SystemGestureExclusion.kt
/*
* Copyright 2022 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.foundation
import android.os.Build
import android.view.View
import androidx.annotation.RequiresApi
import androidx.compose.runtime.Composable
import androidx.compose.runtime.DisposableEffect
import androidx.compose.runtime.collection.mutableVectorOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.graphics.toAndroidRect
import androidx.compose.ui.layout.LayoutCoordinates
import androidx.compose.ui.layout.OnGloballyPositionedModifier
import androidx.compose.ui.layout.boundsInRoot
import androidx.compose.ui.platform.LocalView
import androidx.compose.ui.platform.debugInspectorInfo
import kotlin.math.roundToInt
/**
* Excludes the layout rectangle from the system gesture.
*
* @see View.setSystemGestureExclusionRects
*/
fun Modifier.systemGestureExclusion() =
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
this
} else {
composed(inspectorInfo = debugInspectorInfo {
name = "systemGestureExclusion"
}) {
excludeFromSystemGestureR(null)
}
}
/**
* Excludes a rectangle within the local layout coordinates from the system gesture.
* After layout, [exclusion] is called to determine the [Rect] to exclude from the system
* gesture area.
*
* The [LayoutCoordinates] of the [Modifier]'s location in the layout is passed as passed as
* [exclusion]'s parameter.
*
* @see View.setSystemGestureExclusionRects
*/
fun Modifier.systemGestureExclusion(exclusion: (LayoutCoordinates) -> Rect) =
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
this
} else {
composed(inspectorInfo = debugInspectorInfo {
name = "systemGestureExclusion"
properties["exclusion"] = exclusion
}) {
excludeFromSystemGestureR(exclusion)
}
}
@Suppress("NOTHING_TO_INLINE", "ComposableModifierFactory", "ModifierFactoryExtensionFunction")
@RequiresApi(Build.VERSION_CODES.R)
@Composable
private inline fun excludeFromSystemGestureR(
noinline exclusion: ((LayoutCoordinates) -> Rect)?
): Modifier {
val view = LocalView.current
val modifier = remember(view, exclusion) { ExcludeFromSystemGestureModifier(view, exclusion) }
DisposableEffect(modifier) {
onDispose {
modifier.removeRect()
}
}
return modifier
}
@RequiresApi(Build.VERSION_CODES.R)
private class ExcludeFromSystemGestureModifier(
val view: View,
val exclusion: ((LayoutCoordinates) -> Rect)?
) : OnGloballyPositionedModifier {
var rect: android.graphics.Rect? = null
override fun onGloballyPositioned(coordinates: LayoutCoordinates) {
val newRect = if (exclusion == null) {
coordinates.boundsInRoot().toAndroidRect()
} else {
calcBounds(coordinates, exclusion.invoke(coordinates))
}
replaceRect(newRect)
}
fun removeRect() {
replaceRect(null)
}
fun replaceRect(newRect: android.graphics.Rect?) {
val rects = mutableVectorOf<android.graphics.Rect>()
rects.addAll(view.systemGestureExclusionRects)
rect?.let { rects.remove(it) }
if (newRect?.isEmpty == false) {
rects += newRect
}
view.systemGestureExclusionRects = rects.asMutableList()
rect = newRect
}
private fun calcBounds(
layoutCoordinates: LayoutCoordinates,
rect: Rect
): android.graphics.Rect {
val root = findRoot(layoutCoordinates)
val topLeft = root.localPositionOf(layoutCoordinates, rect.topLeft)
val topRight = root.localPositionOf(layoutCoordinates, rect.topRight)
val bottomLeft = root.localPositionOf(layoutCoordinates, rect.bottomLeft)
val bottomRight = root.localPositionOf(layoutCoordinates, rect.bottomRight)
val left = minOf(topLeft.x, topRight.x, bottomLeft.x, bottomRight.x)
val top = minOf(topLeft.y, topRight.y, bottomLeft.y, bottomRight.y)
val right = maxOf(topLeft.x, topRight.x, bottomLeft.x, bottomRight.x)
val bottom = maxOf(topLeft.y, topRight.y, bottomLeft.y, bottomRight.y)
return android.graphics.Rect(
left.roundToInt(),
top.roundToInt(),
right.roundToInt(),
bottom.roundToInt()
)
}
private fun findRoot(layoutCoordinates: LayoutCoordinates): LayoutCoordinates {
var coordinates = layoutCoordinates
var parent = layoutCoordinates.parentLayoutCoordinates
while (parent != null) {
coordinates = parent
parent = coordinates.parentLayoutCoordinates
}
return coordinates
}
}