How to add gradient channel to an item.

itemGradChannel.cpp

/*
 * An example on how to add gradient channel to a custom item.
 * Gradient will also have default 1.0 flat value.
 */
	LxResult
CPackage::pkg_SetupChannels (
	ILxUnknownID		 addChan)
{
	CLxUser_AddChannel	 ac (addChan);

	ac.NewChannel	(GRADIENT_CHAN_NAME, LXsTYPE_PERCENT);
	ac.SetGradient	(LXsTYPE_PERCENT);
	ac.SetDefault	(1.0, 0.0);

	return LXe_OK;
}

/*
 * And here, on the instance gradient can be initialized with some keys.
 * m_item is a cached interface of the instanced item.
 */
	LxResult
CInstance::pins_Newborn (ILxUnknownID original_obj, unsigned flags)
{
	CLxUser_Scene		 scene;
	CLxUser_ChannelWrite	 chan_write;
	CLxUser_Envelope	 envelope;
	CLxUser_Keyframe	 keyframe;
	
	if (!m_item.test () || !m_item.GetContext (scene))
		return LXe_FAILED;
	
	scene.SetChannels (chan_write, LXs_ACTIONLAYER_SETUP);

	if (chan_write.Envelope (m_item, m_item.ChannelIndex (GRADIENT_CHAN_NAME), envelope))
	{
		if (keyframe.fromEnvObject (envelope)) {
			keyframe.AddF (0.0, 1.0);
			keyframe.AddF (1.0, 0.0);
		}
	}
	
	return LXe_OK;
}