Adobe After Effects CS4 - Manual (Page 668)

662 USING AFTER EFFECTS CS4
Expressions
Last updated 12/21/2009
timeToCurrentFormat(t = time + thisComp.displayStartTime, fps = 1.0 / thisComp.frameDuration, isDuration = false)
Return type: String.
Argument type: t and fps are Numbers; isDuration is a Boolean.
Converts the value of t to a String representing time in the current Project Settings display format. See timeToFrames
for a definition of all of the arguments.
If you want more control over the look of timecode in your footage, use the timeToCurrentFormat method or other
timeTo methods to generate the timecode instead of using the Timecode or Numbers effect. Create a text layer, add
an expression to the Source Text property, and enter timeToCurrentFormat() in the expression field. With this method,
you can format and animate the timecode text. In addition, the timecode uses the same display style defined by the current
project settings.
More Help topics
“ Time display units ” on page 52
Vector Math methods (expression reference)
Vector Math functions are global methods that perform operations on arrays, treating them as mathematical vectors.
Unlike built-in JavaScript methods, such as
Math.sin , these methods are not used with the Math prefix. Unless
otherwise specified, Vector Math methods are lenient about dimensions and return a value that is the dimension of
the largest input Array object, filling in missing elements with zeros. For example, the expression
add([10, 20], [1,
2, 3]) returns [11, 22, 3] .
JJ Gifford’s website provides explanations and examples that show how to use simple geometry and trigonometry with
expressions.
add(vec1, vec2) Return type: Array.
Argument type: vec1 and vec2 are Arrays.
Adds two vectors.
sub(vec1, vec2) Return type: Array.
Argument type: vec1 and vec2 are Arrays.
Subtracts two vectors.
mul(vec, amount) Return type: Array.
Argument type: vec is an Array, amount is a Number.
Multiplies every element of the vector by the amount.
div(vec, amount) Return type: Array.
Argument type: vec is an Array, amount is a Number.
Divides every element of the vector by the amount.
clamp(value, limit1, limit2) Return type: Number or Array.
Argument type: value, limit1, and limit2 are Numbers or Arrays.
The value of each component of value is constrained to fall between the values of the corresponding values of limit1
and limit2.
dot(vec1, vec2) Return type: Number.