I need to be able to interact with a representation of a cilinder that has many different parts in it. When the users taps over on of the small rectangles, I need to display a popover related to the specific piece (form).
The next image demonstrates a realistic 3d approach. But, I repeat, I need to solve the problem, the 3d is NOT required (would be really cool though). A representation that complies the functional needs will suffice.
The info about the parts to make the drawing comes from an API (size, position, etc)
I dont need it to be realistic really. The simplest aproximation would be to show a cilinder in a 2d representation, like a rectangle made out of interactable small rectangles.
So, as I mentioned, I think there are (as I see it) two opposite approaches: Realistic or Simplified
Is there a way to achieve a nice solution in the middle? What libraries, components, frameworks that I should look into?
My research has led me to SceneKit, but I still dont know if I will be able to interact with it. Interaction is a very important part as I need to display a popover when the user taps on any small rectangle over the cylinder.
Thanks
You don't need any special frameworks to achieve an interaction like this. This effect can be achieved with standard UIKit and UIView and a little trigonometry. You can actually draw exactly your example image using 2D math and drawing. My answer is not an exact formula but involves thinking about how the shapes are defined and break the problem down into manageable steps.
A cylinder can be defined by two offset circles representing the end pieces, connected at their radii. I will use an orthographic projection meaning the cylinder doesn't appear smaller as the depth extends into the background (but you could adapt to perspective if needed). You could draw this with CoreGraphics in a UIView drawRect.
A square slice represents an angle piece of the circle, offset by an amount smaller than the length of the cylinder, but in the same direction, as in the following diagram (sorry for imprecise drawing).
This square slice you are interested in is the area outlined in solid red, outside the radius of the first circle, and inside the radius of the imaginary second circle (which is just offset from the first circle by whatever length you want the slice).
To draw this area you simply need to draw a path of the outline of each arc and connect the endpoints.
To check if a touch is inside one of these square slices:
Check if the touch point is between angle a from the origin at a.
Check if the touch point is outside the radius of the inside circle.
Check if the touch point is inside the radius of the outside circle. (Note what this means if the circles are more than a radius apart.)
To find a point to display the popover you could average the end points on the slice or find the middle angle between the two edges and offset by half the distance.
Theoretically, doing this in Scene Kit with either SpriteKit or UIKit Popovers is ideal.
However Scene Kit (and Sprite Kit) seem to be in a state of flux wherein nobody from Apple is communicating with users about the raft of issues folks are currently having with both. From relatively stable and performant Sprite Kit in iOS 8.4 to a lot of lost performance in iOS 9 seems common. Scene Kit simply doesn't seem finished, and the documentation and community are both nearly non-existent as a result.
That being said... the theory is this:
Material IDs are what's used in traditional 3D apps to define areas of an object that have different materials. Somehow these Material IDs are called "elements" in SceneKit. I haven't been able to find much more about this.
It should be possible to detect the "element" that's underneath a touch on an object, and respond accordingly. You should even be able to change the state/nature of the material on that element to indicate it's the currently selected.
When wanting a smooth, well rounded cylinder as per your example, start with a cylinder that's made of only enough segments to describe/define the material IDs you need for your "rectangular" sections to be touched.
Later you can add a smoothing operation to the cylinder to make it round, and all the extra smoothing geometry in each quadrant of unique material ID should be responsive, regardless of how you add this extra detail to smooth the presentation of the cylinder.
Idea for the "Simplified" version:
if this representation is okey, you can use a UICollectionView.
Each cell can have a defined size thanks to
collectionView:layout:sizeForItemAtIndexPath:
Then each cell of the collection could be a small rectangle representing a
touchable part of the cylinder.
and using
collectionView:(UICollectionView *)collectionView
didSelectItemAtIndexPath:(NSIndexPath *)indexPath
To get the touch.
This will help you to display the popover at the right place:
CGRect rect = [collectionView layoutAttributesForItemAtIndexPath:indexPath].frame;
Finally, you can choose the appropriate popover (if the app has to work on iPhone) here:
https://www.cocoacontrols.com/search?q=popover
Not perfect, but i think this is efficient!
Yes, SceneKit.
When user perform a touch event, that mean you knew the 2D coordinate on screen, so your only decision is to popover a view or not, even a 3D model is not exist.
First, we can logically split the requirement into two pieces, determine the touching segment, showing right "color" in each segment.
I think the use of 3D model is to determine which piece of data to show in your case if I don't get you wrong. In that case, the SCNView's hit test method will do most of work for you. What you should do is to perform a hit test, take out the hit node and the hit's local 3D coordinate of this node, you can then calculate which segment is hit by this touch and do the decision.
Now how to draw the surface of the cylinder would be the only left question, right? There are various ways to do, for example simply paint each image you need and programmatically and attach it to the cylinder's material or have your image files on disk and use as material for the cylinder ...
I think the problem would be basically solved.
Related
Currently, RealityKit doesn't have any method that provides the currently visible entities. In SceneKit we do have a method for that particular functionality—nodesInsideFrustum(pointOfView).
Our internal solution is to create a big fake bounding box in front of the camera. We then check intersections between the "frustum" bounding box and each entity's bounding box. That, of course, is a bit cumbersome and inaccurate. I wonder if someone can come up with a better solution who is willing to share it.
You could combine two ARView methods:
ARView.project(position) to get the 2D point in screen space
ARView.bounds.contains(point) to know if it's visible on screen
But it's not enough, you also have to check if the object is behind you:
Entity.position(relativeTo: cameraAnchor) (with cameraAnchor being an AnchorEntity(.camera)) to have the local position
the sign of localPosition.z shows if it's in front or behind the camera
Without using SpriteKit, is it possible to simulate gravity for UIView object? What I'm trying to achieve is a center UIView with other object floating around it. Almost like planets around a Sun. And also have it attract and repulse from the center object.
I know you can add horizontal and vertical gravity to the superview.
Thanks!
The solution is to use UIAttachmentBehavior.
let attachment = UIAttachmentBehavior(item: node, attachedTo: self.ownerNode)
self.animator.addBehavior(attachment)
The above code will have the node objects attached to the self.ownerNode. I also added UISnapBehavior to self.ownerNode so that when dragged away from the center, the self.ownerNode will always snap back to the center and all have all other nodes follow it.
let snapCenter = UISnapBehavior(item: self.ownerNode, snapTo: self.view.center)
self.animator.addBehavior(snapCenter)
Another approach: Use a field.
UIKit Dynamics brought fields to the table sometime around iOS 9, I think.
Fields provide same, similar or unique vectors of "force" for all the positions within their... field of influence. Hence the name.
You can switch a field, so it's pushing at one moment, pulling at another, or even combine them, layer them and align them around a screen in regions of influence.
A single field can act like planetary gravitational force in the middle of your screen, making satellites move around it, fall into it, or be repelled away.
Fields are a very powerful feature of UIKit Dynamics, both in terms of creativity and influence. They're also remarkably efficient because they only act on those things you stipulate to be influenced by them. So whilst their field size might be large, and their functions determining positional influence complex, they're still very efficient.
You can read/watch/listen to more about them here:
https://developer.apple.com/videos/play/wwdc2015/229/
I've been trying to find a way to solve this problem, and haven't been able to find anything useful, so forgive me if this is a duplicate of something I couldn't find.
I have, essentially, a large complicated image in the style of a stained glass window in a scroll view so that I can pan and zoom around it. Each of the individual segments of the window has some information associated with it. What I need to be able to do is tap on any of the segments and determine which segment was tapped so that I can display the information. What I'm not sure of is how to do the mapping between touch points and segments. Most of the segments aren't even regular polygon shapes let alone orthogonal squares, so I can't think of a straightforward way to determine which segment I've tapped.
If anybody has any ideas as to how I might go about implementing this, it would be most appreciated!
Cheers
Put each individual segment in a different layer. Now you can do hit-testing on what layer was tapped. Your test must be designed so that if a layer was tapped but on a transparent area (i.e. outside its segment), your test will fall through to the next layer behind it. Thus the test will succeed if and when you discover a layer's non-transparent region under the tap. Since it is one segment per layer, the segment is the one corresponding to that layer.
So I'm looking into UIKit Dynamics and the one problem I have run into is if I want to create a UIView with a custom drawRect: (for instance let's say I want to draw a triangle), there seems to be no way to specify the path of the UIView (or rather the UIDynamicItem) to be used for a UICollisionBehavior.
My goal really is to have polygons on the screen that collide with one another exactly how one would expect.
I came up with a solution of stitching multiple views together but this seems like overkill for what I want.
Is there some easy way to do this, or do I really have to stitch views together?
Dan
Watch the WWDC 2013 videos on this topic. They are very clear: for the sake of efficiency and speed, only the (rectangular) bounds of the view matter during collisions.
EDIT In iOS 9, a dynamic item can have a customized collision boundary. You can have a rectangle dictated by the frame, an ellipse dictated by the frame, or a custom shape — a convex counterclockwise simple closed UIBezierPath. The relevant properties, collisionBoundsType and (for a custom shape) collisionBoundingPath, are read-only, so you will have to subclass in order to set them.
If you really want to collide polygons, you might consider SpriteKit and its physics engine (it seems to share a lot in common with UIDynamics). It can mix with UIKit, although maybe not as smoothly as you'd like.
I am a Core Animation newbie and I want to animate a pulsating blue dot very similar to what the Maps application does with the GPS position.
This is not in a map, and this doesn't use Map Kit. It's inside one of my own views (a UIImageView subclass actually), itself inside a UIScrollView.
I am just starting and I am hopeful for suggestions, best practices, perhaps sample code, to speed up my development.
Note a peculiar twist: the look (size) of the pulsating blue dot should preferably not depend on the zoom factor of the host view in its scroll view. I believe Map Kit behaves similarly.
The intent is to attract the user's attention to a specific tiny portion of a crowded image.
Thanks for any suggestion.
You could use two pre-generated images (one with "low light" and one with "high") and animate the transition between the two images. You'd want to use an ease-in curve similar to the map dot (speeds up as it gets brighter) and have it auto-reverse and repeat.
Alternatively, you could use a view with a blue-tinted shadow whose blur radius property is animated between zero and several pixels. With this latter approach, your custom-drawn dot could easily take the scale factor into account when drawing.