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Now the arc drawing part works: it needed a little change of the
"implemented protocol" or request sequence:<br>
First map the window, second listen for events. Third draw the arc.<br>
<br>
That was the third round after authentication and putting a window
on the screen. It would be nice if these sequences were documented
as part of the protocol. For now it remembers me that I need to
change the low level IO routines to then buffer the graphics
operations in a drawing graph and connect it the repaint events and
...<br>
<br>
<tt>(X-polifill-arc X (second v) (second g) 150 200 60 60 (* 10 64)
(* 350 64)) => 24 ; doesn't appear</tt><tt><br>
</tt><tt>(X-map-window X (second v)) => 8</tt><tt><br>
</tt><tt>(X-control X) => Window #"254 255 31 4" received a key
event #"9" down.</tt><tt><br>
</tt><tt>escaping-X-control</tt><tt><br>
</tt><tt>VSI> (X-polifill-arc X (second v) (second g) 150 200 60
60 (* 10 64) (* 350 64)) ; OK appears</tt><tt><br>
</tt><tt>(X-polifill-arc X (second v) (second g) 150 200 60 60 (* 10
64) (* 350 64)) => 24</tt><tt><br>
</tt><tt>VSI> (X-control X)</tt><tt><br>
</tt><tt>...</tt><tt><br>
</tt><br>
<br>
VSI:
<a class="moz-txt-link-freetext" href="https://code.launchpad.net/~michael-tiedtke-i/viper-system-interface/alfa">https://code.launchpad.net/~michael-tiedtke-i/viper-system-interface/alfa</a><br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 11/12/2015 22:02, Michael Titke
wrote:<br>
</div>
<blockquote cite="mid:566B39FE.8020607@o2online.de" type="cite">
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Hello!<br>
<br>
As part of a first incursion into the possibility to implementing
native support for X starting from the wire protocol (w/o any
Xlib/XCB support) I ran into a couple of situations where
documentation didn't match implementation.<br>
<br>
The first surprise was the "magic" of the MIT Magic Cookie which
needs that little deviation from the protocol encoding where you
have to put the padding bytes at the end. Now I really made it to
open a window and receive key codes destined for it but no keysyms
as the request for the keyboard mappings is silently ignored. The
XKB extension as far as I understand it essentially replaced that?
But there is no addendum to core protocol specifications.<br>
<br>
The next round was about creating a circle: somehow I found out
that another map request on the window was needed to see the
respective errors due to simple mistakes during the preparation of
the request and some misleading protocol encoding which states
3+3n for the request length.<br>
<br>
<title>Konsole output</title>
<div> <span style="font-family:monospace"><span
style="color:#b2b2b2;background-color:#000000;">(define X
(X-connection))</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#1818b2;background-color:#000000;">#<unspecified></span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">(define
v (X-create-window X 50 50 300 400))</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#1818b2;background-color:#000000;">#<unspecified></span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">v</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#b2b2b2;background-color:#000000;">(44 #"254
255 255 3")</span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">(X-map-window
X (second v))</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#b2b2b2;background-color:#000000;">8</span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">(define
g (X-create-gc X (second v)))</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#1818b2;background-color:#000000;">#<unspecified></span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">g</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#b2b2b2;background-color:#000000;">(16 #"253
255 255 3")</span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">(X-polifill-arc
X (second v) (second g) 150 200 100 100 (* 170 64) (* 180
64))</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#b2b2b2;background-color:#000000;">24</span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">(X-map-window
X (second v))</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#b2b2b2;background-color:#000000;">8</span><span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#b2b2b2;background-color:#000000;">(X-control
X)</span><span
style="color:#18b218;background-color:#000000;"> => </span><span
style="color:#b2b2b2;background-color:#000000;">VSI SCA/X:
unhandled error: Length#"0 16 4 0 253 255 255 3 0 0 71 0
0</span><br>
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0"<span
style="color:#000000;background-color:#ffffff;"> </span><br>
<span style="color:#1818b2;background-color:#000000;">#<unspecified></span><br>
<span style="color:#000000;background-color:#ffffff;"> </span><br>
</span></div>
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My question is: will this continue like this? Are there any plans
to finally deliver the protocol specifications where these kinds
of interactions are layed out? Or some up to date updates on the
core protocol? But as I have heard the X server doesn't even know
about all registered extensions anymore - at least on Ubuntu with
Unity one of the first events to be received was an impossible
operation code of 192 which wasn't reported by <i>xdpyinfo</i> to
belong to any registered extension. The current state of X11 is a
bit puzzling: it when works better than ever on the hardware I
know of but it seems to become a pure C API without a valid wire
protocol?<br>
<br>
<tt>(repl-transcript</tt><tt><br>
</tt><tt>(define X (X-connection))</tt><tt><br>
</tt><tt>;X</tt><tt><br>
</tt><tt>(define v (X-create-window X 50 50 300 400))</tt><tt><br>
</tt><tt>v</tt><tt><br>
</tt><tt>; (X-get-keyboard-mapping X) DEFUNCT</tt><tt><br>
</tt><tt><br>
</tt><tt>(define g (X-create-gc X (second v)))</tt><tt><br>
</tt><tt>g</tt><tt><br>
</tt><tt>(X-polifill-arc X (second v) (second g) 150 200 100 100
(* 170 64) (* 180 64))</tt><tt><br>
</tt><tt>(X-map-window X (second v)) ; We need this to see errors
of the graphic request.</tt><tt><br>
</tt><tt>(X-control X)</tt><tt><br>
</tt><tt>)</tt><tt><br>
</tt><br>
It's easy to make mistakes when implementing things on a bit and
byte level but if anyone knows the "one true sequence" to draw a
real circle that would be helpful. The FAQ mentions the Xlib
flush/sync mechanism but I wasn't able to find any correspondence
in the wire protocol and it seems to affect the xlib client
buffers only.<br>
<br>
Thanks in advance!<br>
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