Richard Suchenwirth 2004-04-23 - Yet another tiny fun project, here's how to convert a string of digits and some other characters to a multiline string that in a fixed-pitch font looks like a 7-segment LCD/LED display:
proc num->7seg string {
foreach i {a b c} {set $i " "}
array set 7segment {
0 {{ _ } {| |} {|_|}}
1 {{ } { |} { |}}
2 {{ _ } { _|} {|_ }}
3 {{ _ } { _|} { _|}}
4 {{ } {|_|} { |}}
5 {{ _ } {|_ } { _|}}
6 {{ _ } {|_ } {|_|}}
7 {{ _ } { |} { |}}
8 {{ _ } {|_|} {|_|}}
9 {{ _ } {|_|} { _|}}
- {{ } { _ } { }}
E {{ _ } {|_ } {|_ }}
r {{ } { _ } {| }}
o {{ } { _ } {|_|}}
A {{ _ } {|_|} {| |}}
B {{ } {|_ } {|_|}}
C {{ _ } {| } {|_ }}
D {{ } { _|} {|_|}}
F {{ _ } {|_ } {| }}
}
foreach char [split $string ""] {
if {$char eq "."} {
set c [string replace $c end end .]
} else {
foreach i {a b c} row $7segment($char) {
append $i $row " "
}
}
}
return $a\n$b\n$c
}
% num->7seg 12345.67890-Error_ _ _ _ _ _ _ _ _ | _| _| |_| |_ |_ | |_| |_| | | _ |_ _ _ _ _ | |_ _| | _|.|_| | |_| _| |_| |_ | | |_| |
MPJ : "Drive-by hacking" ... I added A,B,C,D,F so hex displays look right ;-) - RS: Thanks Mike, but that B is indistinguishable from 8, and D from 0... We'd have to use lowercase for these two:
B {{ } {|_ } {|_|}}
D {{ } { _|} {|_|}}
% num->7seg 012345.6789ABCDEF
_ _ _ _ _ _ _ _ _ _ _ _
| | | _| _| |_| |_ |_ | |_| |_| |_| |_ | _| |_ |_
|_| | |_ _| | _|.|_| | |_| _| | | |_| |_ |_| |_ | MPJ: You're right; I just saw that on LCD hexa panel.
TV Such things can also be applied to hardware LED display driven by the parallel port under tcl control, my routine wasn't as neatly defining the segments, just a list of decimal numbers...
FW: I thought of a (seemingly) clever way to store these characters, to make a little obfuscated puzzler, but the result is really not that much shorter, and not even as obfuscated as I had hoped. Ah well ;) It just replaces the "array set" construct with this:
foreach {char pc} [split "0o1\t2^3\[495s6w7I8\1779{_\20Evr\24o\27A}B7CfD Ft" ""] {
binary scan $pc B8 bin
set b2 ""
for {set i 1} {$i < 8} {incr i} {append b2 [expr {[string index $bin $i] ? ([lsearch {1 3 6} $i] != -1 ? "_" : "|") : " "}]}
set 7segment($char) [list " [string index $b2 0] " [string range $b2 1 3] [string range $b2 4 6]]
}