RoundedBackgroundColorSpanCorners.kt

    private fun drawRightCorner(c: Canvas, path: Path, rect: RectF, radius: Float) {
        path.reset()
        path.moveTo(rect.left, rect.top + radius)
        path.lineTo(rect.left, rect.top - radius)
        path.lineTo(rect.left + radius, rect.top)
        path.lineTo(rect.left, rect.top + radius)

        c.drawPath(path, paint)
    }

    private fun drawTopCorner(c: Canvas, path: Path, rect: RectF, radius: Float) {
        path.reset()
        path.moveTo(prevRight + radius, rect.top)
        path.lineTo(prevRight - radius, rect.top)
        path.lineTo(prevRight, rect.top - radius)
        path.cubicTo(
            prevRight, rect.top - radius,
            prevRight, rect.top,
            prevRight + radius, rect.top
        )

        c.drawPath(path, paint)
    }

    private fun drawBottomCorner(c: Canvas, path: Path, rect: RectF, radius: Float) {
        path.reset()
        path.moveTo(rect.right + radius, rect.top)
        path.lineTo(rect.right - radius, rect.top)
        path.lineTo(rect.right, rect.top + radius)
        path.cubicTo(
            rect.right, rect.top + radius,
            rect.right, rect.top,
            rect.right + radius, rect.top
        )

        c.drawPath(path, paint)
    }

    private fun drawLeftCorner(c: Canvas, path: Path, rect: RectF, radius: Float) {
        path.reset()
        path.moveTo(rect.right, rect.top - radius)
        path.lineTo(rect.right, rect.top + radius)
        path.lineTo(rect.right - radius, rect.top)
        path.lineTo(rect.right, rect.top - radius)

        c.drawPath(path, paint)
    }