詳解iOS裁剪圓形圖像并顯示(類似于微信頭像)

  <key>NSVideoSubscriberAccountUsageDescription</key>
  <string></string>
  <key>NSBluetoothPeripheralUsageDescription</key>
  <string>藍(lán)牙權(quán)限</string>
  <key>NSSpeechRecognitionUsageDescription</key>
  <string>語音識(shí)別權(quán)限</string>
  <key>NSSiriUsageDescription</key>
  <string>Siri權(quán)限</string>
  <key>NSRemindersUsageDescription</key>
  <string></string>
  <key>NSPhotoLibraryUsageDescription</key>
  <string>相冊(cè)權(quán)限</string>
  <key>kTCCServiceMediaLibrary</key>
  <string></string>
  <key>NSMotionUsageDescription</key>
  <string>運(yùn)動(dòng)權(quán)限</string>
  <key>NSMicrophoneUsageDescription</key>
  <string>麥克風(fēng)權(quán)限</string>
  <key>NSAppleMusicUsageDescription</key>
  <string>音樂權(quán)限</string>
  <key>NSLocationWhenInUseUsageDescription</key>
  <string>地理位置權(quán)限</string>
  <key>NSLocationUsageDescription</key>
  <string>地理位置權(quán)限</string>
  <key>NSLocationAlwaysUsageDescription</key>
  <string>地理位置權(quán)限</string>
  <key>NSHomeKitUsageDescription</key>
  <string></string>
  <key>NSHealthUpdateUsageDescription</key>
  <string>健康權(quán)限</string>
  <key>NSHealthShareUsageDescription</key>
  <string>健康權(quán)限</string>
  <key>NSContactsUsageDescription</key>
  <string>通訊錄權(quán)限</string>
  <key>NSCameraUsageDescription</key>
  <string>攝像頭權(quán)限</string>
  <key>NSCalendarsUsageDescription</key>
  <string>日歷權(quán)限</string>

#import <UIKit/UIKit.h>

@interface UIImage (DY)

+ (instancetype)circleOldImage:(UIImage *)originalImage borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)borderColor;

@end

#import "UIImage+DY.h"

@implementation UIImage (DY)

+ (instancetype)circleOldImage:(UIImage *)originalImage borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)borderColor
{
  // 1.加載原圖
  UIImage *oldImage = originalImage;

  // 2.開啟上下文
  CGFloat imageW = oldImage.size.width + 2 * borderWidth;
  CGFloat imageH = oldImage.size.height + 2 * borderWidth;
  CGSize imageSize = CGSizeMake(imageW, imageH);
  UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);

  // 3.取得當(dāng)前的上下文
  CGContextRef ctx = UIGraphicsGetCurrentContext();

  // 4.畫邊框(大圓)
  [borderColor set];
  CGFloat bigRadius = imageW * 0.5; // 大圓半徑
  CGFloat centerX = bigRadius; // 圓心
  CGFloat centerY = bigRadius;
  CGContextAddArc(ctx, centerX, centerY, bigRadius, 0, M_PI * 2, 0);
  CGContextFillPath(ctx); // 畫圓

  // 5.小圓
  CGFloat smallRadius = bigRadius - borderWidth;
  CGContextAddArc(ctx, centerX, centerY, smallRadius, 0, M_PI * 2, 0);
  // 裁剪(后面畫的東西才會(huì)受裁剪的影響)
  CGContextClip(ctx);

  // 6.畫圖
  [oldImage drawInRect:CGRectMake(borderWidth, borderWidth, oldImage.size.width, oldImage.size.height)];

  // 7.取圖
  UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

  // 8.結(jié)束上下文
  UIGraphicsEndImageContext();

  return newImage;
}


@end

#import <UIKit/UIKit.h>
#import "UIImage+DY.h" //加載類別

@interface ViewController : UIViewController<UINavigationControllerDelegate, UIImagePickerControllerDelegate> //一定要添加這兩個(gè)Delegate


@property (strong, nonatomic) UIImagePickerController *imagePickerController;

- (IBAction)btnPressed:(id)sender;

@property (strong, nonatomic) IBOutlet UIImageView *ablumImageView;


@end

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

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


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


- (IBAction)btnPressed:(id)sender {

  if([UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypePhotoLibrary]) {

    //首先判斷是否支持照片庫，這個(gè)方法中的參數(shù)要和_imagePickerController.sourceType的值保持一致

    //如果支持

    _imagePickerController = [[UIImagePickerController alloc]init];

    _imagePickerController.view.backgroundColor = [UIColor orangeColor];
    _imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    _imagePickerController.delegate = self;
    _imagePickerController.allowsEditing = YES; //該參數(shù)默認(rèn)是NO，建議設(shè)置為YES，否則裁剪成圓形圖片的方法將獲取到的是橢圓形的圖片，與你的預(yù)想大相徑庭

    [self presentViewController:_imagePickerController animated:YES completion:nil];

  }


}


- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

  _ablumImageView.image = [UIImage circleOldImage:[info objectForKey:UIImagePickerControllerEditedImage] borderWidth:30.0f borderColor:[UIColor orangeColor]]; 
  //該方法中Info的Key值“UIImagePickerControllerEditedImage”表示的是選擇裁剪后的圖片，如果使用這個(gè)Key值，則_imagePickerController.allowsEditing的值需要設(shè)置為YES。

  //如果_imagePickerController.allowsEditing的值設(shè)置的NO，則這個(gè)Key的值應(yīng)該設(shè)置為UIImagePickerControllerOriginalImage

  /*
  info中的Key的值有如下幾個(gè)：

  NSString *const UIImagePickerControllerMediaType ;指定用戶選擇的媒體類型（文章最后進(jìn)行擴(kuò)展）
NSString *const UIImagePickerControllerOriginalImage ;原始圖片
NSString *const UIImagePickerControllerEditedImage ;修改后的圖片
NSString *const UIImagePickerControllerCropRect ;裁剪尺寸
NSString *const UIImagePickerControllerMediaURL ;媒體的URL
NSString *const UIImagePickerControllerReferenceURL ;原件的URL
NSString *const UIImagePickerControllerMediaMetadata;當(dāng)來數(shù)據(jù)來源是照相機(jī)的時(shí)候這個(gè)值才有效

  */


  [self dismissViewControllerAnimated:YES completion:nil];

}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{


  [self dismissViewControllerAnimated:YES completion:nil];

}

@end