Question

如何在图像上的UIPanGestureRecognizer中添加直线垂直幻灯片。我有一些代码：

- (IBAction)HandlePan:(UIPanGestureRecognizer *)panner
{
    CGPoint translation = [panner translationInView:panner.view];
    CGPoint newCenter = CGPointMake(self.pesawat.center.x + translation.x, self.pesawat.center.y);

    int offset = 80; // pixels to offset

    if (newCenter.x < offset)
        newCenter = CGPointMake(offset, newCenter.y);
    else if (newCenter.x > self.view.bounds.size.width - offset) 
        newCenter = CGPointMake(self.view.bounds.size.width - offset, newCenter.y);

    self.pesawat.center = newCenter;
    [panner setTranslation:CGPointMake(0, 0) inView:panner.view];
}

如果我将代码改为这样：

CGPoint newCenter = CGPointMake(self.pesawat.center.x + translation.x, self.pesawat.center.y + translation.y);

它变得可以拖动（水平，垂直，对角线），我想要的只是使它垂直和水平直线而没有图像移动对角线

和这个viewdidload：

UIPanGestureRecognizer * panner = [[UIPanGestureRecognizer alloc]init];
[panner addTarget:self action:@selector(HandlePan:)];
[self.view addGestureRecognizer:panner];

任何人都可以提示吗？

Answer 1

CGPoint translation = [panner translationInView:panner.view];
if (translation.x > translation.y)
    translation.y = 0.0f;
else
    translation.x = 0.0f;

CGPoint newCenter = CGPointMake(self.pesawat.center.x + translation.x, self.pesawat.center.y + translation.y);

这仅适用于translation的较大部分。

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