围绕定位点问题旋转UIImageView

Question

我试图围绕锚点旋转UIImageView来模拟“雷达扫描”风格的动画。我对锚点的理解让我相信（1，1）应该是radar image的右下角。但是，将ImageView的定位点设置为此并不会给我预期的行为。这可以查看here。

可以看出，定位点是图片右侧的一种方式，尽管它位于中心位置。我想要的是图像围绕中心点旋转，就像雷达扫描一样。

下面是相关代码：

self.radarView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, barDimension, barDimension)]; 
self.radarView.contentMode = UIViewContentModeScaleAspectFill; 
self.radarView.image = [UIImage imageNamed:@"radarSweep.png"]; 
self.radarView.layer.anchorPoint = CGPointMake(1, 1); 
self.radarView.layer.position = CGPointMake(screenWidth/2.0, screenHeight/2.0); 
[self.mapView addSubview:self.radarView]; 

CABasicAnimation *opacityInAnim = [CABasicAnimation animationWithKeyPath:@"opacity"]; 
[opacityInAnim setFromValue:[NSNumber numberWithFloat:0.0]]; 
[opacityInAnim setToValue:[NSNumber numberWithFloat:1.0]]; 
opacityInAnim.duration = 0.25; 
opacityInAnim.fillMode = kCAFillModeForwards; 
opacityInAnim.removedOnCompletion = NO; 
opacityInAnim.beginTime = 0.0; 
opacityInAnim.delegate = self; 
[opacityInAnim setValue:@"radarSweep" forKey:@"animName"]; 

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"]; 
animation.fromValue = [NSNumber numberWithFloat:0.0]; 
animation.toValue = [NSNumber numberWithFloat:2 * M_PI]; 
animation.duration = 1.0f; 
animation.fillMode = kCAFillModeForwards; 
animation.repeatCount = 2; 
animation.removedOnCompletion = NO; 
[animation setBeginTime:0.0]; 
animation.delegate = self; 
[animation setValue:@"radarSweep" forKey:@"animName"]; 
animation.removedOnCompletion = YES; 

CABasicAnimation *opacityOutAnimBar = [CABasicAnimation animationWithKeyPath:@"opacity"]; 
[opacityOutAnimBar setFromValue:[NSNumber numberWithFloat:1.0f]]; 
[opacityOutAnimBar setToValue:[NSNumber numberWithFloat:0.0f]]; 
opacityOutAnimBar.delegate = self; 
opacityOutAnimBar.fillMode = kCAFillModeForwards; 
opacityOutAnimBar.removedOnCompletion = NO; 
[opacityOutAnimBar setDuration:0.25]; 
[opacityOutAnimBar setValue:@"radarSweep" forKey:@"animName"]; 
[opacityOutAnimBar setBeginTime:1.35]; 

CAAnimationGroup *group = [CAAnimationGroup animation]; 
[group setDuration:2.0]; 
group.delegate = self; 
group.fillMode = kCAFillModeForwards; 
group.removedOnCompletion = NO; 
[group setAnimations:@[opacityInAnim, animation, opacityOutAnimBar]]; 
[group setValue:@"radarSweep" forKey:@"animName"]; 
[self.radarView.layer addAnimation:group forKey:@"group"]; 

任何意见将不胜感激。提前致谢。

Answer 1

您的雷达图像不是正方形，但imageview是，所以图像出血越过imageView的边界。您可以执行self.radarView.layer.clipsToBounds = YES或将内容模式更改为ScaleToFit。或者您可以调整图像视图的大小以匹配雷达图像的比例。