Core Animation笔记（变换）

1.仿射变换

CGAffineTransformMakeScale : 

CGAffineTransformMakeTranslation

CGAffineTransformMakeRotation(CGFloat angle)

  CGAffineTransform scaleTrans =  CGAffineTransformMakeScale(1.2, 1.2);
   
    CGAffineTransform tanslation = CGAffineTransformMakeTranslation(0, 100);
  
    //复合两个变换受，第二个受到第一个影响,所以这里位移小于100
    CGAffineTransform compact = CGAffineTransformConcat(scaleTrans, tanslation  
    
    self.imgView.layer.affineTransform = compact;

    //生成一个初始化的空值 单位矩阵
    CGAffineTransform indentity = CGAffineTransformIdentity;
    indentity = CGAffineTransformRotate(indentity, M_PI/2);
    //这里是右移 但实际效果是左移动，因为在之前做个旋转变换，上个变换会影响到下个变换，也就是说位移变换也要旋转90度相当于向左移！
    indentity = CGAffineTransformTranslate(indentity, 0, 200) ;

    self.imgView.layer.affineTransform = indentity;

2.3D 效果

  //透视效果
    CATransform3D indentity3d = CATransform3DIdentity;
    //设置m34来设置透视效果（看上去有立体感）
    indentity3d.m34 = -1.0/500;
    indentity3d = CATransform3DRotate(indentity3d, M_PI/4, 0, 1, 0);
    self.imgView.layer.transform = indentity3d;
    //是否绘制背面图形，默认YES 即图层的背面是正面的镜像
    self.imgView.layer.doubleSided = true;

    //为子类图层添加变换
    self.containerView.layer.sublayerTransform = indentity3d;