| /* |
| * 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.compose.getValue |
| import androidx.compose.setValue |
| import androidx.ui.core.LayoutCoordinates |
| import androidx.ui.core.clipboard.ClipboardManager |
| import androidx.ui.core.gesture.DragObserver |
| import androidx.ui.geometry.Offset |
| import androidx.ui.core.selection.Selection |
| import androidx.ui.core.selection.Selectable |
| |
| internal class DesktopSelectionManager(private val selectionRegistrar: DesktopSelectionRegistrar) { |
| private var dragBeginPosition = Offset.Zero |
| |
| private var dragTotalDistance = Offset.Zero |
| |
| var containerLayoutCoordinates: LayoutCoordinates? = null |
| |
| var clipboardManager: ClipboardManager? = null |
| var onSelectionChange: (Selection?) -> Unit = {} |
| var selection: Selection? = null |
| |
| val observer = Observer() |
| |
| inner class Observer : DragObserver { |
| override fun onStart(downPosition: Offset) { |
| mergeSelections( |
| startPosition = Offset(-1f, -1f), |
| endPosition = Offset(-1f, -1f), |
| previousSelection = selection |
| ) |
| if (selection != null) onSelectionChange(null) |
| dragBeginPosition = downPosition |
| dragTotalDistance = Offset.Zero |
| } |
| |
| override fun onDrag(dragDistance: Offset): Offset { |
| dragTotalDistance += dragDistance |
| val newSelection = mergeSelections( |
| startPosition = dragBeginPosition, |
| endPosition = dragBeginPosition + dragTotalDistance, |
| previousSelection = selection |
| ) |
| |
| if (newSelection != selection) onSelectionChange(newSelection) |
| return dragDistance |
| } |
| } |
| |
| internal fun mergeSelections( |
| startPosition: Offset, |
| endPosition: Offset, |
| longPress: Boolean = false, |
| previousSelection: Selection? = null, |
| isStartHandle: Boolean = true |
| ): Selection? { |
| |
| val newSelection = selectionRegistrar.sort(requireContainerCoordinates()) |
| .fold(null) { mergedSelection: Selection?, |
| handler: Selectable -> |
| merge( |
| mergedSelection, |
| handler.getSelection( |
| startPosition = startPosition, |
| endPosition = endPosition, |
| containerLayoutCoordinates = requireContainerCoordinates(), |
| longPress = longPress, |
| previousSelection = previousSelection, |
| isStartHandle = isStartHandle |
| ) |
| ) |
| } |
| return newSelection |
| } |
| |
| internal fun requireContainerCoordinates(): LayoutCoordinates { |
| val coordinates = containerLayoutCoordinates |
| require(coordinates != null) |
| require(coordinates.isAttached) |
| return coordinates |
| } |
| } |
| |
| private fun merge(lhs: Selection?, rhs: Selection?): Selection? { |
| return lhs?.merge(rhs) ?: rhs |
| } |