Question

我有一个问题，我有一个UIPinchGestureRecognizer，我用来扩展我的相机预览和相应的AVCaptureConnection进出。第一次放大和缩小没有问题，直到你完成捏缩放后手指抬起。如果我尝试向内捏（缩放回正常1.0刻度），手势不会重置预览并且AVCaptureConnection缩小，因此预览和AVCaptureConnection保持相同的大小。

我怎么能解决这个问题呢？ if语句确保比例不低于1.0，因为我们不允许将比例设置为低于1.0的AVCaptureConnection。

- (void)zoomPreview:(UIPinchGestureRecognizer *)recognizer
{
    CGFloat scale = recognizer.scale;

    NSLog(@"Scale: %f",scale);

    if (scale >= 1.0)
    {
        [[self.stillImageOutput.connections objectAtIndex:0] setVideoScaleAndCropFactor:scale];

        self.previewView.transform = CGAffineTransformMakeScale(scale, scale);
    }
}

Answer 1

通过反复试验解决了自己：

@property (nonatomic, assign) CGFloat lastScale;
@property (nonatomic, assign) CGFloat currentScale;

- (void)zoomPreview:(UIPinchGestureRecognizer *)recognizer
{
    self.currentScale += recognizer.scale - self.lastScale;
    self.lastScale = recognizer.scale;

    if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled)
    {
        self.lastScale = 1.0;
    }

    if (self.currentScale < 1.0)
    {
        self.currentScale = 1.0;
    }

    if (self.currentScale > 5.0)
    {
        self.currentScale = 5.0;
    }

    if (self.currentScale >= 1.0 && self.currentScale <= 5.0)
    {
        [[self.stillImageOutput.connections objectAtIndex:0]setVideoScaleAndCropFactor:self.currentScale];

        self.previewView.transform = CGAffineTransformMakeScale(self.currentScale, self.currentScale);
    }
}

UIPinchGestureRecognizer缩放AVCaptureConnection;不缩小

1 个答案: