I took a look at the test.pdf file produced by the "pdf example.rb"
project. There are several serious problems which need to be
addressed.
Serious Problems that must be fixed :
1. The object references in the cross reference table point to the
wrong offsets in the file.
2. The "stream" keyword must not be followed by a single carriage
return.
It must be followed by a carriage return line feed combination or by a
single line feed.
3. The startxref in the document trailer has the wrong value.
Things that really should be fixed :
4. The second line of the file header only specifies four bytes of data
whose values are greater then 128.
The extra bytes in the header look like they are contributing to the
error in item #1.
5. When drawing sequential runs of text to the page; using Begin Text
(BT) and End Text (ET) for each drawing occurrence is unnecessary. The
stream on page two really only needs one BT/ET pair.
6. Don't keep setting the same fonts and colors over and over again
when not making any changes to the font or color settings.
7. The same /Resources dictionary is used for both pages. Even-though,
the streams on both pages do not use the same resources.
Stylistic Notes :
8. When drawing multiple lines of text; you may find it more convenient
to simply use the TD or Td operators.
These are shorthands for moving to the start of the next line
instead of setting the Text Matrix (Tm).
9. Extra carriage returns after each "endobj" are unnecessary.
10. The document information dictionary is missing.
11. /F1 and /F2 are the same font duplicated within the file.
If, when opening a PDF file; Acrobat displays the warning that a file
is being repaired: this is typically an indication that the document
cross reference table is malformed. Acrobat can NOT always repair
document which contain malformed cross reference tables. Acrobat does
go through a lot of effort to try to repair and display all PDF files;
but, it doesn't perform miracles. You need to give any PDF viewer a
fighting chance to display your document by at least giving it a valid
file. Many third-party PDF consumers will fail at reading this file.
For example, the Enfocus Browser application, a low level PDF debugging
tool, can not open the test.pdf file.
Regards,
Mark Gavin
Chief Technology Officer
Appligent, Inc.
60 South Lansdowne Avenue
Lansdowne, PA 19050
(610) 284-4006
http://www.appligent.com
Am 28.10.2005 um 15:20 schrieb REAL News:
Toby W. Rush Design releases REALbasic PDF
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