Compressing / down size / resize image while storing image in iPhone application

Question

To understand my question please go through following:

• In my application user first taps on a button.
• Image picker controller is displayed
• user selects images / an image from it.
• all that images must be saved to my iPhone application.

I have already implemented this and for doing this I have implemented following code.

 -(IBAction)setPhoto:(id)sender {
    facPhotoPicker=[[UIImagePickerController alloc]init];
    facPhotoPicker.delegate=self;
    facPhotoPicker.sourceType=UIImagePickerControllerSourceTypePhotoLibrary;
    facPhotoPicker.allowsImageEditing=YES;
    facPhotoPicker.navigationBar.barStyle=UIBarStyleBlackOpaque;
    [self presentModalViewController:facPhotoPicker animated:YES];
}

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info {
    NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],1);
    UIImage *img=[[UIImage alloc] initWithData:imgData];
    facImgView.image=img;
    [img release];
    NSString *str=[NSString stringWithFormat:@"%i.jpg",[currentFaculty facultyNo]];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [NSString stringWithFormat:@"%@/%@", [paths objectAtIndex:0], str];
    [imgData writeToFile:path atomically:YES];
    [picker dismissModalViewControllerAnimated:YES];
}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    [picker dismissModalViewControllerAnimated:YES];
}

But the problem is the user's iPhone may have larger images.

I don't want to store that large images within application. for example

• user selects an image having size of 1200 x 800

• But I want only 80 x 80 size image

  1. selected images should be down sized to my requirement / 8 mb image to less then 500 kb
  2. how to store image within resource directory instead of storing in documents directory?

Answer 1

This is solved.

The main key for downsizing. I downsized an image up to 116 kb.

---

NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
while ([imgData length]>50000) { 
    compressionRatio=compressionRatio*0.5;
    imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
}

---

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
double compressionRatio=1;
NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
while ([imgData length]>50000) { 
    compressionRatio=compressionRatio*0.5;
    imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
}
UIImage *img=[[UIImage alloc] initWithData:imgData];
facImgView.image=img;
NSLog(@"%@",[info objectForKey:@"UIImagePickerControllerOriginalImage"],3);
[img release];


NSString *str=[NSString stringWithFormat:@"%i.jpg",[currentFaculty facultyNo]];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [NSString stringWithFormat:@"%@", [paths objectAtIndex:0]];
path=[path stringByDeletingLastPathComponent];
path=[NSString stringWithFormat:@"%@/%@",path,str];
[imgData writeToFile:path atomically:YES];
[picker dismissModalViewControllerAnimated:YES];
}

Answer 2

1. any one can store in resource directory / up level directory of documents directory by implementing following logic.

---

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],1);
UIImage *img=[[UIImage alloc] initWithData:imgData];
facImgView.image=img;
NSLog(@"%@",[info objectForKey:@"UIImagePickerControllerOriginalImage"],3);
[img release];
NSString *str=[NSString stringWithFormat:@"%i.jpg",[currentFaculty facultyNo]];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [NSString stringWithFormat:@"%@", [paths objectAtIndex:0]];
path=[path stringByDeletingLastPathComponent];
path=[NSString stringWithFormat:@"%@/%@",path,str]; // storing path
[imgData writeToFile:path atomically:YES]; // stores successfully 
[picker dismissModalViewControllerAnimated:YES];
}

Answer 3

2) You can not store in the Resources directory now in any directory within the application.