DonutView.kt

import android.content.Context
import android.graphics.*
import android.util.AttributeSet
import android.view.View

class DonutView(context: Context?, attrs: AttributeSet?) : View(context, attrs) {

    private val icingPathEffect = ComposePathEffect(
        CornerPathEffect(50f),
        DiscretePathEffect(80f, 50f)
    )

    private val basePaint = Paint().apply {
        isAntiAlias = true
    }

    private val icingPaint = Paint().apply {
        isAntiAlias = true
        style = Paint.Style.FILL
        color = Color.parseColor("#491F0E")
        pathEffect = icingPathEffect
    }

    private val holePath = Path()
    private var holeRad: Float = 0.0f

    override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) {
        super.onLayout(changed, left, top, right, bottom)

        holePath.reset()
        val cx = (width / 2).toFloat()
        val cy = (height / 2).toFloat()
        this.holeRad = ((if (width > height) height else width) / 6).toFloat()
        holePath.addCircle(cx, cy, holeRad, Path.Direction.CW)
    }

    private val rect = RectF()

    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)


        canvas?.apply {

            // Open hole
            save()

            val cx = (width / 2).toFloat()
            val cy = (height / 2).toFloat()
            scale(1f, 1f, cx, cy)
            clipPath(holePath, Region.Op.DIFFERENCE)

            // Drawing base
            val padding = 100
            val baseRad = ((if (width > height) height else width) / 2).toFloat() - padding
            basePaint.color = Color.parseColor("#B34B00")
            drawCircle(cx, cy, baseRad, basePaint)

            // Drawing icing
            val icingRad = baseRad - (baseRad / 5.5f)
            drawCircle(cx, cy, icingRad, icingPaint)


            // Close hole
            restore()

        }
    }
}