Apple Final Cut Pro 5 User Manual download pdf (Page 280)

280 Chapter 16

Conditional Statements

A conditional statement says that something should happen if a certain condition is met.

Conditional statements always begin with

if and end with end if.

This example comes from the Bevel ﬁlter script, which places a beveled border around the

picture.

if framewidth<frameheight

framemin=framewidth;

framemax=frameheight;

else

framemin=frameheight;

framemax=framewidth;

end if;

This statement is conditional upon the values of two variables, framewidth and frameheight.

It changes the values of two other variables, framemin and framemax, depending upon the

relative values of the variable pair mentioned in the conditional statement.

You can add more conditions by placing else if clauses into the conditional statement.

Each

else if clause allows you to add one more condition to the statement.

The

else clause means “in all other cases not covered by the previous condition or

conditions.” It is not essential to place

else statements in scripts unless you want to specify

what should happen if none of the conditions are met.

Input Statements

Input statements are extremely powerful and versatile. They enable you to place user

controls into a script, so that an effect can be ﬁnely adjusted. The user controls appear in the

Input controls tab in the FXBuilder window, and also in the Viewer when a script is added to

the Timeline for a sequence.

There are several types of input control. You can choose the type of control that meets the

needs of the script most closely. You can have more than one input control in a script; some

have three or four.

Loops

A loop is a section of code that repeats, usually according to certain conditions speciﬁed by

the needs of the script. There are two basic types of loops in FXScript: the For/Next loop

and the Repeat/End Repeat loop, which has several speciﬁc forms.

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Apple Final Cut Pro 5 User Manual Page 280