什么是沿着一系列点移动图像的最佳方式?
我的建议是将UIImage放入UIImageView中,并使用CAKeyframeAnimation来沿着一个通过你的三个点的路径动画你的UIImageView的层:
UIImage *image = [UIImage imageNamed:@"image.png"];
imageView = [[UIImageView alloc] initWithImage:image];
[mainView addSubview:imageView];
// Remember to remove the image view and release it when done with it
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.duration = 1.0f;
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;
CGMutablePathRef pointPath = CGPathCreateMutable();
CGPathMoveToPoint(pointPath, NULL, viewOrigin.x, viewOrigin.y);
CGPathAddLineToPoint(pointPath, NULL, point1.x, point1.y);
CGPathAddLineToPoint(pointPath, NULL, point2.x, point2.y);
CGPathAddLineToPoint(pointPath, NULL, point3.x, point3.y);
pathAnimation.path = pointPath;
CGPathRelease(pointPath);
[imageView.layer addAnimation:pathAnimation forKey:@"pathAnimation"];
请注意,默认情况下,图层的位置在图层的中心。如果您想相对于其他参考点移动图层,可以将图层的anchorPoint属性设置为(0.0,0.0)以表示其左上角(在iPhone上),或者将其设置为(0.0,1.0)以表示其左下角。
另外,这不会更改UIImageView的框架,因此,如果您之后引用该框架,则可能需要考虑这一点,或者在动画结束时添加委托方法回调以将其设置为正确的值。
您还可以通过使用CGPathAddCurveToPoint()替换CGPathAddLineToPoint()的调用,使您的图像沿着曲线移动,而不是直线移动。
编辑(5/14/2009):我添加了缺失的pathAnimation.path = pointPath行,并将一个错误输入的 curvedPath 更改为 pointPath。
最简单的方法是使用UIView动画。
一个快速的示例,假设您能够使用UIImageView来容纳您的图像,并使用NSArray来容纳您的点。
UIImage *image = [UIImage imageNamed:@"image.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[someView addSubview:imageView]; // Assume someView exists
NSValue *firstPoint = [NSValue valueWithCGPoint:CGPointMake(0, 0)];
NSValue *secondPoint = [NSValue valueWithCGPoint:CGPointMake(100, 0)];
NSValue *thirdPoint = [NSValue valueWithCGPoint:CGPointMake(100, 100)];
// And so on....
NSArray *points = [NSArray arrayWithObjects:firstPoint, secondPoint, thirdPoint, nil];
for (NSValue *pointValue in points) {
[UIView beginAnimations:@"UIImage Move" context:NULL];
CGPoint point = [pointValue CGPointValue];
CGSize size = imageView.frame.size;
imageView.frame = CGRectMake(point.x, point.y, size.width, size.height);
[UIView commitAnimations];
}