CHAPTER 4
354
Graphics
FULL NAME
ABBREVIATION
ASCIIHexDecode
ASCII85Decode
LZWDecode
FlateDecode
(PDF 1.2)
RunLengthDecode
CCITTFaxDecode
DCTDecode
AHx
A85
LZW
Fl
(uppercase F, lowercase L)
RL
CCF
DCT
The color space specified by the
ColorSpace
(or
CS
) entry may be any of the stan-
dard device color spaces (
DeviceGray
,
DeviceRGB
, or
DeviceCMYK
). It may not be
a CIE-based color space or a special color space, with the exception of a limited
form of
Indexed
color space whose base color space is a device space and whose
color table is specified by a byte string (see “Indexed Color Spaces” on page 262).
Beginning with PDF 1.2, the value of the
ColorSpace
entry may also be the name
of a color space in the
ColorSpace
subdictionary of the current resource dictio-
nary (see Section 3.7.2, “Resource Dictionaries”). In this case, the name may des-
ignate any color space that can be used with an image XObject.
Note:
The names
DeviceGray
,
DeviceRGB
, and
DeviceCMYK
(as well as their abbre-
viations
G
,
RGB
, and
CMYK
) always identify the corresponding color spaces directly;
they never refer to resources in the
ColorSpace
subdictionary.
The image data in an inline image may be encoded by using any of the standard
PDF filters. The bytes between the
ID
and
EI
operators are treated much the same
as a stream object’s data (see Section 3.2.7, “Stream Objects”), even though they
do not follow the standard stream syntax. (This is an exception to the usual rule
that the data in a content stream is interpreted according to the standard PDF
syntax for objects.)
component in the
DeviceRGB
color space. The image has been encoded using
LZW and ASCII base-85 encoding. The
cm
operator is used to scale it to a width
and height of 17 units in user space and position it at coordinates (298, 388). The
q
and
Q
operators encapsulate the
cm
operation to limit its effect to resizing the
image.