3

就像图片中的路径

（新用户不能发图片，抱歉只能给链接）

http://cdn.dropmark.com/30180/3bd0f0fc6ee77c1b6f0e05e3ea14c821f8b48a82/questiong1-1.jpg

非常感谢您的帮助

4

2 回答 2

3

在触摸事件委托上试试这个（如果你想用触摸事件旋转视图）-

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
  {
    touches = [event allTouches];
    UITouch *touch = [[event allTouches] anyObject];

    CGPoint Pageposition = [touch locationInView:self];

    CGPoint prevPoint = [[[touches allObjects] objectAtIndex:0] previousLocationInView:self];
    CGPoint curPoint = [[[touches allObjects] objectAtIndex:0] locationInView:self];

    float prevAngle = atan2(prevPoint.x, prevPoint.y);
    float curAngle= atan2(curPoint.x, curPoint.y);
    float angleDifference = curAngle - prevAngle;

    CGAffineTransform newTransform3 = CGAffineTransformRotate(self.transform, angleDifference);
    self.transform = newTransform3;
  }

使用变换旋转，并告诉我它是否有效..

于 2012-05-23T13:51:53.917 回答
2

请查看我对“围绕任意点旋转标签”的问题的回答，以获得有关旋转时使用锚点的更详细说明（忽略关键帧动画答案，因为它们更复杂，而不是“正确的工具”工作”，即使答案是这样说的）。

简而言之：将锚点设置为点（在视图层的单位坐标系中）到视图之外的点，然后应用正常的旋转动画。

编辑：要记住的一件事

图层的框架（也是视图的框架）是使用位置、边界和锚点计算的。更改锚点将更改您的视图在屏幕上的显示位置。您可以通过在更改锚点后重新设置框架来解决此问题（这将为您设置位置）。否则，您可以将位置设置为您自己旋转的点。Layer Geometry and Transforms（链接到另一个问题）也提到了这一点。

我在该答案中提供的代码（概括为 UIView 和核心动画而不是 UIView 动画）：

#define DEGREES_TO_RADIANS(angle) (angle/180.0*M_PI)

- (void)rotateView:(UIView *)view 
       aroundPoint:(CGPoint)rotationPoint 
          duration:(NSTimeInterval)duration 
           degrees:(CGFloat)degrees {

    CABasicAnimation *rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];
    [rotationAnimation setDuration:duration];
    // Additional animation configurations here...
    
    // The anchor point is expressed in the unit coordinate
    // system ((0,0) to (1,1)) of the label. Therefore the 
    // x and y difference must be divided by the width and 
    // height of the view (divide x difference by width and 
    // y difference by height).
    CGPoint anchorPoint = CGPointMake((rotationPoint.x - CGRectGetMinX(view.frame))/CGRectGetWidth(view.bounds),
                                      (rotationPoint.y - CGRectGetMinY(view.frame))/CGRectGetHeight(view.bounds));

    [[view layer] setAnchorPoint:anchorPoint];
    [[view layer] setPosition:rotationPoint]; // change the position here to keep the frame
    CATransform3D rotationTransform = CATransform3DMakeRotation(DEGREES_TO_RADIANS(degrees), 0, 0, 1);
    [rotationAnimation setToValue:[NSValue valueWithCATransform3D:rotationTransform]];
    
    // Add the animation to the views layer
    [[view layer] addAnimation:rotationAnimation
                        forKey:@"rotateAroundAnchorPoint"]  
}
于 2012-05-23T13:39:58.527 回答