1. META2 format

META2 format

Goals

The META format is used to store and transport halftoned and cutting data from the RIP (Render) component to the Printer (Spooler) component. The META format must meet the following requirements:

  • Streaming transport format: allowing the RIP component to directly send the data it processes to the Printer component which can immediately start printing without the data stream being complete.

  • Random access store format: allowing the Printer component to nest multiple jobs efficiently. Especially rotating files needs a lot of random access

  • Compression: store and stream compressed data to efficiently use network and disk.

  • Open formats: the file format for storage should be using open formats as much as possible to allow easy re-use in other components (incl. external components).

Store format

The META data is stored in a folder inside the job folder named META. The folder contains the following files:

Info.xml

The info file is an XML that contains all the properties to describe the job data. It contains general setup information. Definition of the keywords below in”META Job dictionary”

00001.xml

An XML dictionary that contains the page information for page 1. Definition of the keywords below in “META Page dictionary”

00001.bmp

The preview of page 1 in Windows BMP format. Current implementation is restricted to 24 bits RGB.

00001.rtl

Halftoned data in HP/RTL format. This file is only available for printers and not for cutters. Current implementation is restricted to planar interleaved RLE compressed lines. The number of bits per pixel is restricted to 1, 2, 4 and 8. See implementation limits below: HP-RTL implementation.

00001.idx

Index file containing the offsets per line in the *.rtl file indicating where the Esc *b command of the first plane/channel of that line starts. This index file contains 64 bits pointers and is used by the Printer component to get fast random access to the raster data for nesting purposes. This file is required when halftone data is present.

00001.plt

Cutting commands om HPGL/2 format. The file is only available for cutters and hybrid devices. Current implementation only supports a small subset of HPGL/2 document below: HPGL/2 implementation.

00002.*

Every page consist of at least the page XML with the page number written in 5 digits. The other files are optional and are only required when they are referenced from within the page XML.

META Job dictionary

Tag

Tag

Description

Job

Dictionary containing the keywords below

Name

Display name of the job

QueueName

Name of the queue

UserName

Name of the user

PrintMode

Name of the print mode (informational)

Reference

Name of normalization profile used  (informational)

Copies

Number of copies to be output

Pages

Number of pages in this job, is only available when the job is completely rendered

MediaName

Name of the media type to be used (informational)

MediaSize

Definition of the media size to be used. Attributes:

  • Name : Media size name

  • Width : Physical width of the media in Units (1/18 inch)

  • Length : Physical length of the media in Units

  • Roll : Boolean indicating roll or sheet

  • Transverse : Boolean indicating orientation

  • Margins : Left, Top, Right, Bottom non printable margins in format %f,%f,%f,%f

ContentRect

The unionized area used by the image on all pages defined in Unit (1/18 inch). Left, Top, Right, Bottom in format %f,%f,%f,%f

TrayName

Name of the tray to be used

Collate

Boolean to indicate collate of copies

DeviceDriver

Driver to use

DeviceURL

URL of the connection to the device (printer/cutter), relative to the location of the spooler

DriverSettings

Driver settings XML used to create the META data

Raster

Boolean indicating if the job contains raster data

Vector

Boolean indicating if the job contains vector data

Reference

Reference profile used to produce this job. Only present when a reference profile was used

Resolution

Resolution of the image data in this job in units of 1/18th of an inch. The resolution is stored in the attributes “X” and “Y”

META Page dictionary

Tag

Tag

Tag

Tag

Description

Page

Dictionary containing the keywords below

Name

Optional Name of the page or tile

MediaSize

Definition of the media size to be used. Attributes:

  • Name : Media size name

  • Width : Physical width of the media in Units (1/18 inch)

  • Length : Physical length of the media in Units

  • Roll : Boolean indicating roll or sheet

  • Transverse : Boolean indicating orientation

  • Margins : Left, Top, Right, Bottom non printable margins in format %f,%f,%f,%f

TrayName

Name of the tray to be used

ContentRect

The unionized area used by the image on all pages defined in Unit (1/18 inch). Left, Top, Right, Bottom in format %f,%f,%f,%f

Feed

Feed method to use after finishing the page. Values:

Cut

Boolean defining if the machine must cut the media after printing/cutting

Raster

Dictionary describing the raster/halftone data of this page. Attribute “File” contains the name of the file containing the RTL formated halftone data.

Size

Dimensions of the raster/halftone data in pixels. Stored in the attributes “Width” and “Height”

Position

Position of the raster/halftone data in pixels relative to the image-able area of the page. Stored in the attributes “X” and “Y”

Inks

Dictionary describing the inks per channel / plane. Attribute “Count” defines the number of inks in the dictionary

Ink

Ink channel description. Attibribute “Name” defines the channel name, attibute “Dotsize” defines the dot weights in the format %f,%f,…

Vector

Attribute “File” contains the name of the file containing the HPGL/2 cutting data.

Preview

Attribute “File” contains the name of the file containing the preview of the page.

Current implementation requires referenced files to follow the document structure described above. Therefore the files are assumed to have the same base name (name without extension) as the page XML and are assumed to be next to the page XML.

HP-RTL implementation

The following HP-RTL commands are honored and are mandatory:

  • Esc %0A : Start HP/RTL at current position

  • Esc *p x X : Define left position of raster in pixels

  • Esc *p y Y : Define top position of raster in pixels

  • Esc *r width S : Define width of raster in pixels

  • Esc *r height T : Define height of raster in pixels

  • Esc *r- plane count U : Define number of planes / color channels

  • Esc *b2M : Select RLE compression

  • Esc *r0A : Start raster data

  • Esc *b byte count V data : Line of data per plane/channel RLE compressed

  • Esc *b byte count W data : Last plane/channel of data of the current line

  • Esc *rC : End raster data

  • Esc %0B : Stop HP-RTL mode HP-RTL commands that are not listed here are ignored.

HPGL/2 implementation

Two types of cutting commands exist. The sets are mutually exclusive. The first set is for driving conventional cutting plotters that are usually driven by languages like HPGL/2. The second set is for defining contour information for NC and contour cutting systems like i-Cut.

Low level cutting

The coordinates used for X and Y are defined as absolute locations in integers at the step resolution of the cutting plotter.

Command

Parameters

Description

IN

Initialize. Starts cutting data

QL

0

Quality level. Set to 0 for low-level cutting

SP

pen #

Select pen/tool. 1 = knife. 2 = pencil.

PU

Lift the tool

PD

Lower the tool

PA

X, Y

Move/draw/cut line to absolute position

BS

Start of a sequence of curve segments

BE

End of a sequence of curve segments

PG

Advance page. End of cutting data for this page

High level cutting

The coordinates used for X and Y are defined as absolute locations in real numbers at 18 steps per inch (=Unit).

Command

Parameters

Description

IN

Initialize. Starts cutting data

QL

100

Quality level. Set to 100 for high-level cutting

SP

pen #

Select pen/tool. 1 = knife. 2 = pencil.

PC

pen #, color

Sets the color of the tool. Tool 1 = RGB, Tool 2 = CMYK. Color values in range 0-255.

PU

Lift the tool

PD

Lower the tool

PA

X, Y

Move/draw/cut line to absolute position

BZ

X1, Y1, X2, Y2, X3, Y3

Draw/cut a bezier curve

CO

ID, Value

Passes private information specific to the driver. Both ID and Value are integers

PG

Advance page. End of cutting data for this page

Streaming format

The streaming format is a TCP stream that packages the files one after the other in the following sequence:

  • Job XML

  • Page XML of page 1

    • RTL data (if present)

    • Index data (if present)

    • HPGL/2 data (if present)

    • Preview

  • Page XML of page 2

    • etc.

Every file is sent as a sequence of chunks. The chunks allow the sender to start sending without having to know the final size. The last chunk of a file contains an EOF marker. Each chunk follows the following format in i386 format (thus needs swaps on PowerPC):

Magic

Uint32

0x4D455441 (‘META’) to check validity of the chunk structure

Seq.

Uint32

Chunk sequence number. Starts with 0.

Type

Uint32

  1. Start of file

  2. Data

  3. Last data

Size

Uint32

Size of data following this chunk

Data

If the type is 1 then the name of the file. An empty name indicates last file has been send.

If the type is 2 or 3 the amount of data specified by Size is send.