I was working on a GD based module, when i came up with a functional fix (so, it's not pretty, but mostly just to prove it works).
#!/usr/bin/perl
use GD;
my $image = new GD::Image(110,110);
my $red = $image->colorAllocate(255,0,0);
my $blue = $image->colorAllocate(0,0,255);
my $white = $image->colorAllocate(255,255,255);
$image->fill(0,0,$white);
my $poly = new GD::Polygon;
$poly->addPt(50,0); ### add your points
$poly->addPt(99,99);
$poly->addPt(0,99);
$image->polygon($poly);
### do the work
my $base_point = [109,109]; # known outside
my $test_point = [50,50]; # unknown
$image->fill($test_point->[0],$test_point->[1],$red);
my $clrindex = $image->getPixel($base_point->[0],$base_point->[1]);
if ($clrindex == $red) {
warn "Point is outside of polygon.";
exit 0;
} else {
warn "Point is inside of polygon.";
exit 1;
}
so, if it is the answer you seek, i like this way ... if it is the mathmatics of it (which it probably is), this is not use.
can't sleep clowns will eat me
-- MZSanford