CGAffineTransform 实用技巧

struct CGAffineTransform {
   CGFloat a;
   CGFloat b;
   CGFloat c;
   CGFloat d;
   CGFloat tx;
   CGFloat ty;
};

a表示x水平方向的缩放，tx表示x水平方向的偏移
d表示y垂直方向的缩放，ty表示y垂直方向的偏移
如果b和c不为零的话，那么视图肯定发生了旋转

位移代码

-(void)positionAnimation{
    _demoView.transform = CGAffineTransformIdentity;
    [UIView animateWithDuration:1.0f animations:^{
        _demoView.transform = CGAffineTransformMakeTranslation(100, 100);
    }];
}

缩放代码

-(void)scaleAnimation{
    _demoView.transform = CGAffineTransformIdentity;
    [UIView animateWithDuration:1.0f animations:^{
        _demoView.transform = CGAffineTransformMakeScale(2, 2);
    }];
}

旋转变换

-(void)rotateAnimation{
    _demoView.transform = CGAffineTransformIdentity;
    [UIView animateWithDuration:1.0f animations:^{
        _demoView.transform = CGAffineTransformMakeRotation(M_PI);
    }];
}

组合 变换

-(void)combinationAnimation{
    //仿射变换的组合使用
    _demoView.transform = CGAffineTransformIdentity;
    [UIView animateWithDuration:1.0f animations:^{
        CGAffineTransform transform1 = CGAffineTransformMakeRotation(M_PI);
        CGAffineTransform transform2 = CGAffineTransformScale(transform1, 0.5, 0.5);
        _demoView.transform = CGAffineTransformTranslate(transform2, 100, 100);
    }];
}

矩阵反转

-(void)invertAnimation{
    _demoView.transform = CGAffineTransformIdentity;
    [UIView animateWithDuration:1.0f animations:^{
        //矩阵反转
        _demoView.transform = CGAffineTransformInvert(CGAffineTransformMakeScale(2, 2));
    }];
}

四、补充

CGAffineTransformIdentity ： 单位矩阵变换，一般用于仿射变换的初始化或者还原。
CGAffineTransformEqualToTransform(CGAffineTransform t1, 
CGAffineTransform t2) ： 判断两个变换矩阵是否相等
CGAffineTransformConcat(CGAffineTransform t1, 
CGAffineTransform t2) ： 得到两个矩阵相加后得到的最终矩阵
CGPoint CGPointApplyAffineTransform(CGPoint point, 
CGAffineTransform t) ： 某点通过矩阵变换之后的点
CGSize CGSizeApplyAffineTransform(CGSize size, CGAffineTransform t) ： 某个size通过矩阵变换之后的size
CGRect CGRectApplyAffineTransform(CGRect rect, CGAffineTransform t) ： 某个Rect通过矩阵变换之后的区域