Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Lars Ingebrigtsen]

Po Lu via Mailing list for Emacs changes <emacs-diffs@gnu.org> writes:

>     Implement `alpha-background' on non-Cairo builds

By the way, the `alpha-background' frame parameter should have a NEWS
entry.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Po Lu via Mailing list for Emacs changes <emacs-diffs@gnu.org> writes:
>
>>     Implement `alpha-background' on non-Cairo builds
>
> By the way, the `alpha-background' frame parameter should have a NEWS
> entry.

I thought there was one, but evidently there isn't.
I'll write one up, thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Tassilo Horn]

Po Lu <luangruo@yahoo.com> writes:

>> Po Lu via Mailing list for Emacs changes <emacs-diffs@gnu.org>
>> writes:
>>
>>>     Implement `alpha-background' on non-Cairo builds
>>
>> By the way, the `alpha-background' frame parameter should have a NEWS
>> entry.
>
> I thought there was one, but evidently there isn't.
> I'll write one up, thanks.

Hey, nice feature.  Unfortunately, it doesn't seem to work for me
(current master --with-pgtk) while `alpha' works fine.  I've just
changed my

  (setq default-frame-alist '((width . 90)
                              (height . 50)
                              (alpha . 97)))

to

  (setq default-frame-alist '((width . 90)
                              (height . 50)
                              (alpha-background . 97)))

in .emacs.d/early-init.el.  Am I doing something wrong?

Bye,
Tassilo

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

hi,

On Mon, Jan 31 2022, Tassilo Horn wrote:

> Hey, nice feature.  Unfortunately, it doesn't seem to work for me
> (current master --with-pgtk) while `alpha' works fine.  I've just
> changed my

as another data point, i've tried in an emacs with --with-x-toolkit=no
and it works well for me in a regular window manager (e.g. xmonad) with
picom as the compositor.  however, alpha-background doesn't work well in
exwm (while alpha does; alpha-background tints the background of the
window but doesn't show the underlying desktop wallpaper). that might
well be a problem in exwm rather than on emacs's side, though.

cheers,
jao
-- 
“Some people, when confronted with a problem, think ‘I know, I’ll use
multithreading’. Nothhw tpe yawrve o oblems.” (Eiríkr Åsheim, 2012)

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Tassilo Horn <tsdh@gnu.org> writes:

> Hey, nice feature.  Unfortunately, it doesn't seem to work for me
> (current master --with-pgtk)

It isn't supported by the PGTK build yet.  I'll get around to
implementing it there, but if someone else wants to do it, patches
welcome.

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> however, alpha-background doesn't work well in exwm (while alpha does;
> alpha-background tints the background of the window but doesn't show
> the underlying desktop wallpaper). that might well be a problem in exwm
> rather than on emacs's side, though.

It will only work on a composited display.  You could try running
compton (or some other lightweight compositing manager that doesn't come
with its own window manager) under exwm, and see if that works.

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Tassilo Horn]

Po Lu <luangruo@yahoo.com> writes:

>> Hey, nice feature.  Unfortunately, it doesn't seem to work for me
>> (current master --with-pgtk)
>
> It isn't supported by the PGTK build yet.  I'll get around to
> implementing it there,

Alright then.  No need to hurry. :-)

> but if someone else wants to do it, patches welcome.

Sorry, not my area of expertise.

Bye,
Tassilo

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Stephen Berman]

[-- Attachment #1: Type: text/plain, Size: 1681 bytes --]

On Mon, 31 Jan 2022 15:11:37 +0800 Po Lu <luangruo@yahoo.com> wrote:

> Jose A Ortega Ruiz <jao@gnu.org> writes:
>
>> however, alpha-background doesn't work well in exwm (while alpha does;
>> alpha-background tints the background of the window but doesn't show
>> the underlying desktop wallpaper). that might well be a problem in exwm
>> rather than on emacs's side, though.
>
> It will only work on a composited display.  You could try running
> compton (or some other lightweight compositing manager that doesn't come
> with its own window manager) under exwm, and see if that works.

I just tried alpha-background and noticed a couple of seeming
inconsistencies: the text area displays the set amount of opacity
regardless of whether the frame is in focus or not, but while the tool
bar remains completely opaque in both case, the menu bar is completely
opaque when the frame is not in focus but completely transparent
(regardless of the setting of alpha-background) when the frame is in
focus (see attached images).  Are these differences expected?

This is on
GNU Emacs 29.0.50 (build 3, x86_64-pc-linux-gnu, GTK+ Version 3.24.31, cairo version 1.17.4)
 of 2022-01-31 built on strobelfs2
Repository revision: 790ad61fcf91c75811ed30d21518e1dac99be044
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Linux From Scratch r11.0-115

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBSYSTEMD LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP X11 XDBE XIM
XPM XWIDGETS GTK3 ZLIB

Steve Berman


[-- Attachment #2: alpha-background-1.png --]
[-- Type: image/png, Size: 54809 bytes --]

[-- Attachment #3: alpha-background-2.png --]
[-- Type: image/png, Size: 57329 bytes --]

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Stephen Berman <stephen.berman@gmx.net> writes:

> I just tried alpha-background and noticed a couple of seeming
> inconsistencies: the text area displays the set amount of opacity
> regardless of whether the frame is in focus or not

That's also intended behaviour.

> but while the tool bar remains completely opaque in both case, the
> menu bar is completely opaque when the frame is not in focus but
> completely transparent (regardless of the setting of alpha-background)
> when the frame is in focus (see attached images).  Are these
> differences expected?

Yes, it's a well known bug in GTK+.  I plan to install a workaround in
the next day or two.

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Stephen Berman]

On Mon, 31 Jan 2022 21:21:52 +0800 Po Lu <luangruo@yahoo.com> wrote:

> Stephen Berman <stephen.berman@gmx.net> writes:
>
>> I just tried alpha-background and noticed a couple of seeming
>> inconsistencies: the text area displays the set amount of opacity
>> regardless of whether the frame is in focus or not
>
> That's also intended behaviour.

Yes, that's what I thought and it makes sense.

>> but while the tool bar remains completely opaque in both case, the
>> menu bar is completely opaque when the frame is not in focus but
>> completely transparent (regardless of the setting of alpha-background)
>> when the frame is in focus (see attached images).  Are these
>> differences expected?
>
> Yes, it's a well known bug in GTK+.

Just the difference with the menu bar or also the lack of transparency
in the tool bar?

>                                      I plan to install a workaround in
> the next day or two.

Thanks.

Steve Berman

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Stephen Berman <stephen.berman@gmx.net> writes:

> Just the difference with the menu bar or also the lack of transparency
> in the tool bar?

The bug is just the transparent menu bar, the tool bar is behaving
correctly.

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Mon, Jan 31 2022, Po Lu wrote:

> Jose A Ortega Ruiz <jao@gnu.org> writes:
>
>> however, alpha-background doesn't work well in exwm (while alpha does;
>> alpha-background tints the background of the window but doesn't show
>> the underlying desktop wallpaper). that might well be a problem in exwm
>> rather than on emacs's side, though.
>
> It will only work on a composited display.  You could try running
> compton (or some other lightweight compositing manager that doesn't come
> with its own window manager) under exwm, and see if that works.

as mentioned, i am running a composited display, via picom (a modern
fork of compton).  with xmonad+picom things work well.


cheers,
jao

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Tassilo Horn]

Po Lu <luangruo@yahoo.com> writes:

>> Hey, nice feature.  Unfortunately, it doesn't seem to work for me
>> (current master --with-pgtk)
>
> It isn't supported by the PGTK build yet.  I'll get around to
> implementing it there,

Well, that was very quick.  It works very good and looks tasty.  Thanks!

Bye,
Tassilo

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

>> It will only work on a composited display.  You could try running
>> compton (or some other lightweight compositing manager that doesn't come
>> with its own window manager) under exwm, and see if that works.

> as mentioned, i am running a composited display, via picom (a modern
> fork of compton).  with xmonad+picom things work well.

Perhaps there's some toggle in Picom you can use to allow windows to be
transparent.  I'm not sure about that, since I don't use Picom.

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Tue, Feb 01 2022, Po Lu wrote:

> Jose A Ortega Ruiz <jao@gnu.org> writes:
>
>>> It will only work on a composited display.  You could try running
>>> compton (or some other lightweight compositing manager that doesn't come
>>> with its own window manager) under exwm, and see if that works.
>
>> as mentioned, i am running a composited display, via picom (a modern
>> fork of compton).  with xmonad+picom things work well.
>
> Perhaps there's some toggle in Picom you can use to allow windows to be
> transparent.  I'm not sure about that, since I don't use Picom.

xmonad and picom show transparent windows, with the same
configuration. exwm and picom also obeys alpha.  same thing with
compton.  so i'm pretty sure it's an exwm problem, not a picom/compton
one.  thanks anyway!

jao
-- 
"In the beginning the Universe was created. This has made a lot of people
very angry and been widely regarded as a bad move."
 - Douglas Adams

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Tue, Feb 01 2022, Jose A Ortega Ruiz wrote:

> On Tue, Feb 01 2022, Po Lu wrote:

[...]

>> Perhaps there's some toggle in Picom you can use to allow windows to be
>> transparent.  I'm not sure about that, since I don't use Picom.
>
> xmonad and picom show transparent windows, with the same
> configuration. exwm and picom also obeys alpha.  same thing with
> compton.  so i'm pretty sure it's an exwm problem, not a picom/compton
> one.  thanks anyway!

let me add that i just tried with emacs compiled with lucid and there
alpha-background works well with exwm and picom, so it seems only the
no-toolkit variant is affected (or maybe something was fixed today, i
haven't tried it back since yesterday).  so all is mostly well, thanks!

jao
-- 
It is a truism of escape plans that the problem with going anywhere is
that you take yourself with you -- Emma Brockes

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> let me add that i just tried with emacs compiled with lucid and there
> alpha-background works well with exwm and picom

That shouldn't be possible, since it's disabled on Emacs builds with Xt,
as Xt doesn't really know what to do with a 32-bit visual.  (i.e. Xt
will crash and lwlib will "accidentally" draw things with the alpha
channel set to zero.)

Please evaluate (x-display-planes) in that Emacs build and tell me what
it returns.  Or perhaps you used the old `alpha' frame parameter, which
does work on Xt builds, but also changes the opacity of the foreground
text?

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Tue, Feb 01 2022, Po Lu wrote:

> Jose A Ortega Ruiz <jao@gnu.org> writes:
>
>> let me add that i just tried with emacs compiled with lucid and there
>> alpha-background works well with exwm and picom
>
> That shouldn't be possible, since it's disabled on Emacs builds with Xt,
> as Xt doesn't really know what to do with a 32-bit visual.  (i.e. Xt
> will crash and lwlib will "accidentally" draw things with the alpha
> channel set to zero.)

(what is it supposed to happen with --with-x-toolkit=no then?)

>
> Please evaluate (x-display-planes) in that Emacs build and tell me what

24.

> it returns.  Or perhaps you used the old `alpha' frame parameter, which
> does work on Xt builds, but also changes the opacity of the foreground
> text?

well, i double checked frame-parameters, and it said alpha-background.
but the effect was the same as with alpha, so i guess it was possibly a
perhaps unintended fallback.

nonetheless, after your update yesterday to apply a mask to images, and
a recompilation, alpha-background stopped working at all both in lucid
and no toolkit, which i guess is what you expect, even with a compositor
like compton.  if that's so, all is well.  i am actually happy with
alpha for my use cases (alpha-background is working well in wayland
with a pgtk build, when i'm not in x11).

cheers,
jao
-- 
To see ourselves as others see us is a most salutary gift. Hardly less
important is the capacity to see others as they see themselves.
 -Aldous Huxley, novelist (1894-1963)

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> (what is it supposed to happen with --with-x-toolkit=no then?)

It should work there, since Emacs is the only program talking to X,
without libraries such as Xt interfering.

> 24.

That means it is disabled correctly.  `alpha-background' requires a
visual with an alpha channel, which on modern X servers is typically
32-bit.

> nonetheless, after your update yesterday to apply a mask to images, and
> a recompilation, alpha-background stopped working at all both in lucid
> and no toolkit, which i guess is what you expect, even with a compositor
> like compton.  if that's so, all is well.  i am actually happy with
> alpha for my use cases (alpha-background is working well in wayland
> with a pgtk build, when i'm not in x11).

That's nice to see, thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Po Lu <luangruo@yahoo.com> writes:

>> and no toolkit

I missed this part.  It should work with the no-toolkit build, so could
you try that on a compositor that is known to work, such as GNOME Shell?

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Wed, Feb 02 2022, Po Lu wrote:

> Po Lu <luangruo@yahoo.com> writes:
>
>>> and no toolkit
>
> I missed this part.  It should work with the no-toolkit build, so could
> you try that on a compositor that is known to work, such as GNOME Shell?

sorry, i'm afraid i can't. i don't have gnome installed, nor want to
have it :) and i don't even know if exwm (the emacs window manager,
which is the only one with which alpha-background is not working) can
run inside gnome shell.

compton and picom work well with most non-desktop window managers
(e.g. xmonad, or even exwm when not trying alpha-background), and in
fact xmonad+picom+emacs with alpha-background work well too, so i think
that picom is a compositor "that is known to work".

cheers,
jao
-- 
I wrote some code in Java once.  It was in the Lisp language, but I
was in Java at the time. - rms, bug#43887

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Wed, Feb 02 2022, Jose A Ortega Ruiz wrote:

> On Wed, Feb 02 2022, Po Lu wrote:
>
>> Po Lu <luangruo@yahoo.com> writes:
>>
>>>> and no toolkit
>>
>> I missed this part.  It should work with the no-toolkit build, so could
>> you try that on a compositor that is known to work, such as GNOME Shell?
>
> sorry, i'm afraid i can't. i don't have gnome installed, nor want to
> have it :) and i don't even know if exwm (the emacs window manager,
> which is the only one with which alpha-background is not working) can
> run inside gnome shell.
>
> compton and picom work well with most non-desktop window managers
> (e.g. xmonad, or even exwm when not trying alpha-background), and in
> fact xmonad+picom+emacs with alpha-background work well too, so i think
> that picom is a compositor "that is known to work".

i forgot to add that, when built with no-toolkit and without any alpha
or alpha-background spec, there's another new problem with exwm.  exwm
has a "system tray" where it puts applets like nm-applet.  before the
last changes to support alpha-background in non-gtk builds, exwm's
system tray had been working for me flawlessly.  now it doesn't work at
all (the icons don't show up in the tray area, and new, empty buffers
are created instead).  

when compiling with the lucid toolkit there's no such problem, and tray
icons in exwm still work well.

maybe this has nothing to do with alpha-background, but started at the
same time it was implemented for non-gtk toolkits.

thanks,
jao
-- 
“I’m all these words, all these strangers, this dust of words, with no
ground for their setting, no sky for their dispersing.”
 - Samuel Beckett, The Unnamable

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> i forgot to add that, when built with no-toolkit and without any alpha
> or alpha-background spec, there's another new problem with exwm.  exwm
> has a "system tray" where it puts applets like nm-applet.  before the
> last changes to support alpha-background in non-gtk builds, exwm's
> system tray had been working for me flawlessly.  now it doesn't work at
> all (the icons don't show up in the tray area, and new, empty buffers
> are created instead).  

EXWM probably doesn't know about 32-bit visuals.  I suspect it's
creating a window to hold the system tray with depth and visual set to
CopyFromParent, but not creating true-color pixels correctly.

You can work around the problem by adding:

  Emacs.visualClass: TrueColor-24

To your X defaults file, but that will also prevent `alpha-background'
from working.

Thanks.

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

> On Wed, Feb 02 2022, Jose A Ortega Ruiz wrote:
>
> i forgot to add that, when built with no-toolkit and without any alpha
> or alpha-background spec, there's another new problem with exwm.  exwm
> has a "system tray" where it puts applets like nm-applet.  before the
> last changes to support alpha-background in non-gtk builds, exwm's
> system tray had been working for me flawlessly.  now it doesn't work at
> all (the icons don't show up in the tray area, and new, empty buffers
> are created instead).  
>
> when compiling with the lucid toolkit there's no such problem, and tray
> icons in exwm still work well.

and yet another experiment: exwm's system tray is also broken when
compiling --with-x-toolkit=gtk.  maybe lucid is the only survivor
because alpha-background-related code changes left its code unmodified?

cheers,
jao
-- 
It does not do to leave a live dragon out of your calculations, if you
live near him. -J.R.R. Tolkien, novelist and philologist (1892-1973)

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Jose A Ortega Ruiz]

On Thu, Feb 03 2022, Po Lu wrote:

> EXWM probably doesn't know about 32-bit visuals.  I suspect it's
> creating a window to hold the system tray with depth and visual set to
> CopyFromParent, but not creating true-color pixels correctly.
>
> You can work around the problem by adding:
>
>   Emacs.visualClass: TrueColor-24

yes, that fixes the problem for me, thank you.

> To your X defaults file, but that will also prevent `alpha-background'
> from working.

well, alpha-background doesn't work with exwm anyway, so that's not a
big deal.

cheers,
jao
-- 
Any sufficiently advanced technology is indistinguishable from magic.
 -Arthur C Clarke, science fiction writer (1917- )

Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> maybe lucid is the only survivor because alpha-background-related code
> changes left its code unmodified?

Indeed, those changes are explictly disabled on Lucid and Motif, since
they don't work.  (You might want to tell the EXWM developers.)