iOS视图动画效果 CPAnimationSequence

     编写iOS视图UIView的动画效果需要很多代码，虽然iOS 4支持块定义，对视图动画的定义减少了不少代码，但语法依旧不好看。CPAnimationSequence是一个开源代码库，可以一种间接快捷的方式来定义描述动画队列，克服了写繁多的代码。下面一个使用例子：    <pre class="brush:cpp; toolbar: true; auto-links: false;">CPAnimationSequence* shakespeare = [CPAnimationSequence sequenceWithSteps:     [CPAnimationStep           for:0.2 animate:^{ self.romeo.alpha = 1.0; }],     [CPAnimationStep           for:0.2 animate:^{ self.julia.alpha = 1.0;  }],     [CPAnimationStep after:1.0 for:0.7 animate:^{                             CGPoint love = CGPointMake((self.romeo.center.x + self.julia.center.x)/2,                                                        (self.romeo.center.y + self.julia.center.y)/2);                             self.romeo.center = love;                             self.julia.center = love;     }],     [CPAnimationStep after:2.0 for:0.5 animate:^{ self.romeo.alpha = 0.0;                                                   self.julia.alpha = 0.0; }]     nil]; [shakespeare run];</pre>    <p><strong>项目主页：</strong><a href="http://www.open-open.com/lib/view/home/1326072094546" target="_blank">http://www.open-open.com/lib/view/home/1326072094546</a></p>