NSView 不绕中心旋转答案

【问题标题】：NSView not rotating around centerNSView 不绕中心旋转
【发布时间】：2018-11-26 08:35:18
【问题描述】：

我正在尝试围绕其中心旋转 NSView。但即使我更改了锚点，NSView 也会继续围绕其左上角旋转。 只是精度：我正在开发 OSX 10.8.5。

提前感谢您的帮助。

这是我的代码：

// myView.m
- (id)initWithFrame:(NSRect)rect
{
    if(self = [super initWithFrame:(NSRect)rect])
    {
        self.frame = rect;
        [self setWantsLayer:YES];
        self.layer.backgroundColor = [NSColor whiteColor].CGColor;
        self.layer.borderColor = [NSColor grayColor].CGColor;
        self.layer.borderWidth = 1.0;

        NSView *aView = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 50, 50)];
        [aView setWantsLayer:YES];
        aView.layer.backgroundColor = [NSColor redColor].CGColor;
        aView.layer.anchorPoint = CGPointMake(0.5, 0.5);

        [self addSubview:aView];

        CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
        rotateAnimation.byValue = [NSNumber numberWithFloat:2*M_PI];
        rotateAnimation.duration = 4;
        rotateAnimation.repeatCount = INFINITY;

        [aView.layer addAnimation:rotateAnimation forKey:@"rotationAnimation"];
    }
}

2018 年 11 月 30 日编辑：我设法使用图层获得居中旋转：

// myView.m
- (id)initWithFrame:(NSRect)rect
{
    if(self = [super initWithFrame:(NSRect)rect])
    {
        self.frame = rect;
        [self setWantsLayer:YES];
        self.layer.backgroundColor = [NSColor whiteColor].CGColor;
        self.layer.borderColor = [NSColor grayColor].CGColor;
        self.layer.borderWidth = 1.0;

        NSView *aView = [[NSView alloc] init];
        [aView setWantsLayer:YES];
        aView.layer.backgroundColor = [NSColor redColor].CGColor;
        aView.layer.bounds = CGRectMake(0, 0, 50, 50);
        aView.layer.frame = CGRectMake(0, 0, 50, 50);
        aView.layer.anchorPoint = CGPointMake(0.5, 0.5);
        aView.layer.position = CGPointMake(0, 0);

        [self.layer addSublayer:aView.layer];

        CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
        rotateAnimation.byValue = [NSNumber numberWithFloat:2*M_PI];
        rotateAnimation.duration = 4;
        rotateAnimation.repeatCount = INFINITY;

        [aView.layer addAnimation:rotateAnimation forKey:@"rotationAnimation"];
    }
}

【问题讨论】：

非常有用的例子！对于初学者，我喜欢添加两件事：1.）它需要添加 Quartz 框架库才能运行。 2.) 使用 Jeff 的示例代码，必须将 myView 的 View 添加到任何窗口。

标签： nsview cabasicanimation anchorpoint

【解决方案1】：

如果你想旋转视图，你可以这样做：

-(void)rotateByCenter:(NSView*)aView {

[aView setWantsLayer:YES];
aView.layer.anchorPoint = CGPointMake(0.5, 0.5);
aView.layer.position = CGPointMake(aView.frame.origin.x + aView.frame.size.width/2.,aView.frame.origin.y + aView.frame.size.height/2.) ;

CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
rotateAnimation.byValue = [NSNumber numberWithFloat:2*M_PI];
rotateAnimation.duration = 20;
rotateAnimation.repeatCount = INFINITY;

[aView.layer addAnimation:rotateAnimation forKey:@"rotationAnimation"]; }

【讨论】：