ios - scroll and pinch in multiple UiScrollViews at the same time -


i have uicollectionview 4 custom cells. cell's delegate main view contains collectionview , extends custom cell delegate. each cell contains single uiscrollview in turn contains , displays uiimageview. now, can pinch , doubletap zoom in , out , move image inside cell's scrollviews.

i have in application "lock views" button should lock views together, if pinch (zoom or move) in cell, change should "copied" in other cells. 10% zoom increase in cell should trigger 10% zoom increase in others cells (independently each cell current zoomscale). similarly, 10 unit movement left in 1 cell should move others cells 10 units left.

i'm using scrollviewdidscroll(_ scrollview: uiscrollview) method detect change in scrollviews , call delegate in turn have access others cells in main uicollectionview

my first problem when used uiscrollview.zoom(to : rect) or uiscrollview.zoomscale trigger again scrollviewdidscroll(_ scrollview: uiscrollview) in others cells creating king of infinite loop, managed fix using :

var iszooming = false  func scrollviewcustomzoom(to rect: cgrect, animated : bool ) {         iszooming = true         scrollview.zoom(to: rect, animated: animated)         iszooming = false     }

and :

func scrollviewdidscroll(_ scrollview: uiscrollview) {         if iszooming { return }         // stuff, typically call delegate     }

but problem : need calculate in scrollviewdidscroll method, , need set in each cell in delegate in order have behavior i'm looking for?

i've tried play around scrollview.bounds, scrollview.origin or scrollview.size, couldn't scaling factor behave properly.

any welcome , appreciated.

found solution own question. solution not call scrollviewdidscroll() in others cells, wanted.

here trick : 

// pinch-pan detection : func scrollviewdidscroll(_ scrollview: uiscrollview) {     let neworigin = scrollview.bounds.origin     let dx = neworigin.x - currentscrollvieworigin.x     let dy = neworigin.y - currentscrollvieworigin.y      let newscale = scrollview.zoomscale     let ds = newscale - currentzoomscale      if let d = delegate{         d.notifymouvementincell(self, dx: dx, dy: dy, ds: ds)     }      currentscrollvieworigin = scrollview.bounds.origin     currentzoomscale = scrollview.zoomscale }

in delegate : 

func notifymouvementincell(_ cell: customcell, dx: cgfloat, dy: cgfloat, ds: cgfloat){     if areviewslocked{         visiblecell in collectionview.visiblecells as! [imecasesmultidisplaycollectionviewcell]{             if visiblecell == cell { continue }             visiblecell.copymouvementinforeigncell(horoffset: dx, vertoffset: dy, scaleoffset: ds)         }     } }

and in cells :

func copymouvementinforeigncell(horoffset dx: cgfloat, vertoffset dy: cgfloat, scaleoffset ds: cgfloat){     var neworigin = scrollview.bounds.origin     neworigin.x += dx     neworigin.y += dy     scrollview.bounds.origin = neworigin      var newscale = scrollview.zoomscale     newscale += ds     let affinetrans = cgaffinetransform(a: newscale, b: 0, c: 0, d: newscale, tx: 0, ty: 0)     // imageview view contained in each of cell's scrollviews     imageview.layer.setaffinetransform(affinetrans)      currentzoomscale = scrollview.zoomscale     currentscrollvieworigin = scrollview.bounds.origin }

hope someday !


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