将图像大小限制为ScrollView，Swift

Question

我有一个在滚动视图中设置的图像，虽然我已经将scrollView的框架设置为固定的高度和宽度，如下所示，图像超出了边界（见下图）。

如何限制图片以适应scrollView。

imageScrollView.frame = CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight-50)
imageScrollView.clipsToBounds = true // Has no affect on the image

Answer 1

你有对UIImageView的引用吗？如果是，则将其内容模式设置为纵横比较。像这样：

        theImageView.contentMode = .scaleAspectFit

您设置的clipsToBounds只会覆盖父视图边界以外的子视图的任何部分，这就是为什么它不会为您做任何事情。

如果您使用的是Interface Builder，请设置此选项：

那么，如果你没有对UIImageView的引用怎么办？... 您可以遍历滚动视图的子视图，每当找到UIImageView时，您都可以设置内容模式。类似的东西：

//This is off the top of my head, so my filtering may not be right...
//This is also a one and done solution if you've got a lot of images in your scroll view
for anImgVw in imageScrollView.subviews.filter({$0.isKind(of: UIImageView.self)})
{
    anImgVw.contentMode = .scaleAspectFit
}

否则，我不确定是否可以不引用UIImageView。

Answer 2

您正在使用的库被编码为与设备方向的缩放相匹配。因此，如果图像方向与视图方向不匹配，最终您的图像在滚动视图中不太合适。

您需要编辑ImageScrollView.swift源文件。假设您使用的是与您提供的链接相同的版本（https://github.com/huynguyencong/ImageScrollView），请更改setMaxMinZoomScalesForCurrentBounds()功能，如下所示：

fileprivate func setMaxMinZoomScalesForCurrentBounds() {
    // calculate min/max zoomscale
    let xScale = bounds.width / imageSize.width    // the scale needed to perfectly fit the image width-wise
    let yScale = bounds.height / imageSize.height   // the scale needed to perfectly fit the image height-wise

    // fill width if the image and phone are both portrait or both landscape; otherwise take smaller scale
    //let imagePortrait = imageSize.height > imageSize.width
    //let phonePortrait = bounds.height >= bounds.width
    //var minScale = (imagePortrait == phonePortrait) ? xScale : min(xScale, yScale)
    //
    // just take the min scale, so the image will completely fit regardless of orientation
    var minScale = min(xScale, yScale)

    let maxScale = maxScaleFromMinScale*minScale

    // don't let minScale exceed maxScale. (If the image is smaller than the screen, we don't want to force it to be zoomed.)
    if minScale > maxScale {
        minScale = maxScale
    }

    maximumZoomScale = maxScale
    minimumZoomScale = minScale * 0.999 // the multiply factor to prevent user cannot scroll page while they use this control in UIPageViewController
}

Answer 3

您可以使用screenHeight而不是viewHeight

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