Add support for pie chart

JetChart/build.gradle

@@ -59,7 +59,7 @@ afterEvaluate {
                 from components.release
                 groupId = 'io.jetchart'
                 artifactId = 'JetChart'
-                version = '1.1.0'
+                version = '1.2.0'
             }
         }
     }

JetChart/src/main/java/io/jetchart/pie/PieChart.kt

@@ -0,0 +1,74 @@
+package io.jetchart.pie
+
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.AnimationSpec
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
+import io.jetchart.common.animation.fadeInAnimation
+import io.jetchart.pie.renderer.FilledSliceDrawer
+import io.jetchart.pie.renderer.SliceDrawer
+
+@Composable
+fun PieChart(
+  pies: Pies,
+  modifier: Modifier = Modifier,
+  animation: AnimationSpec<Float> = fadeInAnimation(),
+  sliceDrawer: SliceDrawer = FilledSliceDrawer()
+) {
+  val transitionProgress = remember(pies.slices) { Animatable(initialValue = 0f) }
+
+  LaunchedEffect(pies.slices) {
+    transitionProgress.animateTo(1f, animationSpec = animation)
+  }
+
+  DrawChart(
+    pies = pies,
+    modifier = modifier.fillMaxSize(),
+    progress = transitionProgress.value,
+    sliceDrawer = sliceDrawer
+  )
+}
+
+@Composable
+private fun DrawChart(
+  pies: Pies,
+  modifier: Modifier,
+  progress: Float,
+  sliceDrawer: SliceDrawer
+) {
+  val slices = pies.slices
+
+  Canvas(modifier = modifier) {
+    drawIntoCanvas {
+      var startArc = 0f
+
+      slices.forEach { slice ->
+        val arc = angleOf(
+          value = slice.value,
+          totalValue = pies.totalSize(),
+          progress = progress
+        )
+
+        sliceDrawer.drawSlice(
+          drawScope = this,
+          canvas = drawContext.canvas,
+          area = size,
+          startAngle = startArc,
+          sweepAngle = arc,
+          slice = slice
+        )
+
+        startArc += arc
+      }
+    }
+  }
+}
+
+fun angleOf(value: Float, totalValue: Float, progress: Float): Float {
+  return 360f * (value * progress) / totalValue
+}

JetChart/src/main/java/io/jetchart/pie/Pies.kt

@@ -0,0 +1,5 @@
+package io.jetchart.pie
+
+data class Pies(val slices: List<Slice>) {
+  fun totalSize(): Float = slices.map { it.value }.sum()
+}

JetChart/src/main/java/io/jetchart/pie/Slice.kt

@@ -0,0 +1,5 @@
+package io.jetchart.pie
+
+import androidx.compose.ui.graphics.Color
+
+data class Slice(val value: Float, val color: Color)

JetChart/src/main/java/io/jetchart/pie/renderer/FilledSliceDrawer.kt

@@ -0,0 +1,59 @@
+package io.jetchart.pie.renderer
+
+import androidx.compose.ui.geometry.Rect
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Canvas
+import androidx.compose.ui.graphics.Paint
+import androidx.compose.ui.graphics.PaintingStyle
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import io.jetchart.pie.Slice
+
+class FilledSliceDrawer(private val thickness: Float = 30f) : SliceDrawer {
+
+  private val sectionPaint = Paint().apply {
+    isAntiAlias = true
+    style = PaintingStyle.Stroke
+  }
+
+  override fun drawSlice(
+    drawScope: DrawScope,
+    canvas: Canvas,
+    area: Size,
+    startAngle: Float,
+    sweepAngle: Float,
+    slice: Slice
+  ) {
+    val sliceThickness = calculateSectorThickness(area = area)
+    val drawableArea = calculateDrawableArea(area = area)
+
+    canvas.drawArc(
+      rect = drawableArea,
+      paint = sectionPaint.apply {
+        color = slice.color
+        strokeWidth = sliceThickness
+      },
+      startAngle = startAngle,
+      sweepAngle = sweepAngle,
+      useCenter = false
+    )
+  }
+
+  private fun calculateSectorThickness(area: Size): Float {
+    val minSize = minOf(area.width, area.height)
+
+    return minSize * (thickness / 200f)
+  }
+
+  private fun calculateDrawableArea(area: Size): Rect {
+    val sliceThicknessOffset =
+      calculateSectorThickness(area = area) / 2f
+    val offsetHorizontally = (area.width - area.height) / 2f
+
+    return Rect(
+      left = sliceThicknessOffset + offsetHorizontally,
+      top = sliceThicknessOffset,
+      right = area.width - sliceThicknessOffset - offsetHorizontally,
+      bottom = area.height - sliceThicknessOffset
+    )
+  }
+}

JetChart/src/main/java/io/jetchart/pie/renderer/SliceDrawer.kt

@@ -0,0 +1,17 @@
+package io.jetchart.pie.renderer
+
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Canvas
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import io.jetchart.pie.Slice
+
+interface SliceDrawer {
+  fun drawSlice(
+    drawScope: DrawScope,
+    canvas: Canvas,
+    area: Size,
+    startAngle: Float,
+    sweepAngle: Float,
+    slice: Slice
+  )
+}

README.md

@@ -39,7 +39,7 @@ allprojects {
 2. Add the dependency
 ```groovy
 dependencies {
-    implementation 'com.github.fracassi-marco:JetChart:1.1.0'
+    implementation 'com.github.fracassi-marco:JetChart:1.2.0'
 }
 ```
 
@@ -115,4 +115,23 @@ fun LineChartComposable() {
 
 @Composable
 private fun points(count: Int) = (1..count).map { Point(Random.nextFloat(), "Point$it") }
+```
+
+## Pie Chart
+![Pie Chart big](docs/pie1.gif) ![Pie Chart small](docs/pie2.gif)
+
+### Features
+You can:
+- animate the drawing
+
+### Example
+```kotlin
+@Composable
+fun PieChartComposable() {
+    PieChart(pies = Pies(listOf(Slice(35f, Red), Slice(45f, JetGreen), Slice(15f, Yellow), Slice(5f, Cyan))),
+        modifier = Modifier.height(340.dp),
+        animation = fadeInAnimation(4000),
+        sliceDrawer = FilledSliceDrawer(thickness = 60f)
+    )
+}
 ```

app/src/main/java/io/jetchart/demo/MainActivity.kt

@@ -21,8 +21,10 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color.Companion.Blue
+import androidx.compose.ui.graphics.Color.Companion.Cyan
 import androidx.compose.ui.graphics.Color.Companion.Red
 import androidx.compose.ui.graphics.Color.Companion.Transparent
+import androidx.compose.ui.graphics.Color.Companion.Yellow
 import androidx.compose.ui.unit.dp
 import io.jetchart.bar.Bar
 import io.jetchart.bar.BarChart
@@ -43,6 +45,10 @@ import io.jetchart.line.renderer.line.SolidLineDrawer
 import io.jetchart.line.renderer.point.FilledPointDrawer
 import io.jetchart.line.renderer.xaxis.LineXAxisDrawer
 import io.jetchart.line.renderer.yaxis.LineYAxisWithValueDrawer
+import io.jetchart.pie.PieChart
+import io.jetchart.pie.Pies
+import io.jetchart.pie.Slice
+import io.jetchart.pie.renderer.FilledSliceDrawer
 import kotlin.random.Random
 
 class MainActivity : ComponentActivity() {
@@ -58,6 +64,8 @@ class MainActivity : ComponentActivity() {
                         JetDivider()
                         LineChartComposable()
                         JetDivider()
+                        PieChartComposable()
+                        JetDivider()
                     }
                 }
             }
@@ -71,7 +79,7 @@ fun BarChartComposable(text: MutableState<String>) {
     val width = numberOfBars * 80
     BarChart(chars = Bars(
         bars = (1..numberOfBars).map {
-            Bar(label = "BAR$it", value = Random.nextFloat(), color = JetGreen) {
+            Bar(label = "BAR$it", value = Random.nextFloat(), color = if(it % 2 == 0) JetGreen else Red) {
                     bar -> text.value = "You clicked on the bar ${bar.label}!"
             }
         }),
@@ -105,6 +113,15 @@ fun LineChartComposable() {
 @Composable
 private fun points(count: Int) = (1..count).map { Point(Random.nextFloat(), "Point$it") }
 
+@Composable
+fun PieChartComposable() {
+    PieChart(pies = Pies(listOf(Slice(35f, Red), Slice(45f, JetGreen), Slice(15f, Yellow), Slice(5f, Cyan))),
+        modifier = Modifier.height(340.dp),
+        animation = fadeInAnimation(4000),
+        sliceDrawer = FilledSliceDrawer(thickness = 60f)
+    )
+}
+
 @Composable
 private fun JetDivider() {
     Divider(modifier = Modifier.padding(horizontal = 5.dp, vertical = 50.dp), thickness = 1.dp, color = JetGreen)