Adobe After Effects CS4 - Manual (Page 674)

668 USING AFTER EFFECTS CS4
Expressions
Last updated 12/21/2009
thisComp.marker.nearestKey(time).time
marker.numKeys Return type: Number.
Returns the total number of composition markers in the composition.
numLayers Return type: Number.
Returns the number of layers in the composition.
activeCamera Return type: Camera.
Returns the Camera object for the camera through which the composition is rendered at the current frame. This
camera is not necessarily the camera through which you are looking in the Composition panel.
width Return type: Number.
Returns the composition width, in pixels.
Apply the following expression to the Position property of a layer to center the layer in the composition frame:
[thisComp.width/2, thisComp.height/2]
height Return type: Number.
Returns the composition height, in pixels.
duration Return type: Number.
Returns the composition duration, in seconds.
displayStartTime Return type: Number.
Returns the composition start time, in seconds.
frameDuration Return type: Number.
Returns the duration of a frame, in seconds.
shutterAngle Return type: Number.
Returns the shutter-angle value of the composition, in degrees.
shutterPhase Return type: Number.
Returns the shutter phase of the composition, in degrees.
bgColor Return type: Array [4].
Returns the background color of the composition.
pixelAspect Return type: Number.
Returns the pixel aspect ratio of the composition.
name Return type: String.
Returns the name of the composition.
Footage attributes and methods (expression reference)
To use a footage item from the Project panel as an object in an expression, use the global footage method, as in
footage("file_name") . You can also access a footage object using the source attribute on a layer whose source is a
footage item.
width Return type: Number.