iOS图片上传及压缩

提到从摄像头/相册获取图片是面向终端用户的，由用户去浏览并选择图片为程序使用。在这里，我们需要过UIImagePickerController类来和用户交互。

使用UIImagePickerController和用户交互，我们需要实现2个协议<UIImagePickerControllerDelegate,UINavigationControllerDelegate>。

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代码如下 复制代码

#pragma mark 从用户相册获取活动图片

- (void)pickImageFromAlbum

{

imagePicker = [[UIImagePickerController alloc] init];

imagePicker.delegate =self;

imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

imagePicker.allowsEditing =YES;

[self presentModalViewController:imagePicker animated:YES];

}

我们来看看上面的从相册获取图片，我们首先要实例化UIImagePickerController对象，然后设置imagePicker对象为当前对象，设置imagePicker的图片来源为UIImagePickerControllerSourceTypePhotoLibrary，表明当前图片的来源为相册，除此之外还可以设置用户对图片是否可编辑。

代码如下 复制代码

#pragma mark 从摄像头获取活动图片

- (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;//自定义照片样式

[self presentViewController:pickerImage animated:YEScompletion:nil];

}

以上是从摄像头获取图片，和从相册获取图片只是图片来源的设置不一样，摄像头图片的来源为UIImagePickerControllerSourceTypeCamera。

　　　　在和用户交互之后，用户选择好图片后，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.TakePhotoBtn setImage:m_selectImage forState:UIControlStateNormal];

[picker dismissModalViewControllerAnimated:YES];

return ;

}

[picker release];

}

//对图片尺寸进行压缩--

-(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;

}

图片保存到本地document里面--以及图片格式的转换

IOS开发之保存图片到Documents目录及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];

[ipc dismissModalViewControllerAnimated:YES];

} else {

NSLog(@"MEdia");

}

上面的代码是当从相册里面选取图片之后保存到本地程序沙盒，在上面我们得到的图片中不能够得到图片名字，
以及不清楚图片格式，所以这个时候我们需要将其转换成NSdata二进制存储，

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

NSData *data;

if (UIImagePNGRepresentation(image) == nil) {

data = UIImageJPEGRepresentation(image, 1);

} else {

data = UIImagePNGRepresentation(image);

}

UIImagePNGRepresentation转换PNG格式的图片为二进制，如果图片的格式为JPEG则返回nil；

[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

我们也可以写成下面的格式存储图片

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

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

[data writeToFile:pngImage atomically:YES];

[data writeToFile:jpgImage atomically:YES];