ActionScript 2.0 Language Reference - Adobe Help and Support

The colors, alphas, and ratios properties are all related. The first element in the colors
array corresponds to the first element in the alphas array and in the ratios array, and so on.
To understand how the colors in a gradient bevel are distributed, think first of the colors that
you want in your gradient bevel. Consider that a simple bevel has a highlight color and
shadow color; a gradient bevel has a highlight gradient and a shadow gradient. Assume that
the highlight appears on the top-left corner, and the shadow appears on the bottom-right
corner. Assume that one possible usage of the filter has four colors in the highlight and four in
the shadow. In addition to the highlight and shadow, the filter uses a base fill color that
appears where the edges of the highlight and shadow meet. Therefore the total number of
colors is nine, and the corresponding number of elements in the ratios array is nine.
If you think of a gradient as composed of stripes of various colors, blending into each other,
each ratio value sets the position of the color on the radius of the gradient, where 0 represents
the outermost point of the gradient and 255 represents the innermost point of the gradient.
For a typical usage, the middle value is 128, and that is the base fill value. To get the bevel
effect shown in the image below, assign the ratio values as follows, using the example of nine
colors:
■ The first four colors range from 0-127, increasing in value so that each value is greater
than or equal to the previous one. This is the highlight bevel edge.
■ The fifth color (the middle color) is the base fill, set to 128. The pixel value of 128 sets the
base fill, which appears either outside the shape (and around the bevel edges) if the type is
set to outer; or inside the shape, effectively covering the object's own fill, if the type is set
to inner.
■ The last four colors range from 129-255, increasing in value so that each value is greater
than or equal to the previous one. This is the shadow bevel edge.
If you want an equal distribution of colors for each edge, use an odd number of colors, where
the middle color is the base fill. Distribute the values between 0-127 and 129-255 equally
among your colors, then adjust the value to change the width of each stripe of color in the
gradient. For a gradient bevel with nine colors, a possible array is [16, 32, 64, 96, 128, 160,
192, 224, 235]. The following image depicts the gradient bevel as described:
GradientBevelFilter (flash.filters.GradientBevelFilter) 637