Blur using GPUImage

#pragma mark Helpers

- (void)blurIn
{
    if (_bluringTimer)
        return;
    
    GPUImageiOSBlurFilter *blurFilter = [[GPUImageiOSBlurFilter alloc] init];
    
    if ([[blurFilter targets] count] == 0)
    {
        blurFilter.blurRadiusInPixels = 0.0f;
        blurFilter.saturation = 1.4;
        blurFilter.downsampling = 8;
        self.cameraView.currentFilter = (GPUImageFilter*)blurFilter;
    }
    
    _bluringTimer = [NSTimer timerWithTimeInterval:0.01
                                            target:self
                                          selector:@selector(blurTimerStep:)
                                          userInfo:@(YES)
                                           repeats:YES];
    
    [[NSRunLoop mainRunLoop] addTimer:_bluringTimer forMode:NSRunLoopCommonModes];
}

- (void)blurOut
{
    if (_bluringTimer)
        return;
    
    _bluringTimer = [NSTimer timerWithTimeInterval:0.025
                                            target:self
                                          selector:@selector(blurTimerStep:)
                                          userInfo:@(NO)
                                           repeats:YES];
    
    [[NSRunLoop mainRunLoop] addTimer:_bluringTimer forMode:NSRunLoopCommonModes];
}

- (void)blurTimerStep:(NSTimer *)timer

{
    static NSInteger Step;
    
    BOOL blurringIn = [[timer userInfo] boolValue];
    
    static CGFloat MaxBlur = 16.0f;
    
    CGFloat bluringStepsCount = 10;
    CGFloat blurSizeStep = MaxBlur/bluringStepsCount;
    
    ((GPUImageiOSBlurFilter*)self.cameraView.currentFilter).blurRadiusInPixels += (blurringIn ? blurSizeStep : -blurSizeStep);
    
    Step++;
    
    if (Step > bluringStepsCount)
    {
        [_bluringTimer invalidate];
        _bluringTimer = nil;
        Step = 0;
        
        if (!blurringIn)
            [self.cameraView restoreCameraOptions];
    }
}