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lib/Math/Zap/Line2.pm  view on Meta::CPAN

=head3 accuracy

Get/Set accuracy for comparisons

=cut


my $accuracy = 1e-10;

sub accuracy
 {return $accuracy unless scalar(@_);
  $accuracy = shift();
 }


=head3 short 

Short line?                      

=cut


sub short($$)
 {my $l = shift;  # Line       
  my $a = 1e-4;   # Accuracy
  my $A = shift;  # Action 0: return indicator, 1: confess 
  my $n =
     ($l->{a}{x}-$l->{b}{x})**2 + ($l->{a}{y}-$l->{b}{y})**2                                      
    < $a;
  confess "Short line2" if $n and $A;
  $n;      
 }


=head3 check 

Check its a line

=cut


sub check(@)
 {unless (debug)
   {for my $l(@_)
     {confess "$l is not a line" unless ref($l) eq __PACKAGE__;
     }
   }
   @_;
 }


=head3 is

Test its a line

=cut


sub is(@)
 {for my $l(@_)
   {return 0 unless ref($l) eq __PACKAGE__;
   }
  'line2';
 }


=head3 a,b,ab,ba

Components of line

=cut


sub a($)  {check(@_) if (debug); $_[0]->{a}}
sub b($)  {check(@_) if (debug); $_[0]->{b}}
sub ab($) {check(@_) if (debug); vector2($_[0]->{b}{x}-$_[0]->{a}{x}, $_[0]->{b}{y}-$_[0]->{a}{y})}
sub ba($) {check(@_) if (debug); $_[0]->a-$_[0]->b}


=head3 clone 

Create a line from another line

=cut


sub clone($)
 {my ($l) = check(@_); # Lines
  bless {a=>$l->a, b=>$l->b}; 
 }


=head3 print 

Print line

=cut


sub print($)
 {my ($l) = check(@_); # Lines
  my ($a, $b) = ($l->a, $l->b);
  my ($A, $B) = ($a->print, $b->print);  
  "line2($A, $B)";
 } 


=head3 angle 

Angle between two lines

=cut


sub angle($$)
 {my ($a, $b) = check(@_); # Lines
  $a->a-$a->b < $b->a-$b->b;     
 } 


=head3 parallel

Are two lines parallel

=cut


sub parallel($$)
 {my ($a, $b) = check(@_); # Lines

# return 1 if abs(1 - abs($a->ab->norm * $b->ab->norm)) < $accuracy;
  return 1 if abs(1 - abs($a->ab->norm * $b->ab->norm)) < 1e-3;     
  0;
 }


=head3 intersect