Coverage Summary for Class: PolyrhythmCircleKt (com.vsevolodganin.clicktrack.ui.piece)

 package com.vsevolodganin.clicktrack.ui.piece
 
 import androidx.compose.animation.core.Animatable
 import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.tween
 import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.layout.aspectRatio
 import androidx.compose.foundation.layout.size
 import androidx.compose.material.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.State
 import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.geometry.center
 import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.Shader
 import androidx.compose.ui.graphics.ShaderBrush
 import androidx.compose.ui.graphics.StrokeCap
 import androidx.compose.ui.graphics.SweepGradientShader
 import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.drawscope.Fill
 import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.graphics.drawscope.rotate
 import androidx.compose.ui.graphics.drawscope.scale
 import androidx.compose.ui.graphics.drawscope.withTransform
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.util.lerp
 import com.vsevolodganin.clicktrack.ui.theme.ClickTrackTheme
 import com.vsevolodganin.clicktrack.utils.compose.Angle
 import com.vsevolodganin.clicktrack.utils.compose.AngleSector
 import com.vsevolodganin.clicktrack.utils.compose.AnimatableFloat
 import com.vsevolodganin.clicktrack.utils.compose.FULL_ANGLE_DEGREES
 import com.vsevolodganin.clicktrack.utils.compose.Preview
 import com.vsevolodganin.clicktrack.utils.compose.toRadians
 import kotlinx.coroutines.launch
 import kotlin.math.cos
 import kotlin.math.roundToInt
 import kotlin.math.sin
 
 @Composable
 fun PolyrhythmCircle(
     outerDotNumber: Int,
     innerDotNumber: Int,
     modifier: Modifier = Modifier,
     progressAngle: Float? = null,
     // Degrees per second
     progressVelocity: Float = 15f,
 ) {
     val primaryColor = MaterialTheme.colors.primary
     val secondaryColor = MaterialTheme.colors.secondary
 
     val innerDots = dots(number = innerDotNumber)
     val outerDots = dots(number = outerDotNumber)
     val innerDotPulses = dotPulses(number = innerDotNumber, progressAngle = progressAngle)
     val outerDotPulses = dotPulses(number = outerDotNumber, progressAngle = progressAngle)
 
     val sweepAngle = remember { Animatable(0f) }
     LaunchedEffect(progressAngle == null) {
         if (progressAngle == null) {
             sweepAngle.snapTo(0f)
         } else {
             val duration = (PROGRESS_LINE_MAX_SWEEP_ANGLE_DEGREES * 1000f / progressVelocity).roundToInt()
             sweepAngle.animateTo(
                 PROGRESS_LINE_MAX_SWEEP_ANGLE_DEGREES,
                 tween(duration, easing = LinearEasing),
             )
         }
     }
 
     Canvas(modifier = modifier.aspectRatio(1f)) {
         val outerCircleRadius = size.maxDimension / 2.0f
         val innerCircleRadius = size.maxDimension / 4.0f
 
         drawPolyrhythmCircle(
             primaryColor = primaryColor,
             secondaryColor = secondaryColor,
             innerDots = innerDots,
             innerCircleRadius = innerCircleRadius,
             innerDotPulses = innerDotPulses,
             outerDots = outerDots,
             outerCircleRadius = outerCircleRadius,
             outerDotPulses = outerDotPulses,
         )
 
         if (progressAngle != null) {
             val color = secondaryColor
             val start = center
             val end = start + Offset(
                 x = cos(progressAngle.toRadians()) * outerCircleRadius,
                 y = sin(progressAngle.toRadians()) * outerCircleRadius,
             )
             val strokeWidth = 2.dp.toPx()
 
             rotate(-90f) {
                 drawLine(
                     color = color,
                     start = start,
                     end = end,
                     strokeWidth = strokeWidth,
                     cap = StrokeCap.Round,
                 )
 
                 rotate(progressAngle - sweepAngle.value) {
                     drawArc(
                         brush = Brush.sweepGradient(
                             0f to Color.Transparent,
                             sweepAngle.value / FULL_ANGLE_DEGREES to color.copy(alpha = 0.7f),
                         ),
                         startAngle = 0f,
                         sweepAngle = sweepAngle.value,
                         useCenter = true,
                         style = Fill,
                         topLeft = center - Offset(outerCircleRadius, outerCircleRadius),
                         size = Size(outerCircleRadius * 2, outerCircleRadius * 2),
                     )
                 }
             }
         }
     }
 }
 
 private fun DrawScope.drawPolyrhythmCircle(
     primaryColor: Color,
     secondaryColor: Color,
     innerDots: List<Dot>,
     innerCircleRadius: Float,
     innerDotPulses: List<DotPulse>,
     outerDots: List<Dot>,
     outerCircleRadius: Float,
     outerDotPulses: List<DotPulse>,
 ) {
     drawCircleWithDots(
         primaryColor = primaryColor,
         secondaryColor = secondaryColor,
         dots = innerDots,
         circleRadius = innerCircleRadius,
     )
 
     drawDotAnimations(
         color = secondaryColor,
         dotAnimations = innerDotPulses,
         radius = innerCircleRadius,
     )
 
     drawCircleWithDots(
         primaryColor = primaryColor,
         secondaryColor = secondaryColor,
         dots = outerDots,
         circleRadius = outerCircleRadius,
     )
 
     drawDotAnimations(
         color = secondaryColor,
         dotAnimations = outerDotPulses,
         radius = outerCircleRadius,
     )
 }
 
 private fun DrawScope.drawCircleWithDots(primaryColor: Color, secondaryColor: Color, dots: List<Dot>, circleRadius: Float) {
     val brush = sweepGradient(
         breadth = 0.08f,
         centerColor = secondaryColor,
         borderColor = primaryColor.copy(alpha = 0.1f),
     )
 
     val dotsSortedByAngle = dots.sortedBy { it.angle.value }
 
     dotsSortedByAngle.forEachIndexed { index, dot ->
         rotate(dot.angle.value - 90f) {
             fun drawArc(sweepAngle: Float) = drawArc(
                 brush = brush,
                 startAngle = 0f,
                 sweepAngle = sweepAngle,
                 useCenter = false,
                 style = Stroke(width = STROKE_WIDTH.toPx()),
                 topLeft = center - Offset(circleRadius, circleRadius),
                 size = Size(circleRadius * 2, circleRadius * 2),
             )
 
             val nextCcwDotAngle = dotsSortedByAngle.getOrNull(index - 1)?.angle?.value
                 ?: (dotsSortedByAngle.last().angle.value - 360)
             val nextCcwDotDistance = dot.angle.value - nextCcwDotAngle
             drawArc(-nextCcwDotDistance / 2)
 
             val nextCwDotAngle = dotsSortedByAngle.getOrNull(index + 1)?.angle?.value
                 ?: (dotsSortedByAngle.first().angle.value + 360)
             val nextCwDotDistance = nextCwDotAngle - dot.angle.value
             drawArc(nextCwDotDistance / 2)
 
             drawCircle(
                 brush = brush,
                 radius = DOT_RADIUS.toPx(),
                 center = center + Offset(x = circleRadius, y = 0f),
             )
         }
     }
 }
 
 private fun DrawScope.drawDotAnimations(color: Color, dotAnimations: List<DotPulse>, radius: Float) {
     for (dotAnimation in dotAnimations) {
         val center = center + Offset(x = radius, y = 0f)
         val animationProgress = dotAnimation.animationProgress.value
         val scale = lerp(1f, 3f, animationProgress)
         val alpha = lerp(0.5f, 0f, animationProgress)
         val modulatedColor = color.copy(alpha = color.alpha * alpha)
 
         withTransform(transformBlock = {
             rotate(dotAnimation.angle - 90f)
             scale(scale = scale, pivot = center)
         }) {
             drawCircle(
                 color = modulatedColor,
                 radius = DOT_RADIUS.toPx(),
                 center = center,
             )
         }
     }
 }
 
 @Composable
 private fun dots(number: Int): List<Dot> {
     val activeDots = remember { mutableStateListOf<Dot>() }
     val deletedDots = remember { mutableStateListOf<Dot>() }
 
     LaunchedEffect(number) {
         val angleIncrement = FULL_ANGLE_DEGREES / number
         val createdNumber = maxOf(0, number - activeDots.size)
         val deletedNumber = maxOf(0, activeDots.size - number)
 
         repeat(deletedNumber) {
             deletedDots += activeDots.removeAt(activeDots.lastIndex)
         }
 
         repeat(createdNumber) {
             activeDots += Dot(Animatable(activeDots.lastOrNull()?.angle?.value ?: 0f))
         }
 
         activeDots.forEachIndexed { index, dot ->
             launch {
                 dot.angle.animateTo(angleIncrement * index)
             }
         }
 
         deletedDots.forEach { dot ->
             launch {
                 dot.angle.animateTo(activeDots.lastOrNull()?.angle?.targetValue ?: 0f)
                 deletedDots -= dot
             }
         }
     }
 
     return activeDots + deletedDots
 }
 
 @Composable
 private fun dotPulses(number: Int, progressAngle: Float?): List<DotPulse> {
     val coroutineScope = rememberCoroutineScope()
     val pulses = remember {
         mutableStateListOf<DotPulse>()
     }
 
     if (progressAngle == null) return pulses
 
     val previousProgressAngle = remember { mutableStateOf(progressAngle) }
 
     val angleIncrement = FULL_ANGLE_DEGREES / number
     for (i in 0 until number) {
         val dotAngle = angleIncrement * i
         if (Angle(dotAngle) in AngleSector(previousProgressAngle.value, progressAngle)) {
             val progressAnimatable = Animatable(0f)
 
             val dotPulse = DotPulse(
                 angle = dotAngle,
                 animationProgress = progressAnimatable.asState(),
             )
             pulses += dotPulse
 
             coroutineScope.launch {
                 progressAnimatable.animateTo(
                     targetValue = 1f,
                     animationSpec = tween(durationMillis = 300, easing = LinearEasing),
                 )
                 pulses -= dotPulse
             }
         }
     }
 
     previousProgressAngle.value = progressAngle
 
     return pulses
 }
 
 private class Dot(
     val angle: AnimatableFloat,
 )
 
 private class DotPulse(
     val angle: Float,
     val animationProgress: State<Float>,
 )
 
 private fun sweepGradient(breadth: Float, centerColor: Color, borderColor: Color): Brush {
     return object : ShaderBrush() {
         override fun createShader(size: Size): Shader {
             val center = size.center
             return SweepGradientShader(
                 center = center,
                 colors = listOf(centerColor, borderColor, borderColor, centerColor),
                 colorStops = listOf(0f, breadth, 1f - breadth, 1f),
             )
         }
     }
 }
 
 private val STROKE_WIDTH = 8.dp
 private val DOT_RADIUS = 8.dp
 private const val PROGRESS_LINE_MAX_SWEEP_ANGLE_DEGREES = 15f
 
 @Preview
 @Composable
 private fun Preview() {
     ClickTrackTheme {
         PolyrhythmCircle(
             outerDotNumber = 3,
             innerDotNumber = 4,
             progressAngle = 30f,
             modifier = Modifier.size(100.dp),
         )
     }
 }