Overlayer (groundsdk 1.7.0 API)

```
public interface Overlayer
```
Allows to overlay custom graphics on top of a stream rendered by a GsdkStreamView.
After each frame is rendered, overlay(Rect, Rect, Histogram) will be called; client code must implement this method to render the appropriate overlay on top of the rendered frame.
Overlayer interface also allows to receive color histogram computations, when enabled onto which the overlayer is installed.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static interface Overlayer.Histogram
Color histogram information.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`overlay(Rect renderZone, Rect contentZone, Overlayer.Histogram histogram)`	Renders custom overlay on top of current frame.

- Method Detail
  - overlay
```
void overlay(@NonNull
             Rect renderZone,
             @NonNull
             Rect contentZone,
             @NonNull
             Overlayer.Histogram histogram)
```
    Renders custom overlay on top of current frame.
    Called on GsdkStreamView GL rendering thread.
    
    Parameters:
    
    renderZone - area where the frame was rendered (including any padding introduced by scaling), invalid after this method returns
    
    contentZone - area where frame content was rendered (excluding any padding introduced by scaling), invalid after this method returns
    
    histogram - color histogram info, invalid after this method returns