“Secondhand Lions” writer-director Tim McCanlies will adapt the Piers Anthony novel “Spell for Chameleon” for Warner Bros. Pictures and director Wolfgang Petersen.In “Spell for Chameleon,” a young man lives in a country where everyone possesses magical powers and faces exile if he can’t figure out what his own powers might be. McCanlies’ credits include writing “Iron Giant” as well as writing and directing “Dancer, Texas Pop. 81.” David Benioff produces with Petersen and his partner in Radiant Prods., Diana Rathbun. Samuel Dickerman is executive producer. Warners exec VP Courtenay Valenti and creative exec Geoff Shaevitz oversee the project. “Spell for Chameleon” was the first of Anthony’s 30-book Xanth Development series.