OK, so I have this iOS 3.x code base that I need to update. I have the following code, to make a thumbnail image:
... // let's say we have a UIImage *selectedImage with a size of 1000 x 1000 UIImage *newImage; NSData *imageData; UIGraphicsBeginImageContext(CGSizeMake(44.0, 44.0)); [selectedImage drawInRect:CGRectMake(0.0, 0.0, 44.0, 44.0)]; newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); imageData = UIImagePNGRepresentation(newImage); ... Code is simplified, just for illustrative purposes. I store imageData as a binary property (called "listImage") in a Core Data entity and use it as a thumbnail image in a UITableView, like so: cell.imageView.image = [UIImage imageWithData:item.listImage]; It's small, so no problems. On both a normal and retina screen iPhone running iOS 4 this works OK, although we don't make use of the increased resolution, yet. In order to do that, I update the code with: UIGraphicsBeginImageContextWithOptions(CGSizeMake(44.0, 44.0), YES, 0); Now, when I generate a new image on an iPhone with a retina screen, in which case the above UIGraphicsBeginImageContextWithOptions uses a scale of 2.0, the image in the table view shows too big. This is because [UIImage imageWithData:item.listImage] always returns a 1.0 scaled image. Now I can solve this by using something like: UIImage *theImage = [UIImage imageWithData:listImage]; [UIImage imageWithCGImage:theImage.CGImage scale:theImage.size.width > 44.0 ? 2.0 : 1.0 orientation:theImage.imageOrientation]; But this seems kludgy and it's using programmer's knowledge, so to speak. I watched WWDC2010 session 134 "Optimize your iPhone App for the Retina Display" again, searched stackoverflow etc. but I can't find a more elegant solution. What would be a more thorough approach? Maybe it's staring me in the face but I don't see it... Thanks for your answers, - Ray. _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
