尝试对 UIView 上的椭圆进行动画处理,使其保持在中心位置进行缩放转换。
我找到了 CALayer - CABasicAnimation not scaling around center/anchorPoint ,然后将 bounds
属性添加到 maskLayer
CAShapeLayer
然而,这以掩码位于左角只有 1/其中有 4 个显示。我希望蒙版保持在屏幕中央。
@synthesize maskedView;
- (void)viewDidLoad
{
[super viewDidLoad];
UIViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"Next"];
vc.view.frame = CGRectMake(0,0, self.view.frame.size.width, self.view.frame.size.height);
vc.view.layer.bounds = self.view.layer.bounds;
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
CGRect maskRect = CGRectMake((self.view.frame.size.width/2)-50, (self.view.frame.size.height/2)-50, 100, 100);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddEllipseInRect(path, nil, maskRect);
[maskLayer setPath:path];
CGPathRelease(path);
vc.view.layer.mask = maskLayer;
[self.view addSubview:vc.view];
maskedView = vc.view;
[self startAnimation];
}
动画...
-(void)startAnimation
{
maskedView.layer.mask.bounds = CGRectMake((self.view.frame.size.width/2)-50, (self.view.frame.size.height/2)-50, 100, 100);
maskedView.layer.mask.anchorPoint = CGPointMake(.5,.5);
maskedView.layer.mask.contentsGravity = @"center";
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
animation.duration = 1.0f;
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation.fromValue = [NSNumber numberWithFloat:1.0f];
animation.toValue = [NSNumber numberWithFloat:5.0f];
[maskedView.layer.mask addAnimation:animation forKey:@"animateMask"];
}
更新
我似乎已经通过 position
键上的第二个动画修复了这个问题。这是正确的还是有更好的方法?
CABasicAnimation *animation2 = [CABasicAnimation animationWithKeyPath:@"position"];
animation2.duration = 1.0f;
animation2.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation2.fromValue = [NSValue valueWithCGPoint:CGPointMake((self.view.frame.size.width/2), (self.view.frame.size.height/2))];
animation2.toValue = [NSValue valueWithCGPoint:CGPointMake((self.view.frame.size.width/2), (self.view.frame.size.height/2))];
[toBeMask.layer.mask addAnimation:animation2 forKey:@"animateMask2"];
最佳答案
您可以围绕对象的中心而不是 (0, 0) 创建一个比例尺,如下所示:
CABasicAnimation *scale = [CABasicAnimation animationWithKeyPath:@"transform"];
CATransform3D tr = CATransform3DIdentity;
tr = CATransform3DTranslate(tr, self.bounds.size.width/2, self.bounds.size.height/2, 0);
tr = CATransform3DScale(tr, 3, 3, 1);
tr = CATransform3DTranslate(tr, -self.bounds.size.width/2, -self.bounds.size.height/2, 0);
scale.toValue = [NSValue valueWithCATransform3D:tr];
所以我们从“身份”转换开始(意思是“无转换”)。然后我们平移(移动)到物体的中心。然后我们扩展。然后我们回到原点,这样我们就回到了开始的地方(我们只想影响缩放操作)。
关于ios - CABasicAnimation - 变换比例保持在中心,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16447236/