NonAcceleratedOverlay 6.1.18 API

All Implemented Interfaces:

org.osmdroid.views.util.constants.OverlayConstants
```
public abstract class NonAcceleratedOverlay
extends Overlay
                    
```
This will allow an Overlay that is not HW acceleration compatible to work in a HW accelerated MapView. It will create a screen-sized backing Bitmap for the Overlay to draw to and then will draw the Bitmap to the HW accelerated canvas. Due to the extra work, it does not draw the shadow layer. If the Canvas passed into the Overlay is not HW accelerated or if isUsingBackingBitmap returns false then it draws normally (including the shadow layer) without the backing Bitmap. TODO:
- Implement a flag to determine if the drawing has actually changed. If not, then reuse the last frame's backing bitmap. This will prevent having to re-upload the bitmap texture to GPU.

Constructor Summary

Constructors
Constructor	Description
`NonAcceleratedOverlay(Context ctx)`	Use NonAcceleratedOverlay instead
`NonAcceleratedOverlay()`

Method Summary

Modifier and Type	Method	Description
`boolean`	`isUsingBackingBitmap()`	Allow forcing this overlay to skip drawing using backing Bitmap by returning false.
`void`	`onDetach(MapView mapView)`	Override to perform clean up of resources before shutdown.
`final void`	`draw(Canvas c, MapView osmv, boolean shadow)`	Draw the overlay over the map.

Methods inherited from class org.osmdroid.views.overlay.Overlay
draw, draw, getBounds, isEnabled, onDetach, onDoubleTap, onDoubleTapEvent, onDown, onFling, onKeyDown, onKeyUp, onLongPress, onPause, onResume, onScroll, onShowPress, onSingleTapConfirmed, onSingleTapUp, onTouchEvent, onTrackballEvent, setEnabled
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - NonAcceleratedOverlay
```
NonAcceleratedOverlay(Context ctx)
```
    Use NonAcceleratedOverlay instead
  - NonAcceleratedOverlay
```
NonAcceleratedOverlay()
```
- Method Detail
  - isUsingBackingBitmap
```
 boolean isUsingBackingBitmap()
```
    Allow forcing this overlay to skip drawing using backing Bitmap by returning false.
  - onDetach
```
 void onDetach(MapView mapView)
```
    Override to perform clean up of resources before shutdown. By default does nothing.
  - draw
```
 final void draw(Canvas c, MapView osmv, boolean shadow)
```
    Draw the overlay over the map. This will be called on all active overlays with shadow=true,to lay down the shadow layer, and then again on all overlays with shadow=false. Callersshould check isEnabled() before calling draw(). By default, draws nothing.
    changed for 5.6 to be public see https://github.com/osmdroid/osmdroid/issues/466If possible, use draw instead (cf. MapSnapshot