In my project i need to show the different sizes of images in zig-zag fashion. so, i converted the uiimages(url) which are coming from service to NSData and then i get the uiimage. my code is
NSURL *url = [NSURL URLWithString:[[_result objectAtIndex:i ] valueForKey:#"PImage"]];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
so i can get the image size(width and height), But my problem is according to the image size, i need to create UIView, this code is works fine for me, but it is taking too much of time(almost 25 sec) to load 8 images. i figured converting UIImage to NSData is taking time. Is there any way to get the image size(width and height) without converting it into NSData
Thanks for spending time for me.
You can get image properties without actually loading whole image data from disk using ImageIO framework:
#import ImageIO;
...
NSURL *imageURL = … // Init URL somehow
CGImageSourceRef imgSource = CGImageSourceCreateWithURL((__bridge CFURLRef)url, NULL);
NSDictionary* imageProps = (__bridge_transfer NSDictionary*) CGImageSourceCopyPropertiesAtIndex(imgSource, 0, NULL);
NSLog(#"%#", imageProps);
CFRelease(imgSource);
Image width and height will be stored in dictionary under PixelHeight and PixelWidth keys (tested with png image, may be other image formats will use different keys)
Instead of converting url to data and to UIImage, Use EGOImageView OR AsyncImageView. You can simply pass the URL to them. Again setFrame based on size of the image.
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.
http://hauwengweb.azurewebsites.net/api/AccomodationImages/images/1
I'm trying to download image on imageView. If you will paste this url on browser it will show, but on imageView it's not showing. If you will try any other image, then the same code will work, but when I used this url, the image does not show.
The image in question seems to be a WebP image (served with the wrong MIME type of image/png), which is not a format natively supported by UIImage. However, you can use iOS-WebP to decode the image:
Add the framework, header and implementation to your project, then use:
#import "UIImage+WebP.h"
NSURL *url = [NSURL URLWithString:#"http://hauwengweb.azurewebsites.net/api/AccomodationImages/images/1"];
NSData *data = [NSData dataWithContentsOfURL:url];
imageView.image = [UIImage imageWithWebPData:data];
And please remember to do the download and decoding steps asynchronously so as not to block the main UI.
Try this?
NSURL *url = [NSURL URLWithString:#"http://hauwengweb.azurewebsites.net/api/AccomodationImages/images/1"];
NSData *data = [NSData dataWithContentsOfURL:url];
self.img.image = [UIImage imageWithData:data];
Edit
The URL you provided is not an absolute path hence the data being fetched cannot be converted into an UIImage. There is something wrong with the URL or the formatting of it.
I am writing NSData to a file and saving it in the device's app documents folder. For that, is it possible to get thumbnail from ALAssetsRepresentation object in NSData format. If so, any helpful links to that?
I couldn't find anything similar, other than getting CGImageRef from ALAssetsRepresentation. I don't want CGImageRef format as I have to use UIImageJPEGRepresentation or UIImagePNGRepresentation to convert it to NSData.
Try this one
GImageRef iref = [myasset thumbnail];
if (iref)
{
UIImage *theThumbnail = [UIImage imageWithCGImage:iref];
NSData *thumnailData = UIImagePNGRepresentation(theThumbnail);
}
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 have an object ALAsset retrieved from ALAssetLibrary I want to extrapolate a compress JPEG in order to send it to a web services.
any suggestion where to start?
Edit:
I've found a way to get NSData out of the ALAsset
ALAssetRepresentation *rappresentation = [asset defaultRepresentation];
Byte *buffer = (Byte*)malloc(rappresentation.size);
NSUInteger buffered = [rappresentation getBytes:buffer fromOffset:0.0 length:rappresentation.size error:&err];
but I can't find a way to reduce the size of the image by resizing and compressing it.
My idea was to have something like:
UIImage *myImage = [UIImage imageWithData:data];
//resize image
NSData *compressedData = UIImageJPEGRepresentation(myImage, 0.5);
but, first of all, even without resizing, just using this two lines of code compressedData is bigger than data.
and second I'm not sure about what's the best way to resize the UIImage
You can use the
[theAsset thumbnail]
Or;
Compressing might result bigger files after some point, you need to resize the image:
+ (UIImage *)imageWithCGImage:(CGImageRef)cgImage scale:(CGFloat)scale orientation:(UIImageOrientation)orientation
It's easy to get the CGImage from an ALAssetRepresentation:
ALAssetRepresentation repr = [asset defaultRepresentation];
// use the asset representation's orientation and scale in order to set the UIImage
// up correctly
UIImage *image = [UIImage imageWithCGImage:[repr fullResolutionImage] scale:[repr scale] orientation:[repr orientation]];
// then do whatever you want with the UIImage instance