Posted to tcl by patthoyts at Tue Sep 15 23:14:53 GMT 2009view pretty

proc lut {contrast brightness} {
    variable map_values
    set image {}
    foreach col $map_values {
        set row {}
        foreach val $col {
            set v [expr {int($val * $contrast + $brightness)}]
            if {$v > 255} { set v 255}
            #lappend row [lindex $lut $v]
            lappend row [format "#%02x0000" $v]
            #lappend row [format "#%02x%02x%02x" $v $v $v]
        }
        lappend image $row
    }
    mapimage0 put $image
}