:white_check_mark: RESOVED: `Window`*’*s `icon` pr...

# compose-desktop

[theapache64]

✅ RESOVED: `Window`*’*s icon property not working 🧵

[theapache64]

fun main(args: Array<String>) = application(
) {
    Window(
        onCloseRequest = ::exitApplication,
        icon = painterResource("drawables/launcher_icons/linux.png")
    ) {

    }
}

[theapache64]

I’ve verified the image path and the image dimension is 192x192. but am getting below default java icon. Is there anything else i need to do to make it work? In the deprecated Window API it was working fine with the same image.

[Igor Demin]

macOs doesn't work well with setting icon in runtime.

Icon in the Dock can be changed via icon in build.gradle (for native distribution) or via global function:

Taskbar.getTaskbar().iconImage

But I don't recommend to use it, as the icon in the taskbar will be changed not immediately, but after some time (1-2 sec).

We covered that in tutorials:

Note that to change the icon on the taskbar on some OS (macOs), you should change icon in build.gradle

And in JavaDoc:

@param icon Icon in the titlebar of the window (for platforms which support this)

[Igor Demin]

I assume, we should write about macOs in JavaDoc, and even throw an exception with the link to the tutorial.

But I am not 100% sure, will this decision be good for the users of library?

Maybe we should return to the old approach - setting Taskbar.getTaskbar().iconImage in runtime automatically (as in AppWindow) 🤔

Will setting icon in build.gradle be enough for you, or it would be better to set icon in Window, only to not see the default icon every time you debug your application?

[theapache64]

By saying “setting icon in build.gradle”

macOS {
    iconFile.set(iconsRoot.resolve("launcher_icons/macos.icns"))
}

do you mean this? (or is this changed in new APIs) I already have that in place.

[theapache64]

I’ve tried the Taskbar#iconImage it works. but as a developer, I expect to work this via the icon param (Window API)

[Igor Demin]

By saying “setting icon in build.gradle”

Yes, but this will work only for native distribution.

For ./gradlew run you can set it via:

application {
    ...
    jvmArgs("-Xdock:icon=src/jvmMain/resources/ic_launcher.png")

It is not obvious, so I think, we should make it a default.

expect to work this via the icon param

There is another problem - if you set icon for Window not in icns format, then the icon will be changed in 1-2 seconds after you run the application. By “changed” I mean the quality of icon will be changed, if you use something like png (icns have different resolutions, so it scales better)

[theapache64]

Ohh. got it. Would be great if u can add these points to the javDoc 😬 that’s the first place I look when things dont work as expected

[Igor Demin]

Yes, we will write about this. And probably we should write the warning into the console. Exception would be too deadly, because it can be unnoticed in a crossplatform app, if it is not tested on macOs.

[theapache64]

yeah, you’re right. thanks 🙂

[theapache64]

@Igor Demin
I got a stacktrace today saying

java.lang.UnsupportedOperationException: The ICON_IMAGE feature is not supported on the current platform!
        at java.awt.Taskbar.checkFeatureSupport(Unknown:-1)
        at java.awt.Taskbar.setIconImage(Unknown:-1)

This is happening when I call

Taskbar.getTaskbar().iconImage

in Windows 10.

Any idea why its crashing? 🤔

[Igor Demin]

Windows doesn't support setting taskbar icon explicitly. Taskbar icon on Windows always equals to the icon of the current windows (which is set via icon parameter in Window).

If you really want to set the taskbar icon for macOs in Runtime, you should check Taskbar.getTaskbar().isSupported(Taskbar.Feature.ICON_IMAGE)

But the recommendation for Compose is still the same - not to use Taskbar.getTaskbar().iconImage and use icon in build.gradle. We will add -Xdock:icon by default in the future, so the icon will also be working in "debug" mode. Until then, you can add it yourself via jvmArgs.

[theapache64]

Okay 👍