TwDefine (function)

int TwDefine(const char *def)


This function defines optional parameters for tweak bars and variables. For instance, it allows you to change the color of a tweak bar, to set a min and a max value for a variable, to add an help message that inform users of the meaning of a variable, and so on...



A string containing one or more parameter assignments (separated by newlines).

To define bar parameters, the syntax is:

barName  barParam1=xx barParam2=xx ...

where barName is the name of the tweak bar (the same as the one provided to TwNewBar), and barParam n follows the bar parameters syntax.

To define variable parameters, the syntax is:

barName/varName  varParam1=xx varParam2=xx ...

where barName is the name of the tweak bar (the same as the one provided to TwNewBar), varName is the name of the variable (the same as the one provided to TwAddVar*), and varParam n follows the variable parameters syntax.

If barName or varName contains special characters like spaces or quotation marks, you can surround it by quotes (), back-quotes (`) or double-quotes ().


Return value

  • 0 if an error has occurred (call TwGetLastError to retrieve the error).
  • 1 otherwise.


Using a text file to define parameters

One or more parameters can be defined by each TwDefine call. If you want to assign more than one parameter through one TwDefine call, separate them by new lines (\n). This allows, for instance, the read of parameters definition from a file into a string buffer, and then send this string to TwDefine. Doing so, you can modify the behavior of your tweak bars and variables without re-compiling your application.

See also