相册、图库、拍照功能的访问以及图像角度设置

在我们需要访问UIImagePickerController的时候，一般为选择图片，此时我们可能需要做如下操作：

一、访问相册、图库、拍照功能；

二、图片设置；

1、需要将选择的图片缩小 （等比例）；

2、设置图片的形状 （比如：希望选择的图片为圆形）；

3、将图片翻转一定的角度 （比如翻转90度、180度等）

以下是我自己的总结的一些方法：

一、访问功能

- (IBAction)changeIconAction:(UITapGestureRecognizer *)sender {
//    UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:@"选择头像" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"拍照",@"相册",@"图库", nil];
//    [actionSheet showInView:[UIApplication sharedApplication].keyWindow];
    
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    [alertController addAction:[UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        dispatch_async(dispatch_get_main_queue(), ^{
            [self makePhoto];
        });
    }]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        dispatch_async(dispatch_get_main_queue(), ^{
            [self choosePicture];
        });
    }]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"图库" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        dispatch_async(dispatch_get_main_queue(), ^{
            [self pictureLibrary];
        });
    }]];
    
    [alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
    }]];
    
    [self presentViewController:alertController animated:YES completion:nil];
}

//跳转到imagePicker里
- (void)makePhoto{
    pickerController = [[UIImagePickerController alloc] init];
    pickerController.allowsEditing = YES;
    pickerController.delegate = self;
    pickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    [self presentViewController:pickerController animated:YES completion:nil];
}
//跳转到相册
- (void)choosePicture
{
    pickerController.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
    [self presentViewController:pickerController animated:YES completion:nil];
}
//跳转图库
- (void)pictureLibrary
{
    pickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    [self presentViewController:pickerController animated:YES completion:nil];
}
//用户取消退出picker时候调用
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    NSLog(@"%@",picker);
    [pickerController dismissViewControllerAnimated:YES completion:^{
        
    }];
}
//用户选中图片之后的回调
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    
    NSLog(@"%s,info == %@",__func__,info);
    
    UIImage *userImage = [self fixOrientation:[info objectForKey:@"UIImagePickerControllerOriginalImage"]];
    
    userImage = [self scaleImage:userImage toScale:0.3];
    
    //保存图片
//    [self saveImage:userImage name:@"某个特定标示"];
    
    [pickerController dismissViewControllerAnimated:YES completion:^{
        
        
    }];
    [self.headIcon setImage:userImage];
    self.headIcon.contentMode = UIViewContentModeScaleAspectFill;
    self.headIcon.clipsToBounds = YES;
    //照片上传
    [self upDateHeadIcon:userImage];
}

二、图片设置

1、图片缩放

/**
 *  对图片进行缩放 (宽高缩放)
 *
 *  @param image     图片原始对象
 *  @param scaleSize 缩放的倍数
 *
 *  @return 缩放后的图片
 */
+(UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize{
    UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize));
    [image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];
    UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return scaledImage;
}
/**
 *  对图片进行缩放 (容量大小缩至100k以内)
 *
 *  @param image 图片对象
 *  @param scope 图像范围 （scope kb范围内）
 *
 *  @return 处理后的图片对象
 */
+(UIImage *)originImage:(UIImage *)image withInScope:(int)scope{
    //头像 20k   广告 200k
    
    NSData *data = UIImageJPEGRepresentation(image, 1.0);
    if (data.length > scope*1024) {
        if (data.length > 1024*1024) {  //1M以上
            data = UIImageJPEGRepresentation(image, 0.1);
        }
        else if (data.length > 512*1024) {  //500kb - 1000kb
            data = UIImageJPEGRepresentation(image, 0.5);
        }
        else if (data.length > 200*1024) {  //0.25M - 0.5M
            data = UIImageJPEGRepresentation(image, 0.9);
        }
    }
    return [UIImage imageWithData:data];
}

2、显示设置

  2.1、图片合成（两张图片合成一张）

  2.2、缩略图

3、设置水平方向转动角度

//修正照片方向(手机转90度方向拍照)
- (UIImage *)fixOrientation:(UIImage *)aImage {
    
    // No-op if the orientation is already correct
    if (aImage.imageOrientation == UIImageOrientationUp)
        return aImage;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        default:
            break;
    }
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        default:
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
                                             CGImageGetBitsPerComponent(aImage.CGImage), 0,
                                             CGImageGetColorSpace(aImage.CGImage),
                                             CGImageGetBitmapInfo(aImage.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (aImage.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}