IOS 图片上传处理 图片压缩 图片处理详解手机开发

 
 
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>。 
 
 
 
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:YES completion: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; 
 
}