How can I know when the user is zooming in or zooming out? I want to start an animation if the user zooms after some level. Is it possible to know this when the event zoomstart is triggered?
How can I know when the user is zooming in or zooming out?
At every zoom level, calculate how much map.getZoom() has changed.
Is it possible to know this when the event zoomstart is triggered?
No.
Consider the following scenario: A user, using a touchscreen (phone/tablet).
The user puts two fingers down on the screen. Half a frame after, one of the fingers moves a couple of pixels towards the center, triggering a pinch-zoom with a tiny change in the zoom level.
Your code catches the zoomstart and zoom events that happen inmediately after. "I know!" - your code says - "The user is zooming out!".
And then the user starts moving their fingers wider and wider, zooming in. And your code gets confused.
But the user changes their mind, and then starts zooming out for whatever reason. And then in again. And then out again. And then they lift the fingers and the zoom snaps to a zoom level.
This is why you can not know what the final zoom level is going to be when you listen to a zoomstart or zoom event in Leaflet.
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I am working on a UI system for a mobile game in Unreal. I have functionality already in place that basically reads in if the player has swiped by basically getting the player's initial touch location and then checking if the player moves their finger a certain pixel distance and then it changes between pages.
I am trying to add a scroll box to the page as I find that not all of my content will fit on the screen. However, now that I have added it to my Widget, my swiping function no longer works. I am assuming this is because the scroll box is consuming the touch event. Is there a way to make it so that the scrolling does not consume the input event?
I had the same problem but unfortunately, I couldn't find how to continue to read touch events.
As a workaround, I created my own scrollbox, so that I could read the finger location while I'm scrolling.
I am using Leaflet in a mobile app and want to get rid of the two zooming buttons in the top corner, but I need the exact same effect (zooming without the possibility of panning around with it) but using a pinching gesture. Alas, the default pinching gesture does not keep the view centred!
I don't know why, but keeping the zoom centred when using the mousewheel or doubleclick are available options for the map object:
If passed 'center', double-click zoom will zoom to the center of the view regardless of where the mouse was.
If passed 'center', it will zoom to the center of the view regardless of where the mouse was.
But not for touchZoom, I tried. maybe the nice people at Leaflet thought the effect doesn't "feel" nice, but I really wish I could try it nonetheless and judge it by myself.
Anyone knows how to get a similar effect? I don't really want to end up calling setView() at every "zoom" event call, if that even was an option...
Found out that I could use the maxBounds option. If you set both corners on a single point (the one you'd use for setView, for example), the map won't be able to pan away from it.
I have a UIScrollView with a content view that the user can zoom in/out. The min zoom level is less than 1, and the max zoom level is greater than 1.
It is easy for the user to zoom all the way in, or all the way out. What can I do to get the UIScrollView to snap to zoom level 1 as well? Not just when the the user lifts their fingers, but as the they are zooming in/out as well.
Write a method, that gets called every time the user stops zooming, which then checks to see if the current zoom scale is very close to 1.0 (like something between 0.8 and 1.2). If this returns true, the zoom scale is set exactly to 1.0 to snap.
The trick is to override or disable the pinch and add your own. When you start a pinch gesture, you DO NOT update the display and resize the image until the pinch is complete, then issue your zoomToRect.
I'm currently drawing some mockups of my future iPhone app.
One of the app's functionalities is to display a bar graph showing the evolution of a value over time. Users can perform few gestures on the graph :
swipe/drag to move through time;
pinch to zoom in or zoom out (and therefore display a longer or shorter period of time);
double tap to add a cursor to the graph (i.e. a vertical line with a label on top).
What I'm afraid of is users not noticing these gestures. Of course, I would provide buttons for doing the same tasks, but if users ended up only using those, the interface's usability would not be very great...
Therefore, I am wondering if there is any way to show some visual clues to indicate the presence of gestures on the interface. Do you know any app that does something similar?
I think if you animate mentioned graph behavior it would be a great clue for user to perform this actions by fingers. For example if he(she) choose another date you should move you graph through time smoothly with easyInOut animation. Or if user changed scale you should gradually zoom from scale 1 to scale 2.
I am working on a photo gallery iPhone app.
Approach is fairly inspired from the ScrollingMadness code available on github.
I have a scroll view which holds all my image views when in paging mode. When user zooms an image using pinch out gesture, I remove all the image views but the current one - and set the content offset to 0,0 (obviously).
Everything works perfect on simulator but on device I face this crazy issue.
When a user pinch out to zoom an image, it goes off screen and when the pinch out touch event ends, it comes back to the screen.
After zooming the image once, if I zoom it further - it does not give me the buggy experience. This leads me to a conclusion that patch needs to be applied where I am removing the other image views from the scroll view and holding the one which is being zoomed.
Not able to figure out how I should make it to work like the iPhone's Photo app. The - magical - Photos app!
Anyone who can point to a direction to get this thing up and running - would be all the help I need right now!
Well, since when you zoom you are moving your picture to (0,0) effectivly the first page, you would expect when the user pinches any page thats not the first one, the image will have to move to 0,0 and therefore you are expiriencing your image moving. After you zoomed once, the image is already at 0,0 so subsequent zooms work fine. Are you finding that zooming on the very first page gives you the behavior you want and only other pages have this issue? If so a fix might be not to move the zooming picture to (0,0) but just keep it where it is and have some dummy view for all your other pages so you dont take up memory from the other pictures. Hope this helps