Xcode:当我的图像旋转到非90度的角度时，它会改变位置

Question

我有一个程序，我想要有一个图像，可以使用以下选项之一手动旋转:左1度或5度，右1度或5度，或设置旋转到的特定度数。所有的机制都工作得很好，但只要图像旋转到一定程度(而不是0、90、180、270或360度)，整个图像就会向下右移。它一直这样做，直到它达到45度角，然后开始移回起始位置，我不知道为什么。我尝试了许多修复方法，但都没有任何效果。

h.file：

    //
//  AirNavViewController.h
//  Compass
//
//  Created by JDS on 5/26/14.
//  Copyright (c) 2014 THE OHIO STATE UNIVERSITY. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface AirNavViewController : UIViewController {


    int Rotation;
    float degrees;


}

@property (weak, nonatomic) IBOutlet UIImageView *Compass;
@property (weak, nonatomic) IBOutlet UILabel *RotationLabel;
@property (weak, nonatomic) IBOutlet UISlider *DegreesSlider;

    -(IBAction)Left5:(id)sender;
    -(IBAction)Left1:(id)sender;
    -(IBAction)Right1:(id)sender;
    -(IBAction)Right5:(id)sender;
    -(IBAction)SliderMoved:(id)sender;
    -(IBAction)CustomRotate:(id)sender;


@end

m.file：

//
//  AirNavViewController.m
//  Compass
//
//  Created by JDS on 5/26/14.
//  Copyright (c) 2014 THE OHIO STATE UNIVERSITY. All rights reserved.
//

#import "AirNavViewController.h"

@interface AirNavViewController ()

@end

@implementation AirNavViewController


    @synthesize Compass, RotationLabel, DegreesSlider;


- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    RotationLabel.text = [NSString stringWithFormat:@"0°"];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(IBAction)SliderMoved:(id)sender{

    degrees = DegreesSlider.value;
    RotationLabel.text = [NSString stringWithFormat:@"%.0f°", degrees];

}


-(IBAction)CustomRotate:(id)sender{

    Compass.transform = CGAffineTransformMakeRotation(degrees*M_PI/180);
    Rotation = degrees;

}


-(IBAction)Left5:(id)sender{

    Rotation = Rotation-5;

    if (Rotation > 359) {Rotation = Rotation-360;}
    if (Rotation < 0) {Rotation = Rotation+360;}

    Compass.transform = CGAffineTransformMakeRotation((Rotation*M_PI)/180);

}


-(IBAction)Left1:(id)sender{

    Rotation = Rotation-1;

    if (Rotation > 359) {Rotation = Rotation-360;}
    if (Rotation < 0) {Rotation = Rotation+360;}

    Compass.transform = CGAffineTransformMakeRotation((Rotation*M_PI)/180);

}


-(IBAction)Right1:(id)sender{

    Rotation = Rotation+1;

    if (Rotation > 359) {Rotation = Rotation-360;}
    if (Rotation < 0) {Rotation = Rotation+360;}

    Compass.transform = CGAffineTransformMakeRotation((Rotation*M_PI)/180);
}


-(IBAction)Right5:(id)sender{

    Rotation = Rotation+5;

    if (Rotation > 359) {Rotation = Rotation-360;}
    if (Rotation < 0) {Rotation = Rotation+360;}

    Compass.transform = CGAffineTransformMakeRotation((Rotation*M_PI)/180);
}

@end

Answer 1

首先，一些代码注释。

删除@synthesize代码。不再需要它。属性和iVars应以小写字母开头。

无论如何，从布局代码的缺乏来看，我猜测您使用的是AutoLayout。

在这种情况下，将对图像视图进行约束，以指定...

从顶部到左侧的距离。(或底部或右侧)。

这些工作的方式是，它们采用图像视图的最小封闭(非旋转)矩形，并定位该矩形，使其符合约束。

因为当旋转到45度时，封闭的矩形会变得更大，所以图像看起来像是在移动。

您可以将约束条件更改为如下所示：

将中心与屏幕的中心对齐或类似的东西。