Quickies for Core Text

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General

• Drawing wrapped text in CoreText [permalink]
  Say you have a string, and you just want to draw it pretty plain, but wrapped in a rectangle. CoreText can do that for you:

  - (void) drawText: (NSString *) text  inRect: (CGRect) rect {
  
      CTFontRef font = CTFontCreateWithName (CFSTR("Helvetica"), 15.0, NULL);
      NSDictionary *attributes =
          @{ (__bridge id)kCTFontAttributeName : (__bridge id) font };
  
      CFAttributedStringRef attrString =
          CFAttributedStringCreate (kCFAllocatorDefault,
                                    (__bridge CFStringRef) text,
                                    (__bridge CFDictionaryRef) attributes);
  
      CTFramesetterRef fsetter = CTFramesetterCreateWithAttributedString (attrString);
      CGPathRef path = CGPathCreateWithRect (rect, NULL);
  
      CTFrameRef frame = CTFramesetterCreateFrame (fsetter,
                                        CFRangeMake (0, 0),
                                        path, NULL);
  
      CGContextRef context = ...;
      CGContextSetTextMatrix (context, CGAffineTransformIdentity);
  
      CTFrameDraw (frame, context);
  
       CFRelease (font);
       CFRelease (attrString);
       CFRelease (fsetter);
       CGPathRelease (path);
  
  } // drawTextInRect

• Getting wrapped height from CoreText [permalink]
  You're drawing wrapped text in a simple rectangle in CoreText, and you want to figure out the height of it. (fixed width, flexible height).

      CTFramesetterRef fsetter = CTFramesetterCreateWithAttributedString (attrString);
  
      CFRange fitRange;
      CGSize frameSize =
          CTFramesetterSuggestFrameSizeWithConstraints (fsetter,
                                                        CFRangeMake (0, 0),
                                                        NULL,  // frame attributes
                                                        CGSizeMake (rect.size.width,
                                                                    CGFLOAT_MAX),
                                                        &fitRange);
  

  fitRange is the range of characters that fit in. Given a height of CGFLOAT_MAX, this should be the entire string. frameSize is the width and height the text will be wrapped in. A { 0, 0} range means to use the whole string.

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