macos - 如何使用 Facebook Pop 动画从中心缩放 NSView？

Question

请注意，这是一个与 Mac OS X (NSView) 相关的问题。

我正在尝试使用 Facebook 的 POP 动画从中心缩放 NSView(到其大小的 75%)，然后再回到 100%，但我无法让它工作。鉴于 kPOPLayerScaleXY 似乎不起作用，我做了以下操作，但这给了我不正确的结果(因为它似乎从左上角缩小，并且当 zoomIn 为 false , 它太大了:

  CGRect baseRect = CGRectMake(0, 0, 30, 24);
  CGFloat scale = (zoomIn) ? 0.75 : 1.0;

  CGFloat x = baseRect.origin.x;
  CGFloat y = baseRect.origin.y;
  CGFloat width = baseRect.size.width;
  CGFloat height = baseRect.size.height;

  if (zoomIn) {
    width -= floorf((1.0 - scale) * width);
    height -= floorf((1.0 - scale) * height);

    x += floorf((width * (1.0f - scale)) / 2);
    y += floorf((height * (1.0f - scale)) / 2);
  }

  CGRect scaleRect = CGRectMake(x, y, width, height);

  [myView.layer pop_removeAllAnimations];

  POPSpringAnimation *animation = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerBounds];
  animation.springBounciness = 8;
  animation.toValue = [NSValue valueWithCGRect: scaleRect];
  [myView.layer pop_addAnimation:animation forKey:@"zoom"];

Answer 1

我最终通过使用两个动画来让它工作:

  CGRect baseRect = CGRectMake(0, 0, 30, 24);
  CGFloat scale = (zoomIn) ? 0.80 : 1.0;

  CGFloat x = baseRect.origin.x;
  CGFloat y = baseRect.origin.y;

  if (zoomIn) {
    x = floorf((baseRect.size.width * (1.0 - scale)) / 2);
    y = floorf((baseRect.size.height * (1.0 - scale)) / 2);
  }

  [myView.layer pop_removeAllAnimations];

  POPSpringAnimation *animation = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];
  animation.springBounciness = 8;
  animation.toValue = [NSValue valueWithCGSize:CGSizeMake(scale, scale)];
  [myView.layer pop_addAnimation:animation forKey:@"zoom"];

  animation = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerTranslationXY];
  animation.springBounciness = 8;
  animation.toValue = [NSValue valueWithCGPoint:CGPointMake(x, y)];
  [myView.layer pop_addAnimation:animation forKey:@"translate"];