Setting up camera in Andengine

public EngineOptions onCreateEngineOptions() {

this.display = getWindowManager().getDefaultDisplay();//get screen from system
        this.screenwidth  = display.getWidth();
        this.screenheight = display.getHeight();


float screenratio;
int screenscale = 300; /* sets height, width is derived from following equation*/

if(screenwidth>screenheight)
        {
            screenratio=screenwidth/screenheight;
            height = screenscale;
            width = (int)(screenscale*screenratio);
        }
        else
        {
            screenratio=screenheight/screenwidth;
            width = screenscale;
            height = (int) (screenscale*screenratio);
        }



screenwidth = width;
screenheight = height;


this.mCamera = new SmoothCamera(0, 0, width, height, 1000, 1000, 10);//create smooth scrolling camera


this.engineOptions = new EngineOptions(true, ScreenOrientation.LANDSCAPE_FIXED, new RatioResolutionPolicy(screenratio), mCamera);
return engineOptions;
}