Rounded corners in each pie chart slice

[kelvinofula]

Hi, was wondering if you could please help me achieve this look. I've tried but nothing seems to work. I just want my slices to be rounded the way it's displayed in this image below. Thank you

[Khislatjon]

I have the same problem.

[4np]

You could probably accomplish this by overriding the pie renderer, like in #4297

[ecemmine]

@kelvinofula Hi,

Did you this? I have same problem. I can't do slices rounded

[Paget96]

Maybe this can help you, I cannot help more than this. This is a renderer code for MPAndroidChart PieChart but on Android

import android.graphics.Canvas
import android.graphics.Path
import android.graphics.RectF
import com.github.mikephil.charting.animation.ChartAnimator
import com.github.mikephil.charting.charts.PieChart
import com.github.mikephil.charting.interfaces.datasets.IPieDataSet
import com.github.mikephil.charting.renderer.PieChartRenderer
import com.github.mikephil.charting.utils.MPPointF
import com.github.mikephil.charting.utils.ViewPortHandler
import com.github.mikephil.charting.utils.Utils
import kotlin.math.abs
import kotlin.math.cos
import kotlin.math.sin

class RoundedSlicesPieChartRenderer(
    chart: PieChart?,
    animator: ChartAnimator?,
    viewPortHandler: ViewPortHandler?
) : PieChartRenderer(chart, animator, viewPortHandler) {

    init {
        chart?.setDrawRoundedSlices(true)
    }

    override fun drawDataSet(c: Canvas?, dataSet: IPieDataSet) {
        var angle = 0f
        val rotationAngle = mChart.rotationAngle
        val phaseX = mAnimator.phaseX
        val phaseY = mAnimator.phaseY
        val circleBox = mChart.circleBox
        val entryCount = dataSet.entryCount
        val drawAngles = mChart.drawAngles
        val center = mChart.centerCircleBox
        val radius = mChart.radius
        val drawInnerArc = mChart.isDrawHoleEnabled && !mChart.isDrawSlicesUnderHoleEnabled
        val userInnerRadius = if (drawInnerArc) radius * (mChart.holeRadius / 100f) else 0f
        val roundedRadius = (radius - radius * mChart.holeRadius / 100f) / 2f
        val roundedCircleBox = RectF()
        var visibleAngleCount = 0
        for (j in 0 until entryCount) {
            // draw only if the value is greater than zero
            if (abs(dataSet.getEntryForIndex(j).y) > Utils.FLOAT_EPSILON) {
                visibleAngleCount++
            }
        }
        val sliceSpace = if (visibleAngleCount <= 1) 0f else getSliceSpace(dataSet)
        val pathBuffer = Path()
        val mInnerRectBuffer = RectF()
        for (j in 0 until entryCount) {
            val sliceAngle = drawAngles[j]
            var innerRadius = userInnerRadius
            val e = dataSet.getEntryForIndex(j)

            // draw only if the value is greater than zero
            if (abs(e.y) <= Utils.FLOAT_EPSILON) {
                angle += sliceAngle * phaseX
                continue
            }

            // Don't draw if it's highlighted, unless the chart uses rounded slices
            if (mChart.needsHighlight(j) && !drawInnerArc) {
                angle += sliceAngle * phaseX
                continue
            }
            val accountForSliceSpacing = sliceSpace > 0f && sliceAngle <= 180f
            mRenderPaint.color = dataSet.getColor(j)
            val sliceSpaceAngleOuter =
                if (visibleAngleCount == 1) 0f else sliceSpace / (Utils.FDEG2RAD * radius)
            val startAngleOuter = rotationAngle + (angle + sliceSpaceAngleOuter / 2f) * phaseY
            var sweepAngleOuter = (sliceAngle - sliceSpaceAngleOuter) * phaseY
            if (sweepAngleOuter < 0f) {
                sweepAngleOuter = 0f
            }
            pathBuffer.reset()
            val arcStartPointX =
                center.x + radius * cos(startAngleOuter * Utils.FDEG2RAD).toFloat()
            val arcStartPointY =
                center.y + radius * sin(startAngleOuter * Utils.FDEG2RAD).toFloat()
            if (sweepAngleOuter >= 360f && sweepAngleOuter % 360f <= Utils.FLOAT_EPSILON) {
                // Android is doing "mod 360"
                pathBuffer.addCircle(center.x, center.y, radius, Path.Direction.CW)
            } else {
                if (drawInnerArc) {
                    val x =
                        center.x + (radius - roundedRadius) * cos(startAngleOuter * Utils.FDEG2RAD)
                    val y =
                        center.y + (radius - roundedRadius) * sin(startAngleOuter * Utils.FDEG2RAD)
                    roundedCircleBox[x - roundedRadius, y - roundedRadius, x + roundedRadius] =
                        y + roundedRadius
                    pathBuffer.arcTo(roundedCircleBox, startAngleOuter - 180, 180F)
                }
                pathBuffer.arcTo(
                    circleBox,
                    startAngleOuter,
                    sweepAngleOuter
                )
            }

            // API < 21 does not receive floats in addArc, but a RectF
            mInnerRectBuffer[center.x - innerRadius, center.y - innerRadius, center.x + innerRadius] =
                center.y + innerRadius
            if (drawInnerArc && (innerRadius > 0f || accountForSliceSpacing)) {
                if (accountForSliceSpacing) {
                    var minSpacedRadius = calculateMinimumRadiusForSpacedSlice(
                        center, radius,
                        sliceAngle * phaseY,
                        arcStartPointX, arcStartPointY,
                        startAngleOuter,
                        sweepAngleOuter
                    )
                    if (minSpacedRadius < 0f) minSpacedRadius = -minSpacedRadius
                    innerRadius = innerRadius.coerceAtLeast(minSpacedRadius)
                }
                val sliceSpaceAngleInner =
                    if (visibleAngleCount == 1 || innerRadius == 0f) 0f else sliceSpace / (Utils.FDEG2RAD * innerRadius)
                val startAngleInner = rotationAngle + (angle + sliceSpaceAngleInner / 2f) * phaseY
                var sweepAngleInner = (sliceAngle - sliceSpaceAngleInner) * phaseY
                if (sweepAngleInner < 0f) {
                    sweepAngleInner = 0f
                }
                val endAngleInner = startAngleInner + sweepAngleInner
                if (sweepAngleOuter >= 360f && sweepAngleOuter % 360f <= Utils.FLOAT_EPSILON) {
                    // Android is doing "mod 360"
                    pathBuffer.addCircle(center.x, center.y, innerRadius, Path.Direction.CCW)
                } else {
                    val x =
                        center.x + (radius - roundedRadius) * cos(endAngleInner * Utils.FDEG2RAD)
                    val y =
                        center.y + (radius - roundedRadius) * sin(endAngleInner * Utils.FDEG2RAD)
                    roundedCircleBox[x - roundedRadius, y - roundedRadius, x + roundedRadius] =
                        y + roundedRadius
                    pathBuffer.arcTo(roundedCircleBox, endAngleInner, 180F)
                    pathBuffer.arcTo(mInnerRectBuffer, endAngleInner, -sweepAngleInner)
                }
            } else {
                if (sweepAngleOuter % 360f > Utils.FLOAT_EPSILON) {
                    if (accountForSliceSpacing) {
                        val angleMiddle = startAngleOuter + sweepAngleOuter / 2f
                        val sliceSpaceOffset = calculateMinimumRadiusForSpacedSlice(
                            center,
                            radius,
                            sliceAngle * phaseY,
                            arcStartPointX,
                            arcStartPointY,
                            startAngleOuter,
                            sweepAngleOuter
                        )
                        val arcEndPointX = center.x +
                                sliceSpaceOffset * cos(angleMiddle * Utils.FDEG2RAD)
                        val arcEndPointY = center.y +
                                sliceSpaceOffset * sin(angleMiddle * Utils.FDEG2RAD)
                        pathBuffer.lineTo(
                            arcEndPointX,
                            arcEndPointY
                        )
                    } else {
                        pathBuffer.lineTo(
                            center.x,
                            center.y
                        )
                    }
                }
            }
            pathBuffer.close()
            mBitmapCanvas.drawPath(pathBuffer, mRenderPaint)
            angle += sliceAngle * phaseX
        }
        MPPointF.recycleInstance(center)
    }
}

https://user-images.githubusercontent.com/10515077/229819307-0918e035-4eb9-497a-9b3e-75d3ec17d81c.mp4

[minhDTNHust]

@4np, sorry, how can I make corner radius for pie chart, can you give an example?

[4np]

@minhDTNHust , you would need create a custom renderer (example) and override:

• func renderFill(with color: NSUIColor, for path: CGPath, in context: CGContext, dataSet: PieChartDataSetProtocol, entry: ChartDataEntry), and
• func render(highlight: Highlight, with color: NSUIColor, for path: CGPath, in context: CGContext, dataSet: PieChartDataSetProtocol, entry: ChartDataEntry?)

In the overrides, render a path with rounded corners. You get the pie segment path, it's up to you to transform it into one with rounded corners which shouldn't be too hard (see UIBezierPath).

[engineertoplu]

not highlight ?