Retrieve information from the render context. This is NOT a counterpart to
mpv_render_context_set_parameter(), because you generally can't read
parameters set with it, and this function is not meant for this purpose.
Instead, this is for communicating information from the renderer back to the
user. See mpv_render_param_type; entries which support this function
explicitly mention it, and for other entries you can assume it will fail.
You pass param with param.type set and param.data pointing to a variable
of the required data type. The function will then overwrite that variable
with the returned value (at least on success).
@param ctx a valid render context
@param param the parameter type and data that should be retrieved
@return error code. If a parameter could actually be retrieved, this returns
success, otherwise an error code depending on the parameter type
and situation. MPV_ERROR_NOT_IMPLEMENTED is used for unknown
param.type, or if retrieving it is not supported.
Retrieve information from the render context. This is NOT a counterpart to mpv_render_context_set_parameter(), because you generally can't read parameters set with it, and this function is not meant for this purpose. Instead, this is for communicating information from the renderer back to the user. See mpv_render_param_type; entries which support this function explicitly mention it, and for other entries you can assume it will fail.
You pass param with param.type set and param.data pointing to a variable of the required data type. The function will then overwrite that variable with the returned value (at least on success).
@param ctx a valid render context @param param the parameter type and data that should be retrieved @return error code. If a parameter could actually be retrieved, this returns success, otherwise an error code depending on the parameter type and situation. MPV_ERROR_NOT_IMPLEMENTED is used for unknown param.type, or if retrieving it is not supported.