Use Scrollview like MapView ,with scroll and zoom option - iphone

I have some map images and i want that i can scroll that images and i can zoom that images.
Like , MKMapView we can zoom images and the placeMark will remains as it is (it would not zoom).
same thing i want to do without MKMapView with my static images.with the help of scrollview or any other.
is it possible ?,is there any code available?

The class you are looking for is called CATiledLayer. Be warned, it is not trivial. Try reading Matt Gallagher's excellent write up.

Related

Performance Issue with Scrollview above MapView

We are developing a map based application which displays large number of annotations above the map using MKMapKit.
We are using a scrollview placed above MapView for differentiating between pinch and drag gestures. We are able to differentiate between pinch and drag but the responsiveness of the Application becomes sluggish while dragged.
We will appreciate any suggestions for improving responsiveness of map while using the scrollview above MapView.
Thanks in advance.
Combining MKMapView and UIScrollView was always a bad idea. Try not to use it. Use UIView with gesture recognizers over the map instead.

Handling touch events in uiscrollview

I have a UIScrollView and an UIImageView as its subview. I want to draw on the imageview in response to the single touches. And I want to zoom and pan the image view in the scroll view on pinch and pan gestures respectively. I found many solutions. But its not perfect. Please give me a straight forward solution.
use after subclassing UIScrollview.See the link.If you are doing application for iphone4 OS,try to use UIGestureRecogniser.see the sample code for it in Apple site.
If you are only using the scrollview for panning and zooming, I would suggest subclassing UIImageView to provide that functionality yourself along with the drawing. This will allow you to have finer control over it and quicker code. A scrollview is not very good at allowing complex gestures within it. (other than taps)

UIScrollView map with pins that stay at a fixed size?

In my app, I have a ScrollView that shows a map(just a jpeg).
On top of the ScrollView, I added some pins(UIImageView)
So far so good.
But when I zoom in, the pins also get larger.
I would like the pins to stay at a fixed size, just like the pins on the google map application on the iPhone.
How do I solve this?
Thanks!
I've been looking into this for a few days and I've come to the conclusion that there is currently no good way to do this.
First, put your pins as a direct subview of the UIScrollView. Now they'll stay the same size, but will move around when you zoom.
In OS version >=3.2 in UIScrollViewDelegate there is -scrollViewDidZoom:, where you can update the pins to the right coords as it scrolls, and this works great. But in 3.1 we're out of luck. I tried having a NSTimer going and updating the coords instead, but it's not performant on the device.
As a fallback what I do is hide the pins when zooming starts (viewForZoomingInScrollView) and when zooming ends (scrollViewDidEndZooming) update their coords and unhide them.
Make a container UIView that is the same size as the map. Add the map to the UIView with autoresizing of flexible width and height. Add all the pins as individual images, each with flexible margins. Use the container as the zooming view.
If the system autoresizeing does not retain the margin ratio then you can implement layoutSubviews in a custom container view.

Zooming in UIScrollView is not smooth

I created a minesweeper clone game in iphone. My implementaion of the cells in the grid is this, I created a UIView and added buttons in the UIView and then I added the UIView in a UIScrollView, but every time I zoom out or zoom in using zoomToRect method of UIScrollView the zooming is not smooth and the zoom out was distorted. How can implement smooth zooming in UIScrollView?
I would try rendering your content view into a bitmap image when scrolling or zooming begins, and replacing the large grid of buttons with the bitmap until the scrolling/zooming is completed. The UIScrollViewDelegate protocol should provide you with the necessary information to know when to swap the bitmap in or out. Part of the problem is that your content view is so computationally intensive to render (all those buttons).
A more sophisticated approach would be to re-implement your game grid at a lower level using coreanimation and more fundamental touch event handling, but that might be overkill if the bitmap hack works well enough.
You know how in the maps app, while panning or zooming, there are grey tiles that show up? That means that the iPhone is currently downloading the tiles. In Safari, there is a similar effect where Safari lays down checkered grey instead of webpage, as it is currently rendering it and will be just a moment. Both of these mean that scrolling will not wait for content to load before displaying the area, it will let scrolling be smooth.
You could try looking here [http://stackoverflow.com/questions/1098234/optimized-image-loading-in-a-uiscrollview] for some ideas, and a point in the right direction would be to use threading to load views in the background while displaying grey in its place.

How to zoom image in iPhone?

I need to zoom an image in iphone...while the user double clicks on the image it will be zoomed in and on the next click it will be zoomed out....Can anybody direct me to how to do this???
You would probably have to use the size property of UIImage, triggered by UIImageView's touchesBegan method.
You can also use animations if you want the zoom effect to be smooth.
Another option could be to place your UIImageView inside a UIScrollView, or use a UIWebView.
Also, I suggest you take a look at the Three20 project. I think TTPhotoView supports zooming.
If you want to zoom and scroll your view, you need a UIScrollView. Tricking it to do what you want used to be very hard, however the problem of programmatic zooming of UIScrollView is now solved.
I have a described how to do it, created ZoomScrollView class (a drop-in subclass of UIScrollView) to encapsulate the solution and provided a working example at github.com/andreyvit/ScrollingMadness/ (the README contains a long description of two UIScrollView tricks and the reasoning behind them).