在iOS中旋转视图时，如何计算仿射平移参数？
我的iOS应用程序中有一个UIToolbar，我使用CGAffineTransform在willRotateToInterfaceOrientation函数中以编程方式旋转它。变换需要缩放、旋转和平移。我知道如何计算比例和旋转参数，但似乎不知道如何计算平移参数，以便视图处于正确位置。经过多次尝试和错误，我确定了将视图移动到iPad上正确位置的确切数字，但我不希望硬编码这些数字，这样代码就不会太依赖于设备。如何计算转换参数 这是我当前在包含工具栏的视图控制器中的willRotateToInterfaceOrientation函数。我想知道如何计算下面的tx和ty，而不是硬编码值。我尝试过使用工具栏和窗口大小的各种功能，但是工具栏总是在一个奇怪的位置重叠窗口，或者完全在窗口之外，而不是在窗口的底部在iOS中旋转视图时，如何计算仿射平移参数？,ios,objective-c,cgaffinetransform,screen-rotation,translate-animation,Ios,Objective C,Cgaffinetransform,Screen Rotation,Translate Animation,我的iOS应用程序中有一个UIToolbar，我使用CGAffineTransform在willRotateToInterfaceOrientation函数中以编程方式旋转它。变换需要缩放、旋转和平移。我知道如何计算比例和旋转参数，但似乎不知道如何计算平移参数，以便视图处于正确位置。经过多次尝试和错误，我确定了将视图移动到iPad上正确位置的确切数字，但我不希望硬编码这些数字，这样代码就不会太依赖于设备。如何计算转换参数 这是我当前在包含工具栏的视图控制器中的willRotateToInterf
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
if (UIInterfaceOrientationIsLandscape(toInterfaceOrientation))
{
// First, apply identify transformation to simplify later calculations and also because we need the toolbar's frame and Apple's docs say you cannot use a view's frame if the transform property is not the identity matrix.
self.toolbar.transform = CGAffineTransformIdentity;
// Calculate affine parameters.
// Expand width to the window's height when in landscape mode, leaving the toolbar's height unchanged.
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
CGFloat sx = 1.0;
CGFloat sy = window.frame.size.height / window.frame.size.width;
// Rotate 90 degrees in either direction depending on the orientation direction change.
CGFloat rotate = M_PI_2;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
rotate = -M_PI_2;
}
// Reposition the toolbar.
// TODO: Calculate values rather than hard-coding them. Why is tx not something like ((window.frame.size.width / 2) - (self.toolbar.frame.size.height / 2))?
// Note that these values work for both the original iPad and iPad Retina, presumably because the values represent points not pixels.
CGFloat tx = -365.5;
CGFloat ty = 359.5;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
tx = -tx;
}
// Apply affine transformation.
CGAffineTransform transform = CGAffineTransformMakeScale(sx, sy);
transform = CGAffineTransformRotate(transform, rotate);
transform = CGAffineTransformTranslate(transform, tx, ty);
[UIView animateWithDuration:duration
animations:^{
self.toolbar.transform = transform;
}
completion:NULL
];
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortrait)
{
[UIView animateWithDuration:duration
animations:^{
self.toolbar.transform = CGAffineTransformIdentity;
}completion:NULL
];
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
NSLog(@"Upside-down orientation not supported");
}
}
// The toolbar is strong since this controller must maintain ownership as the toolbar is removed from the parent view when this view disappears.
@property (strong, nonatomic) IBOutlet UIToolbar *toolbar;
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
CGFloat height = CGRectGetHeight(self.tabBarController.tabBar.frame); // Completely cover the tab bar.
CGFloat x = window.frame.origin.x;
CGFloat y = window.frame.size.height - height;
CGFloat width = window.frame.size.width;
self.toolbar.frame = CGRectMake(x, y, width, height);
[window addSubview:self.toolbar];
最后，我使用的Xcode 4.5.1启用了ARC，并在iPad Retina和非Retina 5.1和6.0模拟器上进行了测试。来自UIView类参考：transform-指定应用于接收器的相对于其边界中心的变换。这意味着您的CGAffineTransform正在围绕长方体的中心旋转，而不是围绕帧原点旋转。需要相对于原点相对于旋转的位移偏移原点。这些数字是边界框尺寸的函数
有关使用边界的示例，请参见此处：来自UIView类参考：transform-指定应用于接收器的相对于其边界中心的变换。这意味着您的CGAffineTransform正在围绕长方体的中心旋转，而不是围绕帧原点旋转。需要相对于原点相对于旋转的位移偏移原点。这些数字是边界框尺寸的函数
请参见此处使用边界的示例：使用CGAffineTransform时，您需要非常小心操作顺序，正如David提到的，您需要知道旋转或调整大小的位置。人们经常会对旋转的结果感到惊讶，不管锚点是什么，也不管你用仿射旋转的点是什么 如果我们的出发点是： 您可以使锚点位于0、0或图像的中心。两者都可以。这两者都不可能单独给你想要的东西 这里是从0，0： 如果你只是想旋转一个视图来显示它，如果你有0，0锚定点，你旋转，想知道我的视图发生了什么！！！但是你可以把它翻译到你想要的地方 以下是将定位点设置在图像中心的示例：
您可以看到结果视图，但它在垂直和水平方向上都处于关闭状态，因为它是一个矩形，并且边的长度不同。不过，通过移动x的原始高度差和移动y的原始宽度差，您可以轻松地进行调整。使用CGAffineTransform，您需要非常小心操作顺序，正如David提到的，您需要知道旋转或调整大小的位置。人们经常会对旋转的结果感到惊讶，不管锚点是什么，也不管你用仿射旋转的点是什么 如果我们的出发点是： 您可以使锚点位于0、0或图像的中心。两者都可以。这两者都不可能单独给你想要的东西 这里是从0，0： 如果你只是想旋转一个视图来显示它，如果你有0，0锚定点，你旋转，想知道我的视图发生了什么！！！但是你可以把它翻译到你想要的地方 以下是将定位点设置在图像中心的示例：
您可以看到结果视图，但它在垂直和水平方向上都处于关闭状态，因为它是一个矩形，并且边的长度不同。不过，您可以通过按原始高差移动x和按原始宽度差移动y来轻松地进行调整。在将工具栏的定位点从默认值.5、.5设置为0、0后，我能够解决此问题
// The toolbar is strong since this controller must maintain ownership as the toolbar is removed from the parent view when this view disappears.
@property (strong, nonatomic) IBOutlet UIToolbar *toolbar;
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
// Set anchor point to the top-left corner instead of to the center (.5, .5) so that affine transformations during orientation changes are easier to calculate.
self.toolbar.layer.anchorPoint = CGPointMake(0, 0);
CGFloat height = CGRectGetHeight(self.tabBarController.tabBar.frame); // Completely cover the tab bar.
CGFloat x = window.frame.origin.x;
CGFloat y = window.frame.size.height - height;
CGFloat width = window.frame.size.width;
self.toolbar.frame = CGRectMake(x, y, width, height);
[window addSubview:self.toolbar];
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
[self willRotateView:self.toolbar toInterfaceOrientation:toInterfaceOrientation duration:duration];
}
- (void)willRotateView:(UIView *)view toInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
if (UIInterfaceOrientationIsLandscape(toInterfaceOrientation))
{
// First, apply identify transformation to simplify later calculations and also because we need the view's frame and Apple's docs say you cannot use a view's frame if the transform property is not the identity matrix.
view.transform = CGAffineTransformIdentity;
// Calculate affine parameters.
// Get the window's post-orientation change dimensions.
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
CGFloat rotatedWinWidth = window.frame.size.height;
CGFloat rotatedWinHeight = window.frame.size.width;
// Expand width to the window's height when in landscape mode, leaving the view's height unchanged. The scaling is done along the Y axis since the window's origin will change such that the Y axis will still run along the longer direction of the device.
CGFloat sx = 1.0;
CGFloat sy = rotatedWinWidth / rotatedWinHeight;
// Rotate 90 degrees in either direction depending on the orientation direction change.
CGFloat angle = M_PI_2;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
angle = -M_PI_2;
}
// Reposition the view, assuming that view.layer.anchorPoint is (0, 0).
// Note that the height of the view is used as the X offset as this corresponds to the X direction since the rotated window's origin will also rotate. Also, the position has to take into account the width scale factor.
CGFloat xOffset = view.frame.size.height;
CGFloat tx = -(rotatedWinWidth - xOffset) / sy;
CGFloat ty = -view.frame.size.height;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
tx = -xOffset / sy;
ty = rotatedWinHeight - view.frame.size.height;
}
// Apply affine transformation.
CGAffineTransform transform = CGAffineTransformMakeScale(sx, sy);
transform = CGAffineTransformRotate(transform, angle);
transform = CGAffineTransformTranslate(transform, tx, ty);
[UIView animateWithDuration:duration
animations:^{
view.transform = transform;
}
completion:NULL
];
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortrait)
{
[UIView animateWithDuration:duration
animations:^{
view.transform = CGAffineTransformIdentity;
}completion:NULL
];
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
DLog(@"Upside-down orientation not supported");
}
}
在将工具栏的锚点从默认值.5、.5设置为0,0后，我能够解决这个问题
// The toolbar is strong since this controller must maintain ownership as the toolbar is removed from the parent view when this view disappears.
@property (strong, nonatomic) IBOutlet UIToolbar *toolbar;
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
// Set anchor point to the top-left corner instead of to the center (.5, .5) so that affine transformations during orientation changes are easier to calculate.
self.toolbar.layer.anchorPoint = CGPointMake(0, 0);
CGFloat height = CGRectGetHeight(self.tabBarController.tabBar.frame); // Completely cover the tab bar.
CGFloat x = window.frame.origin.x;
CGFloat y = window.frame.size.height - height;
CGFloat width = window.frame.size.width;
self.toolbar.frame = CGRectMake(x, y, width, height);
[window addSubview:self.toolbar];
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
[self willRotateView:self.toolbar toInterfaceOrientation:toInterfaceOrientation duration:duration];
}
- (void)willRotateView:(UIView *)view toInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
if (UIInterfaceOrientationIsLandscape(toInterfaceOrientation))
{
// First, apply identify transformation to simplify later calculations and also because we need the view's frame and Apple's docs say you cannot use a view's frame if the transform property is not the identity matrix.
view.transform = CGAffineTransformIdentity;
// Calculate affine parameters.
// Get the window's post-orientation change dimensions.
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
CGFloat rotatedWinWidth = window.frame.size.height;
CGFloat rotatedWinHeight = window.frame.size.width;
// Expand width to the window's height when in landscape mode, leaving the view's height unchanged. The scaling is done along the Y axis since the window's origin will change such that the Y axis will still run along the longer direction of the device.
CGFloat sx = 1.0;
CGFloat sy = rotatedWinWidth / rotatedWinHeight;
// Rotate 90 degrees in either direction depending on the orientation direction change.
CGFloat angle = M_PI_2;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
angle = -M_PI_2;
}
// Reposition the view, assuming that view.layer.anchorPoint is (0, 0).
// Note that the height of the view is used as the X offset as this corresponds to the X direction since the rotated window's origin will also rotate. Also, the position has to take into account the width scale factor.
CGFloat xOffset = view.frame.size.height;
CGFloat tx = -(rotatedWinWidth - xOffset) / sy;
CGFloat ty = -view.frame.size.height;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
tx = -xOffset / sy;
ty = rotatedWinHeight - view.frame.size.height;
}
// Apply affine transformation.
CGAffineTransform transform = CGAffineTransformMakeScale(sx, sy);
transform = CGAffineTransformRotate(transform, angle);
transform = CGAffineTransformTranslate(transform, tx, ty);
[UIView animateWithDuration:duration
animations:^{
view.transform = transform;
}
completion:NULL
];
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortrait)
{
[UIView animateWithDuration:duration
animations:^{
view.transform = CGAffineTransformIdentity;
}completion:NULL
];
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
DLog(@"Upside-down orientation not supported");
}
}
谢谢你的回复。我的理解是，非Make函数CgaffinetTransformTranslate而不是CgaffinetTransformMakeTranlate通过将给定参数应用于现有仿射变换来构造新的变换矩阵。@user19480您完全正确，我的错误，我忽略了它不是Make类型的事实。抱歉，谢谢你的回复。我的理解是，非Make函数CgaffinetTransformTranslate而不是CgaffinetTransformMakeTranlate通过将给定参数应用于现有仿射变换来构造新的变换矩阵。@user19480您完全正确，我的错误，我忽略了它不是Make类型的事实。抱歉。谢谢你提供的信息和非常有用的图表。是的，我需要更改视图的定位点，这使我能够计算所需的转换值。感谢您提供的信息和非常有用的图表。是的，我需要更改视图的定位点，这使我能够计算所需的平移值。