Does lgi support Gtk4?

[JeysonFlores]

Hi, I was considering using Lgi with Fennel for one of my future projects. However I develop apps for the eOS platform, and in the next months they'll be releasing Gtk4 (only for developers) to start working on it. So I was wondering Lgi supports (at least decently) Gtk4. It seems one of the latest commits was about not getting errors on Gtk but I don't think that means a full support of the new version of Gtk. Also, if the answer is no, Do you plan to give support to Gtk4 in the near future? Thanks

[Scupake]

Currently, I don't think so.
#226

[jdeut]

the introspection of gtk4 works after #273 at least on my setup. Until now i have encountered no crashes which i would assign to lgi

[JeysonFlores]

@jdeut Oh, those are good news. I'll try it by myself to see if it works

[ousia]

@JeysonFlores, did it work for you?

I mean, maybe support is already there (and this issue could be closed).

[aum7]

the introspection of gtk4 works after #273 at least on my setup. Until now i have encountered no crashes which i would assign to lgi

i tried this, no luck, does not work for me
linux mint 21.1

tried with gtk3, works like a charm

[aum7]

using linux mint 21.1 vera (latest, greatest of them all lol)
testing with
https://github.com/Miqueas/Lua-GTK-Examples/blob/master/GtkApplication.lua
i changed
local gtk = lgi.require('Gtk', '3.0')
to
... lgi.require('Gtk','4.0')
gtk4-dev etc is installed on my sistem
running the example file with luajit, i get an error :
luajit: /usr/local/share/lua/5.1/lgi/override/Gdk.lua:23: bad argument #1 to 'registerlock' (userdata expected, got nil)
is it possible that someone helps me solve this issue, so i can use gtk4 with lgi ?

thank you, bow

[aum7]

also, seems that something has been done in direction to make lgi be used with gtk4, but
those commits were done in 2021, while lgi main page says ...
history ... 0.9.2 (9-Oct-2017)
therefore last update was in 2017 ?
and there is a thread saying ...
psychon deleted the gtk4 branch last year

i am so confused

i have installed lgi with luarocks please install lgi
and luarocks show lgi gives version
lgi 0.9.2-1
that is, ad 2017 version ?

if i git clone and build / compile on my system, should this update lgi to version with 'let's make lgi work with gtk4' commits included ?

godspeed

aum
s love nia

[Aire-One]

Hello @aum7. Yeah, the release cycle of LGI is a mess. Currently, the latest release is the one version from 2017. It's the version distro packages should be, and also the one you'll install by default with Luarocks.

To use the latest developments from here, you have to either, manually build from sources, or use the rockspec file from #305 as described in the PR message.

[aum7]

@Aire-One thank you for the clear & useful answer

since i am low-level programmer (lol, meaning not an experienced one), i would like to clarify, before i (again) brake my os (though i recently got used to do dev in qemu vm)

1. $ luarocks uninstall lgi
2. $ luarocks install https://raw.githubusercontent.com/lgi-devs/...
3. use lgi as nothing has changed = use same directives / includes etc
   but now i will have latest dev version, which should allow me to use gtk4 lib ?

thank you for your help, really appreciate

ps : is there a particular reason that public version has not been updated, especially since gtk4 is already mature for few years now ? (i might be wrong here.) and this is really useful binding, afaik. just curious

pps: if i ask devs for public update, will it make any difference ?

have fun

aum
s love nia

[Aire-One]

1. $ luarocks uninstall lgi
2. $ luarocks install https://raw.githubusercontent.com/lgi-devs/...
3. use lgi as nothing has changed = use same directives / includes etc
   but now i will have latest dev version, which should allow me to use gtk4 lib ?

Looks good to me.

pps: if i ask devs for public update, will it make any difference ?

It wouldn't change much. We already have this request on other threads... The SCM rockspec is actually a community initiative to distribute an up-to-date version.

[aum7]

he he he
community rules !

while installing lgi, i got compiler warnings
and send bug report to glib2.0 devs
i just got reply from them that i should file bug report with lgi
quote :
"You should open an issue against the Lua bindings, as they are using deprecated API."
and i replied to them that it would probably be a futile attempt
since last public commit was in 2017

i might nevertheless try it, can not hurt, wright ? lol

thanks for your help

have fun
godspeed

[Aire-One]

while installing lgi, i got compiler warnings
and send bug report to glib2.0 devs
i just got reply from them that i should file bug report with lgi
quote :
"You should open an issue against the Lua bindings, as they are using deprecated API."

This is indeed an issue on our side. You can silently ignore these warnings. They are just deprecation notices because LGI still uses ancient libraries. It shouldn't affect your work.

[aum7]

all hail aireone !
removed old, & installed new luarocks lgi lib
tested with few gtk3 examples, including one above, from jdeut
works like a charm
i can now use lgi with gtk4
i am soon to be 48 years old, and i feel like a little kid
with new toy (lgi / gtk) with new batteries (lunar vim) lol
thank you aire-one & thank you all developers
bow

have fun
aum
s love nia

[aum7]

just for the sake of completeness, here is a reply from glib devs :
quote

The warnings come from lgi using deprecated GLib API. GLib has nothing to do with it. The appropriate fix is for lgi not to use deprecated API. If they wish to continue using deprecated API while avoiding the compiler warnings that come from that choice, then they have two options:

use a blanket #define GLIB_DISABLE_DEPRECATION_WARNINGS before including the GLib headers
define GLIB_VERSION_MIN_REQUIRED and GLIB_VERSION_MAX_ALLOWED, to define the minimum required version of GLib they depend on (and only get deprecation warnings if they try to use a symbol that was deprecated in earlier versions) and the maximum required version of GLib they allow (and get warnings if they try use API provided by a newer version of GLib).

quote end

have fun

[aum7]

not sure, maybe this is not a good place for such questions, i trust you will let me know ;)

i would kindly ask if someone can offer some help :
i have succeeded with compiling my gtk(4) app, using .ui (.glade, xml) builder file
but would like to code the gui from scratch, using lgi & gtk4, and lua
i have peeked into lgi/samples/gtk-demo, trying to convert those gtk3 examples into gtk4
i did manage to get a basic, empty application / window, in gtk4
but, (there is always but lol) proceeding with code, i got stucked, ie
lgi/samples/gtk-demo/demo-application.lua file, line 10

-- Register icon. Gtk.stock_add { Gtk.StockItem { stock_id = 'demo-gtk-logo', label = "_GTK!", } }

gives me a runtime error
because gtk4 switched to freedesktop icon theme specs for icon manipulation
it seems i need to use gtk.image
and there are more examples of code that does not work in gtk4 and
i have a hard time converting it to gtk4

qs:

1. can somebody please share their lgi/gtk4 code, as an examples ?

2. best thing for a beginner like me would be to use gtk4 docs, and use that for coding.
   problem : original code is in c language, and i am not familiar with how to convert that to lgi / lua.
   yes, i did read lgi/docs/*.md files, but the text is way above my coding skills, beside, i learn best with images
   i would kindly ask for an example, how can an api doc (https://gtk.org/gtk4/) be used / converted into lgi / lua code

3. my ide (lunarvim) does not give me code completion / intellisense suggestions,
   which could help me with gtk.___ code; therefore i thought,
   if i dump whole lgi / gtk library, i might have some insight into gtk4 code, what and how can i access
   so i tried with the code, found in lgi/docs/guide.md file

dump(Gtk.Widget:_resolve(true), 3)

which again gives me an runtime error ( attempt to call global 'dump' (a nil value) ), this time i guess because i do not have cli-debugger lua package. neither luarocks nor uncle google knows anything about this package. dead end for me.
therefore i am asking for a help with dumping the whole gtk4 lib, which might help me learn more about its guts

i am particularly interested in :

• application / window
• icons
• gtk box
• button, entry tooltips
• gtk entry
• gtk paned
• gtk drawing area

using lnx mint 21.1

thank you for your understanding

godspeed

[aum7]

while browsing some more, i might have found partial answer to q2 :
comparing code from demo-application.lua and gtk3 online docs, plus gtk4 docs,
i tried a gtk4 code :

local icon = gtk_image_new_from_file('path/to/file.png')

then it occurred i might try :

local icon = gtk.Image.new_from_file(...)

running the code produced no error. good.

now i need to use this icon.

how ?

[aum7]

olo
i am still trying to use / convert lgi gtk3 samples, into gtk4 code
i have posted my question on stackexchange :
https://stackoverflow.com/questions/75534970/gtk4-lgi-luajit-how-to-draw-area-with-cairo

kindly asking for a help, i got stuck here
thank you
have fun

godspeed

[Aire-One]

Recent finding: Here is a repository with some GTK4 code examples in Lua with LGI https://github.com/Miqueas/GTK-Examples/tree/main/lua/gtk4 that can be used as references. (CC @Miqueas)

[Miqueas]

Recent finding: Here is a repository with some GTK4 code examples in Lua with LGI https://github.com/Miqueas/GTK-Examples/tree/main/lua/gtk4 that can be used as references. (CC @Miqueas)

Yes, the repo isn't so much very active, but in there you may found useful examples

[aum7]

thanks for update

have fun

aum

[ghost]

Fellas, i poked around and found out.
id-based widget referencing and nested-dictionary widget constructors don't work.

Here's some investigative work:

• Code at lgi/overrides/Gtk.lua:119 (the id set function) fires up when you run on GTK3, but doesn't happen under GTK4.
• At lgi/namespace.lua:174 (namespace.require()), overrides happen for GTK and its dependencies, regardless of version.

Not sure what's going on here. Do these features rely on the now nonexistant Container class? is this even supposed to work on anything other than version 3?

Paste and run this lua code for a blank window (It's supposed to have a button)

Snippet: lgi gtk4 window (from constructors)

lgi = require 'lgi'
gtk = lgi.require('Gtk','4.0')

local app= gtk.Application{application_id = 'org.phicross.gtk4lua.intro'}
local handles = {application = app}

function app:on_startup()

end

function app:on_activate()
    handles.window = gtk.ApplicationWindow{
        id = 'theWindow',
        application = self,
        title = "intro app.",
        default_width = 200,
        default_height = 200,
        gtk.Grid {
            id='atop',
            orientation = gtk.Orientation.VERTICAL,
            gtk.Button {
                id = "theButton",
                gtk.Label{
                    id = 'intro',
                    label = 'whatsup.'
                }
                , on_clicked = function(self)
                    print 'did you just slap me?'
                end
            }
        }
    }

    handles.window:show()

end

app:run(arg)

Now paste and run this new (ugly) version, and this time the button shows up.

Snippet: lgi gtk4 window (explicitly setting hierarchy)

lgi = require 'lgi'
gtk = lgi.require('Gtk','4.0')

local app= gtk.Application{application_id = 'org.phicross.gtk4lua.intro'}
local handles = {application = app}

function app:on_startup()

end

function app:on_activate()
    handles.window = gtk.ApplicationWindow{
        application = self,
        title = "intro app.",
        default_width = 200,
        default_height = 200
    }

    handles.atop = gtk.Box{ orientation = gtk.Orientation.VERTICAL}
    handles.window:set_child(handles.atop)
    print('ready.')
    handles.theButton = gtk.Button {
        label = 'slap',
        on_clicked = function(self)
            print 'did you just slap me?'
        end
    }
    handles.atop:append(handles.theButton)

    function handles.theButton:on_clicked()
        print 'overriden click callback.'
    end

    handles.window:show()

end

app:run(arg)

[Aire-One]

@PhiCross5 that's probably a copy/past issue, but your first snippet can't work because the line function app:on_startup() is out of its place. It either shouldn't be there, or should have a proper body.

[ghost]

@PhiCross5 that's probably a copy/past issue, but your first snippet can't work because the line function app:on_startup() is out of its place. It either shouldn't be there, or should have a proper body.

Oops, sorry about that. Both the snippets had been improperly pasted, so i fixed them now.

[ghost]

Early work in GTK4 migration

As of #313 , nested constructors work again on GTK4, but only for Boxes.

Containers were the secret sauce.

Nested constructors were one of the custom niceties provided by lgi's internal GTK override. In GTK3, they relied on methods from the Container class.
However, as of GTK4, Containers don't exist anymore, thus not only us, but also any other binding that wrapped that class, will now have to swtich from Container.add() to the specific methods of each subclass, as in: Box.append(), Grid.attach(), Paned.set_start_child() and others.

Help us migrate

Contributors are welcome to help reimplement these wrappings or propose a new way to describe a widget hierarchy neatly in lua code without somehow bringing back "the diddly gosh darned Generic Containers" GTK4 wants everyone to drop so much.
I intend on discussing this more carefully when i come up with a pull request (re)covering more of those container classes.

What to do if "i want GTK4 now"

Just like any other C library with a G-Introspection package available for it, you can use the methods directly as if they were just renamed C functions under a namespace. Because lgi does support GTK4, it just doesn't have all the fancy object-oriented bindings for it like it did for GTK3. When in doubt, follow the C examples by GTK themselves and convert the functions to lgi's calling convention (it is described in the documentation)