The following information is provided as is, and the authors take no responsibility for the correctness.
PCL XL is a Hewlett-Packard LaserJet printer language optimized for printing from graphical user interfaces (GUI) like Microsoft Windows® and OS/2®.
The PCL XL language commands are designed to optimally match the graphics printing requirements for GUI-based applications.
In most cases, for every graphics print command that a GUI wishes to perform, there is a matching PCL XL language command. This reduces the number of commands required to describe a graphics page.
Draw tools: Support drawing lines, arcs/ellipses/chords, (rounded) rectangles, polygons, Bezier paths, clipped paths, raster images, scanlines, raster operations.
Color handling: Support 1/4/8-bit palettes, RGB/grey color space. Support custom halftone patterns (max 256 patterns).
Compression: Supports RLE.
Units of measurement: Inch, millimetre, tenth of millimetre.
Paper handling: Support custom or predefined sets of paper types, including common Letter, Legal, A4, etc. Can choose paper from manual feed, trays, cassettes. Paper can be duplexed horizontally or vertically. Paper can be oriented in portrait, landscape, or 180 degree rotation of the former two.
Font: Supports bitmap or TrueType fonts, 8 or 16-bit code points. Choosing character set uses different symbol set code from PCL 5. When bitmap font is used, many scaling commands are unavailable. When TrueType font is used, variable length descriptors, continuation blocks are not supported. Outline font can be rotated, scaled, or sheared.
Compression: Added a proprietary JPEG compression called JetReady.
Paper handling: Media can redirected to different output bins (up to 256). Added A6 and Japanese B6 preset media sizes. Added Third cassette preset, 248 external tray media sources.
Font: Text can be written vertically.
Color handling: Added Color matching feature.
Compression: Added Delta Row.
Paper handling: Orientation, media size are optional when declaring a new page. Added B5, JIS 8K, JIS 16K, JIS Exec paper types.
Color handling: Allow using different halftone settings for vector or raster graphics, text. Supports adaptive halftoning.
Protocol: Supports PCL passthrough, allowing PCL 5 features to be used by PCL 6 streams. However, some PCL 6 states are not preserved when using this feature.
Font: Supports PCL fonts.
Viewer/Converter: PCLReader (freeware) can view, convert or print any level of PCL 6 (including JetReady) to any printer.
The latest technical reference manuals can be ordered or downloaded from Hewlett-Packard.