Question

默认的PTArrowCreate类在屏幕上绘制指向用户最初点击的箭头。我希望箭头指向用户确实拖动手指的位置。

请给我一个提示，我如何实现这一目标。

Answer 1

当前没有内置选项，但是您可以通过子类实现。箭头注释是使用工具PTAnnotCreate创建的，可以在创建PTDocumentViewController之前通过注册子类来对其进行子类化：

[PTOverrides overrideClass:[PTArrowCreate class] withClass:[FWArrowCreate class]];

然后在子类中将箭头的头部与箭头的尾部交换如下：

@interface FWArrowCreate : PTArrowCreate

@end

@implementation FWArrowCreate

-(void)swapStartAndEndPoints
{
    CGPoint savedStartPoint = self.startPoint;
    self.startPoint = self.endPoint;
    self.endPoint = savedStartPoint;
}

-(void)drawRect:(CGRect)rect
{
    [self swapStartAndEndPoints];
    [super drawRect:rect];
    [self swapStartAndEndPoints];
}

- (BOOL)pdfViewCtrl:(PTPDFViewCtrl*)pdfViewCtrl onTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self swapStartAndEndPoints];

    BOOL result = [super pdfViewCtrl:pdfViewCtrl onTouchesEnded:touches withEvent:event];

    [self swapStartAndEndPoints];

    return result;
}

@end

Answer 2

Swift中相同的答案：

class MyArrowCreate: PTArrowCreate {
  override func draw(_ rect: CGRect) {
    swapPoints()
    super.draw(rect)
    swapPoints()
  }

  override func pdfViewCtrl(_ pdfViewCtrl: PTPDFViewCtrl, onTouchesEnded touches: Set<UITouch>, with event: UIEvent?) -> Bool {
    swapPoints()
    let result = super.pdfViewCtrl(pdfViewCtrl, onTouchesEnded: touches, with: event)
    swapPoints()
    return result
  }

  private func swapPoints() {
    let tmpPoint = startPoint
    startPoint = endPoint
    endPoint = tmpPoint
  }
}

PDFTron更改箭头注释方向iOS

2 个答案: