添加到NSAttributedString时图像被翻转 [英] Images being flipped when adding to NSAttributedString

问题描述

在调整NSAttributedString中图像的大小时，我遇到一个奇怪的问题.调整大小的扩展名工作正常，但是将图像添加到NSAttributedString时，由于某种原因，它会垂直翻转.

I have a strange problem when resizing an image that's in a NSAttributedString. The resizing extension is working fine, but when the image is added to the NSAttributedString, it gets flipped vertically for some reason.

这是调整大小的扩展名:

This is the resizing extension:

extension NSImage {
  func resize(containerWidth: CGFloat) -> NSImage {

    var scale : CGFloat = 1.0
    let currentWidth = self.size.width
    let currentHeight = self.size.height

    if currentWidth > containerWidth {
      scale = (containerWidth * 0.9) / currentWidth
    }

    let newWidth = currentWidth * scale
    let newHeight = currentHeight * scale

    self.size = NSSize(width: newWidth, height: newHeight)

    return self
  }
}

这是属性字符串中图像的枚举:

And here is the enumeration over the images in the attributed string:

newAttributedString.enumerateAttribute(NSAttributedStringKey.attachment, in: NSMakeRange(0, newAttributedString.length), options: []) { value, range, stop in
    if let attachement = value as? NSTextAttachment {
        let image = attachement.image(forBounds: attachement.bounds, textContainer: NSTextContainer(), characterIndex: range.location)!

        let newImage = image.resize(containerWidth: markdown.bounds.width)
        let newAttribute = NSTextAttachment()
        newAttribute.image = newImage
        newAttributedString.addAttribute(NSAttributedStringKey.attachment, value: newAttribute, range: range)
    }
}

我已经设置了断点并检查了图像，它们都处于正确的旋转状态，除非到达此行:

I've set breakpoints and inspected the images, and they are all in the correct rotation, except when it reaches this line:

newAttributedString.addAttribute(NSAttributedStringKey.attachment, value: newAttribute, range: range)

图像垂直翻转的地方.

我不知道是什么原因导致垂直翻转.有办法解决这个问题吗?

I have no clue what could be causing this vertical flip. Is there a way to fix this?

推荐答案

我知道了，它比我做的要简单得多.

I figured it out and it was so much simpler than I was making it.

因为图像位于一个附加到NSTextView的NSAttribuetdString中，所以我不需要调整NSAttributedString中每个图像的大小，而只需要使用

Because the image was in a NSAttribuetdString being appended into a NSTextView I didn't need to resize each image in the NSAttributedString, rather I just had to set the attachment scaling inside the NSTextView with

markdown.layoutManager?.defaultAttachmentScaling = NSImageScaling.scaleProportionallyDown 

只需要一行即可

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