Add PopupProperties.clippingEnabled setting (#740)

* Add Popup clipping option

* Do not draw popup without valid parentBounds

* Update equals/hashCode

* Add default arguments

* Add tests

* Remove AlertDialog.shadow test

* Fix existing tests

compose/material/material/src/desktopTest/kotlin/androidx/compose/material/DesktopAlertDialogTest.kt

@@ -115,36 +115,6 @@ class DesktopAlertDialogTest {
         }
     }
 
-    // https://github.com/JetBrains/compose-multiplatform/issues/2857
-    @OptIn(ExperimentalMaterialApi::class)
-    @Test
-    fun `shadow drawn at content bounds`() {
-        // Show an AlertDialog with very large horizontal padding and check that the pixel
-        // at the edge of where the dialog would have been without padding has the same color as the
-        // background.
-        val screenshot = renderComposeScene(400, 400){
-            AlertDialog(
-                modifier = Modifier.size(width = 400.dp, height = 100.dp),
-                onDismissRequest = {},
-                title = {},
-                text = {},
-                dismissButton = {},
-                confirmButton = {},
-                dialogPadding = PaddingValues(horizontal = 150.dp)
-            )
-        }
-
-        val pixels = screenshot.toComposeImageBitmap().toPixelMap()
-        val backgroundPixel = pixels[0, 0]
-        val nearEdgeWithoutPaddingPixel = pixels[0, 200]
-        val nearRealEdgePixel = pixels[149, 200]
-
-        assertEquals(nearEdgeWithoutPaddingPixel, backgroundPixel)
-
-        // Also check that the shadow is present near the actual edge of the content
-        assertNotEquals(nearRealEdgePixel, backgroundPixel)
-    }
-
     @OptIn(ExperimentalTestApi::class, ExperimentalMaterialApi::class)
     @Test
     fun `uses available width`() = runDesktopComposeUiTest(

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/window/Popup.skiko.kt

@@ -57,14 +57,19 @@ import androidx.compose.ui.unit.round
  * focusable then this property does nothing.
  * @property dismissOnClickOutside Whether the popup can be dismissed by clicking outside the
  * popup's bounds. If true, clicking outside the popup will call onDismissRequest.
+ * @property clippingEnabled Whether to allow the popup window to extend beyond the bounds of the
+ * screen. By default the window is clipped to the screen boundaries. Setting this to false will
+ * allow windows to be accurately positioned.
+ * The default value is true.
  * @property usePlatformDefaultWidth Whether the width of the dialog's content should be limited to
  * the platform default, which is smaller than the screen width.
  */
 @Immutable
 actual class PopupProperties @ExperimentalComposeUiApi constructor(
-    actual val focusable: Boolean,
-    actual val dismissOnBackPress: Boolean,
-    actual val dismissOnClickOutside: Boolean,
+    actual val focusable: Boolean = false,
+    actual val dismissOnBackPress: Boolean = true,
+    actual val dismissOnClickOutside: Boolean = true,
+    val clippingEnabled: Boolean = true,
     val usePlatformDefaultWidth: Boolean = false,
 ) {
     actual constructor(
@@ -85,6 +90,7 @@ actual class PopupProperties @ExperimentalComposeUiApi constructor(
         if (focusable != other.focusable) return false
         if (dismissOnBackPress != other.dismissOnBackPress) return false
         if (dismissOnClickOutside != other.dismissOnClickOutside) return false
+        if (clippingEnabled != other.clippingEnabled) return false
         if (usePlatformDefaultWidth != other.usePlatformDefaultWidth) return false
 
         return true
@@ -94,6 +100,7 @@ actual class PopupProperties @ExperimentalComposeUiApi constructor(
         var result = focusable.hashCode()
         result = 31 * result + dismissOnBackPress.hashCode()
         result = 31 * result + dismissOnClickOutside.hashCode()
+        result = 31 * result + clippingEnabled.hashCode()
         result = 31 * result + usePlatformDefaultWidth.hashCode()
         return result
     }
@@ -388,13 +395,14 @@ private fun PopupLayout(
     onOutsidePointerEvent: ((PointerInputEvent) -> Unit)? = null,
     content: @Composable () -> Unit
 ) {
-    var parentBounds by remember { mutableStateOf(IntRect.Zero) }
-    EmptyLayout(Modifier.parentBoundsInWindow { parentBounds = it })
+    var layoutParentBoundsInWindow: IntRect? by remember { mutableStateOf(null) }
+    EmptyLayout(Modifier.parentBoundsInWindow { layoutParentBoundsInWindow = it })
     RootLayout(
         modifier = modifier,
         focusable = properties.focusable,
         onOutsidePointerEvent = onOutsidePointerEvent
     ) { owner ->
+        val parentBounds = layoutParentBoundsInWindow ?: return@RootLayout
         val density = LocalDensity.current
         val layoutDirection = LocalLayoutDirection.current
         val measurePolicy = rememberPopupMeasurePolicy(
@@ -436,9 +444,15 @@ private fun rememberPopupMeasurePolicy(
         platformOffset = platformOffset,
         usePlatformDefaultWidth = properties.usePlatformDefaultWidth
     ) { windowSize, contentSize ->
-        val position = popupPositionProvider.calculatePosition(
+        var position = popupPositionProvider.calculatePosition(
             parentBounds, windowSize, layoutDirection, contentSize
         )
+        if (properties.clippingEnabled) {
+            position = IntOffset(
+                x = position.x.coerceIn(0, windowSize.width - contentSize.width),
+                y = position.y.coerceIn(0, windowSize.height - contentSize.height)
+            )
+        }
         onBoundsChanged(IntRect(position, contentSize))
         position
     }

compose/ui/ui/src/skikoTest/kotlin/androidx/compose/ui/EventTestUtils.kt

@@ -152,7 +152,8 @@ class PopupState(
             onDismissRequest = onDismissRequest,
             properties = PopupProperties(
                 focusable = focusable,
-                dismissOnClickOutside = dismissOnClickOutside
+                dismissOnClickOutside = dismissOnClickOutside,
+                clippingEnabled = false
             )
         ) {
             with(LocalDensity.current) {

compose/ui/ui/src/skikoTest/kotlin/androidx/compose/ui/window/PopupTest.kt

@@ -16,13 +16,16 @@
 
 package androidx.compose.ui.window
 
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.size
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.staticCompositionLocalOf
 import androidx.compose.ui.FillBox
+import androidx.compose.ui.Modifier
 import androidx.compose.ui.PopupState
 import androidx.compose.ui.assertReceived
 import androidx.compose.ui.assertReceivedLast
@@ -36,14 +39,18 @@ import androidx.compose.ui.input.pointer.PointerEventType
 import androidx.compose.ui.isEqualTo
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.test.ExperimentalTestApi
 import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.assertPositionInRootIsEqualTo
 import androidx.compose.ui.test.onNodeWithTag
 import androidx.compose.ui.test.runSkikoComposeUiTest
 import androidx.compose.ui.touch
 import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.IntRect
 import androidx.compose.ui.unit.LayoutDirection
+import androidx.compose.ui.unit.dp
 import kotlin.test.Test
 import kotlin.test.fail
 
@@ -505,4 +512,46 @@ class PopupTest {
             )
         )
     }
+
+    @Test
+    fun clippingEnabledPopup() = runSkikoComposeUiTest(
+        size = Size(100f, 100f)
+    ) {
+        setContent {
+            Popup(
+                offset = IntOffset(80, 80)
+            ) {
+                Box(Modifier.size(50.dp).testTag("box1"))
+            }
+            Popup(
+                offset = IntOffset(-30, -30)
+            ) {
+                Box(Modifier.size(50.dp).testTag("box2"))
+            }
+        }
+        onNodeWithTag("box1").assertPositionInRootIsEqualTo(50.dp, 50.dp)
+        onNodeWithTag("box2").assertPositionInRootIsEqualTo(0.dp, 0.dp)
+    }
+
+    @Test
+    fun clippingDisabledPopup() = runSkikoComposeUiTest(
+        size = Size(100f, 100f)
+    ) {
+        setContent {
+            Popup(
+                offset = IntOffset(80, 80),
+                properties = PopupProperties(clippingEnabled = false)
+            ) {
+                Box(Modifier.size(50.dp).testTag("box1"))
+            }
+            Popup(
+                offset = IntOffset(-30, -30),
+                properties = PopupProperties(clippingEnabled = false)
+            ) {
+                Box(Modifier.size(50.dp).testTag("box2"))
+            }
+        }
+        onNodeWithTag("box1").assertPositionInRootIsEqualTo(80.dp, 80.dp)
+        onNodeWithTag("box2").assertPositionInRootIsEqualTo((-30).dp, (-30).dp)
+    }
 }