I'm developing some kind of custom map, which will present additional information above map content (I will call it overlay). But overlay rendering very hard process so I render only that part which user can see on the screen at this moment. But I also want when user zoom or pan map, overlay zoom and pan too (without re-rendering, of course, because it require a time to do it). So my overlay is UIView with UIImageView subview. During user pan I look for contentOffset changes (map content presents on UIScrollView) and move my imageView to that offset (change origin of it's frame), so this is very quickly. When user detach fingers from screen I set initial frame to imageView and re-render it. How can I do similar with zoom? I tried monitor for zoomScale changes and contentOffset, but imageView move not like map content. Any suggestion how to do it will be useful for me
I solved my by problem coming from another side to it. Instead of calculating offsets and zoom scales, I add overlay to map content as subview, so it moves and scales with it very good. When user detach fingers from map, I remove it from superview and re-render it
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I am trying to figure out how to achieve this. I want to have a view centred on the screen that can be pinched for zoom in and zoom out but also be panned across the screen. One way I thought of trying to replicate this was to have a UIView within UIScrollView. Let's say the UIView is just a black square. The UIView will be the same size as the UIScrollView and always remain centred. When I pinch the UIView to zoom out, as it gets smaller and the UIScrollView will zoom in at the same rate. This allows space to pan. The UIView would of shrunk, remained centred and the UIScrollView's content area increased. Is this something that is possible? Is using a UIScrollView the wrong way to go about it?
I am going through the sample code (https://github.com/vfr/Reader), and tried to add the same zooming effect in all the pages at the same time. for ex: if the user increase the zoom effect in 2nd page it will set the same zoom effect in all the pages. Not getting any idea how to do this...Edit:
In Short,how to resize all the subviews of UIScrollView according to the zoomin / zoomout.
The reader you are using provides zoom in and zoom out options by default. If that doesn't work just check if you have allowed multiple touches.
I don't know what this effect is called. Fancy uses it in its app. It works like this.
You have an image at the top of a scrollview.
Drag down and the image gets zoomed to fill the extra top space, so its top edge always remains at the top edge of this scrollview
release your finger and it bounces back
Please give me some idea on how to build this effect. Thanks!
There are many open source implementations of this, such as:
https://github.com/apping/APParallaxHeader
https://github.com/modocache/MDCParallaxView
https://github.com/quemb/QMBParallaxScrollViewController
The basic idea behind these is to have an imageview as a subview of the scrollview. When scrolling, you monitor the content offset of the scrollview, and when you reach a certain threshold, you start increasing the image view's height. If you set the image view's contentMode to UIViewContentModeScaleAspectFill, you will get the effect you want.
I'm implementing a map feature in my app where I allow the user to set their current location by panning around.
All this time, I want to have an MKAnnotation in the centerCoordinate. So what I want to do is keep track of when the map's centerCoordinate changes and change the annotation's coordinate correctly. The behaviour would be similar to that of Uber, Hailo and others.
I tried a time based implementation where every 0.00001s the centerCoordinate would be checked and the annotation would also be moved. But if the map isn't flicked gently, the annotation jumps from one place to another which doesn't make for a good UI.
Another implementation I tried is by way of gesture recognisers and the delegate methods of MKMapView (regionDidChange/regionWillChange). This, again, makes for a very abrupt transition.
Can anyone please advise me on how to do this better?
I suggest not using an actual id<MKAnnotation> at all (at least for this "current location setting" mode).
Instead:
Add a view (eg. UIImageView) containing an image of a pin (or whatever icon you like) in front of the map view.
This pin view should not be a subview of the map view.
The pin view should be a subview of the same view that the map view is a subview of (eg. both should be subviews of the same superview).
The pin view should be sized and positioned such that it appears above the center of the map view (you could make the pin view have the same frame and the same autolayout/autoresizing logic as the map view so they stay visually synchronized regardless of screen size or orientation).
If using a UIImageView, set its content mode to "center" and background color to "clear" (default is clear).
The pin view should have user interaction disabled on it so that the user can still interact with the map view behind it. As the user pans or zooms the map view, the pin view in front will seem to move instantly.
If necessary, the app can get the location coordinates from mapView.centerCoordinate in the regionDidChangeAnimated: MKMapViewDelegate method (or pan/pinch gesture recognizers) or only when the user says they're done positioning. I don't recommend using a timer (especially every 0.00001s) to query the current center coordinate.
When the user indicates that the current position is where they want to finally place the annotation, you can then create and add an actual annotation at that coordinate and hide the "location setting mode" pin view.
I want to zoom a CAlayer placed on UIView, and this view is on UISCrollview. I'm using scrollviews delegate methods for zooming. It zooms but it blurs. How to remove blur and improve zooming?
I have tried with CATiledLayer but I don't want to show tiling effect. So how can I improve zooming using CALayer?
I had a similar experience when zooming in content. When a UIScrollView is zooming, it takes a snapshot of the View, and zooms in on that picture. This is the reason it gets blocky when zooming. When the zooming/panning is complete, use the delegate to re-render the content according to your zoom level. The content then should be 'crisp'.
Warning: do not zoom in too far, the memory used by the snapshot will soon be larger than your available memory.
I didn't use images, but CAShapeLayers and paths. I put together a demo project and explanation here : http://simplicate.weebly.com/1/post/2013/06/fixing-blocky-paths-in-ios.html
I hope that helps.