Onscreen controls overview
Many effects, transitions, and other items use onscreen controls, superimposed over the video in the Viewer, to make it easier to adjust a variety of parameters. In many cases, these onscreen controls duplicate controls in the inspectors, although in some cases the controls are unique and provide the only way to adjust a particular parameter.
The controls can be as simple as defining the center of a fisheye effect or defining the more complex diameter, width, and position of a vignette effect.
This section focuses on the types of onscreen controls found in clip effects and transitions. Onscreen controls are also available in other areas of Final Cut Pro, including the following:
Built-in effects: Onscreen controls are used extensively for all built-in effects. See Built-in effects overview.
Chroma keying: You use specialized onscreen controls when configuring a chroma keyer. See Use chroma keys.
Color corrections: Color corrections can contain onscreen controls used for creating color masks and shape masks. See Manual color correction overview.