Objective-C转换为X和Y.

Question

我一直在研究CGAffineTransforms,并想知道是否有办法拍摄你的视图并放大x,y坐标.我有缩放部分功能:

       CGAffineTransformMakeScale(4.00 ,4.00);

但是我不确定如何将缩放与可能的x,y坐标联系起来.有没有人做过这样的事情？我可能在使用这些功能时不正确吗？

       -(void)buttonSelected:(id)sender
       {
          UIButton *b = sender;
          CGPoint location = b.frame.origin;

          [UIView animateWithDuration:1.3f delay:0.0f options:UIViewAnimationCurveEaseIn animations:^{
               CGAffineTransform totalTransform =
               CGAffineTransformMakeTranslation(-location.x  , -location.y );
               totalTransform = CGAffineTransformScale(totalTransform, 4.0f, 4.0f);
               totalTransform = CGAffineTransformTranslate(totalTransform, location.x , location.y );
               [self.view setTransform:totalTransform];
           }completion:^(BOOL finished) {
           }];

       }

Answer 1

您可以构建一个执行以下三个步骤的转换:

• 移动点,您想要缩放到图层的中心;
• 规模;
• 将物体移回原位,使原来的中心回到中心位置.

所以,例如

// to use a point that is (109, 63) from the centre as the point to scale around
CGAffineTransform totalTransform =
                  CGAffineTransformMakeTranslation(-109.0f, -63.0f);
totalTransform = CGAffineTransformScale(totalTransform, 4.0f, 4.0f);
totalTransform = CGAffineTransformTranslate(totalTransform, 109.0f, 63.0f);

或者,可以说是更简单地调整view.layer的anchorPoint.第二个想法的问题是,当你第一次调整锚点时,你会得到一个立即变换,因为所有其他定位都是以中心为中心.