I am using ALAsset framework for selecting multiple images from the image library. I want to store the selected images into the database. These stored images are then to be used to show the slideshow of the images. My problem i am storing the image URL into the database, URL is in format - assets-library://asset/asset.JPG?id=1000000007&ext=JPG. Now for displaying the images i need UIImage object, so how do i create a UIImage object from this kind of URL. I have tried -
for(NSDictionary *dict in info)
{
NSString* path = [[NSString alloc] initWithString:[dict objectForKey:#"UIImagePickerControllerReferenceURL"]];
UIImage* ui;
ui = [[UIImage alloc] initWithContentsOfFile:path];
}
This did not worked. Please some one tell me how do i do it..
Related
let image_data = UIImageJPEGRepresentation(self.imagetoadd.image!,0.0)
The image in ios, am using swift 3 to do this is being uploaded rotated.How can I solve such thing?
JPEG images usually contain an EXIF dictionary, here are stored a lot information about how the image was taken, image rotation is one of it.
UIImage instances keeps these information (if the original image has it) as well inside a specific property called imageOrientation.
As far as I remember this information is ripped of by using the method UIImageJPEGRepresentation.
To create a correct data instance with the above information you must use Core Graphics methods, or normalize the rotation before sending the image.
To normalize the image something like that should be enough:
CGImageRef cgRef = imageToSave.CGImage;
UIImage * fixImage = [[UIImage alloc] initWithCGImage:cgRef scale:imageToSave.scale orientation:UIImageOrientationUp];
To keep the rotation information:
CFURLRef url = (__bridge_retained CFURLRef)[NSURL fileURLWithPath:path];//Save data path
NSDictionary * metadataDictionary = [self imageMetadataForPath:pathToOriginalImage];
CFMutableDictionaryRef metadataImage = (__bridge_retained CFMutableDictionaryRef) metadata;
CGImageDestinationRef destination = CGImageDestinationCreateWithURL(url, kUTTypeJPEG, 1, NULL);
CGImageDestinationAddImage(destination, image, metadataImage);
if (!CGImageDestinationFinalize(destination)) {
DLog(#"Failed to write image to %#", path);
}
Where the -imageMetadataForPath:
- (NSDictionary*) imageMetadataForPath:(NSString*) imagePath{
NSURL *imageURL = [NSURL fileURLWithPath:imagePath];
CGImageSourceRef mySourceRef = CGImageSourceCreateWithURL((__bridge CFURLRef)imageURL, NULL);
NSDictionary * dict = (NSDictionary *) CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(mySourceRef,0,NULL));
CFRelease(mySourceRef);
return dict;
}
This is a copy and paste from a project of mine, you probably need to do a huge refactoring, also because it is using manual memory management in core foundation and you are using SWIFT. Of course by using this last set of instructions, the backend code must be prepared to deal with image orientation too.
If you want to know more about rotation, here is a link.
In my app, images are being stored on parse. They then get retrieved into an array of PFFiles, however I have to convert them individually to UIImages using this method which takes time.
PFFile *picture = [pictureArray objectAtIndex:indexPath.row];
[picture getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
myimage = [UIImage imageWithData:data];
}];
So I need to store images on parse, and retrieve them, and I don't want to individually convert all of these pictures, I want it all done at once. These are the options I currently see:
Create a loop that loops the code above to convert all the PFFiles to UIImages and add them to an array ready to access.
Find a better way to convert or use PFFiles.
Upload NSData or something else to parse so I don't have to convert the PFFiles.
Can anyone provide me advice or solutions to my problem? As I am presenting a fairly large amount of images in a UICollectionView, I want them to be all loaded at once some how instead of having to load them individually, I want the images in an array ready to go so I can just call:
cell.myimage.image = [pictureArray objectAtIndex:indexPath.row];
and all the images will be loaded instead of waiting for PFFIles to be converted etc.
If you want to present them you should use PFImageView which can load the by itself. It's a subclass of UIImageView and its pretty.
Example:
PFImageView *creature = [[PFImageView alloc] init];
creature.image = [UIImage imageNamed:#”1.jpg”]; // placeholder image
creature.file = (PFFile *)file;
[creature loadInBackground];
If you want to download them for other uses check out this answer.
I'm trying to display a BLOB image (get from web server using Json) in my iOS app, but when I run my application I get an empty UIimageView, here is my code :
NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:encodedUrl]];
NSData *profileImage1 = [[NSData alloc] initWithBytes:[dataURL bytes] length:[dataURL length]];
UIImage *profileImage2 = [UIImage imageWithData:profileImage1];
[profilImage setImage:profileImage2];
How can I fix this problem?
[UIImage imageWithData:data] only parses known image file formats like JPEG, PNG, etc. (Full info in the decomentation). Passing blobs isn't supported by UIImage. You need to do some decoding to be able to use the data for the UIImage. You can use GMTBase.64 for encoding and decoding of data. Read the docs and other posts and you'll find out how to change your code.
Hope this helps.
I am caching an NSData object containing image data retrieved from the web. The image displays correctly before caching. When I retrieve the data object from the cache, the data can no longer be used to create a UIImage, even though the data objects are identical.
Please see the relevant snippets of my code below
NSData *webData= [NSData dataWithContentsOfURL:webPath]; //retrieve from web
UIImage *webImage = [UIImage imageWithData:webData]; //works fine
[webData writeToURL:filePath atomically:YES]; //cache
NSData *cacheData = [NSData dataWithContentsOfURL:filePath]; //get from cache
if ([cacheData isEqualToData:webData]) NSLog(#"Equal"); //Data objects are equal
UIImage *cacheImage = [UIImage imageWithData:cacheData]; //cacheImage is nil
I can fix the problem by changing the way I store my data to the cache
NSData *temp = UIImageJPEGRepresentation(webImage, 1.0):
[temp writeToURL:filePath atomically:YES];
Now the webData and cacheData are no longer equal, but cacheImage is not nil and displays properly.
EDIT - After a bit more testing, I realized I get the same problem using UIImageJPEGRepresentation as well.
Anyone know why this would be?
Thanks.
Figure out the problem was that I was trying to do all this before my view controller was fully loaded.
I had a lot of trouble trying to force the loading of the low-resolution version of some resources on iOS, when the high-res version (#2x) is also present.
The reason I wanted to do this is simple: My app shows a bunch of full-screen images to the user (320x480 on older devices, 640x960 on Retina devices), and the user can upload some of these to TwitPic. I wanted to unify the uploaded images to 320x480, regardless of the device (for consistency, because that size is fine in a web browser).
I found out that no matter what UIImage method I used, when the high-resolution version of a resource file is present it is loaded (even if you pass the full file path): UIImage will out-smart you. But I found a way to out-smart UIImage:
- (UIImage*) lowResImage{
NSString* path = [[NSBundle mainBundle] pathForResource:_fileName
ofType:#"png"
inDirectory:_resourceSubdirectory];
path = [path stringByReplacingOccurrencesOfString:#"##2x" withString:#""];
NSData* imageData = [[NSData alloc] initWithContentsOfFile:path];
UIImage* image = [[UIImage alloc] initWithData:imageData];
[imageData release];
return [image autorelease];
}
The above code works fine on a 4th generation iPod touch.
Anybody came up with a better approach?
Build your path, open data, and then init the image using data as in the example below.
NSString *dataPath = [[[NSBundle mainBundle] bundlePath] stringByAppendingPathComponent:_fileName];
NSData *data = [[NSData alloc] initWithContentsOfFile:dataPath];
UIImage *image3 = [UIImage imageWithData:data];