| /* |
| * 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.core |
| |
| import androidx.ui.graphics.Canvas |
| import androidx.ui.graphics.drawscope.DrawScope |
| |
| /** |
| * A [Modifier.Element] that draws into the space of the layout. |
| */ |
| interface DrawModifier : Modifier.Element { |
| fun ContentDrawScope.draw() |
| } |
| |
| /** |
| * Draw into a [Canvas] behind the modified content. |
| */ |
| fun Modifier.drawBehind( |
| onDraw: DrawScope.() -> Unit |
| ) = this + DrawBackgroundModifier(onDraw) |
| |
| private class DrawBackgroundModifier( |
| val onDraw: DrawScope.() -> Unit |
| ) : DrawModifier { |
| override fun ContentDrawScope.draw() { |
| onDraw() |
| drawContent() |
| } |
| } |
| |
| /** |
| * Creates a [DrawModifier] that allows the developer to draw before or after the layout's |
| * contents. It also allows the modifier to adjust the layout's canvas. |
| */ |
| // TODO: Inline this function -- it breaks with current compiler |
| /*inline*/ fun Modifier.drawWithContent( |
| onDraw: ContentDrawScope.() -> Unit |
| ): Modifier = this + object : DrawModifier { |
| override fun ContentDrawScope.draw() { |
| onDraw() |
| } |
| } |