我正在尝试使用CATransform3DMakeRotation
在UIView图层上执行3D旋转。我很困惑为什么这个简单的示例没有显示透视图,而是看起来像是被压扁了。使用CATransform3DRotate
时,我可以使旋转工作,但是我不想旋转,我想旋转。谢谢。
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
UIView *newView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
[newView setBackgroundColor:[UIColor orangeColor]];
UILabel *newLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, 50, 20)];
[newLabel setText:@"Hello"];
[newView addSubview:newLabel];
[self.window addSubview:newView];
CALayer *layer = newView.layer;
CATransform3D perspective = CATransform3DMakeRotation(1.0, 0, 1, 0);
perspective.m34 = -1 / 500;
layer.anchorPoint = CGPointMake(1.0, 0.5);
layer.zPosition = 99;
layer.transform = perspective;
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
这是它的屏幕截图:
大卫回答后的更新:
为了加强David的观点,即顺序很重要,我想看看矩阵的区别,并对此进行编码:
CATransform3D transform1 = CATransform3DMakeRotation(-1, 0, 1, 0);
transform1.m34 = -1.0 / 500.0;
NSLog(@"%f %f %f %f", transform1.m11, transform1.m12, transform1.m13, transform1.m14);
NSLog(@"%f %f %f %f", transform1.m21, transform1.m22, transform1.m23, transform1.m24);
NSLog(@"%f %f %f %f", transform1.m31, transform1.m32, transform1.m33, transform1.m34);
NSLog(@"%f %f %f %f", transform1.m41, transform1.m42, transform1.m43, transform1.m44);
NSLog(@"==============================");
CATransform3D transform2 = CATransform3DIdentity;
transform2.m34 = -1.0 / 500.0;
transform2 = CATransform3DRotate(transform2, -1, 0, 1, 0);
NSLog(@"%f %f %f %f", transform2.m11, transform2.m12, transform2.m13, transform2.m14);
NSLog(@"%f %f %f %f", transform2.m21, transform2.m22, transform2.m23, transform2.m24);
NSLog(@"%f %f %f %f", transform2.m31, transform2.m32, transform2.m33, transform2.m34);
NSLog(@"%f %f %f %f", transform2.m41, transform2.m42, transform2.m43, transform2.m44);
NSLog(@"==============================");
CATransform3D transform3 = CATransform3DIdentity;
transform3 = CATransform3DRotate(transform3, -1, 0, 1, 0);
transform3.m34 = -1.0 / 500.0;
NSLog(@"%f %f %f %f", transform3.m11, transform3.m12, transform3.m13, transform3.m14);
NSLog(@"%f %f %f %f", transform3.m21, transform3.m22, transform3.m23, transform3.m24);
NSLog(@"%f %f %f %f", transform3.m31, transform3.m32, transform3.m33, transform3.m34);
NSLog(@"%f %f %f %f", transform3.m41, transform3.m42, transform3.m43, transform3.m44);
产生以下输出:
0.540302 0.000000 0.841471 0.000000
0.000000 1.000000 0.000000 0.000000
-0.841471 0.000000 0.540302 -0.002000
0.000000 0.000000 0.000000 1.000000
==============================
0.540302 0.000000 0.841471 -0.001683
0.000000 1.000000 0.000000 0.000000
-0.841471 0.000000 0.540302 -0.001081
0.000000 0.000000 0.000000 1.000000
==============================
0.540302 0.000000 0.841471 0.000000
0.000000 1.000000 0.000000 0.000000
-0.841471 0.000000 0.540302 -0.002000
0.000000 0.000000 0.000000 1.000000
最佳答案
不幸的是,设置m34
值并不能使您了解所有魔术变换。由于旋转更改了变换的许多不同值,因此您需要在身份消息上设置透视图,然后旋转该变换。
CATransform3D rotationWithPerspective = CATransform3DIdentity;
rotationWithPerspective.m34 = -1.0/500.0;
rotationWithPerspective = CATransform3DRotate(rotationWithPerspective, angle, 0, 1, 0);
这与您所做的工作的区别在于,您创建了一个单位矩阵并为其设置了透视图,然后旋转该矩阵。问题是顺序很重要。
如果您知道矩阵数学,则可以验证两个变换之间的差异,并了解为什么您的变换没有任何角度。如果您对学习转换背后的数学感兴趣,我就为此写了a blog post(警告:它很长,仅包含数学)。
关于iphone - 使用CATransform3DMakeRotation时无视角,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/14839645/