head	1.2;
access;
symbols;
locks; strict;
comment	@% @;


1.2
date	2003.05.17.01.41.53;	author cworth;	state Exp;
branches;
next	1.1;

1.1
date	2003.05.16.18.51.41;	author cworth;	state Exp;
branches;
next	;


desc
@@


1.2
log
@Final batch of minor corrections. Should be ready to ship now.
@
text
@\section{Implementation}

As currently implemented, Xr has good support for all functions
described here. The major aspects of the PostScript imaging model that
have not been discussed are text/font support, clipping, and color
management. Xr does include some level of experimental support for
text and clipping already, but these areas need further development.

The Xr system is implemented as 3 major library components: libXr,
libXc, and libIc. LibXr provides the user-level API described in
detail already.

LibXc is the backend of the Xr system. It provides a uniform, abstract
interface to several different low-level graphics systems. Currently,
libXc provides support for drawing to the X Window System or to
in-memory images. The semantics of the libXc interface are consistent
with the X Render Extension so it is used directly whenever available.

LibIc is an image compositing library that is used by libXc when
drawing to in-memory images. LibIc can also be used to provide support
for a low-level system whose semantics do not match the libXc
interface. In this case, libIc is used to draw everything to an
in-memory image and then the resulting image is provided to the
low-level system. This is the approach libXc uses to draw to an X
server that does not support the X Render Extension.

The libIc code is based on the original code for the software fallback
in the reference implementation of the X Render Extension. It would
be useful to convert any X server using that implementation to instead
use libIc.

These three libraries are implemented in approximately 7000 lines of C
code.


@


1.1
log
@Added implementation
@
text
@d23 1
a23 1
in-memory image and then the resulting image is given provided to the
d25 1
a25 1
server that does not support the X Rendering Extension.
d28 1
a28 1
in the reference implementation of the X Rendering Extension. It would
@