I have to show in zoom of a selected area of image continuously. Means if you are changing position simultaneously zoom also to be change. I don't know how to implement this.
UIScrollView has a great method - zoomToRect:animated: - that allows you to zoom on a specific rect. If you have a UIImageView sitting on a UIScrollView then you can zoom around the image view using this one simple method.
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In ViewController I have a big ImageView whose image is captured with a ImagePicker. I want the user to be allowed to zoom in/out the image and then pan it but always inside the ImageView dimensions which must not enlarge, move or dwindle. I have seen I could add a ScrollView to ImageView but I can't figure out how to do that.
Moreover: is it possible to zoom in/out more than one ImageView at a time? I mean I have some smaller imageViews floating upon a bigger imageView. Is it possible to zoom everything all together?
There are plenty of excellent scrollview demo's around.
These will show you where and how to add override functions to implement what you need...
If you have different UIImage Views you can set the zoom programmatically to match the image being "zoomed" ... try experimenting with [UIImage].zoomScale. and the image offset. Its going to get complicated if they are different sizes as you will have to take account of scale when mirroring offset and zoom changes.
I have a view based application. I have to add features like pinch zoom and double tap to zoom the page(UIView) in the iOS application. Its easy to zoom a UIScrollview.
I should create a framework which has the option to pan and zoom the entire app. How do a achieve to zoom a view based application? I welcome your ideas!
The best way to do it, is to put the entire app components in one scrollview and use the zooming of the control.
The other way which is not as stable as the first one, is to scale all objects inside the UIVIEW larger or smaller depending on the pinch zoom, but keep in mind that scaling will affect the look of the entire application, so you need to adjust the position of each object accordingly.
You can create your own zoom functionalities in a UIView by using UIGestureRecognizer and CALayer transform property. Ex. scaling and change the anchorPoint base on the focus point.
I have a UIViewController that implements a UIScrollView with the UIScrollViewDelegate. Attached to it is an UIImageView for which the user must crop the photo via zooming it and panning to fill the entire length of the screen. After the user has finished cropping and they hit done, the original UIImage gets sent to the next UIViewController.
I'm wondering, is there anyway, using the original image, to display it in a UIScrollView and allow the user to zoom and pan it so ONLY the cropped area gets shown? IE none of the image that was outside of the cropped area gets shown in zooming and panning? Is there a way to do this without explicitly cropping the image?
This might head you in the right direction: Displaying part of an image
Not to sure if this will work with the way you are displaying it. But if it does it could be a simple solution. You can also read through UIScrollviews and maybe use panGestureRecognizer and pinchGestureRecognizer to limit the area they can zoom and pan.
Set the content size of the UIScrollView to the rect of the cropped area.
I have an iOS app which boils down to the following:
A view controller which implements all the UIScrollViewDelegate methods.
A customised UIImageView which is the view returned by viewForZoomingInScrollView in the first view controller.
In the drawRect method of the customised UIImageView I overlay some text at various positions on the image, the text can be at various sizes and angles, constrained by a rectangle defined by points on the image. So the co-ordinate system is all relative to the image associated with the UIImageView.
Sometimes the text is having to be rendered into areas that are far too small to allow the text to be readable at the default zoom level.
When I zoom in, however, this doesn't make the text any more readable as the text was rendered on the original UIImageView at the font size appropriate for the bounds it was given.
What I'd like is some way to redraw this text, in the correct location still, at a proportionally larger font size when zoomed in. Is this possible, and how would I do it?
I've been working on a zoomable floorplan myself and dealt with it in a rather simple way.
I put my text in labels and put those labels on top of the ImageView.
While zooming the labels scale with the UIImageView and thus the text within scale as well.
When zooming in too much however text becomes vague and blurry so you might want to update those text labels in the:
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
For me this was sufficient, I hope this might be so for you as well.
Instead of trying to fix this, I'd say your design is a bit wrong. I'd reengineer this so that you're rendering the entire contents that you're displaying in the highest zoom that you want, and then allow the scrollview to zoom in/out of the finished content by specifying the zoom parameters. Otherwise you'll go insane trying to fix text. Just draw the entire image / document as big as you want it to be, then add THOSE contents to the scroll view, at some lower zoom, allowing the user to zoom in/out as they desire. Then you're done.
You can write your overlay text on UILabels, attached to the UIViewController view.
Then you need to make your own custom class from UIScrollView and override
- (void)setContentOffset:(CGPoint)anOffset
here, using the anOffset and self.zoomScale you can place your labels at the places you want, with apropriate font size and all. So, they will change their positions every time your scrollview moves or zooms.
In my App I have a full-screen UIScrollView where the content is a UIImageView containing a map image which is about 2000px square (i.e. larger than the UIScrollView).
Currently, I plot a path across the map and animate a "beacon" image along it using a CAKeyFrameAnimation, which works great.
What I would like to be able to do is to make the UIScrollView content move with the animation in such a way as to keep the beacon image in the centre of the screen (giving the user the impression of tracking along the path).
Any suggestions on how I might achieve this?