I am displaying a big image in CATiledLAyer.
Now i want to draw a line between two points where the user touches on that image.
Would that be possible ?? , if so can you outline me the way to accomplish it ??
Thanks,
Ratna
I did something similar for an app a while back. The strategy I used was to place another view on top of the view with the tiles. Then set your self up as a UIScrollViewDelegate and everytime the tiled view scrolls or zooms, recalculate where the overlayed objects need to be. Just read the contentOffset value and the zoomScale and you should have what you need to correctly figure out where your overlay needs to be positioned. You will also have to make sure that touches are correctly reaching the tile view if they have to pass through your overlay view.
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Is it possible do something like this ?
When I click on the button I need the following animation: button to set some alpha filter and starts to fall down as indicated by the arrow, it will disappear on tab.
Can you tell me how to do this ? Thanks a lot ...
Here is image url: http://img534.imageshack.us/img534/8149/screenqx.jpg
It's definitely possible, but there are some issues you have to overcome. One is that UIBarButtonItem isn't a UIView. One way is to loop through the subviews of the UIToolbar or UINavigationBar. Another way is to figure out the position of the button. Another is to get the view using private api if you're not submitting to the AppStore.
Once you have the view, you can move it to the superview of the UIToolbar or UINavigationBar or you can create a view on top of that (and hide the real UIBarButtonItem since you're done with that). The latter is more difficult because mimicking the look of the default bordered UIBarButtonItem isn't easy.
Now you need to get the center of the UITabBarItem somehow. You can either use private api or you can loop through the subviews.
Create a CGPath using Quartz functions or using UIBezierPath. The start point will be the center of the button and the end point will be the center of the UITabBarItem.
Create a CAKeyFrameAnimation and attach said CGPath.
Create a CABasicAnimation to animate the opacity.
Add both to a CAAnimationGroup.
Attach the animation group to your button view's CALayer.
Make sure to also set the position and the alpha in order to prevent the view from jumping back to its original position after the animation.
Once you attach the animation group, the animation should start, so make sure you're doing all of this in the button's selector method.
You can't really move it from view to view, as your views could clip and then you'd get frames with only a partial image. Probably the best thing to do is to create a view on the fly which covers the whole screen, copy the button image into the view at the original point, remove the button from the original view, then animate that image to where you want it to go, then add the button to the final destination.
In My Application,i am having one scrollVIew containing multiple images.
and out of the scrollview i have one uiimageview.
i want to Drag any image from ScrollView and drop it on uiimageview which is out of the scrollview.
is it possible?
help And suggestions are appreciated
Thanks in advance.
gamozzii's reply is close to what you need to do, but there's one problem. An UIScrollView will eat touches, so tapping on an image will have no effect.
As a result you will have to subclass the UIScrollView
I have written a small functional app to illustrate dragging the image from a scroll view into an image view. You can download the project here.
Yes this should be possible, you will need to implement the touch/drag events directly.
Check out the touchesBegan, touchesMoved etc. delegate methods in UIResponder.
One approach would be to subclass imageview and implement touchesBegan, touchesMoved in it, and use this imageview subclass to display your images in the scroll view.
On the touchesBegan create a new image view and add it to the outer view and set its image to be the same as the one in the scroll view. You need to overlay it directly over your source image in the scroll view so adjust its frame origin to be relative to the outer view you will need to use the scrollview origin and also the content view size and offset of the source image view inside the content view in order to recalculate the new origin in the outer view.
Then on the touches moved, simply readjust the frame of this image in accordance with the coordinates from the touches moved so that the image follows the touch.
Do a boundary check against the frame of your target imageview - once the user drags it into this boundary, make that target imageviews image the same as the image in the view being dragged and remove the dragged image from the containing view and release it.
In case you're still interested in another solution (and for other users of course):
I did implement that behaviour before just like gamozzii recommended.
I set canCancelContentTouches = NO on the UIScrollView to make sure the subviews handle there touches on their own. If a subview (in your case an image) was touched, i moved the view out of the scrollview onto the superview and started tracking it's dragging. (You have to calculate the correct coordinates within the new superview, so it stays in place). After dragging finishes, i checked if the target area was reached, otherwise I moved it back into the scrollview.
The subviews are handling the dragging on there own via (touchesBegan:/Moved:/Ended:/Cancelled:).
If that's not detailed enough, here's my example code: Github: JDDroppableView
Is there a way to a bounding box for a view so that its subviews cannot leave the view?
I currently have UIImageViews which I move around, scale, rotate etc and they are able to leave the view area.
How does one set the superview to bound/hold the subviews within it?
How else can this be done. I currently detect the origin of the image this works to the point that the image moves until it reaches this origin, when it does, the image is stuck.
I use gestureRecognizers and this origin technique only works for panning/moving an image.
Any suggestions?
If you want to stop a view's subviews from being drawn outside its borders, you need to set its clipsToBounds property to YES. (See the UIView class reference for details.)
If you want to stop your views from being in certain positions, don't move them there! It's your code that's putting them where you don't want them to be. If you're using a gesture recogniser, presumably you have a method that responds to gestures by adjusting the frame of a view - put some conditions on this movement that prevent it from happening when you don't want it.
When you write these conditions, bear in mind that a view's origin is relative to its superview. For example, say you have a view controller with a view that takes up the whole screen of the device, and inside that a box that starts at 0, 100, and inside that some squares and circles and squiggly shapes that the user can move around. If you examine containerBox.bounds.origin, you'll find that it's 0, 100, but if you want to put a square in the top left corner of the box, you need to get its frame and set the origin to 0, 0. Something to look out for.
I didn't follow your explanation of the 'origin technique'. If you paste your code, I might be able to help.
I am currently working on an application for a client, and they have made an odd request. The request involves putting a custom image as the indicator for the scrollview. I am not even sure if this is possible but if it is can you please let me know how one would go about doing that.
Thanks
UIScrollView streches a small, semi-transparent circle image to generate its scrollbars. You can find this image as the first subview of a UIScrollView:
UIImageView *circle = [scrollView.subviews objectAtIndex:0];
However, as I said this image is stretched, and as far as I can tell, only the alpha values are considered when drawing the scroll bars.
So for example if you're only interested in changing the top/bottom ends of the scroll bar, you can try to change this image. However, I doubt you'll be able to do anything interesting.
A possible solution that comes to mind, and this is only a theory, is to add a custom, transparent UIView on top of a UIScrollView. Then you can hide the default scroll bar (by using showsHorizontalScrollIndicator and showsVerticalScrollIndicator), pass the necessary touch events to the UIScrollView to scroll the content, and draw the scrollbars in your custom view.
I have drawn few shapes in drawRect function of a view, these shapes color changes after some time repeatedly using setNeedsDisplay that calls the drawRect, secondly a shape name is also to be selected when tapped on it, up till now all works fine.
There are three views each having more than one shapes drawn as above. All these views are added into a scroll view so that user can view shapes on next view.
Now the requirement is to pinch zoom the view containing shapes, also need to select the shapes, drawRect is called repeatedly. all the pinch zoom i have seen are related to images.
I have done it using the following technique.
I created a class that extends from UIScrollView and it can zoom, it contains the View that has shapes. Number of these scroll views are are equal to number of views containing shapes (i.e. 3).
Now these scroll view objects are added to the main scroll view linked with page control.
The touch returns the same point after scaling as without scaling. So algo for selecting shape clicked did not change.