File Coverage

blib/lib/Geo/GoogleMaps/MobileTool.pm

Criterion	Covered	Total	%
statement	60	71	84.5
branch	14	20	70.0
condition	2	3	66.6
subroutine	11	11	100.0
pod	4	4	100.0
total	91	109	83.4

package Geo::GoogleMaps::MobileTool;

use warnings;
use strict;
use Carp;

use version; our $VERSION = qv('0.0.1');

use Math::Trig;
use base 'Exporter';

our @EXPORT = qw(
    lnglat2pixel
    pixel2lnglat
    deltapixel2lnglat
    deltalnglat_perpixel
);

my $zmbase = 128;
my @zmmax;
my $offproj;

sub import {
    my ( $class, $opt ) = @_;

    $offproj = ( $opt && $opt eq 'unableProj' ) ? 1 : 0;
    unless ( $offproj ) {
        eval { require Geo::Proj };
        if ( $@ ) {
            $offproj = 1;
        } else {
            Geo::Proj->import();
        }
    }

    foreach my $zm (0..20) {
        $zmmax[$zm] = $zmbase * 2 ** $zm;
        unless ( $offproj ) {
            my $name    = "gmapzm$zm";
            my $r       = $zmmax[$zm] / pi;
            my $proj    = "+proj=merc +a=$r +b=$r +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=\@null +no
_defs";
            Geo::Proj->new(
                nick  => $name,
                proj4 => $proj,
            );
        }
    }

    local $Exporter::ExportLevel = $Exporter::ExportLevel + 1;

    $class->SUPER::import();
}

sub lnglat2pixel {
    my ( $lng, $lat, $zm, $intoff ) = @_;

    my ( $x, $y );

    if ( $offproj ) {
        $x = $lng / 180.0 * $zmmax[$zm];
        $y = log( tan( pi * ( 0.25 + $lat / 360.0 ) ) ) / pi * $zmmax[$zm];
    } else {
        my $pt = Geo::Proj->to( 'wgs84', "gmapzm$zm", [ $lng, $lat ] );
        ( $x, $y ) = @{ $pt };
    }

    $x  += $zmmax[$zm];
    $y  =  -1.0 * ( $y - $zmmax[$zm] );

    ( $x, $y ) = map { int( $_ ) } ( $x, $y ) unless ( $intoff );

    return wantarray ? ( $x, $y ) : [ $x, $y ];
}

sub pixel2lnglat {
    my ( $x, $y, $zm, $intoff ) = @_;

    ( $x, $y ) = map { $_ + 0.5 } ( $x, $y ) unless ( $intoff );

    $x -= $zmmax[$zm];
    $y =  -1.0 * $y + $zmmax[$zm];

    my ( $lng, $lat );

    if ( $offproj ) {
        $lng   = $x / $zmmax[$zm] * 180.0;
        $lat   = atan( sinh( $y / $zmmax[$zm] * pi ) ) / pi *180.0;
    } else {
        my $pt = Geo::Proj->to( "gmapzm$zm", 'wgs84', [ $x, $y ] );
        ( $lng, $lat ) = @{$pt};
    }

    return wantarray ? ( $lng, $lat ) : [ $lng, $lat ];
}

sub deltapixel2lnglat {
    my ( $lng, $lat, $dpxx, $dpxy, $zm ) = @_;

    my ( $fx, $fy ) = lnglat2pixel( $lng, $lat, $zm, 1 );

    $fx += $dpxx;

    $fy += $dpxy;

    return pixel2lnglat( $fx, $fy, $zm, 1 );
}

sub deltalnglat_perpixel {
    my ( $lng, $lat, $zm ) = @_;

    my $dpx_plng = $zmmax[$zm] / 180.0;
    my $dpy_plat = sec( $lat / 180.0 * pi ) * $zmmax[$zm] / 180.0;

    return map { 1.0 / $_ } ( $dpx_plng, $dpy_plat );
}

1; # Magic true value required at end of module
__END__