iOS实现头像选取（照相或者图片库）、大小等比缩放、生成圆形头像

//弹出actionsheet。选择获取头像的方式



//从相册获取图片-(void)takePictureClick:(UIButton *)sender{//    /*注：使用，需要实现以下协议：UIImagePickerControllerDelegate,//     UINavigationControllerDelegate//     *///    UIImagePickerController *picker = [[UIImagePickerController alloc]init];//    //设置图片源(相簿)//    picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;//    //设置代理//    picker.delegate = self;//    //设置可以编辑//    picker.allowsEditing = YES;//    //打开拾取器界面//    [self PResentViewController:picker animated:YES completion:nil];    UIActionSheet* actionSheet = [[UIActionSheet alloc]                                  initWithTitle:@"请选择文件来源"                                  delegate:self                                  cancelButtonTitle:@"取消"                                  destructiveButtonTitle:nil                                  otherButtonTitles:@"照相机",@"摄像机",@"本地相簿",@"本地视频",nil];    [actionSheet showInView:self.view];    }#pragma mark -#pragma UIActionSheet Delegate- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{    NSLog(@"buttonIndex = [%d]",buttonIndex);    switch (buttonIndex) {        case 0://照相机        {            UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];            imagePicker.delegate = self;            imagePicker.allowsEditing = YES;            imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;//            [self presentModalViewController:imagePicker animated:YES];            [self presentViewController:imagePicker animated:YES completion:nil];        }            break;        case 1://摄像机        {            UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];            imagePicker.delegate = self;            imagePicker.allowsEditing = YES;            imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;            imagePicker.videoQuality = UIImagePickerControllerQualityTypeLow;//            [self presentModalViewController:imagePicker animated:YES];            [self presentViewController:imagePicker animated:YES completion:nil];        }            break;        case 2://本地相簿        {            UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];            imagePicker.delegate = self;            imagePicker.allowsEditing = YES;            imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;//            [self presentModalViewController:imagePicker animated:YES];            [self presentViewController:imagePicker animated:YES completion:nil];        }            break;        case 3://本地视频        {            UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];            imagePicker.delegate = self;            imagePicker.allowsEditing = YES;            imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;//            [self presentModalViewController:imagePicker animated:YES];            [self presentViewController:imagePicker animated:YES completion:nil];        }            break;        default:            break;    }}#pragma mark -#pragma UIImagePickerController Delegate- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{    if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(__bridge NSString *)kUTTypeImage]) {        UIImage *img = [info objectForKey:UIImagePickerControllerEditedImage];        [self performSelector:@selector(saveImage:)  withObject:img afterDelay:0.5];    }    else if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(__bridge NSString *)kUTTypeMovie]) {        NSString *videoPath = [[info objectForKey:UIImagePickerControllerMediaURL] path];        self.fileData = [NSData dataWithContentsOfFile:videoPath];    }//    [picker dismissModalViewControllerAnimated:YES];    [picker dismissViewControllerAnimated:YES completion:nil];}- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{//    [picker dismissModalViewControllerAnimated:YES];        [picker dismissViewControllerAnimated:YES completion:nil];}- (void)saveImage:(UIImage *)image {    //    NSLog(@"保存头像！");    //    [userPhotoButton setImage:image forState:UIControlStateNormal];    BOOL success;    NSFileManager *fileManager = [NSFileManager defaultManager];    NSError *error;        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *documentsDirectory = [paths objectAtIndex:0];    NSString *imageFilePath = [documentsDirectory stringByAppendingPathComponent:@"selfPhoto.jpg"];    NSLog(@"imageFile->>%@",imageFilePath);    success = [fileManager fileExistsAtPath:imageFilePath];    if(success) {        success = [fileManager removeItemAtPath:imageFilePath error:&error];    }//    UIImage *smallImage=[self scaleFromImage:image toSize:CGSizeMake(80.0f, 80.0f)];//将图片尺寸改为80*80    UIImage *smallImage = [self thumbnailWithImageWithoutScale:image size:CGSizeMake(93, 93)];    [UIImageJPEGRepresentation(smallImage, 1.0f) writeToFile:imageFilePath atomically:YES];//写入文件    UIImage *selfPhoto = [UIImage imageWithContentsOfFile:imageFilePath];//读取图片文件//    [userPhotoButton setImage:selfPhoto forState:UIControlStateNormal];    self.img.image = selfPhoto;}// 改变图像的尺寸，方便上传服务器- (UIImage *) scaleFromImage: (UIImage *) image toSize: (CGSize) size{    UIGraphicsBeginImageContext(size);    [image drawInRect:CGRectMake(0, 0, size.width, size.height)];    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    return newImage;}

//2.保持原来的长宽比，生成一个缩略图- (UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize{    UIImage *newimage;    if (nil == image) {        newimage = nil;    }    else{        CGSize oldsize = image.size;        CGRect rect;        if (asize.width/asize.height > oldsize.width/oldsize.height) {            rect.size.width = asize.height*oldsize.width/oldsize.height;            rect.size.height = asize.height;            rect.origin.x = (asize.width - rect.size.width)/2;            rect.origin.y = 0;        }        else{            rect.size.width = asize.width;            rect.size.height = asize.width*oldsize.height/oldsize.width;            rect.origin.x = 0;            rect.origin.y = (asize.height - rect.size.height)/2;        }        UIGraphicsBeginImageContext(asize);        CGContextRef context = UIGraphicsGetCurrentContext();        CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);        UIRectFill(CGRectMake(0, 0, asize.width, asize.height));//clear background        [image drawInRect:rect];        newimage = UIGraphicsGetImageFromCurrentImageContext();        UIGraphicsEndImageContext();    }    return newimage;}

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *documentsDirectory = [paths objectAtIndex:0];    NSString *imageFilePath = [documentsDirectory stringByAppendingPathComponent:@"selfPhoto.jpg"];    NSLog(@"imageFile->>%@",imageFilePath);    UIImage *selfPhoto = [UIImage imageWithContentsOfFile:imageFilePath];//    self.img.image = selfPhoto;    [self.img.layer setCornerRadius:CGRectGetHeight([self.img bounds]) / 2];  //修改半径，实现头像的圆形化    self.img.layer.masksToBounds = YES;