CoreText实现图文混排之尺寸估算及文本选择

///返回排除区域字典
NSDictionary * getExclusionDic(NSArray * paths) {
    if (paths.count == 0) {
        return NULL;
    }
    NSMutableArray *pathsArray = [[NSMutableArray alloc] init];
    [paths enumerateObjectsUsingBlock:^(UIBezierPath * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSDictionary *clippingPathDictionary = [NSDictionary dictionaryWithObject:(__bridge id)(obj.CGPath) forKey:(__bridge NSString *)kCTFramePathClippingPathAttributeName];
        [pathsArray addObject:clippingPathDictionary];
    }];
    return [NSDictionary dictionaryWithObjectsAndKeys:pathsArray,kCTFrameClippingPathsAttributeName, nil];
}

-(CGSize)sizeThatFits:(CGSize)size {
    ///计算绘制尺寸限制
    CGFloat limitWidth = (size.width - self.textInsets.left - self.textInsets.right) > 0 ? (size.width - self.textInsets.left - self.textInsets.right) : 0;
    CGFloat limitHeight = (size.height - self.textInsets.top - self.textInsets.bottom) > 0 ? (size.height - self.textInsets.top - self.textInsets.bottom) : 0;
    
    ///获取排除区域（考虑偏移矫正，保证正确绘制）
    NSArray * exclusionPaths = [self handleExclusionPathsWithOffset:self.textInsets.bottom - self.textInsets.top];
    CGRect frame = CGRectMake(self.textInsets.left, self.textInsets.bottom, limitWidth, limitHeight);
    NSDictionary * exclusionConfig = getExclusionDic(exclusionPaths, frame);
    BOOL needDrawString = self.attributedText.length || self.text.length;
    
    NSMutableAttributedString * mAStr = nil;
    if (needDrawString) {
        ///获取要绘制的文本(初步处理，未处理插入图片、句尾省略号、高亮)
        mAStr = getMAStr(self,limitWidth,exclusionPaths);
    }
    CTFramesetterRef frameSetter4Cal = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)mAStr);
    CTFrameRef frame4Cal = CTFramesetterCreateFrame(frameSetter4Cal, CFRangeMake(0, 0), [UIBezierPath bezierPathWithRect:frame].CGPath, (__bridge_retained CFDictionaryRef)exclusionConfig);
    
    CFRange visibleRange = getRangeToDrawForVisibleString(frame4Cal);
    
    ///处理插入图片
    if (needDrawString) {
        NSMutableArray * arrInsert = self.insertImageArr.copy;
        if (arrInsert.count) {
            ///富文本插入图片占位符
            [self handleStr:mAStr withInsertImageArr:arrInsert arrLocationImgHasAdd:[NSMutableArray array]];
            ///插入图片后重新处理工厂及frame，添加插入图片后的字符串，消除插入图片影响
            CFSAFERELEASE(frameSetter4Cal)
            CFSAFERELEASE(frame4Cal)
            frameSetter4Cal = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)mAStr);
            frame4Cal = CTFramesetterCreateFrame(frameSetter4Cal, CFRangeMake(0, 0), [UIBezierPath bezierPathWithRect:frame].CGPath, (__bridge_retained CFDictionaryRef)exclusionConfig);
            visibleRange = getRangeToDrawForVisibleString(frame4Cal);
        }
    }
    
    if (exclusionPaths.count == 0) {///如果没有排除区域则使用系统计算函数
        CGSize restrictSize = CGSizeMake(limitWidth, MAXFLOAT);
        if (self.numberOfLines == 1) {
            restrictSize = CGSizeMake(MAXFLOAT, MAXFLOAT);
        }
        CGSize suggestSize = CTFramesetterSuggestFrameSizeWithConstraints(frameSetter4Cal, visibleRange, nil, restrictSize, nil);
        CFSAFERELEASE(frameSetter4Cal);
        CFSAFERELEASE(frame4Cal);
        return CGSizeMake(suggestSize.width + self.textInsets.left + self.textInsets.right, suggestSize.height + self.textInsets.top + self.textInsets.bottom);
    }
    
    ///计算drawFrame及drawPath
    UIBezierPath * drawP = [self handleDrawFrameAndPathWithLimitWidth:limitWidth limitHeight:limitHeight frameSetter:frameSetter4Cal rangeToDraw:visibleRange exclusionPaths:exclusionPaths];
    
    CFSAFERELEASE(frameSetter4Cal)
    CFSAFERELEASE(frame4Cal)
    
    ///绘制的工厂
    CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)mAStr);
    ///绘制范围为可见范围加1，防止末尾省略号失效（由于path为可见尺寸，故仅绘制可见范围时有的时候末尾的省略号会失效，同时不可超过字符串本身长度）
    CFRange drawRange = CFRangeMake(0, visibleRange.length < mAStr.length ? visibleRange.length + 1 : mAStr.length);
    CTFrameRef visibleFrame = CTFramesetterCreateFrame(frameSetter, drawRange, drawP.CGPath, (__bridge_retained CFDictionaryRef)exclusionConfig);
    
    __block CGRect desFrame = CGRectZero;
    
    DWCoreTextLayout * layout = [DWCoreTextLayout layoutWithCTFrame:visibleFrame convertHeight:size.height considerGlyphs:NO];
    
    [layout.lines enumerateObjectsUsingBlock:^(DWCTLineWrapper * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        CGRect temp = obj.frame;
        desFrame = CGRectUnion(temp, desFrame);
    }];
    
    CFSAFERELEASE(frameSetter)
    CFSAFERELEASE(visibleFrame)
    
    desFrame = CGRectMake(0, 0, ceil(desFrame.origin.x + desFrame.size.width + self.textInsets.right), ceil(desFrame.origin.y + desFrame.size.height + self.textInsets.bottom));
    
    ///重新获取为矫正偏移的图片实际绘制Path
    exclusionPaths = [self handleExclusionPathsWithOffset:0];
    [exclusionPaths enumerateObjectsUsingBlock:^(UIBezierPath * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        desFrame = CGRectUnion(obj.bounds, desFrame);
    }];
    
    CGRect limitRect = CGRectMake(0, 0, size.width, size.height);
    desFrame = CGRectIntersection(limitRect, desFrame);
    return desFrame.size;
}