in the TriState
      // if the string values are not the same the GUI element will display "Multiple Values"
      SetString(ID_OBJECTNAME, triState);
    }

Functionality

A TriState object stores multiple values:

• TriState::Add(TYPE val): Adds the given value to the TriState.
• TriState::Add(BaseContainer *bc, Int32 id): Adds the value stored in the given BaseContainer to the TriState.

The stored values can be accessed and analysed with:

• TriState::SetTri(): Sets the tristate without touching the value.
• TriState::GetTri(): Returns true if the stored values are not identical.
• TriState::GetValue(): Returns the first added value.
• TriState::HasChanged(): Returns true if values have been added.

    // This example configures and uses a TriState object.
 
    TriState<Int32> triState;
    triState.Add(100);
    triState.Add(100);
 
    // check if the TriState is not empty and if all values are the same
    const Bool isNotTriState = triState.GetTri() == false;
    if (triState.HasChanged() && isNotTriState)
      ApplicationOutput("Everything is the same");
 
    // add a different value
    triState.Add(200);
 
    // check again
    if (triState.GetTri())
    {
      ApplicationOutput("now tristate"_s);
 
      const Int32 value = triState.GetValue();
      ApplicationOutput("Value: " + String::IntToString(value));
    }

Further Reading

• GeDialog Manual