feat(desktop): unify Linux window chrome

desktopApp/src/main/kotlin/com/vnidrop/app/main.kt

@@ -1,27 +1,52 @@
 package com.vnidrop.app
 
+import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.hoverable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.collectIsHoveredAsState
+import androidx.compose.foundation.interaction.collectIsPressedAsState
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.text.BasicText
 import androidx.compose.foundation.window.WindowDraggableArea
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.awt.awtEventOrNull
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.ColorFilter
+import androidx.compose.ui.graphics.PathFillType
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.graphics.StrokeCap
+import androidx.compose.ui.graphics.StrokeJoin
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.graphics.vector.PathBuilder
+import androidx.compose.ui.graphics.vector.path
+import androidx.compose.ui.graphics.vector.rememberVectorPainter
 import androidx.compose.ui.input.pointer.PointerEventType
 import androidx.compose.ui.input.pointer.onPointerEvent
+import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Window
+import androidx.compose.ui.window.WindowPlacement
 import androidx.compose.ui.window.WindowScope
 import androidx.compose.ui.window.application
+import androidx.compose.ui.window.rememberWindowState
 import com.vnidrop.app.platform.DesktopAppearanceBridge
 import com.vnidrop.app.feature.send.DesktopShareBridge
 import com.vnidrop.app.feature.receive.ExternalInvitationController
@@ -35,6 +60,8 @@ import java.io.File
 fun main(args: Array<String>) {
 	val externalInvitations = ExternalInvitationController()
 	val macOs = DesktopAppearanceBridge.isMacOs()
+	val linux = DesktopAppearanceBridge.isLinux()
+	val customWindowChrome = macOs || linux
 	configureMacOsNativeAppearance()
 	configureInvitationOpenHandler(externalInvitations)
 	args.asSequence()
@@ -46,18 +73,39 @@ fun main(args: Array<String>) {
 		DesktopShareBridge.shareFile = MacOsShareSheet::share
 	}
 	application {
+		val windowState = rememberWindowState()
 		Window(
 			onCloseRequest = ::exitApplication,
+			state = windowState,
 			title = "vnidrop",
+			// Compose keeps edge resizers active for this client-decorated Linux window.
+			undecorated = linux,
 		) {
 			App(
 				dependencies = rememberJvmAppDependencies(externalInvitations),
-				windowChromeTopInset = if (macOs) MacOsTitleBarHeight else 0.dp,
-				windowContentTopStartRadius = if (macOs) MacOsContentCornerRadius else 0.dp,
-				windowChrome = if (macOs) {
+				windowChromeTopInset = when {
+					macOs -> MacOsTitleBarHeight
+					linux -> LinuxTitleBarHeight
+					else -> 0.dp
+				},
+				windowContentTopStartRadius = if (customWindowChrome) DesktopContentCornerRadius else 0.dp,
+				windowChrome = when {
+					macOs -> {
 						{ MacOsTitleBar() }
-				} else {
-					null
+					}
+					linux -> {
+						{
+							LinuxTitleBar(
+								isMaximized = windowState.placement == WindowPlacement.Maximized,
+								onMinimize = { windowState.isMinimized = true },
+								onToggleMaximize = {
+									windowState.placement = toggledWindowPlacement(windowState.placement)
+								},
+								onClose = ::exitApplication,
+							)
+						}
+					}
+					else -> null
 				},
 			)
 		}
@@ -91,7 +139,10 @@ private fun configureMacOsNativeAppearance() {
 
 private val MacOsTitleBarHeight = 28.dp
 private val MacOsTrafficLightsWidth = 76.dp
-private val MacOsContentCornerRadius = 20.dp
+private val LinuxTitleBarHeight = 40.dp
+private val LinuxWindowControlWidth = 46.dp
+private val LinuxWindowControlsWidth = 138.dp
+private val DesktopContentCornerRadius = 20.dp
 
 @Composable
 @OptIn(ExperimentalComposeUiApi::class)
@@ -127,3 +178,149 @@ private fun WindowScope.MacOsTitleBar() {
 		}
 	}
 }
+
+@Composable
+@OptIn(ExperimentalComposeUiApi::class)
+private fun WindowScope.LinuxTitleBar(
+	isMaximized: Boolean,
+	onMinimize: () -> Unit,
+	onToggleMaximize: () -> Unit,
+	onClose: () -> Unit,
+) {
+	val colors = LocalVniDropColors.current
+	Box(
+		modifier = Modifier
+			.fillMaxWidth()
+			.height(LinuxTitleBarHeight)
+			.background(colors.backgroundSurface200),
+	) {
+		BasicText(
+			text = "vnidrop",
+			modifier = Modifier.align(Alignment.Center),
+			style = TextStyle(
+				color = colors.foregroundDefault,
+				fontSize = 13.sp,
+				fontWeight = FontWeight.SemiBold,
+			),
+		)
+		WindowDraggableArea(
+			modifier = Modifier
+				.fillMaxSize()
+				.padding(end = LinuxWindowControlsWidth)
+				.onPointerEvent(PointerEventType.Press) { event ->
+					if (event.awtEventOrNull?.clickCount == 2) onToggleMaximize()
+				},
+		) {
+			Box(Modifier.fillMaxSize())
+		}
+		Row(
+			modifier = Modifier
+				.align(Alignment.CenterEnd)
+				.fillMaxHeight(),
+		) {
+			LinuxWindowControlButton(
+				icon = LinuxMinimizeIcon,
+				contentDescription = "Minimize window",
+				onClick = onMinimize,
+			)
+			LinuxWindowControlButton(
+				icon = if (isMaximized) LinuxRestoreIcon else LinuxMaximizeIcon,
+				contentDescription = if (isMaximized) "Restore window" else "Maximize window",
+				onClick = onToggleMaximize,
+			)
+			LinuxWindowControlButton(
+				icon = LinuxCloseIcon,
+				contentDescription = "Close window",
+				isClose = true,
+				onClick = onClose,
+			)
+		}
+	}
+}
+
+@Composable
+private fun LinuxWindowControlButton(
+	icon: ImageVector,
+	contentDescription: String,
+	isClose: Boolean = false,
+	onClick: () -> Unit,
+) {
+	val colors = LocalVniDropColors.current
+	val interactionSource = remember { MutableInteractionSource() }
+	val hovered by interactionSource.collectIsHoveredAsState()
+	val pressed by interactionSource.collectIsPressedAsState()
+	val active = hovered || pressed
+	val background = when {
+		isClose && active -> colors.destructiveDefault
+		active -> colors.backgroundOverlayHover
+		else -> Color.Transparent
+	}
+	Box(
+		modifier = Modifier
+			.width(LinuxWindowControlWidth)
+			.fillMaxHeight()
+			.background(background)
+			.hoverable(interactionSource)
+			.clickable(
+				interactionSource = interactionSource,
+				indication = null,
+				role = Role.Button,
+				onClick = onClick,
+			),
+		contentAlignment = Alignment.Center,
+	) {
+		Image(
+			painter = rememberVectorPainter(icon),
+			contentDescription = contentDescription,
+			colorFilter = ColorFilter.tint(if (isClose && active) Color.White else colors.foregroundLight),
+			modifier = Modifier.size(15.dp),
+		)
+	}
+}
+
+internal fun toggledWindowPlacement(current: WindowPlacement): WindowPlacement =
+	if (current == WindowPlacement.Maximized) WindowPlacement.Floating else WindowPlacement.Maximized
+
+private val LinuxMinimizeIcon = windowControlIcon("Minimize") {
+	moveTo(6f, 12f)
+	lineTo(18f, 12f)
+}
+
+private val LinuxMaximizeIcon = windowControlIcon("Maximize") {
+	moveTo(6.5f, 6.5f)
+	lineTo(17.5f, 6.5f)
+	lineTo(17.5f, 17.5f)
+	lineTo(6.5f, 17.5f)
+	close()
+}
+
+private val LinuxRestoreIcon = windowControlIcon("Restore") {
+	moveTo(8.5f, 8.5f)
+	lineTo(18f, 8.5f)
+	lineTo(18f, 18f)
+	lineTo(8.5f, 18f)
+	close()
+	moveTo(6f, 15.5f)
+	lineTo(6f, 6f)
+	lineTo(15.5f, 6f)
+}
+
+private val LinuxCloseIcon = windowControlIcon("Close") {
+	moveTo(7f, 7f)
+	lineTo(17f, 17f)
+	moveTo(17f, 7f)
+	lineTo(7f, 17f)
+}
+
+private fun windowControlIcon(name: String, block: PathBuilder.() -> Unit): ImageVector =
+	ImageVector.Builder(name, 24.dp, 24.dp, 24f, 24f).apply {
+		path(
+			fill = SolidColor(Color.Transparent),
+			stroke = SolidColor(Color.Black),
+			strokeLineWidth = 1.6f,
+			strokeLineCap = StrokeCap.Round,
+			strokeLineJoin = StrokeJoin.Round,
+			pathFillType = PathFillType.NonZero,
+			pathBuilder = block,
+		)
+	}.build()

desktopApp/src/test/kotlin/com/vnidrop/app/DesktopWindowChromeTest.kt

@@ -0,0 +1,13 @@
+package com.vnidrop.app
+
+import androidx.compose.ui.window.WindowPlacement
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class DesktopWindowChromeTest {
+	@Test
+	fun maximizeControlTogglesBetweenFloatingAndMaximized() {
+		assertEquals(WindowPlacement.Maximized, toggledWindowPlacement(WindowPlacement.Floating))
+		assertEquals(WindowPlacement.Floating, toggledWindowPlacement(WindowPlacement.Maximized))
+	}
+}

desktopApp/src/test/kotlin/com/vnidrop/app/MacOsShareSheetTest.kt

@@ -1,8 +1,10 @@
 package com.vnidrop.app
 
+import com.vnidrop.app.platform.DesktopAppearanceBridge
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
+import org.junit.Assume.assumeTrue
 
 class MacOsShareSheetTest {
 	@Test
@@ -12,6 +14,7 @@ class MacOsShareSheetTest {
 
 	@Test
 	fun nativeMainDispatchQueueCanBeResolved() {
+		assumeTrue(DesktopAppearanceBridge.isMacOs())
 		assertTrue(MacOsShareSheet.hasNativeMainQueue())
 	}
 }

shared/src/jvmMain/kotlin/com/vnidrop/app/platform/PlatformSystemAppearance.jvm.kt

@@ -65,6 +65,7 @@ object DesktopAppearanceBridge {
 	var applyNativeAppearance: ((Boolean) -> Unit)? = null
 
 	fun isMacOs(): Boolean = isMacOs(System.getProperty("os.name"))
+	fun isLinux(): Boolean = isLinux(System.getProperty("os.name"))
 
 	fun toggleMaximized(window: Window) {
 		if (!isMacOs()) return
@@ -77,6 +78,9 @@ object DesktopAppearanceBridge {
 	internal fun isMacOs(osName: String): Boolean =
 		osName.startsWith("Mac", ignoreCase = true)
 
+	internal fun isLinux(osName: String): Boolean =
+		osName.startsWith("Linux", ignoreCase = true)
+
 	internal fun toggledWindowState(currentState: Int): Int =
 		if (currentState and Frame.MAXIMIZED_BOTH == Frame.MAXIMIZED_BOTH) {
 			Frame.NORMAL

shared/src/jvmTest/kotlin/com/vnidrop/app/platform/DesktopSystemAppearanceTest.kt

@@ -10,10 +10,13 @@ import kotlin.test.assertTrue
 
 class DesktopSystemAppearanceTest {
 	@Test
-	fun customWindowChromeIsMacOsOnly() {
+	fun customWindowChromeSupportsMacOsAndLinux() {
 		assertTrue(DesktopAppearanceBridge.isMacOs("Mac OS X"))
-		assertFalse(DesktopAppearanceBridge.isMacOs("Windows 11"))
+		assertFalse(DesktopAppearanceBridge.isLinux("Mac OS X"))
+		assertTrue(DesktopAppearanceBridge.isLinux("Linux"))
 		assertFalse(DesktopAppearanceBridge.isMacOs("Linux"))
+		assertFalse(DesktopAppearanceBridge.isMacOs("Windows 11"))
+		assertFalse(DesktopAppearanceBridge.isLinux("Windows 11"))
 	}
 
 	@Test