Fix IME insets propagation and Scroll To Focused Node behaviour

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/layout/OffsetToFocusedRect.skiko.kt

@@ -0,0 +1,174 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.ui.layout
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.geometry.Rect
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.platform.PlatformInsets
+import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.IntOffset
+import androidx.compose.ui.unit.IntSize
+import kotlin.math.max
+import kotlin.math.min
+import kotlin.math.roundToInt
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.nanoseconds
+
+@Composable
+internal fun OffsetToFocusedRect(
+    insets: PlatformInsets,
+    getFocusedRect: () -> Rect?,
+    size: IntSize?,
+    animationDuration: Duration,
+    animationCompletion: () -> Unit,
+    content: @Composable () -> Unit,
+) {
+    var currentOffset by remember { mutableStateOf(IntOffset.Zero) }
+    var startOffset by remember { mutableStateOf(IntOffset.Zero) }
+    var offsetProgress by remember { mutableStateOf(1f) }
+    val density = LocalDensity.current
+
+    LaunchedEffect(insets, animationDuration) {
+        startOffset = currentOffset
+        if (animationDuration.isPositive()) {
+            if (startOffset == density.adjustedToFocusedRectOffset(
+                    insets = insets,
+                    focusedRect = getFocusedRect(),
+                    size = size,
+                    currentOffset = currentOffset
+                )
+            ) {
+                offsetProgress = 1f
+            } else {
+                withAnimationProgress(animationDuration) {
+                    offsetProgress = it
+                }
+            }
+            animationCompletion()
+        } else {
+            offsetProgress = 1f
+        }
+    }
+
+    Layout(
+        content = content,
+        measurePolicy = { measurables, constraints ->
+            val endOffset = density.adjustedToFocusedRectOffset(
+                insets = insets,
+                focusedRect = getFocusedRect(),
+                size = size,
+                currentOffset = currentOffset
+            )
+
+            // Intentionally update state within composition to trigger second measure and
+            // layout because focus rect may be miscalculated due to simultaneous offset and
+            // window insets changes.
+            currentOffset = startOffset + (endOffset - startOffset) * offsetProgress
+
+            val placeables = measurables.map { it.measure(constraints) }
+            layout(
+                placeables.maxOfOrNull { it.width } ?: constraints.minWidth,
+                placeables.maxOfOrNull { it.height } ?: constraints.minHeight
+            ) {
+                placeables.forEach {
+                    it.place(currentOffset)
+                }
+            }
+        }
+    )
+}
+
+internal fun Density.adjustedToFocusedRectOffset(
+    insets: PlatformInsets,
+    focusedRect: Rect?,
+    size: IntSize?,
+    currentOffset: IntOffset,
+): IntOffset {
+    focusedRect ?: return IntOffset.Zero
+    size ?: return IntOffset.Zero
+    if (insets == PlatformInsets.Zero) {
+        return IntOffset.Zero
+    }
+
+    return IntOffset(
+        x = directionalFocusOffset(
+            contentSize = size.width.toFloat(),
+            contentInsetStart = insets.left.toPx(),
+            contentInsetEnd = insets.right.toPx(),
+            focusStart = focusedRect.left - currentOffset.x,
+            focusEnd = focusedRect.right - currentOffset.x
+        ),
+        y = directionalFocusOffset(
+            contentSize = size.height.toFloat(),
+            contentInsetStart = insets.top.toPx(),
+            contentInsetEnd = insets.bottom.toPx(),
+            focusStart = focusedRect.top - currentOffset.y,
+            focusEnd = focusedRect.bottom - currentOffset.y
+        )
+    )
+}
+
+private fun directionalFocusOffset(
+    contentSize: Float,
+    contentInsetStart: Float,
+    contentInsetEnd: Float,
+    focusStart: Float,
+    focusEnd: Float
+): Int {
+    val hiddenFromPart = contentInsetStart - max(focusStart, 0f)
+    val hiddenToPart = contentInsetEnd - contentSize + min(focusEnd, contentSize)
+
+    return if (hiddenFromPart >= 0 && hiddenToPart >= 0) {
+        0
+    } else if (hiddenToPart < 0) {
+        max(0f, min(hiddenFromPart, -hiddenToPart)).roundToInt()
+    } else {
+        min(0f, max(hiddenFromPart, -hiddenToPart)).roundToInt()
+    }
+}
+
+private suspend fun withAnimationProgress(duration: Duration, update: (Float) -> Unit) {
+    fun easeInOutProgress(progress: Float) = if (progress < 0.5) {
+        2 * progress * progress
+    } else {
+        (-2 * progress * progress) + (4 * progress) - 1
+    }
+
+    update(0f)
+
+    var firstFrameTime = 0L
+    var progressDuration = Duration.ZERO
+    while (progressDuration < duration) {
+        withFrameNanos { frameTime ->
+            if (firstFrameTime == 0L) {
+                firstFrameTime = frameTime
+            }
+            progressDuration = (frameTime - firstFrameTime).nanoseconds
+            val progress = easeInOutProgress(
+                min(1.0, progressDuration / duration).toFloat()
+            )
+            update(progress)
+        }
+    }
+}