Frequently asked question, common issues, tips and tricks
Monitor id does not match compositor
The monitor id property that windows expect is mapped by Gdk, which is not always the same as the compositor. Instead use the gdkmonitor
property which expects a Gdk.Monitor
object.
import { App } from "astal/gtk3"
function Bar(gdkmonitor) {
return <window gdkmonitor={gdkmonitor} />
}
function main() {
for (const monitor of App.get_monitors()) {
if (monitor.model == "your-desired-model") {
Bar(monitor)
}
}
}
App.start({ main })
Environment variables
JavaScript is not an bash.
const HOME = exec("echo $HOME") // does not work
exec
and execAsync
runs the passed program as is, its not run in a shell environment, so the above example just passes $HOME
as a string literal to the echo
program.
Please don't do this
You could pass it to bash, but that is a horrible approach.
const HOME = exec("bash -c 'echo $HOME'")
You can read environment variables with GLib.getenv.
import GLib from "gi://GLib"
const HOME = GLib.getenv("HOME")
Custom SVG symbolic icons
Put the svgs in a directory, named <icon-name>-symbolic.svg
and use App.add_icons
or icons
parameter in App.start
App.start({
icons: `${SRC}/icons`,
main() {
Widget.Icon({
icon: "custom-symbolic", // custom-symbolic.svg
css: "color: green;", // can be colored, like other named icons
})
},
})
INFO
If there is a name clash with an icon from your current icon pack the icon pack will take precedence
Logging
The console
API in gjs uses glib logging functions. If you just want to print some text as is to stdout use the globally available print
function or printerr
for stderr.
print("print this line to stdout")
printerr("print this line to stderr")
Populate the global scope with frequently accessed variables
It might be annoying to always import Gtk only for Gtk.Align
enums.
import Gtk from "gi://Gtk"
declare global {
const START: number
const CENTER: number
const END: number
const FILL: number
}
Object.assign(globalThis, {
START: Gtk.Align.START,
CENTER: Gtk.Align.CENTER,
END: Gtk.Align.END,
FILL: Gtk.Align.FILL,
})
export default function Bar() {
return <window>
<box halign={START} />
</window>
}
import "./globals"
import Bar from "./Bar"
App.start({
main: Bar
})
INFO
It is considered bad practice to populate the global scope, but its your code, not a public library.
Auto create Window for each Monitor
To have Window widgets appear on a monitor when its plugged in, listen to App.monitor_added
.
export default function Bar(gdkmonitor: Gdk.Monitor) {
return <window gdkmonitor={gdkmonitor} />
}
import { Gdk, Gtk } from "astal/gtk3"
import Bar from "./Bar"
function main() {
const bars = new Map<Gdk.Monitor, Gtk.Widget>()
// initialize
for (const gdkmonitor of App.get_monitors()) {
bars.set(gdkmonitor, Bar(gdkmonitor))
}
App.connect("monitor-added", (_, gdkmonitor) => {
bars.set(gdkmonitor, Bar(gdkmonitor))
})
App.connect("monitor-removed", (_, gdkmonitor) => {
bars.get(gdkmonitor)?.destroy()
bars.delete(gdkmonitor)
})
}
App.start({ main })
Error: Can't convert non-null pointer to JS value
These happen when accessing list type properties. Gjs fails to correctly bind List
and other array like types of Vala as a property.
import Notifd from "gi://AstalNotifd"
const notifd = Notifd.get_default()
notifd.notifications // ❌
notifd.get_notifications() // ✅
How to create regular floating windows
Use Gtk.Window
with Widget.astalify.
By default Gtk.Window
is destroyed on close. To prevent this add a handler for delete-event
.
const RegularWindow = Widget.astalify(Gtk.Window)
return <RegularWindow
onDeleteEvent={(self) => {
self.hide()
return true
}}
>
{child}
</RegularWindow>
Is there a way to limit the width/height of a widget?
Unfortunately not. You can set a minimum size with min-width
and min-heigth
css attributes, but you can not set max size.
Custom widgets with bindable properties
In function components you can wrap any primitive to handle both binding and value cases as one.
function MyWidget(props: { prop: string | Binding<string> }) {
const prop = props.prop instanceof Binding
? props.prop
: bind({ get: () => props.prop, subscribe: () => () => {} })
function setup(self: Widget.Box) {
self.hook(prop, () => {
const value = prop.get()
// handler
})
}
return <box setup={setup}>
</box>
}
You can pass the prop the super constructor in subclasses
@register()
class MyWidget extends Widget.Box {
@property(String)
set prop(v: string) {
// handler
}
constructor(props: { prop: string | Binding<string> }) {
super(props)
}
}