1 /*
2  * Copyright 2023 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.compose.windowsizeclass
18 
19 import androidx.compose.material3.windowsizeclass.ExperimentalMaterial3WindowSizeClassApi
20 import androidx.compose.material3.windowsizeclass.WindowSizeClass
21 import androidx.compose.runtime.Composable
22 import androidx.compose.runtime.staticCompositionLocalOf
23 import androidx.compose.ui.graphics.toComposeRect
24 import androidx.compose.ui.platform.LocalConfiguration
25 import androidx.compose.ui.platform.LocalContext
26 import androidx.compose.ui.platform.LocalDensity
27 import androidx.window.layout.WindowMetricsCalculator
28 
29 val LocalWindowSizeClass =
<lambda>null30     staticCompositionLocalOf<WindowSizeClass> {
31         throw IllegalStateException(
32             "No WindowSizeClass configured. Make sure to use LocalWindowSizeClass in a Composable" +
33                 " surrounded by a PlatformTheme {}."
34         )
35     }
36 
37 @OptIn(ExperimentalMaterial3WindowSizeClassApi::class)
38 @Composable
calculateWindowSizeClassnull39 fun calculateWindowSizeClass(): WindowSizeClass {
40     // Observe view configuration changes and recalculate the size class on each change.
41     LocalConfiguration.current
42     val density = LocalDensity.current
43     val context = LocalContext.current
44     val metrics = WindowMetricsCalculator.getOrCreate().computeCurrentWindowMetrics(context)
45     val size = with(density) { metrics.bounds.toComposeRect().size.toDpSize() }
46     return WindowSizeClass.calculateFromSize(size)
47 }
48