Adobe Acrobat SDK
Implementation Notes
Adobe® Supplement to the ISO 32000
Implementation Notes to the PDF Reference, sixth edition 108
10. If an unrecognized filter is encountered, Acrobat viewers report the context in which the filter was
found. If errors occur while a page is being displayed, only the first error is reported. The subsequent
behavior depends on the context, as described in table titled “Acrobat behavior with unknown filter“.
Acrobat operations that process pages, such as the Find command and the Create Thumbnails
command, stop as soon as an error occurs.
If an unrecognized filter is encountered, Acrobat viewers report the context in which the filter was found. If errors occur while a page is being displayed, only the first error is reported. The subsequent behavior depends on the context, as described in the table titled “
Acrobat behavior with unknown filter
”. Acrobat operations that process pages, such as the Find command and the Create Thumbnails command, stop as soon as an error occurs.
3.3.7 DCTDecode Filter
11. Acrobat 4.0 and later viewers do not support the combination of the
DCTDecode
filter with any other
filter if the encoded data uses the progressive format. If a version of the Acrobat viewer earlier than 4.0
encounters
DCTDecode
data encoded in progressive format, an error occurs that is handled according
to the table
“Acrobat behavior with unknown filter” on page 108
.
3.4 File Structure
12. Acrobat viewers do not enforce the restriction on line length.
3.4.1 File Header
13. Acrobat viewers require only that the header appear somewhere within the first 1024 bytes of the file.
14. Acrobat viewers also accept a header of the form
%!PS-Adobe-
N
.
n
PDF-
M
.
m
CCITTFaxDecode
CCF
DCTDecode
DCT
Abbreviations for standard filter names
STANDARD FILTER NAME
ABBREVIATION
Acrobat behavior with unknown filter
CONTEXT
BEHAVIOR
Content stream
Page processing stops.
Indexed color space
The image does not appear, but page processing continues.
Inline image
The image does not appear, but page processing continues.
Thumbnail image
An error is reported and no more thumbnail images are
displayed, but the thumbnails can be deleted and created
again.
Form XObject
The form does not appear, but page processing continues.
Type 3 glyph description
The glyph does not appear, but page processing continues. The
text position is adjusted based on the glyph width.
Embedded font
The viewer behaves as if the font is not embedded.
