Window doesn't apply placement and size after start in 1.4.0-RC1

[Nourepide]

Describe the bug
After switching to version 1.4.0, the window stopped applying the placement and size parameters at the start of the application. If some parameter has been changed, the window immediately applies all the parameters that were passed before.

Affected platforms
Select one of the platforms below:

• Desktop

Versions

• Kotlin version: 1.8.10
• Compose Multiplatform version: 1.4.0-rc01
• OS version(s): Arch Linux KDE
• OS architecture (x86 or arm64): x86
• JDK (for desktop issues): Corretto 18

To Reproduce
Just run this code.

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.Button
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.MutableState
import androidx.compose.runtime.mutableStateOf
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.window.WindowPlacement
import androidx.compose.ui.window.singleWindowApplication
import java.awt.Dimension

data class WindowState(
    val windowPlacement: MutableState<WindowPlacement> = mutableStateOf(WindowPlacement.Fullscreen),
    val windowSize: MutableState<Dimension> = mutableStateOf(Dimension(1366, 768))
)

fun main() {
    val windowState = WindowState()

    singleWindowApplication {
        window.placement = windowState.windowPlacement.value
        window.preferredSize = windowState.windowSize.value
        window.size = windowState.windowSize.value

        Screen(windowState)
    }
}

@Composable
fun Screen(windowState: WindowState) {
    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
        Row {
            Button(onClick = { windowState.windowPlacement.value = WindowPlacement.Floating }) {
                Text("Set floating.")
            }

            Button(onClick = { windowState.windowSize.value = Dimension(1280,720 ) }) {
                Text("Change window size.")
            }
        }
    }
}

Expected behavior
As in 1.3.1

[Nourepide]

Reproduced in Windows 10.

I suspect it's this merge request.
JetBrains/compose-multiplatform-core#442

Appears in v1.4.0-alpha01-dev985
https://github.com/JetBrains/compose-multiplatform/releases/tag/v1.4.0-alpha01-dev985

[igordmn]

Thanks for the investigation!

    singleWindowApplication {
        window.placement = windowState.windowPlacement.value
        window.preferredSize = windowState.windowSize.value
        window.size = windowState.windowSize.value

        Screen(windowState)
    }

It isn't correct to change these properties in the composition, because:

1. Composable's can be called multiple time at any time, and the size/position of the window will be overridden on every recomposition.
2. singleApplicationWindow owns these properties, and there can be concurrent changes, which can lead to unpredictable behavior.

The correct way should be to use built-in WindowState:

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.DpSize
import androidx.compose.ui.unit.dp
import androidx.compose.ui.window.*

fun main() {
    val windowState = WindowState(WindowPlacement.Fullscreen, size = DpSize(1280.dp, 720.dp))

    singleWindowApplication(windowState) {
        Screen(windowState)
    }
}

@Composable
fun Screen(windowState: WindowState) {
    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
        Row {
            Button(onClick = {
                windowState.placement = WindowPlacement.Floating
                windowState.size = DpSize(1280.dp, 720.dp)
            }) {
                Text("Set floating.")
            }

            Button(onClick = { windowState.size = DpSize(1280.dp, 720.dp) }) {
                Text("Change window size.")
            }
        }
    }
}

But it doesn't work unfortenutely, even in Compose 1.2.0/1.3.1. So, Compose has a long standing bug.

Until this is fixed, the workaroround is to use ComposeWindow directly:

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.awt.ComposeWindow
import androidx.compose.ui.window.AwtWindow
import androidx.compose.ui.window.WindowPlacement
import androidx.compose.ui.window.application
import java.awt.Dimension
import java.awt.event.WindowAdapter
import java.awt.event.WindowEvent
import javax.swing.JFrame

fun main() {
    var isOpen by mutableStateOf(true)

    application {
        if (isOpen) {
            AwtWindow(
                create = {
                    ComposeWindow().apply {
                        setContent {
                            Screen(this@apply)
                        }
                        defaultCloseOperation = JFrame.DO_NOTHING_ON_CLOSE
                        addWindowListener(object : WindowAdapter() {
                            override fun windowClosing(e: WindowEvent?) {
                                isOpen = false
                            }
                        })
                        placement = WindowPlacement.Fullscreen
                    }
                },
                dispose = ComposeWindow::dispose
            )
        }
    }
}

@Composable
fun Screen(window: ComposeWindow) {
    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
        Row {
            Button(onClick = {
                if (window.placement != WindowPlacement.Fullscreen) {
                    window.placement = WindowPlacement.Fullscreen
                } else {
                    window.placement = WindowPlacement.Floating
                    window.size = Dimension(1366, 768)
                }
            }
            ) {
                Text("Toggle fullscreen")
            }
        }
    }
}

[m-sasha]

The problem here is in FullscreenAdapter in Skiko. Its componentResized is called before componentShown, which causes _isFullscreen to be false. This is then picked up by the ComponentAdapter in Window.desktop:Window:Window(create) which re-sets WindowState.placement to Floating. So after opening the window in fullscreen, WindowState.placement is actually Floating. Then, when the button sets it to Floating, it doesn't actually do anything.

[m-sasha]

Reproducer/test:

    @Test
    fun `WindowState placement after showing fullscreen window`() = runApplicationTest(useDelay = isLinux) {
        val state = WindowState(placement = WindowPlacement.Fullscreen)

        launchTestApplication {
            Window(onCloseRequest = {}, state) { }
        }

        awaitIdle()

        assertThat(state.placement).isEqualTo(WindowPlacement.Fullscreen)
    }

[okushnikov]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.