uiimagejpegrepresentation

I've read uiimagepickercontroller uiimage memory and more and other relevant questions, but I can't get my head around one thing, and I wonder if there are people around here with experience on this particular aspect. In my app I let the user select an image from his library, ultimately resulting in an upload. (An interesting thing here, is that the images in there may originate from 12-megapixel high quality camera's, since e.g. iTunes happily syncs them into the phone.) For various reasons, I UIImageJPEGRepresentation the thing right away to a locally stored file. Without much thought, I

I create a UIimage using the imageWithData method: - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { UIImage *chosenImage = [info objectForKey:@"UIImagePickerControllerOriginalImage"]; NSData *data1 = UIImageJPEGRepresentation(chosenImage, 1); NSData *data2 = UIImageJPEGRepresentation(chosenImage, 0.5); NSLog(@"data1 = %lu;;;;;;;data2 = %lu",[data1 length],[data2 length]); UIImage *nimg = [UIImage imageWithData:data2]; NSData *data30 = UIImageJPEGRepresentation(nimg, 1); NSData *data31 = UIImageJPEGRepresentation(nimg, 0.8);

In my iPhone App I am storing image into NSData by UIImage *image =imageView.image; NSData *myData = UIImagePNGRepresentation(image); But How to get back "image" from " NSData " and I can display it again into in to UIImageView . Please Help and Suggest, Thanks. have you tried +[UIImage imageWithData:] ? UIImage *img=[UIImage imageWithData:data]; [yourImageView setImage:img]; 来源： https://stackoverflow.com/questions/4655174/iphone-how-to-get-image-back-from-nsdata

I am trying to save an UIImage object to an .jpeg file in device and I am using this code: -(void)saveImageToDocumentsDirectory:(UIImage *)mimage withFileName:(NSString *)fileName { UIImageWriteToSavedPhotosAlbum(mimage,nil,nil,nil); NSData *dataForJPEGFile = UIImageJPEGRepresentation(mimage, 1.0); NSError *error2 = nil; if (![dataForJPEGFile writeToFile:[self getDirectoryFilePath:fileName] options:NSAtomicWrite error:&error2]) { return; } } It will save the image of .jpeg type but take too much memory as compare to the UIImageWriteToSavedPhotosAlbum(mimage,nil,nil,nil) method, which saves the

I would like to apply a filter to a photo from the user's library then write it back to disk. I'm using UIImageJPEGRepresentation . This function takes a UIImage and a compressionQuality value between 0.0 and 1.0. Because I want to preserve the original quality, I set it to 1.0. But I found this actually creates an image file that's larger in file size than the original, somewhat significantly larger even. I noticed in Apple's Sample Photo Editing Extension app they always set the quality to 0.9. I tried that and it does output a file size close to the original photo file size. This doesn't

On iOS 4.2 when I use UIImagePickerController to let the user select a image from the photo library these are the dictionary keys that are returned to me: 2011-03-02 13:15:59.518 xxx[15098:307] didFinishPickingMediaWithInfo: info dictionary: { UIImagePickerControllerMediaType = "public.image"; UIImagePickerControllerOriginalImage = "<UIImage: 0x3405d0>"; UIImagePickerControllerReferenceURL = "assets-library://asset/asset.JPG?id=1000000050&ext=JPG"; } Using one or more of these keys, how can I get a JPEG representation that would include the image metadata (such as exposure information and GPS

I wish to extract the image using ALAssetsLibrary and ALAsset directly in the form of a NSData object. Using a NSURL I take out the image in the following manner. NSURL *referenceURL =newURL; ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init]; [library assetForURL:referenceURL resultBlock:^(ALAsset *asset) { UIImage *copyOfOriginalImage = [UIImage imageWithCGImage:[[asset defaultRepresentation] fullResolutionImage]]; } Now here we take the image as a UIImage, but I need to take the image directly as NSData. I wish to do this because (I have read that) once you take the image in UIImage,