深入理解iOS图文混排原理并自定义图文控件

//获取上下文
CGContextRef c = UIGraphicsGetCurrentContext();
// 将当前图形状态推入堆栈
CGContextSaveGState(c);
// 设置字形变换矩阵为CGAffineTransformIdentity，也就是说每一个字形都不做图形变换
CGContextSetTextMatrix(c, CGAffineTransformIdentity);
// 坐标转换，UIKit 坐标原点在左上角，CoreText 坐标原点在左下角
CGContextTranslateCTM(c, 0.0f, insetRect.size.height);
CGContextScaleCTM(c, 1.0f, -1.0f);
// TODO:进行图文绘制操作
//...
// 绘制完成，将堆栈顶部的状态弹出，返回到之前的图形状态
CGContextRestoreGState(c);

NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
//生成CTFramesetter
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedStr);
CFRelease(framesetter);

CGRect rect = CGRectMake(0, 0, 100, 100);
//生成绘制区域路径
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, rect);
//生成CTFrame
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, [attributedStr length]), path, NULL);

//获取一共有多少行
CFArrayRef lines = CTFrameGetLines(frame);

CFRelease(frame);
CGPathRelease(path);

//获取第一行信息
CTLineRef line = CFArrayGetValueAtIndex(lines, 0);
//上行高、下行高、行间距
CGFloat lineAscent = 0.0f, lineDescent = 0.0f, lineLeading = 0.0f;
//获取行宽、行高信息
CGFloat lineWidth = CTLineGetTypographicBounds(line, &lineAscent, &lineDescent, &lineLeading);

//初始化CTRun的区域大小为CGRectZero
CGRect runBounds = CGRectZero;
//初始化CTRun的上行高、下行高、行间距
CGFloat runAscent = 0.0f, runDescent = 0.0f, runLeading = 0.0f;
//计算得到上下行高、行间距以及CTRun绘制区域宽度
runBounds.size.width = (CGFloat)CTRunGetTypographicBounds(glyphRun, CFRangeMake(0, 0), &runAscent, &runDescent, &runLeading);
//计算高度，注意下行高为负数的情况
CGFloat runHeight = runAscent + fabs(runDescent);
runBounds.size.height = runHeight;

NSDictionary *imgInfoDic = @{kCJImage:image,//需要绘制的图片
                             kCJImageWidth:@(size.width),//需要绘制的图片区域宽度
                             kCJImageHeight:@(size.height),//需要绘制的图片区域高度};
    
//创建CTRunDelegateRef并设置回调函数
CTRunDelegateCallbacks imageCallbacks;
imageCallbacks.version = kCTRunDelegateVersion1;
imageCallbacks.dealloc = RunDelegateDeallocCallback;
imageCallbacks.getWidth = RunDelegateGetWidthCallback;//图片区域宽度回调
imageCallbacks.getAscent = RunDelegateGetAscentCallback;//图片区域上行高回调
imageCallbacks.getDescent = RunDelegateGetDescentCallback;//图片区域下行高回调
CTRunDelegateRef runDelegate = CTRunDelegateCreate(&imageCallbacks, (__bridge void *)imgInfoDic);
//初始化空白占位字符
unichar imgReplacementChar = 0xFFFC;
NSString *imgReplacementString = [NSString stringWithCharacters:&imgReplacementChar length:1];
//插入图片 空白占位符
NSMutableString *imgPlaceholderStr = [[NSMutableString alloc]initWithCapacity:3];
[imgPlaceholderStr appendString:imgReplacementString];
NSRange imgRange = NSMakeRange(0, imgPlaceholderStr.length);
NSMutableAttributedString *imageAttributedString = [[NSMutableAttributedString alloc] initWithString:imgPlaceholderStr];
//将CTRunDelegate记录到NSMutableAttributedString的富文本信息中
[imageAttributedString addAttribute:(NSString *)kCTRunDelegateAttributeName value:(__bridge id)runDelegate range:imgRange];
//kCJImageAttributeName为自定义的记录图片信息的富文本属性
[imageAttributedString addAttribute:kCJImageAttributeName value:imgInfoDic range:imgRange];

/**
 删除线宽度。值为NSNumber。默认 `0.0f`，表示无删除线
 */
extern NSString * const kCJStrikethroughStyleAttributeName;
/**
 删除线颜色。值为UIColor。默认 `[UIColor blackColor]`。
 */
extern NSString * const kCJStrikethroughColorAttributeName;
/**
 对NSAttributedString文本设置锚点属性时候的唯一标识
 */
extern NSString * const kCJLinkStringIdentifierAttributesName;

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    // ![self linkAtPoint:point extendsLinkTouchArea:NO]表示不在锚点点击范围内
    if (![self linkAtPoint:point extendsLinkTouchArea:NO] || !self.userInteractionEnabled || self.hidden || self.alpha < 0.01) {
        //如果支持选择复制
        if (self.enableCopy) {
            return [super hitTest:point withEvent:event];
        }else{
            return nil;
        }
    }
    return self;
}

- (CJGlyphRunStrokeItem *)linkAtPoint:(CGPoint)point extendsLinkTouchArea:(BOOL)extendsLinkTouchArea {
    // CJGlyphRunStrokeItem 对应 CTRun，其中记录了字符区域（bounds）的大小
    CJGlyphRunStrokeItem *resultItem = nil;
    // _linkStrokeItemArray 表示记录了所有锚点信息的数组
    for (CJGlyphRunStrokeItem *item in _linkStrokeItemArray) {
        if (CGRectContainsPoint(item.bounds, point)) {
            resultItem = item;
        }
    }
    return resultItem;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CJGlyphRunStrokeItem *item = [self linkAtPoint:[touch locationInView:self] extendsLinkTouchArea:self.extendsLinkTouchArea];
    //点击锚点存在
    if (item) {
        //TODO: 触发重绘操作，达到点击锚点高亮效果
    }else{
        [super touchesBegan:touches withEvent:event];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    //  如果是长按点击，交由长按点击手势UILongPressGestureRecognizer响应
    if (_longPress) {
        [super touchesEnded:touches withEvent:event];
    }else{
        if (_currentClickRunStrokeItem) {
            // 如果当前是点击锚点事件，抛出点击回调事件
            if (self.delegate && [self.delegate respondsToSelector:@selector(CJLable:didClickLink:)]) {
                [self.delegate CJLable:self didClickLink:linkModel];
            }
            // TODO: 再次重绘，还原点击前的文本显示
        }
        else {
            [super touchesEnded:touches withEvent:event];
        }
    }
}

// 在此时刚接收到手势事件的回调中，将UITouch关联到 UIGestureRecognizer实例
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
    if (gestureRecognizer == self.longPressGestureRecognizer) {
        objc_setAssociatedObject(self.longPressGestureRecognizer, &kAssociatedUITouchKey, touch, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
    else if (gestureRecognizer == self.doubleTapGes) {
        objc_setAssociatedObject(self.doubleTapGes, &kAssociatedUITouchKey, touch, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
    return YES;
}
// 双击点击事件
- (void)tapTwoAct:(UITapGestureRecognizer *)sender {
    // Runtime属性关联，获取到对应的UITouch，并计算得到点击坐标：[touch locationInView:self]
    UITouch *touch = objc_getAssociatedObject(self.doubleTapGes, &kAssociatedUITouchKey);
    CJGlyphRunStrokeItem *item = [self linkAtPoint:[touch locationInView:self] extendsLinkTouchArea:self.extendsLinkTouchArea];
    if (item) {
        //TODO: 如果当前是双击点击锚点事件，抛出点击回调事件
        if (self.delegate && [self.delegate respondsToSelector:@selector(CJLable:didClickLink:)]) {
            [self.delegate CJLable:self didClickLink:linkModel];
        }
        // TODO: 再次重绘，还原点击前的文本显示
    }
    //如果不是点击锚点且开启了选择复制功能
    else {
        if (self.enableCopy) {
            //TODO: 显示选择复制提示视图
        }
    }
}
// 长按点击事件
- (void)longPressGestureDidFire:(UILongPressGestureRecognizer *)sender {
    // Runtime属性关联，获取到对应的UITouch，并计算得到点击坐标：[touch locationInView:self]
    UITouch *touch = objc_getAssociatedObject(self.longPressGestureRecognizer, &kAssociatedUITouchKey);
    CGPoint point = [touch locationInView:self];
    BOOL isLinkItem = [self containslinkAtPoint:[touch locationInView:self]];
    switch (sender.state) {
        //TODO: 如果当前是长按锚点事件，抛出长按回调事件
        case UIGestureRecognizerStateBegan: {
            if (isLinkItem) {
                if (self.delegate && [self.delegate respondsToSelector:@selector(CJLable:didLongPressLink:)]) {
                        [self.delegate CJLable:self didLongPressLink:linkModel];
                    }
            }
            //如果不是点击锚点且开启了选择复制功能
    		else {
        		if (self.enableCopy) {
            		//TODO: 长按显示放大镜
                }
        	}
    	}
            break;
        }
        case UIGestureRecognizerStateEnded:{
            //TODO: 再次重绘，还原长按前的文本显示
            //如果支持复制
            if (self.enableCopy) {
                //TODO: 显示选择复制提示视图
            }
            break;
        }
        case UIGestureRecognizerStateChanged:
    		//如果支持复制
            if (self.enableCopy) {
                //TODO: 更新放大镜位置，以及更新选择复制区域
            }
            break;
        default:
            break;
    }
}

//给每一个字符设置index值，enableCopy=YES时生效
__block NSInteger index = 0;
[attText.string enumerateSubstringsInRange:NSMakeRange(0, [attText length]) options:NSStringEnumerationByComposedCharacterSequences usingBlock:
 ^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
     CJCTRunUrl *runUrl = nil;
     if (!runUrl) {
         NSString *urlStr = [NSString stringWithFormat:@"https://www.CJLabel%@",@(index)];
         runUrl = [CJCTRunUrl URLWithString:urlStr];
     }
     runUrl.index = index;
     runUrl.rangeValue = [NSValue valueWithRange:substringRange];
     [attText addAttribute:NSLinkAttributeName
                     value:runUrl
                     range:substringRange];
     index++;
 }];

- (void)drawInContext:(CGContextRef)ctx {
	CGContextTranslateCTM(ctx, self.frame.size.width/2, self.frame.size.height/2);
	CGContextScaleCTM(ctx, 1.40, 1.40);
	//self.pointToMagnify是更新的放大点坐标
	CGContextTranslateCTM(ctx, -1 * self.pointToMagnify.x, -1 * self.pointToMagnify.y);
	[CJkeyWindow().layer renderInContext:ctx];
	CJkeyWindow().layer.contents = (id)nil;
}

CGContextRef ctx = UIGraphicsGetCurrentContext();
//填充的背景色
UIColor *backColor = CJUIRGBColor(0,84,166,0.2);
[backColor set];
CGContextAddRect(ctx, self.headRect);
CGContextStrokePath(ctx);