Re: Improving work areas with multiple monitors

Alberts Muktupāvels via wm-spec-list <[email protected]> Mon, 31 Dec 2018 13:48:51 +0200
Newsgroups gmane.comp.gnome.wm-spec
Message-ID <CAKX6tkUAb2nE-iPO8LQzRwC_sjmZ7Cqud_CPmkfBf5auOHs8tg@mail.gmail.com>
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On Mon, Dec 31, 2018 at 10:44 AM Martin Fl=C3=B6ser <[email protected]> wr=
ote:

> Am 2018-12-27 22:22, schrieb Alberts Muktup=C4=81vels via wm-spec-list:
> > Hi,
> >
> > I would like to improve work area situation with multiple monitors.
> > Before writing patches I would like to hear what you think about my
> > idea.
> >
> > First I think there should be new property for struts because existing
> > properties can not be used to set struts on edges between two
> > monitors. New property could be named _NET_WM_STRUT_AREA and used to
> > define rectangular area (x, y, width and height) that should be
> > excluded from work area. This property will need to follow at least
> > two rules:
> > - at least one edge of area must match with monitor edge. The window
> > manager must ignore strut if it is not placed at monitor edge.
> > - if strut appears on edge between two monitors it should be ignored
> > when calculating _NET_WORKAREA to ensure backward compatibility.
>
> sounds fine to me.
>
> As a note: in KWin we allow panels on shared edges to set a strut with
> the existing protocol. We just decided that a strut is not allowed to
> cover a complete screen. Technically it's a violation of the current
> protocol, but might be a better idea than introducing yet another
> property.
>

This property probably make sense only with new workarea... For example if
we have left and right monitors put side by side. How do you set strut for
panel / dock that is placed on right monitors left edge? And more
importantly - how would look generated work area? It has to ignore strut or
one monitor is excluded from work area.

It could be a simple textual addition like: "Struts covering a monitor
> completely are ignored for that monitor"
>
> >
> > Next and more important part is new property to allow set work areas
> > for multiple monitors. Currently I am thinking it could be
> > _NET_WORKAREAS_Dn where n is desktop number. For example if
> > _NET_NUMBER_OF_DESKTOPS is set to 3 then there must be
> > _NET_WORKAREAS_D0, _NET_WORKAREAS_D1 and _NET_WORKAREAS_D2 properties.
> >
> > Property would have one or multiple work areas:
> > _NET_WORKAREAS_Dn, x, y, width, height CARDINAL[][4]/32
>
> This property I do not understand. What is the area of x, y, width,
> height? Why per desktop?
>

Per desktop? Because existing  _NET_WORKAREA property have work areas for
each desktop? If you have one desktop you have one rectangle with work
area, if you have 5 desktops it will contain 5 rectangles. To speak truth I
don't know if you really can have different work areas for different
desktops and/or if anyone support/use that...  I don't want to introduce
more changes then needed.

x, y, width, height is work area rectangle. Property format basically is
same as _NET_WORKAREA, except multiple rectangles are not for desktops, but
for monitors. For example two 1280x1024 side by side monitors with 24px
panel on right monitor left edge would produce following property -
_NET_WORKAREAS_D0, [0, 0, 1280, 1024], [1304, 0, 1256, 1024]. And if you
have more then one desktop there would be _NET_WORKAREAS_D1,
_NET_WORKAREAS_D2... properties. That way you can read property for current
desktop - _NET_WORKAREAS_D{_NET_CURRENT_DESKTOP}.

Did I make it more understandable or still not clear enough?

>
> > Window managers adding support for this would need to add
> > _NET_WORKAREAS hint to _NET_SUPPORTED.
>
> And also for the new strut property.
>

Right. I mention only work area hint because I have not seen that panels /
docks would check if property is supported. They just set both properties
and window managers first tries to read _NET_WM_STRUT_PARTIAL and then
_NET_WM_STRUT.


> >
> > Does anyone see reasons why this would not work and/or have better
> > suggestions?
>
> As a note: KWin is feature frozen for X11. This means we will not add
> support for this. I don't know whether other window managers are still
> interested in extending the protocol. For me it's a thing which has been
> broken for ages and we found a workaround for the problem. I don't see a
> need to fix the "legacy" protocol.
>

I guess it is fine, but it should not be reason to not update/improve spec,
right?

For example, how do you workaround following bug?:
https://bugreports.qt.io/browse/QTBUG-60513

Anyway, I am not after workarounds... Right now it does not look like big
and complicated changes so I don't see why would this be rejected unless
someone sees big problems that I have not thought about.

For example metacity based window managers already have work areas for each
monitor - all it needs is to make it available to clients / toolkits. It
would be enough to allow toolkits to fix mentioned bug. And adding
_NET_WM_STRUT_AREA would make it possible to correctly calculate work areas
for many configurations.

I plan to write patches for metacity, mutter, gtk and maybe also for compiz=
.

--=20
Alberts Muktup=C4=81vels

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div di=
r=3D"ltr"><div class=3D"gmail_quote"><div dir=3D"ltr">On Mon, Dec 31, 2018 =
at 10:44 AM Martin Fl=C3=B6ser &lt;<a href=3D"mailto:[email protected]" ta=
rget=3D"_blank">[email protected]</a>&gt; wrote:<br></div><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid r=
gb(204,204,204);padding-left:1ex">Am 2018-12-27 22:22, schrieb Alberts Mukt=
up=C4=81vels via wm-spec-list:<br>
&gt; Hi,<br>
&gt; <br>
&gt; I would like to improve work area situation with multiple monitors.<br=
>
&gt; Before writing patches I would like to hear what you think about my<br=
>
&gt; idea.<br>
&gt; <br>
&gt; First I think there should be new property for struts because existing=
<br>
&gt; properties can not be used to set struts on edges between two<br>
&gt; monitors. New property could be named _NET_WM_STRUT_AREA and used to<b=
r>
&gt; define rectangular area (x, y, width and height) that should be<br>
&gt; excluded from work area. This property will need to follow at least<br=
>
&gt; two rules:<br>
&gt; - at least one edge of area must match with monitor edge. The window<b=
r>
&gt; manager must ignore strut if it is not placed at monitor edge.<br>
&gt; - if strut appears on edge between two monitors it should be ignored<b=
r>
&gt; when calculating _NET_WORKAREA to ensure backward compatibility.<br>
<br>
sounds fine to me.<br>
<br>
As a note: in KWin we allow panels on shared edges to set a strut with <br>
the existing protocol. We just decided that a strut is not allowed to <br>
cover a complete screen. Technically it&#39;s a violation of the current <b=
r>
protocol, but might be a better idea than introducing yet another <br>
property.<br></blockquote><div><br></div><div>This property probably make s=
ense only with new workarea... For example if we have left and right monito=
rs put side by side. How do you set strut for panel / dock that is placed o=
n right monitors left edge? And more importantly - how would look generated=
 work area? It has to ignore strut or one monitor is excluded from work are=
a.<br></div><div><br></div><blockquote class=3D"gmail_quote" style=3D"margi=
n:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex=
">
It could be a simple textual addition like: &quot;Struts covering a monitor=
 <br>
completely are ignored for that monitor&quot;<br>
<br>
&gt; <br>
&gt; Next and more important part is new property to allow set work areas<b=
r>
&gt; for multiple monitors. Currently I am thinking it could be<br>
&gt; _NET_WORKAREAS_Dn where n is desktop number. For example if<br>
&gt; _NET_NUMBER_OF_DESKTOPS is set to 3 then there must be<br>
&gt; _NET_WORKAREAS_D0, _NET_WORKAREAS_D1 and _NET_WORKAREAS_D2 properties.=
<br>
&gt; <br>
&gt; Property would have one or multiple work areas:<br>
&gt; _NET_WORKAREAS_Dn, x, y, width, height CARDINAL[][4]/32<br>
<br>
This property I do not understand. What is the area of x, y, width, <br>
height? Why per desktop?<br></blockquote><div><br></div><div>Per desktop? B=
ecause existing=C2=A0 _NET_WORKAREA property have work areas for each deskt=
op? If you have one desktop you have one rectangle with work area, if you h=
ave 5 desktops it will contain 5 rectangles. To speak truth I don&#39;t kno=
w if you really can have different work areas for different desktops and/or=
 if anyone support/use that...=C2=A0 I don&#39;t want to introduce more cha=
nges then needed.</div><div><br></div><div>x, y, width, height is work area=
 rectangle. Property format basically is same as _NET_WORKAREA, except mult=
iple rectangles are not for desktops, but for monitors. For example two 128=
0x1024 side by side monitors with 24px panel on right monitor left edge wou=
ld produce following property - _NET_WORKAREAS_D0, [0, 0, 1280, 1024], [130=
4, 0, 1256, 1024]. And if you have more then one desktop there would be _NE=
T_WORKAREAS_D1, _NET_WORKAREAS_D2... properties. That way you can read prop=
erty for current desktop - _NET_WORKAREAS_D{_NET_CURRENT_DESKTOP}.</div><di=
v><br></div><div>Did I make it more understandable or still not clear enoug=
h?<br></div><div><br></div><blockquote class=3D"gmail_quote" style=3D"margi=
n:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex=
">
&gt; <br>
&gt; Window managers adding support for this would need to add<br>
&gt; _NET_WORKAREAS hint to _NET_SUPPORTED.<br>
<br>
And also for the new strut property.<br></blockquote><div><br></div><div>Ri=
ght. I mention only work area hint because I have not seen that panels / do=
cks would check if property is supported. They just set both properties and=
 window managers first tries to read _NET_WM_STRUT_PARTIAL and then _NET_WM=
_STRUT.<br></div><div>=C2=A0</div><blockquote class=3D"gmail_quote" style=
=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding=
-left:1ex">
&gt; <br>
&gt; Does anyone see reasons why this would not work and/or have better<br>
&gt; suggestions?<br>
<br>
As a note: KWin is feature frozen for X11. This means we will not add <br>
support for this. I don&#39;t know whether other window managers are still =
<br>
interested in extending the protocol. For me it&#39;s a thing which has bee=
n <br>
broken for ages and we found a workaround for the problem. I don&#39;t see =
a <br>
need to fix the &quot;legacy&quot; protocol.<br>
</blockquote></div></div><div dir=3D"ltr"><br></div><div>I guess it is fine=
, but it should not be reason to not update/improve spec, right?</div><div>=
<br></div><div>For example, how do you workaround following bug?:</div><div=
><a href=3D"https://bugreports.qt.io/browse/QTBUG-60513" target=3D"_blank">=
https://bugreports.qt.io/browse/QTBUG-60513</a><br clear=3D"all"></div><div=
 dir=3D"ltr"><br></div><div>Anyway, I am not after workarounds... Right now=
 it does not look like big and complicated changes so I don&#39;t see why w=
ould this be rejected unless someone sees big problems that I have not thou=
ght about.<br></div><div dir=3D"ltr"><br></div><div>For example metacity ba=
sed window managers already have work areas for each monitor - all it needs=
 is to make it available to clients / toolkits. It would be enough to allow=
 toolkits to fix mentioned bug. And adding _NET_WM_STRUT_AREA would make it=
 possible to correctly calculate work areas for many configurations.</div><=
div><br></div><div>I plan to write patches for metacity, mutter, gtk and ma=
ybe also for compiz.<br></div><div dir=3D"ltr"><br>-- <br><div dir=3D"ltr" =
class=3D"m_3246188659427574235gmail-m_-7293387589141991585gmail_signature">=
<div dir=3D"ltr">Alberts Muktup=C4=81vels<br></div></div></div></div></div>=
</div></div>

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