Thanks Giacomo for your answer, but the problem is not so much that the resizing doesn't work, but that [UIImage imageWithData:listImage] always returns a scale of 1.0 for the image. This means that I encounter the problem described, when images are saved using an iPhone with a retina screen... (deployment target is iOS 4).
On Mar 27, 2012, at 11:57 AM, Giacomo Tufano wrote: > Il giorno 27/mar/2012, alle ore 09:38, Ray ha scritto: > >> 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: >> 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: >> >> 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... > > That's what I use to generate a thumbnail of sideSize side lenght in iOS3.x > code. > It uses iOS4+ functions for retina displays (I remember that you can assume > iOS4+ with retina displays). > > CGSize newSize = CGSizeMake(sideSize, sideSize); > #if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_4_0 > if(UIGraphicsBeginImageContextWithOptions != NULL) > UIGraphicsBeginImageContextWithOptions(newSize, NO, [[UIScreen > mainScreen] scale]); > else > #endif > UIGraphicsBeginImageContext(newSize); > UIGraphicsBeginImageContext(newSize); > [self drawInRect:CGRectMake(0, 0, sideSize, sideSize)]; > // Get the new image from the context > UIImage *thumbnailImage = UIGraphicsGetImageFromCurrentImageContext(); > // End the context > UIGraphicsEndImageContext(); > > It works correctly on retina displays. > To be honest I don't remember why I use that macro to test for iOS4, there > were a reason and that was a workaround but cannot remember why. It works, > anyway. :) > > HTH, > gt > > --- > Giacomo Tufano > Stat rosa pristina nomine, nomina nuda tenemus. > > > _______________________________________________ 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
