When used other than with -Tps, it will draw a box around where
the picture would go.
.nr ps-nargs \\n[.$] . nr ps-llx 0\\$1 . nr ps-lly 0\\$2 . nr ps-urx 0\\$3 . nr ps-ury 0\\$4 .\} ..
.sy echo .ps-bb `psbb \\$1` >/tmp/psbb\\n[$$] .so /tmp/psbb\\n[$$] . nr ps-wid (\\n[ps-urx]-\\n[ps-llx]) . nr ps-ht (\\n[ps-ury]-\\n[ps-lly]) . if \\n[ps-wid]<0 .nr ps-wid 0-\\n[ps-wid] . if \\n[ps-ht]<0 .nr ps-ht 0-\\n[ps-ht] . ie \\n[.$]>=2 .nr ps-deswid (i;\\$2) . el .nr ps-deswid \\n[.l]-\\n[.i]<?\\n[ps-wid]p . ie \\n[.$]>=3 .nr ps-desht (i;\\$3) . el .nr ps-desht \\n[ps-deswid]*1000+(\\n[ps-wid]/2)/\\n[ps-wid]\ *\\n[ps-ht]+500/1000 . ne \\n[ps-desht]u+1v . nr ps-offset \\n[.l]-\\n[.i]-\\n[ps-deswid]/2 . ie \\n[.$]>=3 .ds ps-desht \\n[ps-desht] . el .ds ps-desht \" empty \h'\\n[ps-offset]u'\ \X'ps: invis'\ \Z'\D'p 0 \\n[ps-desht]u \\n[ps-deswid]u 0 0 -\\n[ps-desht]u''\ \X'ps: endinvis'\ \v'\\n[ps-desht]u'\X'ps: import \\$1 \ \\n[ps-llx] \\n[ps-lly] \\n[ps-urx] \\n[ps-ury] \\n[ps-deswid] \\*[ps-desht]' . br . sp \\n[ps-desht]u .\} .sy rm /tmp/psbb\\n[$$] ..