ios - Ipad 的 CGRect 中心

Question

我正在使用 CGRect 创建图像框架。我想将创建的矩形居中。

我在这里以及 Apple 文档中查看了执行此操作的最佳方法，并找到了获取中心坐标的 CGRectGetMidY 和 CGRectGetMidX。

当我尝试将它实现到我自己的代码中时，我遇到了问题。我得到一个在 UIIMageView 类型的对象上找不到的属性大小错误

       #import "MyViewController.h"



    @interface MyViewController ()

    @end

    @implementation MyViewController

    @synthesize mySignatureImage;
    @synthesize lastContactPoint1, lastContactPoint2, currentPoint;
    @synthesize imageFrame;
    @synthesize fingerMoved;
    @synthesize navbarHeight;

    - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
    {
        self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
        if (self) {
            // Custom initialization
        }
        return self;
    }

    - (void)viewDidLoad
    {
        [super viewDidLoad];



        self.view.backgroundColor = [UIColor lightGrayColor];

        CGRect mySignatureImageFrame = CGRectMake(
                                       CGRectGetMidX(self.view.frame) - (mySignatureImage.size.width/ 2.0),
                                       CGRectGetMidY(self.view.frame) - (mySignatureImage.size.height / 2.0),
                                       image.size.width,
                                       image.size.height);




#import <UIKit/UIKit.h>

@interface MyViewController : UIViewController <UIAlertViewDelegate>

@property (nonatomic, strong) UIImageView *mySignatureImage;
@property (nonatomic, assign) CGPoint lastContactPoint1, lastContactPoint2, currentPoint;
@property (nonatomic, assign) CGRect imageFrame;
@property (nonatomic, assign) BOOL fingerMoved;
@property (nonatomic, assign) float navbarHeight;


@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;

Answer 1

假设 image 是 UIImage 类型，那么:

CGRect imageFrame = CGRectMake(
    CGRectGetMidX(self.view.frame) - (image.size.width / 2.0),
    CGRectGetMidY(self.view.frame) - (image.size.height / 2.0),
    image.size.width,
    image.size.height);

假设 imageView 是 UIImageView 类型，那么:

CGRect imageFrame = CGRectMake(
    CGRectGetMidX(self.view.frame) - CGRectGetMidX(imageView.frame),
    CGRectGetMidY(self.view.frame) - CGRectGetMidY(imageView.frame),
    CGRectGetWidth(imageView.frame),
    CGRectGetHeight(imageView.frame));