ios - UIButton-移动和缩放

Question

我有一个以编程方式创建的UIButton。实际上，它不应该是UIButton，我只需要有可能在图像上方标记一些区域。

所以我需要的功能-移动对象并调整其大小。为此，我有2种方法:

- (void) objMove:(id) sender withEvent:(UIEvent *) event
{
 UIControl *control = sender;
 UITouch *t = [[event allTouches] anyObject];
 CGPoint pPrev = [t previousLocationInView:control];
 CGPoint p = [t locationInView:control];
 CGPoint center = control.center;
 center.x += p.x - pPrev.x;
 center.y += p.y - pPrev.y;
 control.center = center;
}

- (void)objScale:(UIPinchGestureRecognizer *)recognizer
{
 UIView *pinchView = recognizer.view;
 CGRect bounds = pinchView.bounds;
 CGPoint pinchCenter = [recognizer locationInView:pinchView];
 pinchCenter.x -= CGRectGetMidX(bounds);
 pinchCenter.y -= CGRectGetMidY(bounds);
 CGAffineTransform transform = pinchView.transform;
 transform = CGAffineTransformTranslate(transform, pinchCenter.x, pinchCenter.y);
 CGFloat scale = recognizer.scale;
 transform = CGAffineTransformScale(transform, scale, scale);
 transform = CGAffineTransformTranslate(transform, -pinchCenter.x, -pinchCenter.y);
 pinchView.transform = transform;
 recognizer.scale = 1.0;
}

规模工作正常。直到我更改对象的大小之前，移动看起来都还不错-当我增加对象的大小时，它变得比手指移动得慢，反之亦然-如果对象小于原始对象，则移动得比手指快。为什么会这样？

Answer 1

我认为您应该在以下位置获得startPoint和startCenter

 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
 // get startPoint and startCenter here
}

- (void) objMove:(id) sender withEvent:(UIEvent *) event
{
 UIControl *control = sender;
 UITouch *t = [[event allTouches] anyObject];
 CGPoint p = [t locationInView:control];
 startCenter.x += p.x - startPoint.x;
 startCenter.y += p.y - startPoint.y;
 control.center = startCenter;
}

像这样更改您的代码，也许可以。

您的中心是当前中心，p是当前点，pPrev是上一个点。
当前中心加上上一点移动的大小是错误的。
您应该获得相对距离，而不是动态距离。