HP2XX, A HP-GL Converter
2.4 Selecting a page
There is a HP-GL command named `PG;' which amounts to a FormFeed.
Thus, there are multi-page HP-GL sources. While hp2xx was
designed for just one output picture per input file, there is a
simple way to cope also with multi-page sources:
hp2xx keeps track of the number of encountered `PG;' commands.
All code up to the next (if any) `PG;' command is considered a
single page. Pages are counted, starting at 1. You can ask hp2xx
to ignore all HP-GL commands other than on page n with option
`-P n', effectively filtering out any one-page graphics.
Sometimes, converting a whole page range makes sense, too. Therefore,
hp2xx also accepts page ranges via `-P n1:n2'.
The default is `-P 0' which selects all pages. The output will
be split into appropriate files whose name is derived from the base name
of the input file by appending the frame number before the filetype
extension. In preview mode, each page will display as a separate image -
in contrast to versions earlier than 3.4.3, which would render everything
in one image.
WARNING: Some HP-GL sources may start with a `PG;' so the first
page of your graphics may be 2 instead of 1. Look for the number of
encountered pages in the diagnostic output if you miss the expected page!
If the detected coordinate range shows unreasonable numbers like 1e10,
you'll be probably looking at an empty page.
