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压缩图片操作和生成圆形图片
1.对本地相册库或相机拍摄下来的图片进行压缩处理，传进来的参数分别有：要压缩的图片和压缩后的大小。
//压缩图片+ (UIImage*)imageWithImageSimple:(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;}
2.将图片压缩转为NSData写入沙盒。压缩后以NSData上传图片。
//sdk中提供了方法可以直接调用 UIImage *img = [UIImage imageNamed:@"some.png"];NSData *dataObj = UIImageJPEGRepresentation(img, 1.0); //下面是sdk中UIImage.h头文件中的内容 UIKIT_EXTERN NSData *UIImagePNGRepresentation(UIImage *image); // return image as PNG. May return nil if image has no CGImageRef or invalid bitmap format UIKIT_EXTERN NSData *UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality); // return image as JPEG. May return nil if image has no CGImageRef or invalid bitmap format. compression is 0(most)..1(least)
JPEG的转换方法里面第二个参数是压缩系数，可以有效的减小图片的大小。UIImagePNGRepresentation(UIImage* image) 要比UIImageJPEGRepresentation(UIImage* image, 1.0) 返回的图片数据量大很多。项目中做图片上传之前，经过测试同一张拍照所得照片png大小在8M，而JPG压缩系数为0.75时候，大小只有1M。而且，将压缩系数降低对图片视觉上并没有太大的影响。
保存图片到沙盒
- (void)saveImage:(UIImage *)tempImage WithName:(NSString *)imageName{ NSData* imageData =http://www.mamicode.com/ UIImagePNGRepresentation(tempImage); NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; // Now we get the full path to the file NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName]; // and then we write it out [imageData writeToFile:fullPathToFile atomically:NO];}
上传图片
- (void)putImagewithImage:(UIImage *)image{ //上传图片 ASIHTTPRequest *requst = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:UPLOADURL]]; [requst setRequestMethod:@"PUT"]; NSData *data =http://www.mamicode.com/ UIImagePNGRepresentation(image); if (data =http://www.mamicode.com/= nil) { data = UIImageJPEGRepresentation(image, 0.1); } [requst appendPostData:data]; [requst startAsynchronous]; [self showLoading:YES]; requst.delegate = self;}
当然也可以用表单的形式上传图片
转自：http://blog.csdn.net/decemberd/article/details/8629996
3.生成固定大小的圆形图片
//2.保持原来的长宽比，生成一个缩略图- (UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize{ UIImage *newimage; if (nil == image) { newimage = nil; } else { CGSize oldsize = image.size; CGRect rect; if (asize.width/asize.height > oldsize.width/oldsize.height) { rect.size.width = asize.height*oldsize.width/oldsize.height; rect.size.height = asize.height; rect.origin.x = (asize.width - rect.size.width)/2; rect.origin.y = 0; } else { rect.size.width = asize.width; rect.size.height = asize.width*oldsize.height/oldsize.width; rect.origin.x = 0; rect.origin.y = (asize.height - rect.size.height)/2; } UIGraphicsBeginImageContext(asize); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]); UIRectFill(CGRectMake(0, 0, asize.width, asize.height));//clear background [image drawInRect:rect]; newimage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); } return newimage;}
最后是调用了
UIImage *smallImage = [self thumbnailWithImageWithoutScale:image size:CGSizeMake(93, 93)]; [UIImageJPEGRepresentation(smallImage, 1.0f) writeToFile:imageFilePath atomically:YES];//写入文件 UIImage *selfPhoto = [UIImage imageWithContentsOfFile:imageFilePath];//读取图片文件
----------------------------------------------------Demo----------------------------------
#import <MobileCoreServices/MobileCoreServices.h>- (void)viewDidLoad{ _tableHeadView = [[UIView alloc]initWithFrame:CGRectMake(0, 0,100,100)]; _headImageView = [[UIImageView alloc]initWithFrame:CGRectMake((250-100)/2,10, 60, 60)]; _headImageView.backgroundColor = [UIColor blackColor]; _headImageView.image = [UIImage imageNamed:@"slide_Login"]; _headImageView.userInteractionEnabled = YES; _headImageView.layer.cornerRadius = 30; _headImageView.layer.masksToBounds = YES; [_tableHeadView addSubview:_headImageView]; [_headImageView release]; UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(changeImageAction:)]; [_headImageView addGestureRecognizer:tap]; [tap release];} /** * 选择图片方法 * * @param sender <#sender description#> */-(void)changeImageAction:(UITapGestureRecognizer *)sender{ UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:@"选择文件来源" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"照相机",@"摄像机",@"本地相册",nil]; [actionSheet showInView:self.view];}#pragma mark -UIActionSheetDelegate Methods-(void)actionSheet:(UIActionSheet *)actionSheetclickedButtonAtIndex:(NSInteger)buttonIndex{ switch (buttonIndex) { case 0://照相机 { if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) { UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init]; imagePicker.delegate = self; imagePicker.allowsEditing = self; imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera; [self presentViewController:imagePicker animated:YES completion:^{ }]; } else { UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"设备不支持摄像头" message:nil delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:nil, nil]; [alertView show]; } break; } case 1://摄像机 { if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) { UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init]; imagePicker.delegate = self; imagePicker.allowsEditing = self; imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera; imagePicker.videoQuality = UIImagePickerControllerQualityTypeLow; [self presentViewController:imagePicker animated:YES completion:^{ }]; } else { UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"设备不支持摄像头" message:nil delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:nil, nil]; [alertView show]; } break; } case 2://本地相册 { UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init]; imagePicker.delegate = self; imagePicker.allowsEditing = self; imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary; [self presentViewController:imagePicker animated:YES completion:^{ }]; break; } default: break; }}#pragma mark -UIImagePickerControllerDelegate Method-(void)imagePickerController:(UIImagePickerController *)pickerdidFinishPickingMediaWithInfo:(NSDictionary *)info{ if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(__bridge NSString *)kUTTypeImage])//等到图片 { UIImage *img = [info objectForKey:UIImagePickerControllerEditedImage]; [self performSelector:@selector(saveImage:) withObject:img afterDelay:0.5]; } else if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(__bridge NSString *)kUTTypeMovie])//得到视频的数据 { NSString *videoPath = (__bridge NSString *)[[info objectForKey:UIImagePickerControllerMediaURL] path]; NSData *fileData =http://www.mamicode.com/ [NSData dataWithContentsOfFile:videoPath]; } else{} [picker dismissViewControllerAnimated:YES completion:^{ }];}-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{ [picker dismissViewControllerAnimated:YES completion:^{ }];}/** * 保存图片 * * @param img <#img description#> */-(void)saveImage:(UIImage *)image{ NSString *imageFilePath = [self getImageFilePath]; NSFileManager *fileManger = [NSFileManager defaultManager]; BOOL success = [fileManger fileExistsAtPath:imageFilePath]; NSError *error; if (success) { success = [fileManger removeItemAtPath:imageFilePath error:&error];//删除原图片 } //尺寸改为60*60 UIImage *smallImage = [self thumbnailWithImageWithoutScale:image size:CGSizeMake(60, 60)]; [UIImageJPEGRepresentation(smallImage, 1.0f) writeToFile:imageFilePath atomically:YES];//写入文件 UIImage *selfPhoto = [UIImage imageWithContentsOfFile:imageFilePath];//读取图片文件 _headImageView.image = selfPhoto;}/** * 获取图片文件路径 * * @return <#return value description#> */-(NSString *)getImageFilePath{ NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString *imageFilePath = [path stringByAppendingPathComponent:@"selfPhone.jpg"]; return imageFilePath; }//2.保持原来的长宽比，生成一个缩略图- (UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize{ UIImage *newimage; if (nil == image) { newimage = nil; } else { CGSize oldsize = image.size; CGRect rect; if (asize.width/asize.height > oldsize.width/oldsize.height) { rect.size.width = asize.height*oldsize.width/oldsize.height; rect.size.height = asize.height; rect.origin.x = (asize.width - rect.size.width)/2; rect.origin.y = 0; } else { rect.size.width = asize.width; rect.size.height = asize.width*oldsize.height/oldsize.width; rect.origin.x = 0; rect.origin.y = (asize.height - rect.size.height)/2; } UIGraphicsBeginImageContext(asize); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]); UIRectFill(CGRectMake(0, 0, asize.width, asize.height));//clear background [image drawInRect:rect]; newimage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); } return newimage;}
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