I am attempting to save and load a UIImage to and from the iPhone documents directory after the image is picked from the iPhone Photo Library. It is able to do so, but for some reason, when I load the image, it rotates it 90 degrees counterclockwise. Here is my saveImage and loadImage methods:
Save Image:
- (void)saveImage: (UIImage*)image{
if (image != nil)
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* path = [documentsDirectory stringByAppendingPathComponent:
[NSString stringWithString: #"lePhoto.png"] ];
//NSData* data = UIImagePNGRepresentation(image);
//[data writeToFile:path atomically:YES];
[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];
}
}
Load Image:
- (NSData*)loadImage{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* path = [documentsDirectory stringByAppendingPathComponent:
[NSString stringWithString: #"lePhoto.png"] ];
NSData *data = [[NSData alloc] initWithContentsOfFile:path];
//UIImage *image = [[UIImage alloc] initWithData:data]; //my second try
//UIImage* image = [UIImage imageWithContentsOfFile:path]; //first try
//return image;
return data;
[data release];
}
And I am now loading the image like this, to see if it would, for some crazy reason, solve my problem (it didn't, obviously):
UIImage* theImage = [[UIImage alloc] initWithData:[self loadImage]];
I have done some testing where I have two UIImageViews side-by-side, one on the left that doesn't save and load the image before display (it just straight-up shows the image once a photo is picked from the ImagePicker), and one on the right that displays AFTER the save load occurs. The one on the right is the only one rotating 90 degrees CCW; the non Save/Load picture is displaying correctly. This only occurs on the actual iPhone. The simulator shows both images correctly. I have spent many, many hours attempting to figure it out, but to no avail. Any ideas as to what could be causing this?
EDIT: It should also be known that the image always says it's oriented up, even when it obviously isn't! It only rotates after ALL of the code has been run. I've tried doing a force redraw in between my code to see if that changes things, but it doesn't (though it is possible I'm even doing that wrong. Who knows, anymore).
Also, it will not autorotate photos that have been screenshot from the iPhone. Only photos that have been taken by the camera. [I haven't tried downloaded photos.] It's the weirdest thing...
And if you're wondering exactly how I'm pulling my picture, here's the method that will at least shed light on what I'm doing (it's not every method needed to do this function, obviously, but it gives insight on how I've written my code):
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
theimageView.image = [info objectForKey:#"UIImagePickerControllerOriginalImage"];
[self saveImage:[info objectForKey:#"UIImagePickerControllerOriginalImage"]];
[picker dismissModalViewControllerAnimated:YES];
}
Any advice is greatly appreciated. And I do know this much: if there's a way to do something crazy to get some stupid, never-before-heard-of problem, chances are, I'll find it, apparently :P
Ok. I figured it out. Apparently when you save things with PNG representation, and not JPEG representation, the image orientation information is not saved with it. Because of this, every image loaded will default to showing orientation up. So, the easiest way is to do this:
NSData* data = UIImageJPEGRepresentation(image,0.0);
[data writeToFile:path atomically:YES];
instead of this:
[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];
And, of course, changing all the picture names from .png to .jpg. The 0.0 part of the code above is to control Alpha levels, which is required of jpegs. Hope this helps people in the future!
I assume you're using the Assets Library Framework to get the image. If so, you'll want to get the orientation of the image in your results block, and manipulate the UIImage to adjust. I have something like the following:
ALAssetsLibraryAssetForURLResultBlock resultBlock = ^(ALAsset* asset)
{
ALAssetRepresentation* rep = [asset defaultRepresentation];
_orientation = rep.orientation;
...
}
Aside: What a great type name, huh? Holy moly, does Objective-C need namespaces!
Thanks so much...
This code has worked and saved several hours of work for me.
NSData* data = UIImageJPEGRepresentation(image,0.0);
[data writeToFile:path atomically:YES];
in the place of
[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];
Related
I am trying to make a simple application using XCode 4.5 which would allow the user to chose any particular image via accessing his photo library, then submit that image for recognition with the help of the Tesseract library.
The problem is that I do not know how to further save the selected user picture, In other words, I can provide the user with an option for going in the picture library and let him chose a picture, but I do not how to then save that selected picture so that it can be further processed.
I hope i made it clear, Appreciate your help.
Try this,
Save image:
NSString *imgName=[#"imgname.png"];
[[NSUserDefaults standardUserDefaults]setValue:imgName forKey:#"imageName"];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:imgName];
UIImage *image = imageView.image; // imageView is my image from camera
NSData *imageData = UIImagePNGRepresentation(image);
[imageData writeToFile:savedImagePath atomically:NO];
Retrive image:
NSString *imgName= [[NSUserDefaults standardUserDefaults]valueForKey:#"imageName"];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
NSString *filePath=[NSString stringWithFormat:#"%#/%#",documentsDir,imageName];
[imageview setImage:[UIImage imageWithContentsOfFile:filePath]];
What you need to do is save the image data after selection inside the following delegate - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { You can get the image via the key UIImagePickerControllerOriginalImage in the info dictionary and possibly assign it to an imageview or save it as mentioned by #Kalpesh. Check out apple's documentation for more info. Also check out this good tutorial that shows how to pick photos from the photo album or the camera.
I am still not clear about what exactly you want.
You can always Save Image in or Retrieve Image from Photo Library.
I have an application which donwloads several images and stores them on the phone. In total it will probably required around 20 images tops. I need to be able to retrieve any of these images at will depending on what screen the user is on. These images will be stored indefinitely, so I don't want to use temp directory.
At present I have a class named Images with these methods
- (void) cacheImage: (NSString *) ImageURLString : (NSString *)imageName
{
NSURL *ImageURL = [NSURL URLWithString: ImageURLString];
// Generate a unique path to a resource representing the image you want
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [paths objectAtIndex: 0];
NSString *docFile = [docDir stringByAppendingPathComponent: imageName];
// Check for file existence
if(![[NSFileManager defaultManager] fileExistsAtPath: docFile])
{
// The file doesn't exist, we should get a copy of it
// Fetch image
NSData *data = [[NSData alloc] initWithContentsOfURL: ImageURL];
UIImage *image = [[UIImage alloc] initWithData: data];
// Is it PNG or JPG/JPEG?
// Running the image representation function writes the data from the image to a file
if([ImageURLString rangeOfString: #".png" options: NSCaseInsensitiveSearch].location != NSNotFound)
{
[UIImagePNGRepresentation(image) writeToFile: docFile atomically: YES];
}
else if([ImageURLString rangeOfString: #".jpg" options: NSCaseInsensitiveSearch].location != NSNotFound ||
[ImageURLString rangeOfString: #".jpeg" options: NSCaseInsensitiveSearch].location != NSNotFound)
{
[UIImageJPEGRepresentation(image, 100) writeToFile: docFile atomically: YES];
}
}
}
- (UIImage *) getCachedImage : (NSString *)imageName
{
NSArray *paths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* cachedPath = [documentsDirectory stringByAppendingPathComponent:imageName];
UIImage *image;
// Check for a cached version
if([[NSFileManager defaultManager] fileExistsAtPath: cachedPath])
{
image = [UIImage imageWithContentsOfFile: cachedPath]; // this is the cached image
}
else
{
NSLog(#"Error getting image %#", imageName);
}
return image;
}
-(void)getImages
{
//example
NSString *image1URL = #"http://test/image1.png";
NSString *image2URL = #"http://test/image2.png";
NSString *image3URL = #"http://test/image3.png";
[self cacheImage:sLogo: #"Image1"];
[self cacheImage:sBlankNav: #"Image2"];
[self cacheImage:buttonLarge :#"Image3"];
}
-(void) storeImages
{
image1 = [self getCachedImage:#"Image1"];
image2 = [self getCachedImage:#"Image2"];
image3 = [self getCachedImage:#"Image3"];
}
So I use the code like this
Images *cache = [[Images alloc]init];
[cache storeImages];
The get images method is called once when the app first starts to get the images, it isn't called again after that, unless the images on the server are updated and I need to retrieve the updated ones.
The code works, but the problem is when I navigate to a screen that uses it, there is a very slight delay before the screen loads as it is loading the images.
My application is a tabbed application, so it begins on tab 1, I click tab 2 which implements the code, there will be a slight pause the first time it loads. It doesn't last very long, but it is noticeable and is very annoying. After that it is fine, as it is already loaded. However with navigation controller, every time you move from the first VC to the second VC, the method will be called again, so each time you navigate the delay will be there.
The images are not very big, biggest one is 68kb, others are much smaller than that. At present I am just testing with 5 images. Is there a more efficient way of storing and retrieving images, or am I doing something wrong with my code? I need to be able to retrieve these images without any noticeable delay in order for my application to remain fluid and not jerky or clunky.
Thanks in advance!!
You have two options to do the image loading work on a background thread - use Grand Central Dispatch or NSInvocationOperation. GCD might be considered the cleaner of the two:
dispatch_queue_t q = dispatch_get_global_queue(0, 0);
dispatch_queue_t main = dispatch_get_main_queue();
dispatch_async(q, ^{
//load images here
dispatch_async(main, ^{
// show on main thread here
});
});
you have delay because you're downloading data synchronously
// NSData *data = [[NSData alloc] initWithContentsOfURL: ImageURL];
Try some smart library like SDWebImage:
it lets you download image asynchronously while you still can display a local image (a proxy image). By the way, you still get cache image for free. So even if u are on local, you can still catch previously downloaded images
https://github.com/rs/SDWebImage
A must have
I want to save images that user selects from the camera roll, when app exits and restart i want to show those images to user. I have searched over internet and not found much useful resource. I know I can write the image in database as blob but I dont want to do it as increases the database size. Is it possible to save the image path and then later use that path to access that image.
Save the Image into the DocumentDirectory
NSString *imageName = "myImage.png";
NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * documentsDirectoryPath = [paths objectAtIndex:0];
NSString *dataPath = [documentsDirectoryPath stringByAppendingPathComponent:imageName];
NSData* settingsData = UIImagePNGRepresentation(imageData);
[settingsData writeToFile:dataPath atomically:YES];
EDIT:
If you want to see your saved images on the iPhone/iPad (or share them) in iTunes->Apps->Documents
jut add in Info.plist "Application supports iTunes file sharing" : "YES"
You have to use UIImagePickerController
to get the media from the Camera roll
You will get the image in the delegate method
- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
Here you can get the image and save is as NSData .. in a file and then retrieve back it next time
Edit :
to Save
Data = UIImageJPEGRepresentation(theImage,1.0);
NSString *imagePath = [ContentFolder stringByAppendingPathComponent:[NSString stringWithFormat:#" %d.plist",Counter]];
NSLog(#" iamge path %#",imagePath);
NSMutableDictionary *objectDictionary = [[NSMutableDictionary alloc]initWithObjectsAndKeys:data,#"data", nil];
[objectDictionary writeToFile:imagePath atomically:YES];
you should be able to change these according to your needs..
Can someone point me in the right direction for saving a webpage as a pdf? I already have a library for an iOS pdf reader, but I need to somehow implement a feature for saving whatever webpage the user is viewing as pdf. I am assuming I would have to use an in-app browser. Any thoughts?
This is not something that I have done, but it seems you are not the first to want to do something like this.
http://www.iphonedevsdk.com/forum/iphone-sdk-development/21451-save-contents-uiwebview-pdf-file.html
The last post in this link provides code to save a UIWebView as an image, and you should be able to convert that image into a PDF. I don't take credit for the code as I did not write it, just connecting you two :)
Here is the code for simplicity:
CGSize sixzevid=CGSizeMake(1024,1100);
UIGraphicsBeginImageContext(sixzevid);
[webview.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData *imageData = UIImagePNGRepresentation(viewImage);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *pathFloder = [[NSString alloc] initWithString:[NSString stringWithFormat:#"%#",#"new.png"]];
NSString *defaultDBPath = [documentsDirectory stringByAppendingPathComponent:pathFloder];
[imageData writeToFile:defaultDBPath atomically:YES];
Chances are pretty good that you will have to tweak this but, hopefully this helps you move in the right direction.
I'm using a UITableView to show 2 to 3 images as thumbnail in each table view cell. The images which I'm showing it in the tableview are huge in size. If I'm using those images directly without any size reduction then the tableview may lose some images if I move back and forth between TableView and other view controllers.
So, I thought of size reduction code which reduces the size of the images. The code given below works great and the previous issue was fixed. But the tableview looses its smooth scrolling because the size reduction code uses a lot of memory. Every time when a new tableview cell is shown, it processes (reduces the size) the images in the particular tableview cell.
There may be a simple solution for this. Thanks in Advance.
//Size Reduction Code
CGSize newSize=CGSizeMake(_new_width, _new_height);
UIGraphicsBeginImageContext( newSize );
[sd._image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
scene_image_preview.image =newImage;
On top of reducing the image you can store the resulting newImage as a file in the documents folder of your app.
NSData *imageData = UIImagePNGRepresentation([UIImage imageWithCGImage:newImage]);
CGImageRelease(newImage);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [NSString stringWithFormat:#"%#/%#%d_%d.png",documentsDirectory, prefix, x, y];
[imageData writeToFile:path atomically:NO];
Depending on how many images you have, you can just keep all the reduced-size images in an NSMutableDictionary that's a property of your class.
In other words:
In your header
#property (nonatomic, retain) NSMutableDictionary *sizedImages;
Then in your cellForRowAtIndexPath: code
UIImage *sizedImage = [sizedImages objectForKey:[NSNumber numberWithInt:indexPath.row]];
//Or you could use the filename as the key
if (!sizedImage) {
sizedImage = [self sizeImage];(your sizing method)
[sizedImages setObject:sizedImage forKey:[NSNumber numberWithInt:indexPath.row]];
}
A few possible options
Perform the resizing in the background so it doesn't hold up the main thread.
Cache the resized image after doing it so there is only a delay the first time (this could be used in conjunction with doing it in the background so there is no delay on the scrolling)
Are you downloading the images? If so, download a thumbnail first and display that. Then if the image is selected, display the thumbnail scaled up to full screen which will look blocky, but then download the full-size image in the background and display that when it has loaded.
If you aren't downloading the images, but they are included in the app, just include thumbnails as well and display them instead
drawing images usually takes time.i think you can try to place the images in imageView by giving the frame sizes as desired.i doesn't make difference in look of the images.
add the imageviews to the cell and add the images to the imageView
These two links are very useful
http://www.fieryrobot.com/blog/2008/10/01/glassy-scrolling-with-uitableview/
and his follow up post
http://www.fieryrobot.com/blog/2008/10/08/more-glassy-scrolling-with-uitableview/
The first link is a few best practices. The second link will eb more useful to you; render your whole table view cell to an image and use that instead - this can be cached to disk to free memory & can be used between runs of the app.
- (void)saveImage:(UIImage *)image withName:(NSString *)name {
[myArray addObject:name];
//save image
NSData *data = UIImageJPEGRepresentation(image, 1.0);
NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:name];
[fileManager createFileAtPath:fullPath contents:data attributes:nil];
}
- (UIImage *)loadImage:(NSString *)name {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:name];
UIImage *res = [UIImage imageWithContentsOfFile:fullPath];
return res;
}
Finally, I got a solution to load number of large sized images simultaneously. First, I reduced the size of the image using the size reduction code above and I saved those sized images to documents directory for the first time and then I loaded the saved images from the documents directory using these saveImage and loadImage functions.
Thanks for all the comments and suggestions to solve this.