iphone - iOS - 在 UIScrollView 上缩放 UIImageView

Question

我正在制作一个图片库，在 UIScrollViews 内有大量 UIImageView，在主 UIScrollView 内。图库允许水平更改图片，并对每张图片进行缩放。

它一般工作正常，但缩放动画效果并不好。

当图像很小并且没有填满整个屏幕时，就会出现问题。当您放大图像，但直到填满整个画廊时，图像会发生一点位移，我用下一个代码进行更正，使其位于 ScrollView 的中心。

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale{

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    aImg.frame = [self centeredFrameForScrollView:myScrollView andUIView:aImg];
    [UIView commitAnimations];
}

最终图像在正确的位置，但似乎有点奇怪。我应该怎么办？

Answer 1

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return imageView;
}

Answer 2

示例代码：

- (void)handleTwoFingerTap:(UIGestureRecognizer *)gestureRecognizer
{
    // two-finger tap zooms out
    float newScale = [scrlView zoomScale] / ZOOM_STEP;
    CGRect zoomRect = [self zoomRectForScale:newScale withCenter:[gestureRecognizer locationInView:gestureRecognizer.view]];
    [scrlView zoomToRect:zoomRect animated:YES];
}

- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center
{
    CGRect zoomRect;
    // the zoom rect is in the content view's coordinates.
    //    At a zoom scale of 1.0, it would be the size of the imageScrollView's bounds.
    //    As the zoom scale decreases, so more content is visible, the size of the rect grows.
    zoomRect.size.height = [scrlView frame].size.height / scale;
    zoomRect.size.width  = [scrlView frame].size.width  / scale;
    // choose an origin so as to get the right center.
    zoomRect.origin.x    = scrlView.center.x - (zoomRect.size.width  / 2.0);
    zoomRect.origin.y    = scrlView.center.y - (zoomRect.size.height / 2.0);
    return zoomRect;
}