I'm doing video conversion using ffmpeg. I'm getting the sequence of images. Now I am using
[UIImagePNGRepresentation(video.currentImage) writeToFile:fileName atomically:YES];
...to save the file into a directory. But this taking lots of time to save. I need to save this image quickly.
Try With UIImageJPEGRepresentation ( UIImage *image, CGFloat compressionQuality)
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In my iPhone App I want to retrieve image from (stored in ) sqlite database table in "BLOB" datafield.
For that I am storing my image in NSData using code
NSData *imageData = UIImagePNGRepresentation(image);
and I am also able to retrieve image from NSData -> UIImage by code
self.img1=[UIImage imageWithData:imageData];
And displaying Image into imageView by
imageView2.image=img1;
I am storing image (in NSData form) into sqlite database table column (of BLOB Datatype) successfully.
I am using below code to retrieve image from database
NSData *imageData2 = [[arraySelect objectAtIndex:0] valueForKey:#"image_column"];
NSLog(#"imagedata2 in retrive :: %#",imageData2);
in NSLOG i am getting the same data stored in database column (in blob datatype "NSData form" )
Now I am retrieving image by
(while debugging it crashes here and showing meaasge EXE_BAD_ACCESS)
self.img3=[UIImage imageWithData:imageData2];
imageview3.image=img3;
But I am not getting that image in imageView.
I checked all outlets but they are ok.
So please Help and Suggest what I should do to get image in imageView from database.
Thanks.
#Prerak i think this will help you something..and solve your problem
http://dblog.com.au/iphone-development-tutorials/iphone-sdk-tutorial-reading-data-from-a-sqlite-database/
In My iPhone App,
I am converting my image in to NSData format and storing it into sqlite database Table in dataType="BLOB",
But, I am retriving that image (stored in NSData format) into NSArray Format from database,
The Problem is I am not able to convert NSArray to NSData ( Which would Help me to get my image back into NSData format )
Please Help and Suggest,
Thanks
Your requirement is so odd.
you can store image in local file system with the file name in sqlite
if you really want images store in sqlite, you can every image in sqlite separately rather than archive images in NSArray than convert to NSData
Use NSKeyedArchiver How to convert NSArray to NSData?
UIImage *imgData = [UIImage imageWithData:[yourArray objectAtIndex:theIndex]];
for multiple images in one array you can loop it
like
for (int i = 0;i<[yourArray count];i++) {
UIImage *img = [UIImage imageWithData:[yourArray objectAtIndex:i];
//do something here with each image
// for example, add it to an ImageView
}
P.S. if theres only one image, its index is 0
hope this helps
In my iPhone App I am picking image from iPhone Image Library as well from device camera,
and I am displaying that image in imageView.
I am able to store my image into iPhone image Library.
But now I want to store my image in some Directory with specific name, so I can use that image again in my application and also I want to store it in sqlite file.
There is a short writeup of this here: http://iosdevelopertips.com/data-file-management/save-uiimage-object-as-a-png-or-jpeg-file.html
Here is the relevant code stolen directly from that site:
// Create paths to output images
NSString *pngPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/Test.png"];
NSString *jpgPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/Test.jpg"];
// Write a UIImage to JPEG with minimum compression (best quality)
// The value 'image' must be a UIImage object
// The value '1.0' represents image compression quality as value from 0.0 to 1.0
[UIImageJPEGRepresentation(image, 1.0) writeToFile:jpgPath atomically:YES];
// Write image to PNG
[UIImagePNGRepresentation(image) writeToFile:pngPath atomically:YES];
To store it in a SQLite Database you would take the code that makes an NSData object (either UIImageJPEGRepresentation or UIImagePNGRepresentation) and save them to a BLOB column.
NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/ImageFileName.jpg"];
[UIImageJPEGRepresentation(yourUIImageView.image,1.0) writeToFile:path atomically:YES];
Documentation: UIImageJPEGRepresentation
If you're handling PNGs there's another method called UIImagePNGRepresentation.
I was storing an image in a sqlite table as blob data and displaying it using the following code:
self.myImage.image = [[[UIImage alloc] initWithData:recipe.image] autorelease];
I'm now using the image file name in the sqlite fields instead and storing the image on the filesystem. what would the code be to display it that way? I'm having a hard time figuring it out.
normally to display an image from the filesystem I'd use:
UIImage *image = [UIImage imageNamed:#"something.png"];
in this case I have to grab the string that's in the table field/attribute.
thanks in advance.
You can load UIImage with absolute filepath by following API.
+ (UIImage *)imageWithContentsOfFile:(NSString *)path;
+(UIImage *)imageNamed:(NSString *)name will look for an image from application's main bundle. In other word, it will look for an image from Resources.
Editted:
You said that you stored the image on the filesystem. So, I think you can retrive the absolute filepath of image from sqlite database, doesn't it?
NSString *imgPath;
/// get imgPath from sqlite database
...
/// get the image by filepath
self.myImage.image = [UIImage imageWithContentOfFile:imgPath];
And, my question is how do you store the image on the filesystem.
I am showing very big size images in UITableView, because of this my app is getting crashed after some time. Now i want to resize the image and save it to disk. can some one help me resizing the image from NSData/UIImage and saving saving it to the disk.
I got the code to resize the image from UIImage, so as the result i have my resized in image in UIImage object, how to save it to iphone sandbox.
Thanks,
Here is code to save to the Documents directory on iOS that is from working code.
// Convert UIImage to JPEG
NSData *imgData = UIImageJPEGRepresentation(image, 1); // 1 is compression quality
// Identify the home directory and file name
NSString *jpgPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/Test.jpg"];
// Write the file. Choose YES atomically to enforce an all or none write. Use the NO flag if partially written files are okay which can occur in cases of corruption
[imgData writeToFile:jpgPath atomically:YES];
You're asking 'how do I write a file' right?
I guess there is a touch of complication in that you probably want to write into the Library/Caches directory, so when the phone gets backed up you don't save those files.
Get the root of the app folder w/ NSHomeDirectory() and then append Library/Caches.
You can write an NSData to the fs w/ a method on NSData. If you have a UIImage, you can do UIImageJPEGRepresentation() or UIImagePNGRepresentation to get data.
NSData *imgData = UIImageJPEGRepresentation(image, 1);
CGImageSourceRef source = CGImageSourceCreateWithData((CFMutableDataRef)imgData, NULL);
NSDictionary *metadata = [(NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source,0,NULL)autorelease];
NSString *jpgPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/Test.jpg"];
[imageMutableData writeToFile:jpgPath atomically:YES];
It will copy your image to documents folder in sandbox with name Test.jpg.
If you want to do it for PNG you can try UIImagePNGRepresentation(image);