Ubuntu Manpage: X11::Protocol::Ext::Composite

Provided by: libx11-protocol-other-perl_31-1_all

NAME

       X11::Protocol::Ext::Composite - off-screen window contents

SYNOPSIS

        use X11::Protocol;
        my $X = X11::Protocol->new;
        $X->init_extension('Composite')
          or print "Composite extension not available";

        $X->CompositeRedirectWindow ($mywindow, 'Automatic');

DESCRIPTION

       The Composite extension holds the full pixel contents of windows in off-screen storage,
       ready for things like "CopyArea()".  Normally the server only keeps the visible parts of a
       window, not areas overlapped or obscured.

       In "Automatic" mode the visible parts of a window are displayed on screen as normal.  The
       off-screen storage is then a little like the backing store feature, but just when one or
       more clients declare an interest in the full content.

       In "Manual" mode the window contents are not drawn on screen, only kept off-screen.  This
       mode is for use by special "composite manager" programs which might make a composite
       display (hence the name of the extension) of the overlapping windows with partial-
       transparency or shadowing effects.

       There's nothing here to draw or combine to actually make a composite window result.  When
       required that's done with the usual core protocol drawing or with drawing extensions such
       as RENDER (see X11::Protocol::Ext::RENDER).

REQUESTS

       The following requests are made available with an "init_extension()", as per "EXTENSIONS"
       in X11::Protocol.

           my $is_available = $X->init_extension('Composite');

   Composite 0.1
       "($server_major, $server_minor) = $X->CompositeQueryVersion ($client_major,
       $client_minor)"
           Negotiate a protocol version with the server.  $client_major and $client_minor is what
           the client would like, the returned $server_major and $server_minor is what the server
           will do, which might be less than requested (but not more than).

           Actually the X.org server circa 1.10 will return a higher minor version than the
           client requests.

           The current code supports up to 0.3 and the intention is to automatically negotiate in
           "init_extension()" if/when necessary.

       "$X->CompositeRedirectWindow ($window, $update)"
       "$X->CompositeRedirectSubwindows ($window, $update)"
       "$X->CompositeUnredirectWindow ($window, $update)"
       "$X->CompositeUnredirectSubwindows ($window, $update)"
           Enable or disable a redirect of $window to off-screen storage.

           "Window()" acts on just the given $window.  "Subwindows()" acts on $window and also
           any subwindows it has now or in the future.  The root window cannot be redirected.

           $update is string "Automatic" or "Manual".  Only one client at a time may use Manual
           mode on a given $window (normally a "composite manager" program).

           Redirection is a per-client setting and is automatically unredirected if the client
           disconnects.  An unredirect when not redirected is a "BadValue" error.  Off-screen
           storage remains in effect while at least one current client has requested it.

       "$X->CompositeCreateRegionFromBorderClip ($region, $window)"
           Create $region (a new XID) as a server-side region object initialized to, umm,
           something about $window and its current border or visible parts or whatnot.

           Region objects are from XFIXES 2.0 (X11::Protocol::Ext::XFIXES).
           "CompositeCreateRegionFromBorderClip()" can be used without "init_extension()" of
           XFIXES, but there's not much which can be done with a region except through XFIXES.

   Composite 0.2
       "$X->CompositeNameWindowPixmap ($window, $pixmap)"
           Set $pixmap (a new XID) to refer to the off-screen storage of $window.  $window must
           be viewable (mapped and all of its parents mapped) and must be redirected (by any
           client).

               my $pixmap = $X->new_rsrc;
               $X->CompositeNameWindowPixmap ($window, $pixmap);

           $pixmap is released with "FreePixmap()" in the usual way.  If $window or a parent is
           unmapped then $pixmap continues to exist, but it's association with $window is lost.
           If $window is mapped and redirected again later then it has a new off-screen storage
           and a new "CompositeNameWindowPixmap()" must be called to get a new pixmap for it.

   Composite 0.3
       "$overlay_window = $X->CompositeGetOverlayWindow ($window)"
           Return the composite overlay window for the screen of $window.

           This window covers the whole screen and is always above ordinary windows but below any
           screen saver, and doesn't appear in a "QueryTree()".  It's created when the first
           client asks for it, and shared by any further clients who ask.

       "$X->CompositeReleaseOverlayWindow ($window)"
           Release the composite overlay window for the screen of $window.  When all clients
           release it the overlay window is destroyed.

HOME PAGE

       <http://user42.tuxfamily.org/x11-protocol-other/index.html>

LICENSE

       Copyright 2011, 2012, 2013, 2014, 2017 Kevin Ryde

       X11-Protocol-Other is free software; you can redistribute it and/or modify it under the
       terms of the GNU General Public License as published by the Free Software Foundation;
       either version 3, or (at your option) any later version.

       X11-Protocol-Other is distributed in the hope that it will be useful, but WITHOUT ANY
       WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
       PURPOSE.  See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with
       X11-Protocol-Other.  If not, see <http://www.gnu.org/licenses/>.

NAME

SYNOPSIS

DESCRIPTION

REQUESTS

SEE ALSO

HOME PAGE

LICENSE