Xr - Rendering library

Compiling
---------
See the INSTALL document for build instructions.

Description
-----------
Xr provides anti-aliased vector-based rendering for X. Paths consist
of line segments and cubic splines and can be rendered at any width
with various join and cap styles. All colors may be specified with
optional translucence (opacity/alpha) and combined using the extended
Porter/Duff compositing algebra as found in the X Render Extension.

Xr exports a stateful rendering API similar in spirit to the path
construction, text, and painting operators of PostScript, (with the
significant addition of translucence in the imaging model). When
complete, the API is intended to support the complete imaging model of
PDF 1.4.

Xr relies on the Xc library for backend rendering. Xc provides an
abstract interface for rendering to multiple target types. As of this
writing, Xc allows Xr to target X drawables as well as generic image
buffers. Future backends such as PostScript, PDF, and perhaps OpenGL
are currently being planned.

Dependencies
------------
Xr currently requires the following supporting libraries:

	Xc
	Xft
	fontconfig
	libic
	libpixregion

Documentation
-------------
There's not much documentation yet apart from the Xr.h header
file. We'll be correcting that shortly.

In the meantime, the xrtest module in CVS provides a few example
programs using Xr. These may be helpful to a programmer just beginning
with Xr. Also, familiarity with the PostScript imaging model will
help in understanding Xr.

History
-------
Xr was developed by Carl Worth <cworth@isi.edu> and Keith Packard
<keithp@keithp.com>. Many thanks are due to Lyle Ramshaw without whose
patient help our ignorance would be much more apparent.

Mailing List
------------
If you have trouble with Xr or you have some ideas for how it could be
improved, please feel free to send a message to xr@xwin.org.

Xr is still under active development and all discussion happens on
that list. So if you want to lurk or, (even better), take part in the
development, take a look. Subscription information and archives are
available:

	http://xwin.org/cgi-bin/mailman/listinfo/xr