| /* |
| * Copyright 2020 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.layout |
| |
| import androidx.ui.core.LayoutDirection |
| import androidx.ui.core.LayoutModifier |
| import androidx.ui.core.ModifierScope |
| |
| /** |
| * A layout modifier that changes the layout direction of the corresponding layout node. |
| */ |
| // TODO(soboleva) Make a public API |
| internal object LayoutDirectionModifier { |
| val Ltr: LayoutModifier = LayoutDirectionModifierImpl(LayoutDirection.Ltr) |
| val Rtl: LayoutModifier = LayoutDirectionModifierImpl(LayoutDirection.Rtl) |
| val Restore: LayoutModifier = LayoutDirectionModifierImpl(null) |
| } |
| |
| private data class LayoutDirectionModifierImpl( |
| val newLayoutDirection: LayoutDirection? |
| ) : LayoutModifier { |
| // if newLayoutDirection set by modifier is null, then we restore to ambient's layout direction |
| override fun ModifierScope.modifyLayoutDirection() = |
| newLayoutDirection ?: ambientLayoutDirection |
| } |