cesar trujillo cetina cesar trujillo cetina - 5 months ago 85
iOS Question

Memory Warning UIImagepickerController IOS 7

Could anybody help me with this issue I'm a bit new to objective c and iOS. I've been working on it but I can't figure out how to fix the problem, My app is really simple it only start the camera take pictures and send them through email to our server. This code was working just fine in iOS6.

When I take pictures my memory is heap growth with each screen capture and I get "Received Memory Warning" and finally - Terminated due to Memory Pressure. -

-(void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{

[self.popoverController2 dismissPopoverAnimated:true];
NSString *mediaType = [info
objectForKey:UIImagePickerControllerMediaType];

if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
_image = [info
objectForKey:UIImagePickerControllerOriginalImage];

_image = [self fixrotation:_image]; //<----- increased memory when UIImageWriteToSavedPhotosAlbum is uncommented IF is comment it doesn't increased memory but after some pictures I start to get "Received Memory Warning" message until the app Crash.

if (_newMedia){
UIImageWriteToSavedPhotosAlbum(_image,
self,@selector(image:finishedSavingWithError:contextInfo:),
nil);
[self dismissViewControllerAnimated:NO completion:nil];
[self performSegueWithIdentifier:@"SeleccionadoCameraR" sender:self];


}else{
[self performSegueWithIdentifier:@"SeleccionadoCameraR" sender:self];

}

}

}

- (UIImage *)fixrotation:(UIImage *)image{


if (image.imageOrientation == UIImageOrientationUp) return image;
CGAffineTransform transform = CGAffineTransformIdentity;

switch (image.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, image.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;

case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;

case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, image.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
case UIImageOrientationUp:
case UIImageOrientationUpMirrored:
break;
}

switch (image.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;

case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, image.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationUp:
case UIImageOrientationDown:
case UIImageOrientationLeft:
case UIImageOrientationRight:
break;
}

// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, image.size.width, image.size.height,
CGImageGetBitsPerComponent(image.CGImage), 0,
CGImageGetColorSpace(image.CGImage),
CGImageGetBitmapInfo(image.CGImage));


CGContextConcatCTM(ctx, transform);
switch (image.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
// Grr...
CGContextDrawImage(ctx, CGRectMake(0,0,image.size.height,image.size.width), image.CGImage);
break;

default:
CGContextDrawImage(ctx, CGRectMake(0,0,image.size.width,image.size.height), image.CGImage); //when I use instruments it shows that My VM is because of this
break;
}

// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);//also this line in Instruments
UIImage *img = [UIImage imageWithCGImage:cgimg];


CGContextRelease(ctx);
CGImageRelease(cgimg);


return img;


}


probably is a memory management. I will appreciate your help

Answer

You're on the right track with your fixRotation method. However, you should also resize the image. Otherwise, the image will be huge, ~30 MB (depending on device).

Checkout this blog post on how to resize images correctly. Specifically, the UIImage category files you want are these:

UIImage+Resize.h

UIImage+Resize.m

It's also a good idea to do this on a background thread. Something like this

- (void)imagePickerController:(UIImagePickerController *)imagePicker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    // Dismiss the image picker first to free its memory
    [self dismissViewControllerAnimated:YES completion:nil];

    UIImage *originalImage = info[UIImagePickerControllerOriginalImage];

    if (!originalImage)
        return;

    // Optionally set a placeholder image here while resizing happens in background

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        // Set desired maximum height and calculate width
        CGFloat height = 640.0f;  // or whatever you need
        CGFloat width = (height / originalImage.size.height) * originalImage.size.width;

        // Resize the image
        UIImage * image = [originalImage resizedImage:CGSizeMake(width, height) interpolationQuality:kCGInterpolationDefault];

        // Optionally save the image here...

        dispatch_async(dispatch_get_main_queue(), ^{
            // ... Set / use the image here...
        });           
    });
}