【iOS】使用PDFKit框架实现PDF文件预览、涂鸦、文字、贴图等功能

开发语言：Objective-C
原生框架：PDFKit.framework
三方框架：Masonry

demo工程在Gitee:pdfkit-demo.git

一、预览PDF文件

使用PDFKit.framework框架中的类有：PDFView、PDFDocument。

1、添加PDFView视图

// 预览PDF的容器视图
self.pdfView = [[PDFView alloc] initWithFrame:self.bounds];
// 设置每一页的内边距
self.pdfView.pageBreakMargins = UIEdgeInsetsMake(1, 0, 0, 0);
// 设置代理
self.pdfView.delegate = self;
// 设置自动适配
self.pdfView.autoScales = YES;
[self addSubview:self.pdfView];

2、给PDFView设置文件

// 创建文件
PDFDocument *document = [[PDFDocument alloc] initWithURL:[NSURL fileURLWithPath:localPDFPath]];
self.pdfView.document = document;

3、监听当前显示页码

// 监听页码发生改变
[[NSNotificationCenter defaultCenter] addObserverForName:PDFViewPageChangedNotification object:nil queue:nil usingBlock:^(NSNotification * _Nonnull note) {
    // 获取当前页码
    NSInteger currentPageIndex = self.pdfView.currentPage.label.integerValue;
    // 获取总页码
    NSInteger totalPageCount = self.pdfView.document.pageCount;
    // 指示器赋值
    weakSelf.indicatorLabel.text = [NSString stringWithFormat:@"%ld / %ld", currentPageIndex, totalPageCount];
}];

二、PDF文件添加涂鸦（绘制曲线）

使用PDFKit.framework框架中的类有：PDFAnnotation、PDFPage。


绘制曲线使用UIBezierPath完成。

原理：在touchesBegan / touchesMoved / touchesEnded方法中，使用UIBezierPath绘制一条曲线，把曲线转化为PDFAnnotation批注对象，并添加到绘制的PDFPage当前页上。

1、触摸开始

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    // 获取touch
    UITouch *touch = touches.anyObject;
    if (![touch.view isEqual:self]) {
        return;
    }
    // 获取开始时的上一次触摸点
    previousPointNew = [touch previousLocationInView:self];
    // 获取当前触摸点
    currentPoint = [touch locationInView:self];
    // 获取触摸点所在PDF页
    self.currentPage = [self.pdfView pageForPoint:previousPointNew nearest:YES];
    // 将触摸点转化为当前页的触摸点
    CGPoint currentPagePoint = [self.pdfView convertPoint:previousPointNew toPage:self.currentPage];
    // 创建PDF贝塞尔曲线(每次都新建曲线)
    self.drawPath = [UIBezierPath bezierPath];
    self.drawPath.lineCapStyle = kCGLineCapRound;
    self.drawPath.lineJoinStyle = kCGLineJoinRound;
    self.drawPath.lineWidth = self.lineWidth;
    [self.drawPath moveToPoint:currentPagePoint];
}

2、触摸移动

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    // 获取touch
    UITouch *touch = touches.anyObject;
    if (![touch.view isEqual:self]) {
        return;
    }
    // 记录上一个触摸点
    previousPointOld = previousPointNew;
    // 获取移动时的上一次触摸点
    previousPointNew = [touch previousLocationInView:self];
    // 获取当前触摸点
    currentPoint = [touch locationInView:self];
    // 将触摸点转化为当前页的触摸点
    CGPoint currentPagePointOld = [self.pdfView convertPoint:previousPointOld toPage:self.currentPage];
    CGPoint currentPagePointNew = [self.pdfView convertPoint:previousPointNew toPage:self.currentPage];
    CGPoint currentPagePointCurrent = [self.pdfView convertPoint:currentPoint toPage:self.currentPage];
    // 添加路径
    [self.drawPath addPathPreviousPreviousPoint:currentPagePointOld withPreviousPoint:currentPagePointNew withCurrentPoint:currentPagePointCurrent];

    // 移动时添加批注，实现手指滑动的过程中，有曲线显示
    if (self.moveAnnotation == nil) {
        CGRect bounds = [self.currentPage boundsForBox:self.pdfView.displayBox];
        self.moveAnnotation = [[PKPDFAnnotation alloc] initWithBounds:bounds forType:PDFAnnotationSubtypeInk withProperties:nil];
    }
    self.moveAnnotation.color = self.lineColor;
    self.moveAnnotation.path = self.drawPath;
    [self.currentPage addAnnotation:self.moveAnnotation];
}

3、触摸结束

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    // 获取touch
    UITouch *touch = touches.anyObject;
    if (![touch.view isEqual:self]) {
        return;
    }
    if (!self.moveAnnotation) {
        return;
    }
    // 移除移动过程中的标注
    [self.currentPage removeAnnotation:self.moveAnnotation];
    // 停止触摸，添加最终的曲线标注
    CGRect bounds = [self.currentPage boundsForBox:self.pdfView.displayBox];
    PKPDFAnnotation *annotation = [[PKPDFAnnotation alloc] initWithBounds:bounds forType:PDFAnnotationSubtypeInk withProperties:nil];
    annotation.color = self.lineColor;
    annotation.path = self.drawPath;
    [self.currentPage addAnnotation:annotation];
  
    // 再撤销数组中添加标注对象
    [self.lastAnnotations addObject:annotation];
    // 更新工具栏按钮状态
    [self updateToolsViewStatus];
    NSLog(@"停止批注个数：%ld", [self.currentPage annotations].count);
}

三、PDF文件添加文字

正在开发

四、PDF文件添加贴图

正在开发