Daniel Henry Holmes Ingalls, Jr. (born 1944) is a pioneer of object-oriented computer programming and the principal architect, designer and implementor of five generations of Smalltalk environments. He designed the bytecoded virtual machine that made Smalltalk practical in 1976. He also invented Bit blit, the general-purpose graphical operation that underlies most bitmap graphics systems today, and pop-up menus. He designed the generalizations of BitBlt to arbitrary color depth, with built-in scaling, rotation, and anti-aliasing. His major contributions to the Squeak system include the original concept of a Smalltalk written in itself and made portable and efficient by a Smalltalk-to-C translator.