Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions
Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions
- Subject: Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions
- From: Ray <email@hidden>
- Date: Tue, 27 Mar 2012 19:19:13 +0200
Andreas:
On Mar 27, 2012, at 6:41 PM, Andreas Mayer wrote:
> The scale value is the same as set in UIGraphicsBeginImageContextWithOptions(), as far as I can tell.
Right, that was what I meant actually.
> But it will be lost when creating PNG data and reading it again. (Since I don't see a way of creating a PNG file without using UIImagePNGRepresentation() it doesn't seem to matter if the data was saved to a file or not.)
You have a point here ;)
> So either imageWithData does not restore the scale from PNG data or UIImagePNGRepresentation() does not store it in the first place.
>
> I see that as a bug, since the PNG format is able to hold that information.
Yes, I think it is imageWithData that is the culprit. In this WWDC session, they actually state that they specifically did this because some older applications would get in trouble. I don't remember how they worded it, it was addressed very briefly. I will watch that part again. Edit: I just checked and they say they do this for compatibility reasons. It's around the 9'40'' mark, session 134 - Optimize your iPhone App for the Retina Display (WWDC 2010, I assume you have access)...
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| References: | |
| | >Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions (From: Ray <email@hidden>) |
| | >Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions (From: Marco Tabini <email@hidden>) |
| | >Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions (From: Andreas Mayer <email@hidden>) |
| | >Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions (From: Ray <email@hidden>) |
| | >Re: Question about UIImage, scaling, and UIGraphicsBeginImageContextWithOptions (From: Andreas Mayer <email@hidden>) |