前一段时间由于公司项目需求（租车项目，需要验车拍照，标记车辆外观的损伤情况）需要对照片进行涂鸦处理，所以就简单研究了一下。示例demo。
主要是通过UIview的- (void)drawRect:(CGRect)rect 方法实现，通过点击手势来进行简单涂鸦。

//顶部图片手势
- (void)origviewGesture:(UITapGestureRecognizer *)Recognizer{
    if (self.currentExmpleImgName) {
        CGPoint point = [Recognizer locationInView:self.origview];
        CGRect rect = CGRectMake(point.x- 15* 0.5, point.y- 15* 0.5, 15, 15);
        NSLog(@"%@", NSStringFromCGPoint(point));
        
        for (NSDictionary *dic in self.allScrArray) {
            CGRect rectTmp = CGRectFromString(dic[@"rect"]);
            BOOL contains = CGRectContainsPoint(rectTmp, point);
            if (contains) {
                [self.allScrArray removeObject:dic];
                self.origview.imageArray = self.allScrArray;
                return;
            }
        }
        
        NSMutableDictionary *tmpDic = [[NSMutableDictionary alloc] init];
        
        NSString *imgPoint = NSStringFromCGPoint(point);
        NSString *imgRect = NSStringFromCGRect(rect);
        
        [tmpDic setValue:imgRect forKey:@"rect"];
        [tmpDic setValue:imgPoint forKey:@"Point"];
        
        [tmpDic setValue:self.currentExmpleImgName forKey:@"imageName"];
        [self.allScrArray addObject:tmpDic];
        self.origview.imageArray = self.allScrArray;
    }else {
        return;
    }
}

for循环主要判断重复点击的位置，如果点击的位置已经涂鸦，就清除当前的，如果没有就先添加涂鸦。

//保存
- (void)saveBtnAction{
    //画布图片存储
    UIGraphicsBeginImageContext(self.origview.frame.size);
    [self.origview.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    NSData *imageData = [[NSData alloc]init];
    imageData = UIImageJPEGRepresentation(viewImage, 0.5);
    self.resultImag.image = viewImage;
}

直接将涂鸦照片生成UIImage。demo有视频操作。