UIScrollView or alternatives for zooming/panning

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UIScrollView or alternatives for zooming/panning

(14 posts) (12 voices)

Started 2 years ago by AbyssNOLF
Latest reply from rsanchezsaez

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AbyssNOLF
Member

I've seen mentions and discussions before about using UIScrollView or other techniques for zooming and panning, but I've never seen follow-ups to any of them that actually discuss the trials and tribulations of such quests.

I have so far created an application in which the Cocos2d view is put inside a UIScrollView. This allows the UIScrollView to work it's magic, but causes game freezes and unexpected troubles managing game touches and zoom/pan touches.

Has anyone managed to resolve these issues (particularly the game freeze)?

Alternatively, while UIScrollView is at least an option, it would be best if zooming/panning could be controlled manually. However, I have failed in all attempts to create a successful replacement for the UIScrollView in terms of fluidity, performance, and results. Does anyone have any tips, clues, suggestions, stories about anything similar?

What is the current state of zooming and panning?

Posted 2 years ago #
conor
Member

Here is a start.

I'm struggling with the same thing. One of the poster's left some code but it's not available on the file share any longer.

Posted 2 years ago #
Sean Carmody
Member

I am also interested in any progress or tips on this. You may want to note this known issue:
http://code.google.com/p/cocos2d-iphone/issues/detail?id=266

Posted 2 years ago #
Joao Caxaria
Member

I'll share the code back if anyone finds it useful. It's also available in the box2d sample I shared in the old forum.

Posted 2 years ago #
slipster216
Moderator

I had so much trouble with UIScrollView that I ended up creating my own scrolling/zooming code for what I wanted to do. In my case, I wanted two fingers to move and one finger to pass the touch though to the subview. UIScrollView doesn't make changes to it's behavior easy, mostly because it uses some unpublished APIs that aren't really available to you. I did find a class someone wrote called ZoomScollView (google it) that allows you to set the zoom on a scroll view manually.

Posted 2 years ago #
Rob Segal
Member

Hey all just wanted to let you know of a solution that worked to the panning with UIScrollView problems some of which are discussed in this thread for me and my team. Full details are available at http://getsetgames.com/2009/08/21/cocos2d-and-uiscrollview/.

Posted 2 years ago #
Codemattic
Moderator

thats an interesting blog with some good cocos code you have there!

Posted 2 years ago #
Rob Segal
Member

Thanks. Just trying to give back a bit to the community which has been very helpful to me so far.

Posted 2 years ago #
oscarmk
Member

I am also using this code and it works great. The only problem is that you cant use CCDirectorDisplayLink, and sometimes when your application starts it tops at 40 fps randomly, most of the time it will start just fine though.

Posted 2 years ago #
exorcyze
Member

I had done a simple scroll-view style implementation in pure Cocos2d which still allows usage of whatever director type you'd like :

http://www.cocos2d-iphone.org/forum/topic/3558#post-21636

Posted 2 years ago #
oscarmk
Member

Thank you exorcyze!! Will take a look at your post.

Posted 2 years ago #
GreenDot
Member

As explained in e.g. here one can use UIScrollView to swipe-scroll a CCLayer. It might be not the best approach for scrolling but it seems to work so far.

However, I am having problems with using the zooming feature of UIScrollView (pinching or reverse pinching the screen). Namely, to be able to use zooming functionality, one needs to implement
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView and
I think usually UIScrollView has a child UIView which is simply returned in this method. With Cocos2d, there is no UIView child. If I return UIScrollView itself in this function, it sort of works for zooming in, but after zoom out the app stops responding to UIScrollView gestures (swipes or pinched). If I return 'nil', my scrollViewDidZoom does not get called.

Did anybody figure a way to use the zoom features of UIScrollView with Cocos2d?

Posted 1 year ago #
xdcdx
Member

I figured it out for zooming: add an "empty" UIView to the UIScrollView, and return that one in - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView.

The you could calculate the appropriate scale in -(void)scrollViewDidZoom: like follows
- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
if (scrollView==self) {
// Obtain scale from automatically resized transparentView
scale_ = transparentView_.frame.size.width/transparentView_.bounds.size.width;
// Propagate scale to Cocos Layer
layer_.scale=scale_;
// Fixes a bug when zooming in the top left corner of the screen
// makes layer to be redisplayed.
[self scrollViewDidScroll:scrollView];
[[[CCDirector sharedDirector] openGLView] setNeedsLayout];
}
}

Cheers.

Posted 1 year ago #
rsanchezsaez
Member

Also, for additional caveats using UIScrollView with cocos2d check my answer to this question:
- http://stackoverflow.com/questions/2457380/uiscrollview-and-cocos2d/5795724#5795724

(Riq, could you confirm if the issue dealt there is a bug in Cocos2D? If so, I'll submit it to the issue tracker)

Posted 1 year ago #

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