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基本关键帧动画(旋转)

core-animation iphone

14

ron · 技术社区 · 17 年前

我试图创建一个非常简单的关键帧动画,通过一个给定的中点,一个图形从一个角度旋转到另一个角度。

(目的是能够通过钝角弧角大于180度,而不是动画“欺骗”和走最短路线,即通过相反方向。 ~~,急性~~ 较小的角度——当只有一个关键帧(即目的地)时会发生这种情况。为了走“远”的路,我想我需要一个额外的关键帧在中间,沿着 渴望的 弧)

以下是我迄今为止的成果(通过最锐利的角度使图形达到所需的旋转角度):

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

...

[UIView beginAnimations:nil context:nil];
CGAffineTransform cgCTM = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(desiredEndingAngle));
[UIView setAnimationDuration:0.5];
graphic.transform = cgCTM;
[UIView commitAnimations];

据我所知,我并不想沿着路径寻找动画(因为这是为了翻译,而不是旋转)。

不管怎样,任何帮助都是非常感谢的!事先谢谢。

3 回复 | 直到 14 年前

1

18

ron 17 年前

我想我明白了。

这里是s代码,它(在本例中)执行完整的270度旋转(1.5*pi弧度),包括可以进一步定制的各种参数:

CALayer *layer = rotatingImage.layer;
CAKeyframeAnimation *animation;
animation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"];
animation.duration = 0.5f;
animation.cumulative = YES;
animation.repeatCount = 1;
animation.values = [NSArray arrayWithObjects:       // i.e., Rotation values for the 3 keyframes, in RADIANS
      [NSNumber numberWithFloat:0.0 * M_PI], 
      [NSNumber numberWithFloat:0.75 * M_PI], 
      [NSNumber numberWithFloat:1.5 * M_PI], nil]; 
animation.keyTimes = [NSArray arrayWithObjects:     // Relative timing values for the 3 keyframes
      [NSNumber numberWithFloat:0], 
      [NSNumber numberWithFloat:.5], 
      [NSNumber numberWithFloat:1.0], nil]; 
animation.timingFunctions = [NSArray arrayWithObjects:
      [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn],    // from keyframe 1 to keyframe 2
      [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut], nil]; // from keyframe 2 to keyframe 3
animation.removedOnCompletion = NO;
animation.fillMode = kCAFillModeForwards;

[layer addAnimation:animation forKey:nil];

谢谢!

2

1

Nathan de Vries 17 年前

试试这个:

UIImageView* rotatingImage = [[UIImageView alloc] init]];
[rotatingImage setImage:[UIImage imageNamed:@"someImage.png"]];

CATransform3D rotationTransform = CATransform3DMakeRotation(1.0f * M_PI, 0, 0, 1.0);
CABasicAnimation* rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];

rotationAnimation.toValue = [NSValue valueWithCATransform3D:rotationTransform];
rotationAnimation.duration = 0.25f;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = 1;

[rotatingImage.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];

3

1

Vinoth 14 年前

CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, 100, 100);
CGPathAddQuadCurveToPoint(path, NULL, 100, 100, 100, 615);
CGPathAddQuadCurveToPoint(path, NULL, 100, 615, 900, 615);
CGPathAddQuadCurveToPoint(path, NULL, 900, 615, 900, 100);
CGPathAddQuadCurveToPoint(path, NULL, 900, 100, 100, 80);
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.path = path;
pathAnimation.duration = 10.0;
[someLayer addAnimation:pathAnimation forKey:nil];