Center NSTextAttachment image next to single line UILabel
I'd like to append an NSTextAttachment image to my attributed string and have it centered vertically.
I've used the following code to create my string
NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:DDLocalizedString(@"title.upcomingHotspots") attributes:attrs];
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
attachment.image = [[UIImage imageNamed:@"help.png"] imageScaledToFitSize:CGSizeMake(14.f, 14.f)];
cell.textLabel.attributedText = [str copy];
However, the image appears to align to the top of the cell's textLabel.
How can I change the rect in which the attachment is drawn?
You can change the rect by subclassing NSTextAttachment and overriding attachmentBoundsForTextContainer:proposedLineFragment:glyphPosition:characterIndex: . Example:
- (CGRect)attachmentBoundsForTextContainer:(NSTextContainer *)textContainer proposedLineFragment:(CGRect)lineFrag glyphPosition:(CGPoint)position characterIndex:(NSUInteger)charIndex {
CGRect bounds;
bounds.origin = CGPointMake(0, -5);
bounds.size = self.image.size;
return bounds;
}
It's not a perfect solution. You have to figure out the Y-origin “by eye” and if you change the font or the icon size, you'll probably want to change the Y-origin. But I couldn't find a better way, except by putting the icon in a separate image view (which has its own disadvantages).
Try - [NSTextAttachment bounds] . No subclassing required.
For context, I am rendering a UILabel for use as the attachment image, then setting the bounds like so: attachment.bounds = CGRectMake(0, self.font.descender, attachment.image.size.width, attachment.image.size.height) and baselines of text within label image and text in attributed string line up as desired.
I found a perfect solution to this, works like a charm for me though, however you have to try it out yourself (probably the constant depends on the resolution of the device and maybe whatever ;)
func textAttachment(fontSize: CGFloat) -> NSTextAttachment {
let font = UIFont.systemFontOfSize(fontSize) //set accordingly to your font, you might pass it in the function
let textAttachment = NSTextAttachment()
let image = //some image
textAttachment.image = image
let mid = font.descender + font.capHeight
textAttachment.bounds = CGRectIntegral(CGRect(x: 0, y: font.descender - image.size.height / 2 + mid + 2, width: image.size.width, height: image.size.height))
return textAttachment
}
Should work and shouldn't be blurry in any way (thanks to CGRectIntegral )