Managing effects with several parameters

Open the Palette project again.
* Merge the layers of this project.
* Stretch them over twenty frames.
* Choose the Blur > Center blur effect.

The following timeline appears:

To make things easier, we have deliberately chosen to work with an animation layer always containing the same image. Everything that follows also applies to an animation layer.

You will see that there are three parameters which may be locked with a FX Stack keyframe:
* the position of the center,
* the power of the blur,
* the radius of the circle in which the blur is not applied.

The position of the circle in which the blur is not applied as well as its center are shown in the preview (see the screenshot above)

Some parameters may be adjusted directly on the screen by clicking and sliding the mouse on the color handles (shown opposite).
When the effect is applied, circle and handles will, of course, have disappeared.

The parameters which are directly adjustable on the screen (handles, circles, spline) are referred to as HUD (HUD stands for Head Up Display).
The Hide HUD of the FX stack is used to hide the latter.

Now let's take a look at the timeline:
* As soon as a FX Stack keyframe is created, a left click on the "+" button near Center Blur in the Timeline displays the name of the parameter which have been set with the FX Stack keyframe.
* To the right of the parameter names, corresponding FX Stack keyframe lines will be displayed as you create your FX Stack keyframes.
It is possible to create FX Stack keyframes for each parameter, for the image of your choice along the timeline.

A separate set of FX Stack keyframes may be created for each parameter (Center of circle, Power, Radius). This means that the parameters may progress in time independently of each other. For example: the power of the centred blur may decrease slowly while its radius may increase rapidly, all at different times…

Thanks to the use of several FX Stack keyframes, the parameters can be adjusted in time. This is the case for the Center parameter in the timeline above: three FX Stack keyframes are placed on the FX Stack keyframe line associated with the Center parameter.

The effect produced using these three FX Stack keyframes can be seen below:

The first FX Stack keyframe line in the timeline has the name of the effect in the stack and displays all its FX Stack keyframes.