🚀 go-pugleaf

In article <C1EMrJ.2M3@mnveger.uucp> michaelv@mnveger.uucp (Michael Vishchers)  
writes:
> This may sound like a silly question, but I would like to know if i
> can expect a point with given coordinates to have the same vertical and
> horizontal distances from the lower left corner on any printer.

The Red Book says (New page 151, old page 65) that you can,
and it's close to right.  The only problem you'll have is
with registration and some broken interpreters.  I
recently heard of a non-Adobe implementation that
seemed to have the origin consistently off the bottom
left corner.

> A problem arises when the printer has unprintable regions, i.e., cannot
> print on the margins. What should I expect if I printed a square box
> with sidelength 1 inch, placed at the origin ? If a printer cannot print
> on, e.g., the left and bottom half inch of the paper, will I see a
> smaller box with the upper right corner at (1 inch, 1 inch), or will I see
> a full but translated box ?

You will get the upper right corner of the box drawn in the
right place, but those sides will end at the margin.  You
won't see the bottom or left side at all. 

In other words, the unprintable region won't be inked,
but it should be handled correctly.  Some devices have
large unprintable regions, some have none (within the
paper, I mean :-) ).  I commonly print out signatures on a
Linotronic, for instance, where the letter-sized pages
are completely usable.  

> I couldn't find an answer in the FAQ or the Red Book, so does anyone know
> if there is a standard behaviour ?

I pointed to the Red Book, but I guess that doesn't quite
explain it.  Do you know what a clipping path is?  Imagine
there's a clipping poath at the margin (there probably
is, actually) that keeps you from drawing outside of
that.  Now imagine the default coordinate system
originates at the lower-left of the page and that the axes
go right and up.

In that situation, something drawn at 100, 100 should be
100 units up and right of the lower-left corner of the
page.  The registration of paper through the printer
mechanism may make that slightly wrong, but it should be
close.  Print several sheets and see how much they vary.

Something drawn very near the origin will get clipped by
the clipping path (or the physical extent of the printing
area, whichever is smaller), but will be in the correct
place.

ab