Hello Karl,
Am 02.03.2018 um 01:25 schrieb k...@aspodata.se:
In my
PostScript Language
Document Structuring
Conventions Specification
Adobe Developer Support
Version 3.0
25 September 1992
possible downloadable from
https://archive.org/details/ps-doc-struc-conv-3
it says:
%%BoundingBox: { <llx> <lly> <urx> <ury> } | (atend)
<llx> ::= <int> (Lower left x coordinate)
<lly> ::= <int> (Lower left y coordinate)
<urx> ::= <int> (Upper right x coordinate)
<ury> ::= <int> (Upper right y coordinate)
This comment specifies the bounding box that encloses all marks
painted
on all pages of a document. That is, it must be a "high water
mark" in all
directions for marks made on any page. The four arguments
correspond to
the lower left (llx, lly) and upper right corners (urx, ury) of
the bounding box
in the default user coordinate system (PostScript units). See
also the
%%PageBoundingBox: comment.
I.e., according to spec, the numbers describe a box that encloses
everything. It doesn't say it must the smallest such box.
Same thing for PageBoundingBox.
I think it *is* the smallest box, but truncated to integers. At least I
can't imagine a box that leaves full units empty.
From what I've seen so far I was confident that the numbers correspond
to what LilyPond sees as \pt, and also in LaTeX I have treated the
numbers as pt (as opposed to bp).
Could this be an issue here?
That is in contrast to:
PostScript language reference manual, 3rd ed, TABLE 5.3:
FontBBox array (Required) An array of four numbers in the glyph coordinate
system giving
the left, bottom, right, and top coordinates, respectively, of
the font bounding
box. The font bounding box is the smallest rectangle enclosing
the shape that
would result if all of the glyphs of the font were placed with
their origins co-
incident, and then painted. This information is used in making
decisions
about glyph caching and clipping. If all four values are 0, the
PostScript inter-
preter makes no assumptions based on the font bounding box.
where they specify the smallest one, but for fonts and other
parts of pages, not whole pages.
Interestingly, here they don't specify the data type of the numbers.
...
Does the -80 mean:
* any value between -79 and -80
* any value between -79.5 and -80.4999999
...
So, if the leftmost painted things is at e.g. -79.1 then llx <= -80,
since llx >= -79 wouldn't do.
Thank you. This makes sense but is exactly the kind of assumption I
didn't want to approach by trial & error.
Best
Urs
Regards,
/Karl Hammar
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