Standard version: 1.4
The kOfxParamPropPluginMayWrite is redundant and not used in practice.
However it was mentioned that it was not clear where parameters can be writen. In general, parameters are read-only everywhere except in descriptor and instance changed.
We might potentially need a property on an host that indicates whether it will allow a plugin to set values on params, and plugins can work around that. I’m not convinced we need that. Also note there is a mechanism to return a status if one attempts to write a parameter and hosts does not support that.
/** @brief Flags whether the plugin will attempt to set the value of a parameter in some callback or analysis pass
This is used to tell the host whether the plug-in is going to attempt to set the value of the parameter. */
#define kOfxParamPropPluginMayWrite “OfxParamPropPluginMayWrite”
(Pierre Jasmin): I think what we need is for doc to be boldly clear about in which action Parameters can be changed (aside InstanceChanged). I am about to test writing Parameter at time for all hosts we support, so I might be more educated in a month :)