CAD::Drawing::Calculate - Calculations for CAD::Drawing
Index
Code Index:
NAME
CAD::Drawing::Calculate - Calculations for CAD::Drawing
DESCRIPTION
This module provides calculation functions for the CAD::Drawing family
of modules.
AUTHOR
Eric L. Wilhelm <ewilhelm at cpan dot org>
http://scratchcomputing.com
COPYRIGHT
This module is copyright (C) 2004-2006 by Eric L. Wilhelm. Portions
copyright (C) 2003 by Eric L. Wilhelm and A. Zahner Co.
LICENSE
This module is distributed under the same terms as Perl. See the Perl
source package for details.
You may use this software under one of the following licenses:
(1) GNU General Public License
(found at http://www.gnu.org/copyleft/gpl.html)
(2) Artistic License
(found at http://www.perl.com/pub/language/misc/Artistic.html)
NO WARRANTY
This software is distributed with ABSOLUTELY NO WARRANTY. The author,
his former employer, and any other contributors will in no way be held
liable for any loss or damages resulting from its use.
Modifications
The source code of this module is made freely available and
distributable under the GPL or Artistic License. Modifications to and
use of this software must adhere to one of these licenses. Changes to
the code should be noted as such and this notification (as well as the
above copyright information) must remain intact on all copies of the
code.
Additionally, while the author is actively developing this code,
notification of any intended changes or extensions would be most helpful
in avoiding repeated work for all parties involved. Please contact the
author with any such development plans.
SEE ALSO
CAD::Drawing
CAD::Calc
Math::Vec
Methods
Extents Calculations
OrthExtents
Calculates the extents of a group of objects (selected according to select_addr()) and returns an array: [xmin,xmax],[ymin,ymax].
@extents = $drw->OrthExtents(\%opts);
getExtentsRec
Alias to OrthExtents() which returns a polyline-form array of points
(counter clockwise from lower-left) describing a rectangle.
@rec = $drw->getExtentsRec(\%opts);
EntOrthExtents
Gets the orthographic extents of the object at $addr. Returns
[\@xpts,\@y_pts] (leaving you to sort through them and find which
is min or max.)
@extents = $drw->EntOrthExtents($addr);
@orthfunc
List of hash references containing code references to reduce
duplication and facilitate natural flow (rather than ifififif
statements.)
Planar Geometry Methods
offset
Intended as any-object offset function (not easy).
$dist is negative to offset outward
$drw->offset($object, $dist);
divide
area
Line Manipulations
pline_to_ray
Transforms a polyline with a nubbin into a ray (line with direction.)
$line_addr = $drw->pline_to_ray($pline_addr);
trim_both
Trims two lines to their intersection.
$drw->trim_both($addr1, $addr2, $tol, \@keep_ends);
See CAD::Calc::line_intersection()
Switch between coordinate system representations.
to_ocs
Change the objects coordinates into the object coordinate system.
Both of these are relatively quick. A simple test shows that one point
can be taken back and forth at about 2KHz, so don't be afraid to use
them.
$drw->to_ocs($addr);
to_wcs
Change the object's coordinates into the world coordinate system.
$drw->to_wcs($addr);
flatten
Puts the object in the wcs, zeros all z-coordinates and deletes the
normal vector. Note that this is fine for projecting polylines and
lines, but may not be what you want if you are trying to make a circle
into an ellipse (at least not yet.)
$drw->flatten($addr);
Functions
Non-OO internal-use functions.
_ocs_axes
Returns the x,y, and z axes for the ocs described by @normal. These
will have arbitrary lengths.
@local_axes = _ocs_axes(@normal);
_wcs_axes
Returns the x,y, and z axes for the world coordinate system in terms of
the @ocs_axes.
@trs_axes = _wcs_axes(@ocs_axes);
package CAD::Drawing::Calculate;
our $VERSION = '0.12';
# use CAD::Drawing;
use CAD::Drawing::Defined;
use CAD::Drawing::Calculate::Finite;
our @ISA = qw(
CAD::Drawing::Calculate::Finite
);
use CAD::Calc qw(
dist2d
line_intersection
);
use Math::Vec qw(NewVec);
use vars qw(
@orthfunc
);
use warnings;
use strict;
use Carp;
########################################################################
########################################################################
########################################################################
sub OrthExtents {
my $self = shift;
my($opts) = @_;
my $retref = $self->select_addr($opts);
my @worklist = @{$retref};
my(@xvals, @yvals);
foreach my $addr (@worklist) {
my ($xdata, $ydata) = $self->EntOrthExtents($addr);
push(@xvals, @$xdata);
push(@yvals, @$ydata);
}
@xvals = sort({$a<=>$b} @xvals);
@yvals = sort({$a<=>$b} @yvals);
return([ $xvals[0], $xvals[-1] ], [$yvals[0], $yvals[-1] ] );
} # end subroutine OrthExtents definition
########################################################################
sub getExtentsRec {
my $self = shift;
my($opts) = @_;
my ($x, $y) = $self->OrthExtents($opts);
return(
[$x->[0], $y->[0]],
[$x->[1], $y->[0]],
[$x->[1], $y->[1]],
[$x->[0], $y->[1]],
);
} # end subroutine getExtentsRec definition
########################################################################
sub EntOrthExtents {
my $self = shift;
my ($addr) = @_;
my $obj = $self->getobj($addr);
# FIXME: this will only get the point items
my $stg = $call_syntax{$addr->{type}}[1];
my ($xpts, $ypts) = $orthfunc[0]{$stg}->($obj->{$stg});
} # end subroutine EntOrthExtents definition
########################################################################
@orthfunc = (
{ # stage one hash ref
"pt" => sub {
my($pt) = @_;
return([$pt->[0]], [$pt->[1]]);
}, # end subroutine $orthfunc[0]{pt} definition
"pts" => sub {
my($pts) = @_;
my @vals = ([], []);
for(my $i = 0; $i < @$pts; $i++) {
foreach my $c (0,1) {
push(@{$vals[$c]}, $pts->[$i][$c]);
}
}
return(@vals);
}, # end subroutine $orthfunc[0]{pts} definition
}, # end stage one hash ref
{ # stage two hash ref
# FIXME: here we put the fun stuff about rad and text
}, # end stage two hash ref
); # end @orthfunc bundle
########################################################################
sub offset {
carp("no offset function yet");
} # end subroutine offset definition
########################################################################
sub divide {
carp("no divide function yet");
} # end subroutine divide definition
########################################################################
sub area {
my $self = shift;
my $addr = shift;
($addr->{type} eq "plines") or croak "only calc area for plines";
my @pgon = $self->Get("pts", $addr);
my $tw_area = 0;
my $x = 0;
my $y = 1;
for(my $i = 0; $i < @pgon; $i++) {
$tw_area += ($pgon[$i][$y] + $pgon[$i-1][$y]) *
($pgon[$i][$x] - $pgon[$i-1][$x]);
}
return( abs($tw_area / 2) );
} # end subroutine area definition
########################################################################
sub pline_to_ray {
my $self = shift;
my ($pl_addr) = @_;
($pl_addr->{type} eq "plines") || carp("not a polyline");
my @pts = $self->Get("pts", $pl_addr);
(@pts == 3) || croak("not 3 points to polyline");
# print "checking: ", dist2d($pts[0], $pts[1]) ,
# "<=>",
# dist2d($pts[1], $pts[2]),
# "\n";
my $dir = dist2d($pts[0], $pts[1]) <=> dist2d($pts[1], $pts[2]);
($dir > 0) || (@pts = reverse(@pts));
my $obj = $self->getobj($pl_addr);
my %lineopts = (
"layer" => $pl_addr->{layer},
"color" => $obj->{color},
"linetype" => $obj->{linetype},
);
return($self->addline([@pts[0,1]], \%lineopts) );
} # end subroutine pline_to_ray definition
########################################################################
sub trim_both {
my $self = shift;
my @items = (shift,shift);
my $tol = shift;
my $ends = shift;
my @keep_ends;
if($ends) {
(ref($ends) eq "ARRAY") or croak(
'CAD::Drawing::Calculate::trim_both() ' .
'\@keep_ends arg must be array'
);
@keep_ends = @$ends;
}
my @lines;
my @vecs;
my @mids;
foreach my $item (@items) {
$item or die "no item\n";
my @pts = $self->Get("pts", $item);
# @pts or die "problem with $item\n";
# print "points: @{$pts[0]}, @{$pts[1]}\n";
my $vec = NewVec(NewVec(@{$pts[1]})->Minus($pts[0]));
my $mid = [NewVec($vec->ScalarMult(0.5))->Plus($pts[0])];
push(@mids, $mid);
push(@vecs, $vec);
push(@lines, [@pts]);
}
my @int = line_intersection(@lines, $tol);
## defined($int[0]) or print("no int\n");
defined($int[0]) or return();
## defined($int[1]) or print("paralell (no)\n");
defined($int[1]) or return(); #parallel
# print "making vec from @int\n";
my $pt = NewVec(@int);
# print "got point: @$pt\n";
foreach my $i (0,1) {
my $end;
if(@keep_ends) {
$end = ! $keep_ends[$i];
}
else {
my $dot = $vecs[$i]->Dot([$pt->Minus($mids[$i])]);
# print "dot product: $dot\n";
# if the dot product is positive,
# intersection is in front of midpoint.
$end = ($dot > 0);
}
# print "end is $end\n";
$lines[$i][$end] = $pt;
$self->Set({pts => $lines[$i]}, $items[$i]);
}
return($pt);
} # end subroutine trim_both definition
########################################################################
sub to_ocs {
my $self = shift;
my ($addr) = @_;
my $obj = $self->getobj($addr);
if(my $n = $obj->{normal}) {
# FIXME: if direction is Z, kill the flags
# print "normal is @$n\n";
if($ac_storage_method{$addr->{type}} eq "ocs") {
# need to translate
my @ocs = _ocs_axes(@{$n});
# print "ocs is: ", join("\n", map({join(",", @{$_})} @ocs)), "\n";
if($obj->{pts}) {
foreach my $pt (@{$obj->{pts}}) {
@{$pt} = map({$ocs[$_]->Comp($pt)} 0..2);
}
}
else {
# safe to assume it is a point?
@{$obj->{pt}} = map({$ocs[$_]->Comp($obj->{pt})} 0..2);
}
} # end if stored in ocs
$obj->{extrusion} = $n;
delete($obj->{normal});
}
else { # object is in xy coords with normal in [0,0,1] direction
return();
}
} # end subroutine to_ocs definition
########################################################################
sub to_wcs {
my $self = shift;
my ($addr) = @_;
my $obj = $self->getobj($addr);
if(my $n = $obj->{extrusion}) {
# FIXME: if direction is Z, kill the flags
# also have to check if this object is stored as WCS or OCS?
if($ac_storage_method{$addr->{type}} eq "ocs") {
# need to translate
my @ocs = _ocs_axes(@{$n});
my @tcs = _wcs_axes(@ocs);
if($obj->{pts}) {
foreach my $pt (@{$obj->{pts}}) {
# warn("pt was: ", join(",", @{$pt}), "\n");
@{$pt} = map({$tcs[$_]->Comp($pt)} 0..2);
# warn("pts being transformed for $addr->{type} ",
# join(",", @{$pt}), "\n");
}
}
else {
# safe to assume it is a point?
# warn("pt was: ", join(",", @{$obj->{pt}}), "\n");
@{$obj->{pt}} = map({$tcs[$_]->Comp($obj->{pt})} 0..2);
# warn("pt being transformed for $addr->{type} ",
# join(",", @{$obj->{pt}}), "\n");
}
} # end if stored in ocs
$obj->{normal} = $n;
delete($obj->{extrusion});
}
else { # object is in xy coords with normal in [0,0,1] direction
return();
}
} # end subroutine to_wcs definition
########################################################################
sub flatten {
my $self = shift;
my ($addr) = @_;
$self->to_wcs($addr);
my $obj = $self->getobj($addr);
if($obj->{pts}) {
foreach my $pt (@{$obj->{pts}}) {
$pt->[2] = 0;
}
}
else {
$obj->{pt}[2] = 0;
}
delete($obj->{normal});
} # end subroutine flatten definition
########################################################################
sub _ocs_axes {
my $z = NewVec(@_);
my $x = NewVec(NewVec(0,0,1)->Cross($z));
($x->Length()) || ($x = NewVec($z->[2],0,0));
my $y = NewVec($z->Cross($x));
return($x,$y,$z);
} # end subroutine _ocs_axes definition
########################################################################
sub _wcs_axes {
my (@ocs) = map({NewVec(@$_)} @_);
my @tcs;
my @wcs = map({NewVec(@$_)} [1,0,0],[0,1,0],[0,0,1]);
foreach my $i (0..2) {
$tcs[$i] = NewVec(map({$ocs[$_]->Comp($wcs[$i])} 0..2));
}
return(@tcs);
} # end subroutine _wcs_axes definition
########################################################################
1;