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.
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