iPhone如何在相机应用程序中获得照片拍摄效果？

Question

I am talking about that effect when user presses button to take photo, it shrinks and moves to toolbar? How is this achieved in general?

Answer 1

so the shrink animation is achived by

 [UIView beginAnimations:@"animationShrink" context:NULL];
    [UIView setAnimationDuration:kSlideInAnimationDuration];

    flipFlopContainer.transform = CGAffineTransformMakeScale(0.01, 0.01);
    [UIView setAnimationDelegate:self];
    [UIView    setAnimationDidStopSelector:@selector(shrinkAnimationFinished:)];
    [UIView commitAnimations];

after this animation in shrinkAnimationFinished method you need to define a path to follow and change the position of your view accroding to that path.

See the following thread for that animation

Resize and move a UIView with Core Animation (CAKeyFrameAnimation)

Answer 2

You can create this by both scaling (applying a transform) and moving (animating the position) of the image.

I wrote about a similar animation (the Open in Background animation from Safari on iPhone) in this blog post . Not all of the code is necessary but some part of it will be useful for the animation you are trying to do.

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You should

• Calculate the scale factor to make the image the appropriate size
• Calculate the path you want to animate the image along.
• Animate a scale with the calculated scale factor
• Animate a position animation along the path (using a CAKeyframeAnimation)

Since you are doing two animations at once you could benefit from using a CAAnimationGroup.

Since you are animating down to a toolbar which probably is another part of the view hierarchy than where the image is you may need to use method like

- (CGRect)convertRect:(CGRect)rect toView:(UIView *)view

and

- (CGPoint)convertPoint:(CGPoint)point toView:(UIView *)view 

To translate coordinates between the different views.