| /* |
| * Copyright 2019 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.ui.desktop |
| |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.Layout |
| import androidx.ui.core.gesture.DragObserver |
| import androidx.compose.Composable |
| import androidx.ui.core.onPositioned |
| import androidx.ui.geometry.Offset |
| import kotlin.math.max |
| import androidx.compose.remember |
| import androidx.compose.state |
| import androidx.ui.core.selection.Selection |
| import androidx.ui.core.selection.SelectionRegistrarAmbient |
| import androidx.compose.Providers |
| import androidx.ui.core.pointerinput.PointerInputModifier |
| import androidx.ui.core.pointerinput.PointerInputFilter |
| import androidx.ui.core.composed |
| import androidx.ui.core.gesture.rawDragGestureFilter |
| import androidx.ui.core.gesture.rawPressStartGestureFilter |
| |
| @Composable |
| private fun Wrap(modifier: Modifier = Modifier, children: @Composable () -> Unit) { |
| Layout(modifier = modifier, children = children) { measurables, constraints -> |
| val placeables = measurables.map { measurable -> |
| measurable.measure(constraints) |
| } |
| |
| val width = placeables.fold(0) { maxWidth, placeable -> |
| max(maxWidth, (placeable.width)) |
| } |
| |
| val height = placeables.fold(0) { minWidth, placeable -> |
| max(minWidth, (placeable.height)) |
| } |
| |
| layout(width, height) { |
| placeables.forEach { placeable -> |
| placeable.placeAbsolute(0, 0) |
| } |
| } |
| } |
| } |
| |
| @Composable |
| internal fun DesktopSelectionContainer(children: @Composable () -> Unit) { |
| val selection = state<Selection?> { null } |
| DesktopSelectionContainer( |
| selection = selection.value, |
| onSelectionChange = { selection.value = it }, |
| children = children |
| ) |
| } |
| |
| private class PointerInputModifierImpl(override val pointerInputFilter: PointerInputFilter) : |
| PointerInputModifier |
| |
| private fun Modifier.selectionFilter(observer: DragObserver): Modifier = composed { |
| val glue = remember { DragGlue(observer) } |
| rawDragGestureFilter(glue, glue::started) |
| .rawPressStartGestureFilter(glue::startDrag, true) |
| } |
| |
| private class DragGlue(val observer: DragObserver) : DragObserver by observer { |
| var started = false |
| |
| fun startDrag(downPosition: Offset) { |
| started = true |
| observer.onStart(downPosition) |
| } |
| |
| override fun onStop(velocity: Offset) { |
| started = false |
| observer.onStop(velocity) |
| } |
| |
| override fun onCancel() { |
| started = false |
| observer.onCancel() |
| } |
| } |
| |
| @Composable |
| fun DesktopSelectionContainer( |
| selection: Selection?, |
| onSelectionChange: (Selection?) -> Unit, |
| children: @Composable () -> Unit |
| ) { |
| val registrarImpl = remember { DesktopSelectionRegistrar() } |
| val manager = remember { DesktopSelectionManager(registrarImpl) } |
| |
| manager.onSelectionChange = onSelectionChange |
| manager.selection = selection |
| |
| val gestureModifiers = |
| Modifier.selectionFilter(manager.observer) |
| |
| val modifier = remember { |
| gestureModifiers.onPositioned { |
| manager.containerLayoutCoordinates = it |
| } |
| } |
| |
| Providers(SelectionRegistrarAmbient provides registrarImpl) { |
| Wrap(modifier) { |
| children() |
| } |
| } |
| } |