| /* |
| * 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.ui.material.studies.rally |
| |
| import androidx.compose.animation.core.CubicBezierEasing |
| import androidx.compose.animation.core.FloatPropKey |
| import androidx.compose.animation.core.LinearOutSlowInEasing |
| import androidx.compose.animation.core.transitionDefinition |
| import androidx.compose.animation.core.tween |
| import androidx.compose.Composable |
| import androidx.compose.animation.transition |
| import androidx.ui.core.DensityAmbient |
| import androidx.ui.core.Modifier |
| 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.ui.graphics.drawscope.Stroke |
| import androidx.ui.unit.dp |
| |
| private const val DividerLengthInDegrees = 1.8f |
| private val AngleOffset = FloatPropKey() |
| private val Shift = FloatPropKey() |
| |
| private val CircularTransition = transitionDefinition { |
| state(0) { |
| this[AngleOffset] = 0f |
| this[Shift] = 0f |
| } |
| state(1) { |
| this[AngleOffset] = 360f |
| this[Shift] = 30f |
| } |
| transition(fromState = 0, toState = 1) { |
| AngleOffset using tween( |
| delayMillis = 500, |
| durationMillis = 900, |
| easing = CubicBezierEasing(0f, 0.75f, 0.35f, 0.85f) |
| ) |
| Shift using tween( |
| delayMillis = 500, |
| durationMillis = 900, |
| easing = LinearOutSlowInEasing |
| ) |
| } |
| } |
| |
| /** when calculating a proportion of N elements, the sum of elements has to be (1 - N * 0.005) |
| * because there will be N dividers of size 1.8 degrees */ |
| @Composable |
| fun AnimatedCircle( |
| modifier: Modifier = Modifier, |
| proportions: List<Float>, |
| colors: List<Color> |
| ) { |
| val stroke = Stroke(5.dp.value * DensityAmbient.current.density) |
| val state = transition(definition = CircularTransition, initState = 0, toState = 1) |
| Canvas(modifier) { |
| val innerRadius = (size.minDimension - stroke.width) / 2 |
| val halfSize = size / 2.0f |
| val topLeft = Offset( |
| halfSize.width - innerRadius, |
| halfSize.height - innerRadius |
| ) |
| val size = Size(innerRadius * 2, innerRadius * 2) |
| var startAngle = state[Shift] - 90f |
| proportions.forEachIndexed { index, proportion -> |
| val sweep = proportion * state[AngleOffset] |
| drawArc( |
| color = colors[index], |
| startAngle = startAngle + DividerLengthInDegrees / 2, |
| sweepAngle = sweep - DividerLengthInDegrees, |
| topLeft = topLeft, |
| size = size, |
| useCenter = false, |
| style = stroke |
| ) |
| startAngle += sweep |
| } |
| } |
| } |