Yes, it is. I've had a similar problem, so I've written it up. Like this:
use Math::Trig;
sub getLonLat {
my ($xtile, $ytile, $zoom) = @_;
my $n = 2 ** $zoom;
my $lon_deg = $xtile / $n * 360.0 - 180.0;
my $lat_deg = rad2deg(atan(sinh(pi * (1 - 2 * $ytile / $n))));
return ($lon_deg, $lat_deg);
}
# convert from permalink OSM format like:
# http://www.openstreetmap.org/?lat=43.731049999999996&lon=15.79375&zoom=13&layers=M
# to OSM "Export" iframe embedded bbox format like:
# http://www.openstreetmap.org/export/embed.html?bbox=15.7444,43.708,15.8431,43.7541&layer=mapnik
sub LonLat_to_bbox {
my ($lat, $lon, $zoom) = @_;
my $width = 425; my $height = 350; # note: must modify this to match your embed map width/height in pixels
my $tile_size = 256;
my ($xtile, $ytile) = getTileNumber ($lat, $lon, $zoom);
my $xtile_s = ($xtile * $tile_size - $width/2) / $tile_size;
my $ytile_s = ($ytile * $tile_size - $height/2) / $tile_size;
my $xtile_e = ($xtile * $tile_size + $width/2) / $tile_size;
my $ytile_e = ($ytile * $tile_size + $height/2) / $tile_size;
my ($lon_s, $lat_s) = getLonLat($xtile_s, $ytile_s, $zoom);
my ($lon_e, $lat_e) = getLonLat($xtile_e, $ytile_e, $zoom);
my $bbox = "$lon_s,$lat_s,$lon_e,$lat_e";
return $bbox;
}
I've also added this info to OSM wiki, so it will be easier to find in the future...