グリフのパス(ベクター)を取得して描画する

gistfile1.m

@import CoreText;
@import QuartzCore;

@implementation RCViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    CTFontRef font = CTFontCreateWithName((CFStringRef)@"HiraKakuProN-W3", 60, NULL);
    const UniChar characters[] = { [@"☃" characterAtIndex:0]};
    
    CGGlyph glyphs[1];
    CTFontGetGlyphsForCharacters(font, characters, glyphs, 1);
    //この関数呼び出しが肝なのだ！
    CGPathRef path = CTFontCreatePathForGlyph(font, glyphs[0], NULL);
    
    CGRect boundingBox = CGPathGetBoundingBox(path);
    NSLog(@"boundingBox = %@", NSStringFromCGRect(boundingBox));
    //boundingBox = {{8.3400002, -2.3999999}, {42.66, 53.100002}}
    //なので、このままだとはみ出る。ので、CGAffineTransformTranslateでPathを移動する
    
    CAShapeLayer* shapeLayer;
    shapeLayer = [CAShapeLayer layer];
    shapeLayer.frame = boundingBox;
    shapeLayer.position = self.view.center;
    shapeLayer.geometryFlipped = YES;
    shapeLayer.fillColor = [UIColor whiteColor].CGColor;
    shapeLayer.backgroundColor = [UIColor blackColor].CGColor;
    
    CGMutablePathRef newPath = CGPathCreateMutable();
    CGAffineTransform transform = CGAffineTransformIdentity;
    transform = CGAffineTransformTranslate(transform, -boundingBox.origin.x, -boundingBox.origin.y);
    CGPathAddPath(newPath, &transform, path);
    
    shapeLayer.path = newPath;
    
    CFRelease(newPath);
    CFRelease(font);
    CFRelease(path);
    
    [self.view.layer addSublayer:shapeLayer];
}