详解iOS 裁剪圆形图像并显示(类似于微信头像)

  <key>NSVideoSubscriberAccountUsageDescription</key>  <string></string>  <key>NSBluetoothPeripheralUsageDescription</key>  <string>蓝牙权限</string>  <key>NSSpeechRecognitionUsageDescription</key>  <string>语音识别权限</string>  <key>NSSiriUsageDescription</key>  <string>Siri权限</string>  <key>NSRemindersUsageDescription</key>  <string></string>  <key>NSPhotoLibraryUsageDescription</key>  <string>相册权限</string>  <key>kTCCServiceMediaLibrary</key>  <string></string>  <key>NSMotionUsageDescription</key>  <string>运动权限</string>  <key>NSMicrophoneUsageDescription</key>  <string>麦克风权限</string>  <key>NSAppleMusicUsageDescription</key>  <string>音乐权限</string>  <key>NSLocationWhenInUseUsageDescription</key>  <string>地理位置权限</string>  <key>NSLocationUsageDescription</key>  <string>地理位置权限</string>  <key>NSLocationAlwaysUsageDescription</key>  <string>地理位置权限</string>  <key>NSHomeKitUsageDescription</key>  <string></string>  <key>NSHealthUpdateUsageDescription</key>  <string>健康权限</string>  <key>NSHealthShareUsageDescription</key>  <string>健康权限</string>  <key>NSContactsUsageDescription</key>  <string>通讯录权限</string>  <key>NSCameraUsageDescription</key>  <string>摄像头权限</string>  <key>NSCalendarsUsageDescription</key>  <string>日历权限</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.加载原图  UIImage *oldImage = originalImage;  // 2.开启上下文  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.取得当前的上下文  CGContextRef ctx = UIGraphicsGetCurrentContext();  // 4.画边框(大圆)  [borderColor set];  CGFloat bigRadius = imageW * 0.5; // 大圆半径  CGFloat centerX = bigRadius; // 圆心  CGFloat centerY = bigRadius;  CGContextAddArc(ctx, centerX, centerY, bigRadius, 0, M_PI * 2, 0);  CGContextFillPath(ctx); // 画圆  // 5.小圆  CGFloat smallRadius = bigRadius - borderWidth;  CGContextAddArc(ctx, centerX, centerY, smallRadius, 0, M_PI * 2, 0);  // 裁剪(后面画的东西才会受裁剪的影响)  CGContextClip(ctx);  // 6.画图  [oldImage drawInRect:CGRectMake(borderWidth, borderWidth, oldImage.size.width, oldImage.size.height)];  // 7.取图  UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();  // 8.结束上下文  UIGraphicsEndImageContext();  return newImage;}@end

#import <UIKit/UIKit.h>#import "UIImage+DY.h" //加载类别@interface ViewController : UIViewController<UINavigationControllerDelegate, UIImagePickerControllerDelegate> //一定要添加这两个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]) {    //首先判断是否支持照片库，这个方法中的参数要和_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; //该参数默认是NO，建议设置为YES，否则裁剪成圆形图片的方法将获取到的是椭圆形的图片，与你的预想大相径庭    [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]];   //该方法中Info的Key值“UIImagePickerControllerEditedImage”表示的是选择裁剪后的图片，如果使用这个Key值，则_imagePickerController.allowsEditing的值需要设置为YES。  //如果_imagePickerController.allowsEditing的值设置的NO，则这个Key的值应该设置为UIImagePickerControllerOriginalImage  /*  info中的Key的值有如下几个：  NSString *const UIImagePickerControllerMediaType ;指定用户选择的媒体类型（文章最后进行扩展）NSString *const UIImagePickerControllerOriginalImage ;原始图片NSString *const UIImagePickerControllerEditedImage ;修改后的图片NSString *const UIImagePickerControllerCropRect ;裁剪尺寸NSString *const UIImagePickerControllerMediaURL ;媒体的URLNSString *const UIImagePickerControllerReferenceURL ;原件的URLNSString *const UIImagePickerControllerMediaMetadata;当来数据来源是照相机的时候这个值才有效  */  [self dismissViewControllerAnimated:YES completion:nil];}- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{  [self dismissViewControllerAnimated:YES completion:nil];}@end