iOS图片上传及处理

从摄像头或者是从相冊中读取图片。须要通过UIImagePickerController类来实现，在使用UIImagePickerController时，须要是实现以下两个协议

<UINavigationControllerDelegate,UIImagePickerControllerDelegate>

1、从相冊中读取图片

首先要实例化UIImagePickerController对象imagePicker。设置imagePicker的图片来源为UIImagePickerControllerSourceTypePhotoLibrary，表明当前图片的来源为用户的相冊。

以及设置图片是否可被编辑allowsEditing。

#pragma mark - 从用户相冊获取图片
- (void)pickImageFromAlbum
{
    imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate =self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    imagePicker.allowsEditing =YES;
    
    [self presentModalViewController:imagePicker animated:YES];
}

2、从相冊中读取图片

#pragma mark - 从摄像头获取图片
- (void)pickImageFromCamera
{
    imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate =self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    imagePicker.allowsEditing =YES;
    
    [self presentModalViewController:imagePicker animated:YES];
}
//打开相机
- (IBAction)touch_photo:(id)sender {
    // for iphone
    UIImagePickerController *pickerImage = [[UIImagePickerController alloc] init];
   if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        pickerImage.sourceType = UIImagePickerControllerSourceTypeCamera;
        pickerImage.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:pickerImage.sourceType];
        
    }
    pickerImage.delegate =self;
    pickerImage.allowsEditing =YES;//自己定义照片样式
    [self presentViewController:pickerImage animated:YES completion:nil];
}

在用户现则好图片后。会回调选择结束的方法

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
    //初始化imageNew为从相机中获得的--
    UIImage *imageNew = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
    //设置image的尺寸
    CGSize imagesize = imageNew.size;
    imageSize.height =626;
    imageSize.width =413;
    //对图片大小进行压缩--
    imageNew = [self imageWithImage:imageNew scaledToSize:imageSize];
    NSData *imageData = UIImageJPEGRepresentation(imageNew,0.00001);
   if(m_selectImage==nil)
    {
        m_selectImage = [UIImage imageWithData:imageData];
        NSLog(@"m_selectImage:%@",m_selectImage);
        [self.takePhotoButton setImage:m_selectImage forState:UIControlStateNormal];
        [picker dismissModalViewControllerAnimated:YES];
       return ;
    }
}

对图片进行压缩

-(UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
    // Create a graphics image context
    UIGraphicsBeginImageContext(newSize);
    
    // Tell the old image to draw in this new context, with the desired
    // new size
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    
    // Get the new image from the context
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // End the context
    UIGraphicsEndImageContext();
    
    // Return the new image.
   return newImage;
}

将图片保存到Documents文件夹及PNG、JPEG格式相互转换

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary*)info {
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    if ([mediaType isEqualToString:@"public.image"]){
        image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
        NSData *data;
        if (UIImagePNGRepresentation(image) == nil) {
            data = UIImageJPEGRepresentation(image, 1);
        } else {
            data = UIImagePNGRepresentation(image);
        }
        
        NSFileManager *fileManager = [NSFileManager defaultManager];
        NSString *filePath = [NSString stringWithString:[self getPath:@"image1"]];         //将图片存储到本地documents
         [fileManager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil];
         [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:dataAttributes:nil];
        
        UIImage *editedImage = [[UIImage alloc] init];
        editedImage = image;
        CGRect rect = CGRectMake(0, 0, 64, 96);
        UIGraphicsBeginImageContext(rect.size);
        [editedImage drawInRect:rect];
        editedImage = UIGraphicsGetImageFromCurrentImageContext();
        
        UIButton *imageButton = [UIButton buttonWithType:UIButtonTypeCustom];
        imageButton.frame = CGRectMake(10, 10, 64, 96);
        [imageButton setImage:editedImage forState:UIControlStateNormal];
        [self.view addSubview:imageButton];
        [imageButton addTarget:self action:@selector(imageAction:)forControlEvents:UIControlEventTouchUpInside];
        [self dismissModalViewControllerAnimated:YES];
    } else {
        NSLog(@"Media");
    }

在上面的方法中不能得到图片的名称及格式。所以须要将其转换成NSData二进制存储

 image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
NSData *data;
        if (UIImagePNGRepresentation(image) == nil) {
            data = UIImageJPEGRepresentation(image, 1);
        } else {
            data = UIImagePNGRepresentation(image);
        }

[fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:data attributes:nil];  //将图片保存为PNG格式
 [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.jpg"] contents:data attributes:nil]; //将图片保存为JPEG格式

【參考资料：http://www.open-open.com/】