see  attached patch (it copypastes badly)<div><br></div><div>it compiles but I tried solid-color track over fading png text (as in black_flash.xml) and I can&#39;t see it working? </div><div><br></div><div>I just hope it can serve as guide what to modify for adding new modes.. </div><div><br></div><div>I tried to write down math from this page:</div><div><a href="https://natron.readthedocs.io/en/rb-2.3/plugins/net.sf.openfx.MergePlugin.html">https://natron.readthedocs.io/en/rb-2.3/plugins/net.sf.openfx.MergePlugin.html</a></div><div><br></div><div><br></div>