| /* |
| * 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. |
| */ |
| @file:OptIn(ExperimentalMaterialApi::class) |
| |
| package androidx.ui.material.ripple |
| |
| import androidx.compose.Composable |
| import androidx.compose.staticAmbientOf |
| import androidx.compose.foundation.Interaction |
| import androidx.compose.foundation.contentColor |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.ui.graphics.luminance |
| import androidx.ui.material.ExperimentalMaterialApi |
| import androidx.ui.material.MaterialTheme |
| |
| /** |
| * Defines the appearance and the behavior for [RippleIndication]s. |
| * |
| * You can define a new theme and apply it via [RippleThemeAmbient]. |
| */ |
| @ExperimentalMaterialApi |
| interface RippleTheme { |
| /** |
| * @return the default [RippleIndication] color at the call site's position in the hierarchy. |
| * This color will be used when a color is not explicitly set in the [RippleIndication] itself. |
| */ |
| @Composable |
| fun defaultColor(): Color |
| |
| /** |
| * @return the [RippleOpacity] used to calculate the opacity for the ripple depending on the |
| * [Interaction] for a given component. This will be set as the alpha channel for |
| * [defaultColor] or the color explicitly provided to the [RippleIndication]. |
| */ |
| @Composable |
| fun rippleOpacity(): RippleOpacity |
| } |
| |
| // TODO: can be a fun interface when we rebase to use Kotlin 1.4 |
| /** |
| * RippleOpacity defines the opacity of the ripple / state layer for a given [Interaction]. |
| */ |
| @ExperimentalMaterialApi |
| interface RippleOpacity { |
| /** |
| * @return the opacity of the ripple for the given [interaction]. Return `0f` if this |
| * particular interaction should not show a corresponding ripple / state layer. |
| */ |
| fun opacityForInteraction(interaction: Interaction): Float |
| } |
| |
| /** |
| * Ambient used for providing [RippleTheme] down the tree. |
| */ |
| @ExperimentalMaterialApi |
| val RippleThemeAmbient = staticAmbientOf<RippleTheme> { DefaultRippleTheme } |
| |
| private object DefaultRippleTheme : RippleTheme { |
| @Composable |
| override fun defaultColor(): Color { |
| val contentColor = contentColor() |
| val lightTheme = MaterialTheme.colors.isLight |
| val contentLuminance = contentColor.luminance() |
| // If we are on a colored surface (typically indicated by low luminance content), the |
| // ripple color should be white. |
| return if (!lightTheme && contentLuminance < 0.5) { |
| Color.White |
| // Otherwise use contentColor |
| } else { |
| contentColor |
| } |
| } |
| |
| @Composable |
| override fun rippleOpacity(): RippleOpacity { |
| val lightTheme = MaterialTheme.colors.isLight |
| val contentLuminance = contentColor().luminance() |
| return when { |
| lightTheme -> { |
| if (contentLuminance > 0.5) { |
| LightThemeHighContrastRippleOpacity |
| } else { |
| LightThemeReducedContrastRippleOpacity |
| } |
| } |
| else -> { |
| DarkThemeRippleOpacity |
| } |
| } |
| } |
| } |
| |
| @Suppress("unused") |
| private sealed class DefaultRippleOpacity( |
| val pressed: Float, |
| val focused: Float, |
| val dragged: Float, |
| val hovered: Float |
| ) : RippleOpacity { |
| override fun opacityForInteraction(interaction: Interaction): Float = when (interaction) { |
| Interaction.Pressed -> pressed |
| Interaction.Dragged -> dragged |
| else -> 0f |
| } |
| } |
| |
| /** |
| * Opacity values for high luminance content in a light theme. |
| * |
| * This content will typically be placed on colored surfaces, so it is important that the |
| * contrast here is higher to meet accessibility standards, and increase legibility. |
| * |
| * These levels are typically used for text / iconography in primary colored tabs / |
| * bottom navigation / etc. |
| */ |
| private object LightThemeHighContrastRippleOpacity : DefaultRippleOpacity( |
| pressed = 0.24f, |
| focused = 0.24f, |
| dragged = 0.16f, |
| hovered = 0.08f |
| ) |
| |
| /** |
| * Alpha levels for low luminance content in a light theme. |
| * |
| * This content will typically be placed on grayscale surfaces, so the contrast here can be lower |
| * without sacrificing accessibility and legibility. |
| * |
| * These levels are typically used for body text on the main surface (white in light theme, grey |
| * in dark theme) and text / iconography in surface colored tabs / bottom navigation / etc. |
| */ |
| private object LightThemeReducedContrastRippleOpacity : DefaultRippleOpacity( |
| pressed = 0.12f, |
| focused = 0.12f, |
| dragged = 0.08f, |
| hovered = 0.04f |
| ) |
| |
| /** |
| * Alpha levels for all content in a dark theme. |
| */ |
| private object DarkThemeRippleOpacity : DefaultRippleOpacity( |
| pressed = 0.10f, |
| focused = 0.12f, |
| dragged = 0.08f, |
| hovered = 0.04f |
| ) |