There was no decree naming Alexander Calder (1898-1976) the capital’s official artist, but walking around the National Mall, you’d think there had been. His abstract sheet-metal sculptures are in the National Gallery of Art Sculpture Garden and on the grounds of the Smithsonian’s Hirshhorn and American History museums, and a mammoth mobile dominates the atrium of the National Gallery’s East Building. An abundance of his works is on display in these museums as well as in the Phillips Collection. He also invented meatl-wire drawing in space. All told, he made a few hundred wire figures before abandoning the medium for abstraction in the 1930s. Among them were several dozen celebrities, athletes and art-world friends that are the main focus of “Calder’s Portraits: A New Language” at the National Portrait Gallery through August 14, 2011.