如何在scrollViewDidZoom中动态调整contentInset？我最初在UIScrollview中设置了UIImageView的contentInset

Question

我正在进行一个定制'Move and Scale' Controller的项目UIImagePickerController.(如果出现控制器imagePickerController.allowsEditing=YES)

我想crop an UIImage在像下面的图片矩形作物.

我制作了一些代码contentInset.

    self.selectedImageView.backgroundColor = [UIColor redColor];

    CGRect cropRect = [SKPhotoCropFrameView getCropRectFromOrientation:self.photoCropOrientation];
    CGRect aspectFitRect = AVMakeRectWithAspectRatioInsideRect(self.selectedImageView.image.size, self.selectedImageView.frame);
    CGFloat difference = fabsf(cropRect.size.height - aspectFitRect.size.height);
    self.contentInset = UIEdgeInsetsMake(difference/2, 0, difference/2 + 20, 0);   // 20 is status bar height

这是结果.

黑色区域是contentInset区域.

但是,如果我捏这个scrollView进行放大,就会发生一些事情.

我想我必须做些什么

    - (void)scrollViewDidZoom:(UIScrollView *)scrollView

动态调整contentInset.我怎样才能做到这一点？请给我一些帮助:)

Answer 1

我希望有人回答这个问题，我很伤心，因为事实并非如此。

但感谢上帝，我解决了这个问题。

在

    - (void)scrollViewDidZoom:(UIScrollView *)scrollView

使用zoomScale动态调整contentInset。我只是Lanscape mode为了测试而实现，但Portrait mode方式完全相同。

// adjust contentInset
CGFloat increasingZoomScale = (scrollView.zoomScale == 1) ? 0 : (-1 * (1 - scrollView.zoomScale));

CGRect cropRect = [SKPhotoCropFrameView getCropRectFromOrientation:self.photoCropOrientation];
CGRect aspectFitRect = AVMakeRectWithAspectRatioInsideRect(self.selectedImageView.image.size, self.selectedImageView.frame);
CGFloat difference = fabsf(cropRect.size.height - aspectFitRect.size.height);

// implement at `Landscape` mode first
if (self.photoCropOrientation == SKPhotoCropOrientationPortrait) {

}else{
    // get scaledFrameHeight because it's `Landscape` crop mode
    CGFloat increasingFrameHeight = scrollView.frame.size.height * increasingZoomScale;
    self.contentInset = UIEdgeInsetsMake(difference/2 - increasingFrameHeight/2, 0, difference/2 - increasingFrameHeight/2, 0);
}

砰。这是屏幕截图。