ios - Swift - UIImageView zooms bigger than UIScrollView -


i'm having problem pinch zooming uiimageview set inside uiscrollview. image zooms in response user's pinch inputs, image zooms , gets bigger until takes entire screen rather staying inside bounds of uiscrollview. have had @ heap of different questions, articles , youtube videos try , find source of problem haven't been able find anything.

the following questions seem loosely related still couldn't resolve problem after looking @ them:

my uiscrollview created in storyboard , used layout constraints created in interface builder anchor in place. set scroll view's delegate self in viewdidload() (and have added uiscrollviewdelegate top of class). uiimageview created programmatically. declare image view @ top of class below:

class vcimageviewer: uiviewcontroller, uiscrollviewdelegate { @iboutlet weak var lblimagetitle: uilabel! @iboutlet weak var btnback: uibutton! @iboutlet weak var scrollview: uiscrollview!  var imageview:uiimageview = uiimageview()  // <-- image view

i add image view sub view of uiscrollview follow line of code, called during viewdidload():

self.scrollview.addsubview(self.imageview)

after adding image view scroll view, load image image view. fetch image url, , load in using following code. again, called in viewdidload().

self.imageview.image = uiimage(data: data)             self.imageview.frame = cgrect(origin: cgpoint(x: 0, y: 0), size: (self.imageview.image?.size)!)             if self.imageview.image != nil {                 self.lblerror.ishidden = true                 self.formatimageviewerwithimage()             }

this confirms image has loaded correctly, hides warning label display if hadn't, , calls self.formatimageviewerwithimage(), below:

func formatimageviewerwithimage() {     // constraints     let constraintimageviewtop:nslayoutconstraint = nslayoutconstraint(item: self.imageview, attribute: nslayoutattribute.top, relatedby: nslayoutrelation.equal, toitem: self.scrollview, attribute: nslayoutattribute.top, multiplier: 1, constant: 0)     let constraintimageviewbottom:nslayoutconstraint = nslayoutconstraint(item: self.imageview, attribute: nslayoutattribute.bottom, relatedby: nslayoutrelation.equal, toitem: self.scrollview, attribute: nslayoutattribute.bottom, multiplier: 1, constant: 0)     let constraintimageviewleft:nslayoutconstraint = nslayoutconstraint(item: self.imageview, attribute: nslayoutattribute.left, relatedby: nslayoutrelation.equal, toitem: self.scrollview, attribute: nslayoutattribute.left, multiplier: 1, constant: 0)     let constraintimageviewright:nslayoutconstraint = nslayoutconstraint(item: self.imageview, attribute: nslayoutattribute.right, relatedby: nslayoutrelation.equal, toitem: self.scrollview, attribute: nslayoutattribute.right, multiplier: 1, constant: 0)     self.view.addconstraints([constraintimageviewtop, constraintimageviewbottom, constraintimageviewleft, constraintimageviewright])      self.scrollview.contentsize = self.imageview.image!.size     self.scrollview.clipstobounds = false     let scrollviewframe = scrollview.frame     let scalewidth = scrollviewframe.size.width / self.scrollview.contentsize.width     let scaleheight = scrollviewframe.size.height / self.scrollview.contentsize.height     let minscale = min(scalewidth, scaleheight)     self.scrollview.minimumzoomscale = minscale      self.scrollview.maximumzoomscale = 1.0     self.scrollview.zoomscale = minscale }

i have implemented scrollviewdidzoom with:

func scrollviewdidzoom(_ scrollview: uiscrollview) {     self.centrescrollviewcontents() } func centrescrollviewcontents() {     let boundssize = self.scrollview.bounds.size     var contentsframe = self.imageview.frame     if contentsframe.size.width < boundssize.width {         contentsframe.origin.x = (boundssize.width - contentsframe.size.width) / 2     } else {         contentsframe.origin.x = 0     }     if contentsframe.size.height < boundssize.height {         contentsframe.origin.y = (boundssize.height - contentsframe.size.height) / 2     } else {         contentsframe.origin.y = 0     }     self.imageview.frame = contentsframe }

and viewforzooming with:

func viewforzooming(in scrollview: uiscrollview) -> uiview? {     return self.imageview }

i have seen previous questions (including listed above) suggested adding code viewwilllayoutsubviews(), have not had success that, viewwilllayoutsubviews() empty.

can see doing wrong?

please change line:

self.scrollview.clipstobounds = false

to line:

self.scrollview.clipstobounds = true

hope helps!


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