CTFrameSetter.h学习

2017-03-02

创建 CTFrame 需要CTFrameSetter.h 类中

该类分四部分，Framesetter Types ， Framesetter Creation ，Frame Creation ， Frame Sizing

1.Framesetter Types

CFTypeID CTFramesetterGetTypeID( void ) 返回一个CTFramesetter 的 id 。

2.Framesetter Creation

1 2	CTFramesetterRef CTFramesetterCreateWithAttributedString(CFAttributedStringRef string ) 用CFAttributedStringRef 属性字符串创建一个CTFramesetterRef

获取Framesetter 只有这一种方式获取

3.Frame Creation

CTFrameRef CTFramesetterCreateFrame(
	CTFramesetterRef framesetter,
	CFRange stringRange,
	CGPathRef path,
	CFDictionaryRef __nullable frameAttributes )
	
该函数返回一个CTFrame 只有这一种方式创建CTFrameRef
参数，需要一个CTFramesetterRef  
      需要一个CFRange
      需要一个CGPathRef
	  需要一个CFDictionaryRef
	  
	  CFRange 控制的是文本的长度。如果设置长度是0，就是将attstr 字符串绘制到结束
	  CGPathRef 就是绘制区域
	  CFDictionaryRef 绘制CTFrame的相关属性设置，key值在CFFrame中

测试代码如下

1 2	CFRange range = CFRangeMake(2, mabstring.length-4); CTFrameRef frame = CTFramesetterCreateFrame(framesetter,range, Path, (__bridge CFDictionaryRef) Framedic);

测试结果：

要是代码如下

1 2	CFRange range = CFRangeMake(0, 0); CTFrameRef frame = CTFramesetterCreateFrame(framesetter,range, Path, (__bridge CFDictionaryRef) Framedic);

测试结果

从上下两个图看的出来，前面图的文本前后各少两个字。所有字体还是对其排列。

CTTypesetterRef CTFramesetterGetTypesetter(
	CTFramesetterRef framesetter ) 
	根据CTFramesetterRef 获取一个CTTypesetterRef  
	目前还不知道CTTypesetterRef 有啥用

4.Frame Sizing

CGSize CTFramesetterSuggestFrameSizeWithConstraints(
	CTFramesetterRef framesetter,
	CFRange stringRange,
	CFDictionaryRef __nullable frameAttributes,
	CGSize constraints,
	CFRange * __nullable fitRange )
获取Frame的大小
这个函数适合创建Frame CGPath是矩形的算法，要是三角形等不规则图形就不适合

测试代码

     
    NSMutableDictionary * Framedic = [NSMutableDictionary dictionary];
    
    [Framedic setObject:@(kCTFrameProgressionTopToBottom) forKey:(__bridge NSString *)kCTFrameProgressionAttributeName];
    [Framedic setObject:@(kCTFramePathFillEvenOdd) forKey:(__bridge NSString *)kCTFramePathFillRuleAttributeName];
    
    NSMutableArray * arr = [NSMutableArray array];
    
    NSMutableDictionary * fillDic = [NSMutableDictionary dictionary];
    CGMutablePathRef clippath = CGPathCreateMutable();
    CGPathAddRect(clippath, NULL ,CGRectMake(100 , 20 ,self.bounds.size.width-150 , self.bounds.size.height-60));
    [fillDic setObject:(__bridge id _Nonnull)(clippath) forKey:(__bridge NSString *)kCTFramePathClippingPathAttributeName];
    [arr addObject:fillDic];
    
    fillDic = [NSMutableDictionary dictionary];
     clippath = CGPathCreateMutable();
    CGPathAddRect(clippath, NULL ,CGRectMake(10 , 20 ,10 , self.bounds.size.height-60));
    [fillDic setObject:(__bridge id _Nonnull)(clippath) forKey:(__bridge NSString *)kCTFramePathClippingPathAttributeName];
    [arr addObject:fillDic];
//    [Framedic setObject:arr forKey:(__bridge NSString *)kCTFrameClippingPathsAttributeName];
    
    
    CFRange range = CFRangeMake(0, 0);
    
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter,range, Path, (__bridge CFDictionaryRef) Framedic);
    
    CGRect rectBoud = CGPathGetBoundingBox(Path);
    CFRange fitRange = CFRangeMake(0, 0);
    
    CGSize size =CTFramesetterSuggestFrameSizeWithConstraints(framesetter, range, (__bridge CFDictionaryRef) Framedic, rectBoud.size, &fitRange);
    NSLog(@" 获取frame 的大小 %f %f %ld %ld",size.height,size.width,fitRange.location,fitRange.location);

这个函数只能测试矩形排版，矩形内必须一次排满路径才行。不能有clip path存在才能准确。局限性比较大。