Last week, while reviewing the Production Printing Extension spec at the IPP
WG meeting, we agreed to allow the sender (client or printer) to specify
media size either by dimensions or by name, instead of only by dimensions.
However, I want to push back on that decision.
ISSUE: We agreed to add "media-size" (type3 keyword | name)
to allow the sender (client or printer) to specify media size either by
dimensions or by name, instead of only by dimensions. However, the
description of the existing "media-size" (collection) member attribute
clearly indicates that the client localizes the size numbers to include the
size name appropriate for the locale of the user.
I checked with several existing clients: the user either
selects from a list that has both the names with dimensions in parentheses,
or has names and the driver echoes back the dimensions when the user selects
a name, or the user selects an arbitrary pair of numbers which has no name.
All this functionality can be accomplished by a single member attribute in
the protocol, namely, "media-size" (collection), where collection contains
the two numbers.
OK to go back to the original specification with just
"media-size" (collection) in which only the dimensions in hundredths of a
millimeter (equivalent to 1/2540 th of an inch resolution)?
Here is the complete description of the "media-size" (collection) member
attribute before last week's meeting (that I want to go back to before last
call on the Production Printing Extensions):
3.8.10 media-size (collection)
The "media-size" member attribute is a collection that
explicitly specifies the numerical media width and height dimensions.
It is RECOMMENDED that a client localize the collection
values to the size names that users are familiar with, such as 'letter' and
'A4', possibly also including the exact dimensions as well (and in the units
appropriate for the user's locale). If a client does not recognize a pair
of numbers as a named size, it can simply display the two numbers instead.
Thus the pair of size dimensions serve the same function as keyword values,
except that the client has an obvious fallback display for an unrecognized
pair, namely, the actual dimension numbers.
The "media-size" collection member attributes are:
Table 8 - "media-size" member attributes
Attribute name attribute syntax request Printer Support
x-dimension integer (0:MAX) MUST MUST
y-dimension integer (0:MAX) MUST MUST
1.1.1.1 x-dimension (integer(0:MAX))
Indicates the size of the media in
hundredths of a millimeter along the bottom edge of the media. See section
2.3 regarding the coordinate system. This unit is equivalent to 1/2540 th
of an inch resolution.
1.1.1.2 y-dimension (integer(0:MAX))
Indicates the size of the media in
hundredths of a millimeter along the left edge of the media. See section
2.3 regarding the coordinate system. This is equivalent to 1/2540 th of an
inch resolution.
1.1.1.3 media-size-supported (1setOf
collection)
Indicates the sizes supported by the
Printer. A requested media size dimension matches a supported media
dimension if it is within an implementation-defined tolerance. For example,
PostScript [redbook] specifies a tolerance of 5 points (5/72 of an inch =
1.7 mm) of a supported dimension, i.e., within 176 units of the value of the
dimension.
The "media-size-supported " collection
member attributes are:
Table 9 - "media-size-coll-supported" member attributes
Attribute name attribute syntax request Printer Support
x-dimension integer (1:MAX) | rangeOfInteger (1:MAX) MUST MUST
y-dimension integer (1:MAX) | rangeOfInteger (1:MAX) MUST MUST
1.1.1.3.1 x-dimension (integer(1:MAX)
| rangeOfInteger(1:MAX))
Indicates the size of the media in
hundredths of a millimeter along the bottom edge of the media. The
rangeOfInteger attribute syntax accommodated variable size implementations,
including web printers. See section 2.3 regarding the coordinate system.
This is equivalent to 1/2540 th of an inch resolution.
1.1.1.3.2 y-dimension (integer(1:MAX)
| rangeOfInteger(1:MAX))
Indicates the size of the media in
hundredths of a millimeter along the left edge of the media. The
rangeOfInteger attribute syntax accommodated variable size implementations,
including web printers. See section 2.3 regarding the coordinate system.
This is equivalent to 1/2540 th of an inch resolution.