如何使用 CABasic 动画从屏幕顶部到底部制作动画时获取图像帧

Question

我正在使用 CABasicAnimation 从屏幕的顶部到底部对图像进行动画处理。我需要 当图像从上到下动画时获取图像的框架......

代码：

-(id)init
  {
    if(self = [super init])
    {
      self.title =@"Apple Catch";
      mView = [[UIView alloc]initWithFrame:CGRectMake(0,0,320,440)];

      // start a timet that will fire 20 times per second
      [NSTimer scheduledTimerWithTimeInterval:(0.9) target:self selector:@selector(onTimer) 
      userInfo:nil repeats:YES];
      self.view=mView;
    }
    return self;

  }

  - (void)onTimer
    {
      CGImageRef imageRef = [[UIImage imageNamed:@"apple.png"] CGImage];
      int startX = round(random() % 460);
      double speed = 1 / round(random() %100) + 1.0;
      CALayer *layer = [CALayer layer];
      layer.name = @"layer";
      layer.contents = imageRef; 
      layer.frame = CGRectMake(startX, self.view.frame.origin.y, CGImageGetWidth(imageRef),
      CGImageGetHeight(imageRef));
      [mView.layer addSublayer:layer];

      CGPoint start = CGPointMake(startX, 0);
      CGPoint end = CGPointMake(startX, self.view.frame.size.height+10);

      CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"];
      animation.delegate = self;
      animation.fromValue = [NSValue valueWithCGPoint:start];
      animation.toValue = [NSValue valueWithCGPoint:end];
      animation.duration = 10*speed;

      //animation.repeatCount = repeatCount;
      animation.autoreverses = NO;
      animation.removedOnCompletion   = YES;
      animation.fillMode = kCAFillModeForwards;

      [layer addAnimation:animation forKey:@"position"];

      BOOL intersects = CGRectIntersectsRect(layer.frame , dragger.frame);
      printf("\n ==== intersects value :%d",intersects);
    }

我需要在视图上路径的每个点处进行动画处理的图像的框架。

你能建议一下这个代码吗？

感谢你

Answer 1

使用 presentationLayer 应用动画的 CALayer 属性。

Answer 2

朋友你好
你可以尝试 if (CGRectIntersectsRect(layer.frame,dragger.frame) ) {

nslog(@"hiiii");

}