围绕固定点旋转图像-Java 学习之路

首先，我是Objective C的新手，任何帮助都将不胜感激 . 我试着写一个Gauge应用程序（最终会显示手机的角度） . 我的问题是当我旋转Needle图像时，它旋转到正确的角度，但不是从Anchor点旋转 - 图像移动位置 . 即使我移动，从0渣到90，再回到0，图像也不会回到原来的位置！我正在使用的代码如下： . （PS我目前只在模拟器上运行应用程序）

*** Rotate Invoked by ....
// Rotate Image
[self rotateImage:_imgNeedle duration: vAnimationDuration curve: UIViewAnimationCurveLinear degrees:vValue];

-(void)rotateImage:(UIImageView *)image
       duration:(NSTimeInterval)duration
          curve:(int)curve
        degrees:(CGFloat)degrees
{
  // Setup the animation
  [self setAnchorPoint:CGPointMake(.44,.85) forView:image];
  // image.transform = CGAffineTransformMakeRotation(d2r(degrees));

  [UIView beginAnimations:nil context:NULL];
  [UIView setAnimationDuration:duration];
  [UIView setAnimationCurve:curve];
  [UIView setAnimationBeginsFromCurrentState:YES];

  // The transform matrix
  CGAffineTransform transform = CGAffineTransformMakeRotation(d2r(degrees));

  image.transform = transform;
  // Commit the changes
  [UIView commitAnimations];
}

// Set Anchor Point
-(void)setAnchorPoint:(CGPoint)anchorPoint forView:(UIView *)view
{
  CGPoint newPoint = CGPointMake(view.bounds.size.width * anchorPoint.x, view.bounds.size.height * anchorPoint.y);
  CGPoint oldPoint = CGPointMake(view.bounds.size.width * view.layer.anchorPoint.x, view.bounds.size.height * view.layer.anchorPoint.y);

  newPoint = CGPointApplyAffineTransform(newPoint, view.transform);
  oldPoint = CGPointApplyAffineTransform(oldPoint, view.transform);

  CGPoint position = view.layer.position;

  position.x -= oldPoint.x;
  position.x += newPoint.x;

  position.y -= oldPoint.y;
  position.y += newPoint.y;

  view.layer.position = position;
  view.layer.anchorPoint = anchorPoint;
}

1 回答

我不确定图层位置，但是当我更改anchorPoint时，框架会发生变化，所以我会调整框架 .

-(void)setAnchorPoint:(CGPoint)anchorPoint forView:(UIView *)view
{
  CGPoint newPoint = CGPointMake(view.bounds.size.width * anchorPoint.x, view.bounds.size.height * anchorPoint.y);
  CGPoint oldPoint = CGPointMake(view.bounds.size.width * view.layer.anchorPoint.x, view.bounds.size.height * view.layer.anchorPoint.y);

  newPoint = CGPointApplyAffineTransform(newPoint, view.transform);
  oldPoint = CGPointApplyAffineTransform(oldPoint, view.transform);
  /* 
  CGPoint position = view.layer.position;

  position.x -= oldPoint.x;
  position.x += newPoint.x;

  position.y -= oldPoint.y;
  position.y += newPoint.y;

  view.layer.position = position;
  */

  view.frame = CGRectOffset(view.frame, newPoint.x-oldPoint.x, newPoint.y-oldPoint.y);
  view.layer.anchorPoint = anchorPoint;
}

而且如果你想通过多次调用rotateImage回到原来的位置，我认为你应该只在此之前设置一个锚点 . 因为如果使用相同的rotateImage方法创建两个单独的动画，则将使用当前实现重新计算锚点 .

-(void)rotateImage:(UIImageView *)image
       duration:(NSTimeInterval)duration
          curve:(int)curve
        degrees:(CGFloat)degrees
{
  // Setup the animation
  // [self setAnchorPoint:CGPointMake(.44,.85) forView:image];
  // image.transform = CGAffineTransformMakeRotation(d2r(degrees));

  [UIView beginAnimations:nil context:NULL];
  [UIView setAnimationDuration:duration];
  [UIView setAnimationCurve:curve];
  [UIView setAnimationBeginsFromCurrentState:YES];

  // The transform matrix
  CGAffineTransform transform = CGAffineTransformMakeRotation(d2r(degrees));

  image.transform = transform;
  // Commit the changes
  [UIView commitAnimations];
}

回复于 2024-05-16T21:06:43+08:00

围绕固定点旋转图像

1 回答

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