| /* |
| * 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.compose.animation.demos |
| |
| import androidx.compose.animation.core.FloatPropKey |
| import androidx.compose.animation.core.spring |
| import androidx.compose.animation.core.transitionDefinition |
| import androidx.compose.Composable |
| import androidx.compose.state |
| import androidx.compose.animation.ColorPropKey |
| import androidx.compose.animation.transition |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.gesture.pressIndicatorGestureFilter |
| import androidx.compose.foundation.Canvas |
| import androidx.compose.ui.geometry.Offset |
| import androidx.compose.ui.geometry.Size |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.fillMaxSize |
| |
| private const val halfSize = 200f |
| |
| private enum class ComponentState { Pressed, Released } |
| |
| private val scale = FloatPropKey() |
| private val color = ColorPropKey() |
| |
| private val definition = transitionDefinition<ComponentState> { |
| state(ComponentState.Released) { |
| this[scale] = 1f |
| this[color] = Color(red = 0, green = 200, blue = 0, alpha = 255) |
| } |
| state(ComponentState.Pressed) { |
| this[scale] = 3f |
| this[color] = Color(red = 0, green = 100, blue = 0, alpha = 255) |
| } |
| transition { |
| scale using spring( |
| stiffness = 50f |
| ) |
| color using spring( |
| stiffness = 50f |
| ) |
| } |
| } |
| |
| @Composable |
| fun GestureBasedAnimationDemo() { |
| val toState = state { ComponentState.Released } |
| val pressIndicator = |
| Modifier.pressIndicatorGestureFilter( |
| onStart = { toState.value = ComponentState.Pressed }, |
| onStop = { toState.value = ComponentState.Released }, |
| onCancel = { toState.value = ComponentState.Released }) |
| |
| val state = transition(definition = definition, toState = toState.value) |
| ScaledColorRect(pressIndicator, scale = state[scale], color = state[color]) |
| } |
| |
| @Composable |
| private fun ScaledColorRect(modifier: Modifier = Modifier, scale: Float, color: Color) { |
| Canvas(modifier.fillMaxSize()) { |
| drawRect( |
| color, |
| topLeft = Offset(center.x - halfSize * scale, center.y - halfSize * scale), |
| size = Size(halfSize * 2 * scale, halfSize * 2 * scale) |
| ) |
| } |
| } |