Today I had program a heading indicator for a Android map-view (osmdroid). My idea was to use a circle sector (similar to most map applications).

After some experiments, I came up with the following code. It uses a *Path and *basic trigonometric functions:

```
private fun Canvas.drawCircleSector(
x: Float,
y: Float,
radius: Float,
bearing: Int,
width: Int,
paint: Paint
) {
val bearingMarker = Path()
bearingMarker.moveTo(x, y)
for (i in (-width / 2)..(width / 2)) {
val rSin = sin((bearing + i) * Math.PI / 180)
val rCos = cos((bearing + i) * Math.PI / 180)
bearingMarker.lineTo(x + rSin.toFloat() * radius, y - rCos.toFloat() * radius)
}
bearingMarker.lineTo(x, y)
this.drawPath(bearingMarker, paint)
}
```