In the present invention, an apparatus and method for performing alpha
blending calculations in a fast and efficient manner is disclosed. When
implemented as an integrated circuit, the apparatus of the present
invention occupies reduced area. The apparatus comprises a plurality of
multiplexers and an adder. Each of multiplexers is configured to receive
a bit value, .alpha..sub.1, of the digital value alpha, .alpha.. Each of
the plurality of multiplexers is configured to receive the first and
second digital image values. Each of the plurality of multiplexers is
also configured to direct to outputs of the multiplexers either the first
or second digital image value responsive to the bit value, .alpha..sub.i.
Each of the outputs of the plurality of multiplexers is shifted left
according to the order of the bit values, .alpha..sub.1, to produce a
plurality of left-shifted outputs. The adder is produces the sum of the
left-shifted outputs.