Display NSAttributedString using CoreText

Question

I have heard that I can display a NSAttributedString using CoreText, can anyone say me how (The simplest way)?

Please, don't answer with CATextLayer or OHAttributedLabel.

I know that there are a lot of questions about this in this forum, but I haven't find the answer

Thanks!!

Fanjet

If you don't want to use those wrappers, have a look inside, how they work. – Flotage

Answer 1

I think that the simplest way (using Core Text) is:

 // Create the CTLine with the attributed string
 CTLineRef line = CTLineCreateWithAttributedString(attrString); 

 // Set text position and draw the line into the graphics context called context
 CGContextSetTextPosition(context, x,  y);
 CTLineDraw(line, context);

 // Clean up
 CFRelease(line);

Using a Framesetter is more efficient IF you are drawing lots of text but this is the method recommended by Apple if you just need to display a small amount of text (like a label) and doesn't require you to create a path or frame (since it is done for you automatically by CTLineDraw).

Prelature

Does this render the line in arbitrary context created by user(using bitmap data), or the context must be current context? – Dripping

@DeepakSharma This renders to a user created context (in this case, I just called it context). – Prelature

Answer 2

Simplest way? Something like this:

CGContextRef context = UIGraphicsGetCurrentContext();

// Flip the coordinate system
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CGContextTranslateCTM(context, 0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);

// Create a path to render text in
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, self.bounds );

// An attributed string containing the text to render
NSAttributedString* attString = [[NSAttributedString alloc]
                                  initWithString:...];

// create the framesetter and render text
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attString); 
CTFrameRef frame = CTFramesetterCreateFrame(framesetter,
                         CFRangeMake(0, [attString length]), path, NULL);

CTFrameDraw(frame, context);

// Clean up
CFRelease(frame);
CFRelease(path);
CFRelease(framesetter);

Chilpancingo

what do you think about this? #55799543 – Hawken

Answer 3

Starting from ios 6 you can do the following :

    NSMutableParagraphStyle *paragrahStyle = [[NSMutableParagraphStyle alloc] init];
[paragrahStyle setLineSpacing:40];
[attributedString addAttribute:NSParagraphStyleAttributeName value:paragrahStyle range:NSMakeRange(0, [labelText length])];

cell.label.attributedText = attributedString ;

Theatrical