pwg subset of cups raster€¦ · web view23/02/2011 · abstract: this standard defines a...

May 27, 2023

Working Draft

The Printer Working Group

IPP Subset of CUPS Raster(IPP Raster)PWG Raster Format

Status: Draft

Abstract: This standard defines a simple proper subset of the CUPS Rraster format for printing, scanning, and facsimile. for use with IPP Printers. The subset The format includes support for a small set of standard and device color spaces and bit depths, and also defines Printer description attributes for IPP that enable a Client to generate or request a supported raster stream for a Printer.

Copyright © 2011 The Printer Working Group. All rights reserved.

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Working Draft


This document is a PWG Candidate Working DraftStandard. For a definition of a "PWG Candidate Working Draft Standard", see: ftp://ftp.pwg.org/pub/pwg/general/pwg-process30.pdf

This document is available electronically at:

ftp://ftp.pwg.org/pub/pwg/ipp/wd/wd-ippraster10-2011012620110223.pdf/.docx


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Working Draft – PWG Subset of CUPS Raster May 27, 2023


This document may be copied and furnished to others, and derivative works that comment on, or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice, this paragraph and the title of the Document as referenced below are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the IEEE-ISTO and the Printer Working Group, a program of the IEEE-ISTO.

Title: IPP Subset of CUPS Raster (IPP Raster)PWG Raster Format

The IEEE-ISTO and the Printer Working Group DISCLAIM ANY AND ALL WARRANTIES, WHETHER EXPRESS OR IMPLIED INCLUDING (WITHOUT LIMITATION) ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

The Printer Working Group, a program of the IEEE-ISTO, reserves the right to make changes to the document without further notice. The document may be updated, replaced or made obsolete by other documents at any time.

The IEEE-ISTO takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights.

of 35 Copyright © 2011 The Printer Working Group, All rights reserved.

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The IEEE-ISTO invites any interested party to bring to its attention any copyrights, patents, or patent applications, or other proprietary rights which may cover technology that may be required to implement the contents of this document. The IEEE-ISTO and its programs shall not be responsible for identifying patents for which a license may be required by a document and/or IEEE-ISTO Industry Group Standard or for conducting inquiries into the legal validity or scope of those patents that are brought to its attention. Inquiries may be submitted to the IEEE-ISTO by e-mail at: [email protected].

The Printer Working Group acknowledges that the IEEE-ISTO (acting itself or through its designees) is, and shall at all times, be the sole entity that may authorize the use of certification marks, trademarks, or other special designations to indicate compliance with these materials.

Use of this document is wholly voluntary. The existence of this document does not imply that there are no other ways to produce, test, measure, purchase, market, or provide other goods and services related to its scope.

About the IEEE-ISTO

The IEEE-ISTO is a not-for-profit corporation offering industry groups an innovative and flexible operational forum and support services. The IEEE-ISTO provides a forum not only to develop standards, but also to facilitate activities that support the implementation and acceptance of standards in the marketplace. The organization is affiliated with the IEEE (http://www.ieee.org/) and the IEEE Standards Association (http://standards.ieee.org/).

For additional information regarding the IEEE-ISTO and its industry programs visit:


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http://www.ieee-isto.org.

About the IEEE-ISTO PWG

The Printer Working Group (or PWG) is a Program of the IEEE Industry Standards and Technology Organization (ISTO) with member organizations including printer manufacturers, print server developers, operating system providers, network operating systems providers, network connectivity vendors, and print management application developers. The group is chartered to make printers and the applications and operating systems supporting them work together better. All references to the PWG in this document implicitly mean “The Printer Working Group, a Program of the IEEE ISTO.” In order to meet this objective, the PWG will document the results of their work as open standards that define print related protocols, interfaces, procedures and conventions. Printer manufacturers and vendors of printer related software will benefit from the interoperability provided by voluntary conformance to these standards.

In general, a PWG standard is a specification that is stable, well understood, and is technically competent, has multiple, independent and interoperable implementations with substantial operational experience, and enjoys significant public support.

For additional information regarding the Printer Working Group visit:

http://www.pwg.org


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c/o The IEEE Industry Standards and Technology Organization

445 Hoes Lane

Piscataway, NJ 08854

USA


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About the Internet Printing Protocol Work Group

The Internet Printing Protocol (IPP) working group has developed a modern, full-featured network printing protocol, which is now the industry standard. IPP allows a print client to query a printer for its supported capabilities, features, and parameters to allow the selection of an appropriate printer for each print job. IPP also provides job information prior to, during, and at the end of job processing.

For additional information regarding IPP visit:

http://www.pwg.org/ipp/

Implementers of this specification are encouraged to join the IPP mailing list in order to participate in any discussions of the specification. Suggested additions, changes, or clarification to this specification, should be sent to the IPP mailing list for consideration.


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Table of Contents

1. Introduction......................................................................................................................7

2. Terminology...................................................................................................................87

2.1 Conformance Terminology.......................................................................................87

2.2 Other Terminology...................................................................................................87

3. Requirements..................................................................................................................8

3.1 Rationale for the PWG Subset of CUPS Raster........................................................8

3.2 Use Models..............................................................................................................98

3.3 Design Requirements..............................................................................................98

4. Subset of CUPS Raster Format...................................................................................109

4.1 Format Version......................................................................................................109

4.2 Word Order............................................................................................................109

4.3 Page Header..........................................................................................................119

4.3.1 cupsBitsPerColor, cupsBitsPerPixel, cupsColorOrder, and cupsColorSpace. 129

4.3.2 cupsWidth and cupsHeight............................................................................1210

4.3.3 HWResolution..................................................Error! Bookmark not defined.10

5. Printer Description Attributes.....................................................................................1410

5.1 cups-back-side (type2 keyword)..........................................................................1410

5.2 cups-raster-supported (1setOf type2 keyword)....................................................1411


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6. Conformance Requirements......................................................................................1611

7. Internationalization Considerations............................................................................1711

8. Security Considerations.............................................................................................1711

9. IANA Considerations.................................................................................................1711

10. References..............................................................................................................1811

10.1 Normative References.......................................................................................1811

11. Author's Addresses..................................................................................................1911

12. Change History........................................................................................................2011

12.1 December 9, 2010.............................................................................................2012

List of Figures

No table of figures entries found.In your document, select the words to include in the table of contents, and then on the Home tab, under Styles, click a heading style. Repeat for each heading that you want to include, and then insert the table of contents in your document. To manually create a table of contents, on the Document Elements tab, under Table of Contents, point to a style and then click the down arrow button. Click one of the styles under Manual Table of Contents, and then type the entries manually.

List of Tables

Table 1 - Required Color Order, Color Space, and Bit Depth Combinations...................129


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1. Introduction

Historically, printer manufacturers have used a variety of proprietary or device-specific variants of industry standard page description languages (PDLs) to support printing, leading to the proliferation of so-called "printer driver" software for every supported operating system and/or platform.

Two high-level PDLs, PostScript and PDF, are sufficiently generic to be used for basic printing, however they require significant resources in the printer and can be difficult to generate and stream from some environments. Existing standard bitmap image formats have issues as well:

JPEG: Lossy compression, no multi-page support

JPEG 2000: Lossy compression, no multi-page support, resource-intensive

MNG: Resource-intensive and not widely implemented or supported

PNG: No multi-page support, resource-intensive

TIFF: Can be resource-intensive, hard to stream, multiple format variants

CUPS Raster [CUPSRASTER] is a simple bitmap container to support printing on all types of printers. It provides the following features:

Support for multiple pages

Support for standard color spaces backed by existing ICC color profiles


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Adaptable byte order for encoding and decoding

A single, lossless compression algorithm that is space, memory, and processor efficient

An easily streamable encoding

CUPS Raster has been used over existing print data transports such as the Internet Printing Protocol (IPP)CUPS Raster [CUPSRASTER] has been used to facilitate raster printing using traditional printer drivers since 1999. The format supports platform-agnostic multi-page printing using many device and standard Color Spaces, bit depths, Color Orders, and printer features. A compressed variant (version 2) uses a combination of run-length encoding compression algorithms to efficiently reduce the size of raster data when transferred over external interfaces such as networks. This variantCUPS Raster can also be further reduced in size using HTTP or IPP compression algorithms such as Compress and Flate when supported by the client or Printer.

This standard defines a proper subset of CUPS Raster for use with IPP Printers. The subset includes support for a small set of standard and device Color Spaces and bit depths, and also defines Printer description attributes for IPP that enable a Client to generate or request a supported raster stream for a Printer.

2. Terminology

2.1 Conformance Terminology

Capitalized terms, such as MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, MAY, and OPTIONAL, have special meaning relating to conformance as defined in RFC 2119 [RFC2119].


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2.2 Other Terminology

Color Component; an individual element or channel for a Color Space or Pixel, for example “Red”, “Green” and “Blue” are Color Components of the “RGB” Color Space.

Color Order; the order of Color Components within the Page Bitmap. These Color Orders are called “Chunked”, “Banded”, and “Planar” in the CUPS Raster Format specification [CUPSRASTER].

Color Space; the interpretation of color in a page bitmap, for example “RGB”, “Grayscale”, “CMYK”, and so forth.

CUPS Raster; the image file format defined by [CUPSRASTER].

PackBits; a simple run-length encoding algorithm for data compression. Each sequence is encoded as a series of repeated or non-repeated Pixels.

Page Bitmap; a rectangular grid of Pixels.

Page Header; the binary dictionary of PostScript and raster key values for a Page Bitmap.

Pixel; a set of Color Components representing a single grid point in a Page Bitmap.


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3. Requirements

[3.1] Rationale for the PWG Subset of CUPS Raster Format

IPP Everywhere [IPPEVE] and IPP Scan [IPPSCAN] both require a standard raster format for printing and scanning of multiple-page documents without printer-specific driver software. CUPS Raster supports many more Color Spaces, Color Orders, bit depths, and byte orders than are needed for a modern Printer. Moreover, the PostScript page device dictionary does not map cleanly to IPP or the PWG Semantic Model, leading to additional complexities that would make interoperability difficult.

By defining a proper subset of CUPS Raster, we both enable support for a new class of IPP Printer without the use of printer- and platform-specific driver software in the client and greatly reduce the number of variables for interoperability.

3.1[3.2] Use Models

Jane has a smart phone with Wi-Fi capability and a built-in camera. She prints photos from her phone to a low-cost Wi-Fi inkjet printer. The printer has limited memory and processor resources that support basic raster printing on a variety of media types and sizes.

John has a desktop PC he uses to write whitepapers and other business documents. He prints these documents to a low-cost Ethernet workgroup laser printer with three paper trays and a duplexing accessory. The printer has enough memory to hold a partial image of one side of a sheet.


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3.2[3.3] Out of Scope

Extensions to the CUPS Raster format and mapping of PostScript page device dictionary key/value pairs to IPP or the PWG Semantic model are out of scope for this specification because the goal is to define a simple subset for basic raster printing, scanning, and facsimile.

3.3 Design Requirements

Since both the client and IPP Printer may have limited memory, a raster format for printing must be streamable to minimize buffering.

Limited network bandwidth requires some form of data compression. Text printing favors lossless compression algorithms to preserve edge detail and resource limitations require simpler compression algorithms.

Because the client may not have sophisticated color management capabilities, standard color spaces should be used to foster improved color fidelity. Similarly, an IPP Printer may have limited space for color tables, however it should still be possible to support a managed color workflow when both the client and IPP Printer are capable. A bi-level imaging mode may also be useful when printing text and line art.

Because the IPP Printer may have limited memory, the client must be able to discover the supported raster resolutions and how to provide duplex page images – no flip, X flip, Y flip, or rotation by 180 degrees (both X and Y flip).


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Finally, to limit the complexity of implementation the order of multi-octet values should be predefined.

[4.] Subset of CUPSPWG Raster Format

The CUPS Raster specification [CUPSRASTER] defines three format variants for the MIME media type “application/vnd.cups-raster”. The following subsections define the subset of the CUPS Raster v2 format used for the MIME media type “image/cupspwg-raster”.

[4.1] Format Versionile Organization

Figure 1 - PWG Raster File Organization shows the general organization of every PWG Raster file. Each file begins with a 32-bit synchronization word followed by zero or more pages. Each page consists of a header followed by the bitmap image for the page. The bitmap image is compressed using a PackBits-like algorithm to reduce file size without significant overhead. Integer values larger than 8-bits are specified in network byte order.


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Figure 1 - PWG Raster File OrganizationAll “image/cups” streams MUST use format version 2.

[4.2] Word OrderSynchronization Word

All “image/cups” streams MUST use network ("big endian") byte orderThe synchronization word is a 32-bit unsigned integer with the value %x52.61.53.32 (“RaS2”).

3.4[4.3] Page Header

Table 1 - PWG Raster Page Header describes the 1796-octet page header that appears at the beginning of each page.All "image/cups" streams MUST initialize the cupsBitsPerColor, cupsBitsPerPixel, cupsBytesPerLine, cupsColorOrder, cupsColorSpace, cupsHeight, cupsWidth, and HWResolution fields in the page header. All other fields MUST be initialized to 0. The bulk of the page header is intentionally unused.


Synchronization Word

Page 1 (Header + Bitmap)

Page 2 (Header + Bitmap)

...

Page N (Header + Bitmap)

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Table 1 - PWG Raster Page Header

Bytes Type Name Values

0-275 Reserved Reserved MUST be 0

276-279 Integer HorizontalResolution As reported by pwg-raster-resolution-supported

280-283 Integer VerticalResolution As reported by pwg-raster-resolution-supported


372-375 Integer Width Width in pixels > 0

376-379 Integer Height Height in lines > 0


384-387 Integer BitsPerColor 1, 8, or 16 as reported by pwg-raster-types-supported

388-391 Integer BitsPerPixel 1, 8, 16, 24, 32, 48, or 64 as reported by pwg-raster-types-supported

392-395 Integer BytesPerLine Calculated from Width and BitsPerPixel

396-399 Integer ColorOrder MUST be 0 (chunky)

400-403 Integer ColorSpace 1 = RGB (device),

3 = Black (device),


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6 = CMYK (device),

18 = sGray,

19 = sRGB, or

20 = AdobeRGB

as reported by pwg-raster-types-supported


420-423 Integer NumColors 1, 3, or 4 as reported by pwg-raster-types-supported


3.4.1 HorizontalResolution and VerticalResolution

The HorizontalResolution and VerticalResolution fields MUST be initialized to either one of the supported values reported by the "pwg-raster-resolution-supported" attribute or a compatible lower resolution. A compatible lower resolution is an integral divisor of a "pwg-raster-resolution-supported" value, for example 360x360dpi for a printer that supports 720x720dpi or 300x300dpi for a printer that supports 2400x1200dpi.

[4.3.1] cupsBitsPerColor, cupsBitsPerPixel, cupsColorOrder, and cupsColorSpace

All “image/cups” streams MUST use one of the following combinations of cupsBitsPerColor, cupsBitsPerPixel, cupsColorOrder, and cupsColorSpace values defined in Table 1, "Allowed Color Order, Color Space, and Bit Depth Combinations".


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[4.3.2] cupsWidth and cupsHHeight

The cupsWidth and cupsHeight fields MUST be initialized to the full width and height of the current page in addressable units as defined by the HWorizontalResolution and VerticalResolution fields. Thus, each page bitmap provides a "full bleed" page image.

3.4.2 BitsPerColor, BitsPerPixel, ColorSpace, and NumColors

The BitsPerColor, BitsPerPixel, ColorSpace, and NumColors fields MUST be initialized to values corresponding to a “pwg-raster-resolution-supported” value, as defined in Table 2 –pwg-raster-types-supported values.

3.4.3 BytesPerLine

The BytesPerLine field MUST be initialized to the number of octets for a single uncompressed line in the page bitmap, as described by the following formula:

BytesPerLine = TRUNCATE((BitsPerPixel * Width + 7) / 8)

[4.3.3] HWResolution

The HWResolution field MUST be initialized to either one of the supported values reported by the "ipp-raster-resolution-supported" attribute or a compatible lower resolution. A

compatible lower resolution is an integral divisor of a "ipp-raster-resolution-supported" value, for example 360x360dpi for a printer that supported 720x720dpi.

Table 1 - Allowed Color Order, Color Space, and Bit Depth Combinations

cupsBits-PerColor

cupsBits-PerPixel

cupsColorSpace

ipp-raster-types-supported

1 1 3 (black) black-1

1 1 18 (sGray) sgray-1 of 35 Copyright © 2011 The Printer Working Group, All rights reserved.

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8 32 6 (CMYK) cmyk-8

8 8 18 (sGray) sgray-8

8 24 19 (sRGB) srgb-8

8 24 20 (AdobeRGB)

adobe-rgb-8


16 64 6 (CMYK) cmyk-16

16 16 18 (sGray) sgray-16

16 48 19 (sRGB) srgb-16

16 48 20 (AdobeRGB)

adobe-rgb-16

[4.4] Page Bitmap

EThe page bitmap is compressed using a PackBits-like algorithm. Pixel color values are packed into an integral number of octets. 8 pixel color values are packed into a single octet for compression when BitsPerPixel is 1.

Each line of raster data begins with a repetition count from 1 to 256 that is encoded using a single octet containing "count - 1".


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After the repetition count, whole color values for that line are run-length encoded using a PackBits-like run-length encoding algorithm: 1 to 128 repeated colors are encoded using an initial octet containing "count - 1" followed by the color value octet(s) while 2 to 128 non-repeating colors are encoded using an initial octet containing "257 - count" followed by the color value octet(s).

Figure 2 - Sample Page Image

For example, the 8x8 24-bit sRGB image shown in Figure 2 - Sample Page Image would be encoded as the following 89 octets:

%x00 %x00.FF.FF.FF %x02.FF.FF.00 %x03.FF.FF.FF

%x00 %xFE.FF.FF.00.00.00.FF.FF.FF.00 %x02.FF.FF.FF %x00.00.FF.00 %x00.FF.FF.FF

%x00 %x01.FF.FF.00 %x02.FF.FF.FF %x02.00.FF.00

%x00 %x02.FF.FF.00 %x02.FF.FF.FF %x00.00.FF.00 %x00.FF.FF.FF


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%x00 %x00.FF.FF.FF %x02.FF.FF.00 %x03.FF.FF.FF

%x00 %x07.FF.FF.FF

%x01 %x07.FF.00.00

The first line (%x00) contains 1 white pixel (%x00.FF.FF.FF), 3 yellow pixels (%x02.FF.FF.00), and 4 white pixels (%x03.FF.FF.FF).

The second line (%x00) contains a sequence of yellow + blue + yellow pixels (%xFE.FF.FF.00.00.00.FF.FF.FF.00), 3 white pixels (%x02.FF.FF.FF), 1 green pixel (%x00.00.FF.00), and 1 white pixel (%x00.FF.FF.FF).

The third line (%x00) contains 2 yellow pixels (%x01.FF.FF.00), 3 white pixels (%x02.FF.FF.FF), and 3 green pixels (%x02.00.FF.00)

The fourth line (%x00) contains 3 yellow pixels (%x02.FF.FF.00), 3 white pixels (%x02.FF.FF.FF), 1 green pixel (%x00.00.FF.00), and 1 white pixel (%x00.FF.FF.FF).

The fifth line (%x00) contains 1 white pixel (%x00.FF.FF.FF), 3 yellow pixels (%x02.FF.FF.00), and 4 white pixels (%x03.FF.FF.FF).

The sixth line (%x00) contains 8 white pixels (%x07.FF.FF.FF).


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The seventh and eighth lines (%x01) contain 8 red pixels (%x07.FF.00.00).ach page bitmap in an "image/cups" stream represents a full-bleed image.

4.[5.] Printer Description Attributes

This specification defines three new Printer attributes.

[5.1] ipppwg-raster-back-side (type2 keyword)

This REQUIRED Printer attribute specifies the bitmap coordinate system for the back side of duplex sheets. The following keyword values are defined:

"normal" - the back side has the origin at the top-left corner of the bitmap,

"manual-tumble" - the back side has the origin at the top-left corner of the bitmap for "two-sided-long-edge" and the bottom-right corner (rotated 180º) of the bitmap for "two-sided-short-edge",

"rotated" - the back side image has the origin at the bottom-right corner (rotated 180º) of the bitmap for "two-sided-long-edge" and the top-left corner of the bitmap for "two-sided-short-edge", or

"flipped" - the back side image has the origin at the bottom-left corner (X flipped) of the bitmap for "two-sided-long-edge" and the top-right corner (Y flipped).


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Figure 3 - Back side bitmap vs. "pwg-raster-back-side" and "sides" values visually shows the effect of each value on the bitmap image.

4.1 pwg-raster-resolution-supported (1setOf resolution)

This REQUIRED Printer attribute lists the supported page bitmap resolutions in dots per inch. Printers MUST accept "image/pwg-raster" streams for the highest reported resolution on the largest supported media.

4.2 pwg-raster-types-supported (1setOf type2 keyword)

This REQUIRED Printer attribute lists the supported Color Space and bit depth combinations. Table 2 – pwg-raster-types-supported values defines the keyword values for each combination.


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Figure 3 - Back side bitmap vs. "pwg-raster-back-side" and "sides" values ipp-raster-resolution-supported (1setOf resolution)

This REQUIRED Printer attribute lists the supported bitmap resolutions in dots per inch. Printers MUST accept "image/cups" streams for the highest reported resolution on the

largest supported media.

ipp-raster-types-supported (1setOf type2 keyword)

This REQUIRED Printer attribute lists the supported Color Space and bit depth combinations. Table 1, "Allowed Color Order, Color Space, and Bit Depth Combinations",

defines the keyword values for each combination.


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Table 2 – pwg-raster-types-supported values

pwg-raster-types-supported

BitsPerColor BitsPerPixel

ColorSpace NumColors

black-1 1 1 3 1

sgray-1 1 1 18 1

black-8 8 8 3 1

cmyk-8 8 32 6 4

sgray-8 8 8 18 1

srgb-8 8 24 19 3

adobe-rgb-8 8 24 20 3

black-16 16 16 3 1

cmyk-16 16 64 6 4

sgray-16 16 16 18 1

srgb-16 16 48 19 3

adobe-rgb-16 16 48 20 3

[6.] Conformance Requirements

4.3[6.1] IPP Printer Conformance Requirements

To claim conformance to this specification, an IPP Printer implementation MUST:


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(a) support the "image/cupspwg-raster" MIME media type as defined in section 4 of this specification,;

(b) support all IPP attributes defined in section 5 of this specification,;

(c) support PWG Raster streams at the highest reported resolution reported by the “pwg-raster-resolution-supported” attribute and largest media size reported by the “media-supported” attribute,

(d) support PWG Raster streams with all resolutions compatible with the values reported by the “pwg-raster-resolution-supported” attribute as defined in section 4.3.1 of this specification, and

(ec) conform to the Internationalization Considerations defined in section 7 of this specification; and

(d) conform to the Security Considerations defined in section 8 of this specification.

An IPP Printer SHOULD:

(a) support the IPP “compression” attribute with the values “compress”, “deflate”, and/or “gzip” to further reduce the size of PWG Raster documents.

4.4[6.2] IPP Client Conformance Requirements

To claim conformance to this specification, an IPP Client MUST:

(a) generate document data conforming to the "image/cupspwg-raster" MIME media type as defined in section 4 of this specification,;

(b) explicitly identify the supported values of all IPP attributes defined in section 5 of this specification;,


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(c) generate PWG Raster streams at a compatible resolution and size as reported by the “pwg-raster-resolution-supported” and “media-supported” attributes and as defined in section 4.3.1 of this specification, and

(dc) conform to the Internationalization Considerations defined in section 7 of this specification; and

(d) conform to the Security Considerations defined in section 8 of this specification.

An IPP Client SHOULD:

(a) support the IPP “compression” attribute with the values “compress”, “deflate”, and/or “gzip” to further reduce the size of PWG Raster documents.

4.5 PWG Raster Consumer Requirements

To claim conformance to this specification, a PWG Raster consumer MUST:

(a) support the "image/pwg-raster" MIME media type as defined in section 4 of this specification and

(b) conform to the Security Considerations defined in section 8 of this specification.

4.6 PWG Raster Producer Requirements

To claim conformance to this specification, a PWG Raster producer MUST:

(a) generate document data conforming to the "image/pwg-raster" MIME media type as defined in section 4 of this specification and

(b) conform to the Security Considerations defined in section 8 of this specification.


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5.[7.] Internationalization Considerations

For interoperability and basic support for multiple languages, conforming implementations MUST support the UTF-8 [RFC3629] encoding of Unicode [UNICODE] [ISO10646]Because PWG Raster streams contain no localizable text, there are no internationalization considerations for the PWG Raster format.

6.[8.] Security Considerations

The security considerations for IPP are described in Section 8 of RFC 2911 [RFC2911]. Consumers of PWG Raster streams IPP Printers MUST range check all page header and bitmap values to protect against integer and buffer overflows.

7.[9.] IANA Considerations

7.1 MIME Media Type Registration

Name : Michael Sweet

E-mail : [email protected]

MIME media type name : Image

MIME subtype name : Standards Tree -– cupspwg-raster

Required parameters : NONE


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Optional parameters : NONE

Encoding considerations :

8-bit (raw) binary data.

Security considerations :

Raster data can be very large, which could fill a filesystem and

cause a denial of service or system failure.

Raster data contains no executables or macros. Authentication and

access control are normally handled by the Internet Printing Protocol

and Hyper-Text Transport Protocol.

Interoperability considerations :

NONE

Published specification :

ftp://ftp.pwg.org/pub/pwg/candidates/cs-ippraster10-YYYYMMDD.pdf


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Applications which use this media :

CUPS

IPP Everywhere

IPP Scan

Additional information :

1. Magic number(s) :

2. File extension(s) :

3. Macintosh file type code :

Person to contact for further information :

1. Name : Michael Sweet

2. E-mail : [email protected]

Intended usage : Common

Used for printing "raw" image data in formats acceptable to printers.

Author/Change controller :


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c/o The IEEE Industry Standards and Technology Organization

445 Hoes Lane

Piscataway, NJ 08854

USAMichael Sweet

Apple Inc.

10431 N. De Anza Blvd.

MS 38-4LPT

Cupertino CA 95014

8.[10.] References

8.1[10.1] Normative References

[CUPSRASTER] “CUPS Raster Format”, http://www.cups.org/spec-raster.html

[RFC2911] "Internet Printing Protocol/1.1: Model and Semantics"

[RFC3805] "Printer MIB v2"

9.[11.] Author's Addresses

Michael Sweet

Apple Inc.

10431 N. De Anza Blvd.


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MS 38-4LPT

Cupertino CA 95014


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10.[12.] Change History

[ PWG Secretary: This section must be removed when Document is approved ]

10.1[12.1] February 23, 2011

1. Updated MIME media type to image/pwg-raster2. Updated IPP attributes to be pwg-raster-xxx instead of ipp-raster-xxx3. Added Out of Scope section4. Updated introduction and rationale to cover scanning5. Updated PWG Raster format definition (section 4) to contain a complete description, including

tables and figures, for the CUPS Raster v2 format.6. Updated pwg-raster-types-supported and pwg-raster-back-side to include figures and tables7. Updated conformance section8. Update IETF registration information

10.2 January 26, 2011

1. Updated document title and filename to use "IPP" as the prefix instead of "PWG".2. Added normative references to RFC 2911 and RFC 38053. Changed "cups-raster" prefix on attributes to "ipp-raster"4. Added "ipp-raster-resolutions-supported" attribute5. Added page bitmap section6. Added conformance requirements7. Added IANA registration info

10.3[12.2] January 24, 2011

Initial draft.


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