更改 NSTextAttachment 图像的大小？答案

【问题标题】：Change size of NSTextAttachment Image?更改 NSTextAttachment 图像的大小？
【发布时间】：2015-08-11 14:56:35
【问题描述】：

我正在使用以下代码将 RSS 提要的原始 HTML 格式化为 NSAttributedString。 HTML 包含<img> 标记，这些标记导致图像作为NSTextAttachment 附加到NSAttributedString 中。问题是图像对于放置属性字符串的 UITextView 来说太大了。有没有办法可以从属性字符串中操纵图像的大小？下面是代表图像附件的整个属性字符串的摘录。

{
    NSAttachment = "<NSTextAttachment: 0x16d29450> \"e0e1d483a922419807a2378a7ec031af.jpg\"";
    NSColor = "UIDeviceRGBColorSpace 0 0 0 1";
    NSFont = "<UICTFont: 0x16ef8a40> font-family: \"Times New Roman\"; font-weight: normal; font-style: normal; font-size: 12.00pt";
    NSKern = 0;
    NSParagraphStyle = "Alignment 4, LineSpacing 0, ParagraphSpacing 12, ParagraphSpacingBefore 0, HeadIndent 0, TailIndent 0, FirstLineHeadIndent 0, LineHeight 0/0, LineHeightMultiple 0, LineBreakMode 0, Tabs (\n), DefaultTabInterval 36, Blocks (null), Lists (null), BaseWritingDirection 0, HyphenationFactor 0, TighteningFactor 0, HeaderLevel 0";
    NSStrokeColor = "UIDeviceRGBColorSpace 0 0 0 1";
    NSStrokeWidth = 0;
}

【问题讨论】：

标签： ios objective-c nstextattachment

【解决方案1】：

您可以遍历您的 NSAttributedString，获取附件、边界并修改它们：

[myAtrrString enumerateAttribute:NSAttachmentAttributeName inRange:NSMakeRange(0, myAtrrString.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
   if (![value isKindOfClass:[NSTextAttachment class]]) {
      return;
   }
   NSTextAttachment *attachment = (NSTextAttachment*)value;
    CGRect bounds = attachment.bounds;
   // modify bounds
   attachment.bounds = bounds;
}];

【讨论】：

【解决方案2】：

你可以设置 NSTextAttachment 的边界，例如（在 Swift3 中）：

        let attachment = NSTextAttachment()
        attachment.image = UIImage(named: "info.png")
        attachment.bounds = CGRect(x: 5, y: -2, width: 15, height: 15)
        let attachmentString = NSAttributedString(attachment: attachment)


        let attributedString = NSMutableAttributedString(string: "My String")
        attributedString.append(attachmentString)
        labelText.attributedText = attributedString

【讨论】：

【解决方案3】：

这是我的解决方案。可能会对某人有所帮助。

[yourSting enumerateAttribute:NSAttachmentAttributeName
                            inRange:NSMakeRange(0, [yourSting length])
                            options:0
                         usingBlock:^(id value, NSRange range, BOOL *stop)
             {
                 
                 if ([value isKindOfClass:[NSTextAttachment class]])
                 {
                     NSTextAttachment *attachment = (NSTextAttachment *)value;
                     UIImage *image = nil;
                     if ([attachment image])
                         image = [attachment image];
                     else
                         image = [attachment imageForBounds:[attachment bounds]
                                              textContainer:nil
                                             characterIndex:range.location];
                     
                     CGSize size = image.size;
                     if(size.width > kSCREEN_WIDTH - 10){

                         // calculate proportional height to width
                         float ratio = image.size.width /( kSCREEN_WIDTH -10);
                         float height = image.size.height / ratio;
                        
                         size = CGSizeMake(kSCREEN_WIDTH - 10, height);
                         
                         attachment.bounds = CGRectMake(0, 0, size.width, size.height);
                         attachment.image = image;
                                                
                     }
                 }
                 
             }]

【讨论】：

这对我来说很完美。在 NSTextView (macOS) 中显示我的属性字符串和使用 [string drawInRect:...] 打印时。