I was reflecting upon the preview functions built into KinoPlus and how I do not like them. I came to realize that they were written prior to the FX layout changes that rendered the preview always available. Then, I realized it was quite simple to display a frame with the video effect applied in the Preview without having to click Preview. Furthermore, after a short investigation, it would be quite simple to let an effect tell FX to update the Preview. And voila, any little change in the effect's option GUI can be instantly previewed. Furthermore, it does not need to be limited to the first frame; it is easy to enable some of the transport controls within FX to let one step through the frames of the region.

How easy is it for a plugin author?

1. Add the "#include <kino/kino_extra.h>" include.
2. Connect the logical "changed" signal for each widget to a single function named "Repaint."
3. Finally, define the Repaint method:

static void Repaint() {

    GetSelectedFramesForFX().Repaint();

}