Speed up set-argb-pixels by using local references to b&w? and alpha-channel?
Speed up set-argb-pixels by using local references to b&w? and alpha-channel?

In set-argb-pixels, the critical loop for each pixel tests the value
of a boolean that was defined at the top level of the class. Forcing
these to be local variables gives a speedup of 1.5.

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket