Adobe After Effects CS4 - Manual (Page 672)

666 USING AFTER EFFECTS CS4
Expressions
Last updated 12/21/2009
Similar to ease , except that the tangent is 0 only on the value1 side and interpolation is linear on the value2 side.
easeIn(t, tMin, tMax, value1, value2) Return type: Number or Array.
Argument type: t, tMin, and tMax are Numbers, and value1 and value2 are Numbers or Arrays.
Similar to ease , except that the tangent is 0 only on the tMin side and interpolation is linear on the tMax side.
easeOut(t, value1, value2) Return type: Number or Array.
Argument type: t is a Number, and value1 and value2 are Numbers or Arrays.
Similar to ease , except that the tangent is 0 only on the value2 side and interpolation is linear on the value1 side.
easeOut(t, tMin, tMax, value1, value2) Return type: Number or Array.
Argument type: t, tMin, and tMax are Numbers, and value1 and value2 are Numbers or Arrays.
Similar to ease , except that the tangent is 0 only on the tMax side and interpolation is linear on the tMin side.
More Help topics
“ Keyframe interpolation ” on page 231
“ Automatically ease speed ” on page 243
Color Conversion methods (expression reference)
Harry Frank provides a video tutorial on his graymachine website that shows how to use these color conversion
methods to change the color of the waves produced by the Radio Waves effect.
rgbToHsl(rgbaArray) Return type: Array [4].
Argument type: rgbaArray is an Array [4].
Converts a color in RGBA space to HSLA space. The input is an Array of normalized red, green, blue, and alpha
channel values, all in the range of 0.0 to 1.0. The resulting value is an Array of hue, saturation, lightness, and alpha
channel values, also in the range of 0.0 to 1.0. Example:
rgbToHsl.effect("Change Color")("Color To Change")
hslToRgb(hslaArray) Return type: Array [4].
Argument type: hslaArray is an Array [4].
Converts a color in HSLA space to RGBA space. This conversion is the opposite of the conversion performed by the
rgbToHsl method.
Other Math methods (expression reference)
degreesToRadians(degrees) Return type: Number.
Argument type: degrees is a Number.
Converts degrees to radians.
radiansToDegrees(radians) Return type: Number.
Argument type: radians is a Number.
Converts radians to degrees.