CTRunDelegate学习

2017-03-02

我们从 Run Delegate Types Run Delegate Callbacks Run Delegate Versions Run Delegate Creation Run Delegate Access 五个方面来学习

1.Run Delegate Types

1	CFTypeID CTRunDelegateGetTypeID( void ) CT_AVAILABLE(10_5, 3_2);

2.Run Delegate Callbacks

1 2	typedef void (CTRunDelegateDeallocateCallback) ( void refCon );

1 2	typedef CGFloat (CTRunDelegateGetAscentCallback) ( void refCon );

1 2	typedef CGFloat (CTRunDelegateGetDescentCallback) ( void refCon );

1 2	typedef CGFloat (CTRunDelegateGetWidthCallback) ( void refCon );

typedef struct
{
	CFIndex							version;
	CTRunDelegateDeallocateCallback	dealloc;
	CTRunDelegateGetAscentCallback	getAscent;
	CTRunDelegateGetDescentCallback	getDescent;
	CTRunDelegateGetWidthCallback	getWidth;
} CTRunDelegateCallbacks;

代码：

void CTRunDelegateDeallocateCallbackFunction (void * refCon ){
    
}
CGFloat CTRunDelegateGetAscentCallbackFunction (void * refCon ){
    return 30;
}
CGFloat CTRunDelegateGetDescentCallbackFunction (void * refCon ){
    return 30;
}
CGFloat CTRunDelegateGetWidthCallbackFunction(void * refCon ){
    return 30;
}
    CTRunDelegateDeallocateCallback  deallocateCallback= CTRunDelegateDeallocateCallbackFunction;
    
    NSLog(@"CTRunDelegateGetAscentCallback 获取ascent");
    CTRunDelegateGetAscentCallback ascentCallback= CTRunDelegateGetAscentCallbackFunction;
    CTRunDelegateGetDescentCallback descentCallback =  CTRunDelegateGetDescentCallbackFunction;
    
    CTRunDelegateGetWidthCallback widthCallBack = CTRunDelegateGetWidthCallbackFunction;
    
    CTRunDelegateCallbacks callBack ;
    callBack.version =kCTRunDelegateCurrentVersion;
    callBack.dealloc = deallocateCallback;
    callBack.getAscent = ascentCallback;
    callBack.getDescent = descentCallback;
    callBack.getWidth = widthCallBack;

3.Run Delegate Versions

enum {
	kCTRunDelegateVersion1 = 1,
	kCTRunDelegateCurrentVersion = kCTRunDelegateVersion1
};

4.Run Delegate Creation

1
2
3

CTRunDelegateRef __nullable CTRunDelegateCreate(
	const CTRunDelegateCallbacks* callbacks,
	void * __nullable refCon ) CT_AVAILABLE(10_5, 3_2);

5.Run Delegate Access

1 2	void * CTRunDelegateGetRefCon( CTRunDelegateRef runDelegate ) CT_AVAILABLE(10_5, 3_2);

代码片段

- (void)drawRect:(CGRect)rect {
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetTextMatrix(context , CGAffineTransformIdentity);
    CGContextTranslateCTM(context , 0 ,self.bounds.size.height);
    CGContextScaleCTM(context, 1.0 ,-1.0);
    
    NSMutableAttributedString *mabstring = [[NSMutableAttributedString alloc]initWithString:@"富文本学习/慢慢来吧。不是一朝一夕之功。ok \n ok ok"];
    
    CTRunDelegateDeallocateCallback  deallocateCallback= CTRunDelegateDeallocateCallbackFunction;
    
    NSLog(@"CTRunDelegateGetAscentCallback 获取ascent");
    CTRunDelegateGetAscentCallback ascentCallback= CTRunDelegateGetAscentCallbackFunction;
    CTRunDelegateGetDescentCallback descentCallback =  CTRunDelegateGetDescentCallbackFunction;
    
    CTRunDelegateGetWidthCallback widthCallBack = CTRunDelegateGetWidthCallbackFunction;
    CTRunDelegateCallbacks callBack ;
    callBack.version =kCTRunDelegateCurrentVersion;
    callBack.dealloc = deallocateCallback;
    callBack.getAscent = ascentCallback;
    callBack.getDescent = descentCallback;
    callBack.getWidth = widthCallBack;
    CTRunDelegateRef delegate=  CTRunDelegateCreate(&callBack, NULL);
    NSDictionary * dic =[NSDictionary dictionaryWithObject:(__bridge id)delegate forKey:(__bridge NSString * )kCTRunDelegateAttributeName];
    unichar placeHolder = 0xFFFC;///占位符
    NSString * placeHolderStr = [NSString stringWithCharacters:&placeHolder length:1];
    NSAttributedString * att = [[NSAttributedString alloc]initWithString:placeHolderStr attributes:dic];
    [mabstring insertAttributedString:att atIndex:3  ];
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)mabstring);
    CGMutablePathRef Path = CGPathCreateMutable();
    CGPathAddRect(Path, NULL ,CGRectMake(10 , 0 ,self.bounds.size.width-10 , self.bounds.size.height-60));
    
    CFRange range = CFRangeMake(0, 0);
    
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter,range, Path, NULL);
    
    CTFrameDraw(frame,context);
    
    CGPathRelease(Path);
    CFRelease(framesetter);
}

效果