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	Start of file Data 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.