Alpha blending is a convex combination of two colors allowing for transparency effects in computer graphics. The value of alpha in the color code ranges from 0.0 to 1.0, where 0.0 represents a fully transparent color, and 1.0 represents a fully opaque color.

The value of the resulting color when color Value1 is drawn over a background of color Value0 is given by:

Value = Value0(1.0 − alpha) + Value1(alpha)

The alpha component is used to blend to red, green and blue components equally, as in 32-bit RGBA, or, alternatively, there are three alpha values specified corresponding to each of the primary colors for spectral color filtering.

Alpha blending is natively supported by these operating systems/GUIs:

• Mac OS X
• Windows Me, 2000, XP
• most Linux GUI's

See also

• Alpha compositing