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LCD.pm  view on Meta::CPAN

$Tk::LCD::VERSION = '1.3';

package Tk::LCD;

use base qw/Tk::Derived Tk::Canvas/;
use vars qw/$ELW %SHAPE %shape %LLCD %ULCD/;
use subs qw/ldifference/;
use strict;

Construct Tk::Widget 'LCD';

# LCD class data.

$ELW = 22;			# element pixel width

# %SHAPE stolen with appreciation from Donal K. Fellows' Tcl game
# of Maze. An LCD element can display a digit, space or minus sign.
# It's made up of 7 segments labelled 'a' through 'g'.  Each segment
# is defined by a series of Canvas widget polygon coordinates.
#
#    b
#    -
#  a| |c
#    -   <--- g
#  f| |d
#    -
#    e

%SHAPE = (
    'a' => [qw/ 3.0  5  5.2  3  7.0  5  6.0 15  3.8 17  2.0 15/],
    'b' => [qw/ 6.3  2  8.5  0 18.5  0 20.3  2 18.1  4  8.1  4/],
    'c' => [qw/19.0  5 21.2  3 23.0  5 22.0 15 19.8 17 18.0 15/],
    'd' => [qw/17.4 21 19.6 19 21.4 21 20.4 31 18.2 33 16.4 31/],
    'e' => [qw/ 3.1 34  5.3 32 15.3 32 17.1 34 14.9 36  4.9 36/],
    'f' => [qw/ 1.4 21  3.6 19  5.4 21  4.4 31  2.2 33  0.4 31/],
    'g' => [qw/ 4.7 18  6.9 16 16.9 16 18.7 18 16.5 20  6.5 20/],
);

# %shape is 1/2 the size of %SHAPE.

foreach my $c (keys %SHAPE) {
    $shape{$c} = [ map {$_ / 2.0} @{$SHAPE{$c}} ];
}

# To display an LCD element we must turn on and off certain segments.
# %LLCD defines a list of segments to turn on for any particular
# symbol.

%LLCD = (
    '0' => [qw/a b c d e f/],
    '1' => [qw/c d/],
    '2' => [qw/b c e f g/],
    '3' => [qw/b c d e g/],
    '4' => [qw/a c d g/],
    '5' => [qw/a b d e g/],
    '6' => [qw/a b d e f g/],
    '7' => [qw/b c d/],
    '8' => [qw/a b c d e f g/],
    '9' => [qw/a b c d e g/],
    '-' => [qw/g/],
    ' ' => [''],
);

# Similarly, %ULCD defines a list of LCD element segments to turn off
# for any particular symbol. In Maze, %ULCD was manually generated,