finally looked at history..

http://git.cinelerra-gg.org/git/?p=goodguy/history.git;a=blobdiff;f=cinelerra-5.1/cinelerra/overlayframe.h;h=730be3741ed638b54703c530809aeaada999e20e;hp=7ca03621e6b6df0b91b165e9566fbc263a2074b0;hb=93d60cc0fdf746cc03b4d7a9e45744c2c424439b;hpb=361dbd9de4e6e4143ea0cac5daa89b30685a4c70

and made this patch (attached) 

it works softer than logical or porter/duff modes, but notiecably  slower ( (on 8 core arm tablet) 


my modes fails to compile - something about me not really knowing how to write macro functions (?)