clipping and scrolling
clipping and scrolling
- Subject: clipping and scrolling
- From: Torsten Curdt <email@hidden>
- Date: Fri, 12 Aug 2011 13:27:28 +0200
Hey folks,
On the Mac we have NSClipView (and NSScrollView). On iOS we have
UIScrollView and yet sometimes I wondering why.
Let me explain: For an iOS project I have an image that does not fit
on the screen. I need to be able to show a portion of it to the user.
There are couple of ways to approach this.
1) I could just create an UIImageView and just move the origin into
the negative. The clipping happens naturally through the parent view.
2) I could use a UIScrollView and add the large UIImageView to it and
move the content offset
3) I could have a custom view that basically just draws a portion of
the image. Something along the lines of
CGImageRef imageRef = CGImageCreateWithImageInRect([largeImage
CGImage], cropRect);
[UIImageView setImage:[UIImage imageWithCGImage:imageRef]];
CGImageRelease(imageRef);
Now I am trying to understand the details of the different approaches.
When I change the origin of view I assume the system is smart enough
to copy content over. So what could be a reason to use UIScrollView
(or NSClipView on Mac) for this? I assume 3) should be the worst
option as it redraws the complete content. But maybe I am also just
completely off.
Which option would you pick and why?
Some insights would be appreciated.
What docs should I read that I haven't?
cheers,
Torsten
_______________________________________________
Cocoa-dev mailing list (email@hidden)
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:
This email sent to email@hidden