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 androidx.tv.material3
18
19 import androidx.compose.foundation.text.selection.LocalTextSelectionColors
20 import androidx.compose.foundation.text.selection.TextSelectionColors
21 import androidx.compose.runtime.Composable
22 import androidx.compose.runtime.CompositionLocalProvider
23 import androidx.compose.runtime.ReadOnlyComposable
24 import androidx.compose.runtime.remember
25
26 /**
27 * Material Theming refers to the customization of your Material Design app to better reflect your
28 * product’s brand.
29 *
30 * Material components such as Button and Checkbox use values provided here when retrieving default
31 * values.
32 *
33 * All values may be set by providing this component with the [colorScheme][ColorScheme],
34 * [typography][Typography] attributes. Use this to configure the overall theme of elements within
35 * this MaterialTheme.
36 *
37 * Any values that are not set will inherit the current value from the theme, falling back to the
38 * defaults if there is no parent MaterialTheme. This allows using a MaterialTheme at the top of
39 * your application, and then separate MaterialTheme(s) for different screens / parts of your UI,
40 * overriding only the parts of the theme definition that need to change.
41 *
42 * @param colorScheme A complete definition of the Material Color theme for this hierarchy
43 * @param shapes A set of corner shapes to be used as this hierarchy's shape system
44 * @param typography A set of text styles to be used as this hierarchy's typography system
45 * @param content The composable content that will be displayed with this theme
46 */
47 @Composable
MaterialThemenull48 fun MaterialTheme(
49 colorScheme: ColorScheme = MaterialTheme.colorScheme,
50 shapes: Shapes = MaterialTheme.shapes,
51 typography: Typography = MaterialTheme.typography,
52 content: @Composable () -> Unit
53 ) {
54 val rememberedColorScheme =
55 remember {
56 // Explicitly creating a new object here so we don't mutate the initial
57 // [colorScheme]
58 // provided, and overwrite the values set in it.
59 colorScheme.copy()
60 }
61 .apply { updateColorSchemeFrom(colorScheme) }
62 val selectionColors = rememberTextSelectionColors(rememberedColorScheme)
63 CompositionLocalProvider(
64 LocalColorScheme provides rememberedColorScheme,
65 LocalShapes provides shapes,
66 LocalTextSelectionColors provides selectionColors,
67 LocalTypography provides typography
68 ) {
69 ProvideTextStyle(value = typography.bodyLarge, content = content)
70 }
71 }
72
73 /**
74 * Contains functions to access the current theme values provided at the call site's position in the
75 * hierarchy.
76 */
77 object MaterialTheme {
78 /** Retrieves the current [ColorScheme] at the call site's position in the hierarchy. */
79 val colorScheme: ColorScheme
80 @Composable
81 @ReadOnlyComposable
82 @SuppressWarnings("HiddenTypeParameter", "UnavailableSymbol")
83 get() = LocalColorScheme.current
84
85 /** Retrieves the current [Typography] at the call site's position in the hierarchy. */
86 val typography: Typography
87 @Composable @ReadOnlyComposable get() = LocalTypography.current
88
89 /** Retrieves the current [Shapes] at the call site's position in the hierarchy. */
90 val shapes: Shapes
91 @Composable @ReadOnlyComposable get() = LocalShapes.current
92 }
93
94 @Composable
95 /*@VisibleForTesting*/
rememberTextSelectionColorsnull96 internal fun rememberTextSelectionColors(colorScheme: ColorScheme): TextSelectionColors {
97 val primaryColor = colorScheme.primary
98 return remember(primaryColor) {
99 TextSelectionColors(
100 handleColor = primaryColor,
101 backgroundColor = primaryColor.copy(alpha = TextSelectionBackgroundOpacity)
102 )
103 }
104 }
105
106 /*@VisibleForTesting*/
107 internal const val TextSelectionBackgroundOpacity = 0.4f
108