ios - 使用 UIPinchGestureRecognizer 捏合时限制 UIPanGestureRecognizer，适用于 iPad

Question

我正在尝试在 iPad View 上同时创建典型的捏缩放和平移。 View 本身包含 4 个其他 subview 。
我遇到的问题是，虽然我可以同时捏缩放和平移，但平移超出了范围，以至于您可以将 View 移出框架。

我尝试了几个平移限制，但它们似乎都只限制 Y 轴，或者同时限制 X 和 Y，但仅限于未放大的情况。

有什么建议么？

这是我用于捏缩放和平移手势的内容:

// for Pan Gesture
- (void) handlePanGestures:(UIPanGestureRecognizer *)recognizer
{
if (recognizer.state != UIGestureRecognizerStateEnded && recognizer.state != UIGestureRecognizerStateFailed)
{
    CGPoint translation = [recognizer translationInView:self.view];
    CGPoint finalPoint = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);

    CGPoint location = [recognizer locationInView:recognizer.view.superview];
    recognizer.view.center = location;

    // set final position
    recognizer.view.center = finalPoint;
    [recognizer setTranslation:CGPointZero inView:self.view];
}
}

// for Pinch Gesture
- (void)handlePinches:(UIPinchGestureRecognizer *)gestureRecognizer
{

if([gestureRecognizer state] == UIGestureRecognizerStateBegan)
{
    // Reset the last scale, necessary if there are multiple objects with different scales
    self.currentScale = [gestureRecognizer scale];
}

if ([gestureRecognizer state] == UIGestureRecognizerStateBegan ||
    [gestureRecognizer state] == UIGestureRecognizerStateChanged)
{

    CGFloat currentScale = [[[gestureRecognizer view].layer valueForKeyPath:@"transform.scale"] floatValue];

    // Constants to adjust the max/min values of zoom
    const CGFloat kMaxScale = 2.0;
    const CGFloat kMinScale = 1.0;

    CGFloat newScale = 1 -  (self.currentScale - [gestureRecognizer scale]);
    newScale = MIN(newScale, kMaxScale / currentScale);
    newScale = MAX(newScale, kMinScale / currentScale);
    CGAffineTransform transform = CGAffineTransformScale([[gestureRecognizer view] transform], newScale, newScale);
    [gestureRecognizer view].transform = transform;

    self.currentScale = [gestureRecognizer scale];  // Store the previous scale factor for the next pinch gesture call
}
}

Answer 1

试试这个，对我有用!

-(void)moveViewWithGestureRecognizer:(UIPanGestureRecognizer *)recognizer{

CGRect xRectRef = self.imageView.superview.frame;
CGPoint translation = [recognizer translationInView:self.imageView];

CGPoint xyNew = CGPointMake(self.imageView.frame.origin.x + translation.x, self.imageView.frame.origin.y + translation.y);

if (recognizer.state == UIGestureRecognizerStateChanged ) {

    if ( (xyNew.y <= xRectRef.origin.y) &&
        (xyNew.y + self.imageView.frame.size.height >= xRectRef.origin.y + xRectRef.size.height) &&
        (xyNew.x <= xRectRef.origin.x ) &&
        (xyNew.x + self.imageView.frame.size.width >= xRectRef.size.width+xRectRef.origin.x)){
        self.imageView.center = CGPointMake(self.imageView.center.x + translation.x,
                                             self.imageView.center.y + translation.y);
        [recognizer setTranslation:CGPointMake(0, 0) inView:self.imageView];
    }
}

}