CoreTextを使ってNSAttributedStringを描画する

#import "NSAttributedString+DrawInRect.h"
#import <CoreText/CoreText.h>
@implementation NSAttributedString (DrawInRect)

-(void)drawInRect:(CGRect)rect {
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGContextSaveGState(ctx);
    CGContextTranslateCTM(ctx, 0.0f, rect.size.height + rect.origin.y * 2);
    CGContextScaleCTM(ctx, 1.0f, -1.0f);    
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)self);
    CGPathRef path = [[UIBezierPath bezierPathWithRect:rect] CGPath];    
    CTFrameRef textFrame = CTFramesetterCreateFrame(framesetter,CFRangeMake(0,0), path, NULL);
    CGPathRelease(path);
    CFRelease(framesetter);
    CTFrameDraw(textFrame, ctx);    
    CGContextRestoreGState(ctx);
}

@end