上傳 圖片 等比例壓縮

提到從攝像頭/相冊獲取圖片是面向終端用戶的，由用戶去瀏覽並選擇圖片爲程序使用。在這裏，我們需要過UIImagePickerController類來和用戶交互。

使用UIImagePickerController和用戶交互，我們需要實現2個協議。

 

View Code

 

代碼如下 複製代碼

 

#pragma mark 從用戶相冊獲取活動圖片

- (void)pickImageFromAlbum

{

    imagePicker = [[UIImagePickerController alloc] init];

    imagePicker.delegate =self;

    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

    imagePicker.allowsEditing =YES;

    

    [self presentModalViewController:imagePicker animated:YES];

}

 

我們來看看上面的從相冊獲取圖片，我們首先要實例化UIImagePickerController對象，然後設置imagePicker對象爲當前對象，設置imagePicker的圖片來源爲UIImagePickerControllerSourceTypePhotoLibrary，表明當前圖片的來源爲相冊，除此之外還可以設置用戶對圖片是否可編輯。

View Code

 

代碼如下 複製代碼

#pragma mark 從攝像頭獲取活動圖片

- (void)pickImageFromCamera

{

    imagePicker = [[UIImagePickerController alloc] init];

    imagePicker.delegate =self;

    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;

    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

    imagePicker.allowsEditing =YES;

    

    [self presentModalViewController:imagePicker animated:YES];

}

 

//打開相機

- (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;//自定義照片樣式

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

}

 

以上是從攝像頭獲取圖片，和從相冊獲取圖片只是圖片來源的設置不一樣，攝像頭圖片的來源爲UIImagePickerControllerSourceTypeCamera。

　　　　在和用戶交互之後，用戶選擇好圖片後，會回調選擇結束的方法。

 

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

{

    //初始化imageNew爲從相機中獲得的--

    UIImage *imageNew = [info objectForKey:@"UIImagePickerControllerOriginalImage"];

    //設置image的尺寸

    CGSize imagesize = imageNew.size;

    imagesize.height =626;

    imagesize.width =413;

    //對圖片大小進行壓縮--

    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.TakePhotoBtn setImage:m_selectImage forState:UIControlStateNormal];

        [picker dismissModalViewControllerAnimated:YES];

       return ;

    }

    [picker release];

}

//對圖片尺寸進行壓縮--

-(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;

}

 

圖片保存到本地document裏面--以及圖片格式的轉換

IOS開發之保存圖片到Documents目錄及PNG，JPEG格式相互轉換

- (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"]];         //將圖片存儲到本地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];

 

        [ipc dismissModalViewControllerAnimated:YES];

    } else {

        NSLog(@"MEdia");

    }

    

上面的代碼是當從相冊裏面選取圖片之後保存到本地程序沙盒，在上面我們得到的圖片中不能夠得到圖片名字，
以及不清楚圖片格式，所以這個時候我們需要將其轉換成NSdata二進制存儲，

 image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];

NSData *data;

        if (UIImagePNGRepresentation(image) == nil) {

            data = UIImageJPEGRepresentation(image, 1);

        } else {

            data = UIImagePNGRepresentation(image);

        }

UIImagePNGRepresentation轉換PNG格式的圖片爲二進制，如果圖片的格式爲JPEG則返回nil；

 [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:data attributes:nil];    將圖片保存爲PNG格式

 [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.jpg"] contents:data attributes:nil];   將圖片保存爲JPEG格式

 

我們也可以寫成下面的格式存儲圖片

NSString *pngImage = [filePath stringByAppendingPathComponent:@"Documents/image.png"];

NSString *jpgImage = [filePath stringByAppendingPathComponent:@"Documents/image.jpg"];

 

[data writeToFile:pngImage atomically:YES];

[data writeToFile:jpgImage atomically:YES];