skikoMain.androidx.compose.ui.layout.OffsetToFocusedRect.skiko.kt Maven / Gradle / Ivy

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Compose UI primitives. This library contains the primitives that form the Compose UI Toolkit, such as drawing, measurement and layout.
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/*
 * 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)
        }
    }
}