MaterialTheme.kt

/*
 * Copyright 2023 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.wear.compose.material3

import androidx.compose.foundation.LocalIndication
import androidx.compose.foundation.text.selection.LocalTextSelectionColors
import androidx.compose.material.ripple.LocalRippleTheme
import androidx.compose.material.ripple.RippleTheme
import androidx.compose.material.ripple.rememberRipple
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.Immutable
import androidx.compose.runtime.ReadOnlyComposable
import androidx.compose.runtime.remember

/**
 * MaterialTheme defines the styling principles from the Wear Material3 design specification
 * which extends the Material design specification.
 *
 * Wear Material components from package/sub-packages in [androidx.wear.compose.material3]
 * use values provided here when retrieving default values.
 *
 * TODO(b/273543423) Update references to Material3 design specs
 *
 * All values may be set by providing this component with the [colors][ColorScheme],
 * [typography][Typography], and [shapes][Shapes] attributes. Use this to configure the
 * overall theme of elements within this MaterialTheme.
 *
 * Any values that are not set will inherit the current value from the theme, falling back to the
 * defaults if there is no parent MaterialTheme. This allows using a MaterialTheme at the
 * top of your application, and then separate MaterialTheme(s) for different screens / parts of
 * your UI, overriding only the parts of the theme definition that need to change.
 *
 * For more information, see the
 * [Theming](https://developer.android.com/training/wearables/components/theme)
 * guide.
 *
 * @param colorScheme A complete definition of the Wear Material Color theme for this hierarchy
 * @param typography A set of text styles to be used as this hierarchy's typography system
 * @param shapes A set of shapes to be used by the components in this hierarchy
 */
@Composable
public fun MaterialTheme(
    colorScheme: ColorScheme = MaterialTheme.colorScheme,
    typography: Typography = MaterialTheme.typography,
    shapes: Shapes = MaterialTheme.shapes,
    content: @Composable () -> Unit
) {
    val rememberedColors = remember {
        // Explicitly creating a new object here so we don't mutate the initial [colors]
        // provided, and overwrite the values set in it.
        colorScheme.copy()
    }.apply { updateColorSchemeFrom(colorScheme) }
    val rippleIndication = rememberRipple()
    val selectionColors = rememberTextSelectionColors(rememberedColors)
    CompositionLocalProvider(
        LocalColors provides rememberedColors,
        LocalShapes provides shapes,
        LocalTypography provides typography,
        LocalContentAlpha provides ContentAlpha.high,
        LocalIndication provides rippleIndication,
        LocalRippleTheme provides MaterialRippleTheme,
        LocalTextSelectionColors provides selectionColors,

        ) {
        ProvideTextStyle(value = typography.bodyLarge, content = content)
    }
}

public object MaterialTheme {
    public val colorScheme: ColorScheme
        @ReadOnlyComposable
        @Composable
        get() = LocalColors.current

    public val typography: Typography
        @ReadOnlyComposable
        @Composable
        get() = LocalTypography.current

    public val shapes: Shapes
        @ReadOnlyComposable
        @Composable
        get() = LocalShapes.current
}

@Immutable
private object MaterialRippleTheme : RippleTheme {
    @Composable
    override fun defaultColor() = RippleTheme.defaultRippleColor(
        contentColor = LocalContentColor.current,
        lightTheme = false
    )

    @Composable
    override fun rippleAlpha() = RippleTheme.defaultRippleAlpha(
        contentColor = LocalContentColor.current,
        lightTheme = false
    )
}