ios - A more efficient method of blurring a small section of a UIView? -

i wanting capture snapshot of small area of screen , apply blur - albeit @ 60fps - not possible code:

let rectangle = cgrect(x: -37, y: -153, width: uiscreen.main.bounds.width, height: uiscreen.main.bounds.height)  capturesnapshotwithgaussianblur(rect: rectangle)  public func capturesnapshotwithgaussianblur(rect: cgrect) -> uiimage {        let screen_size_scale_factor = uiscreen.main.scale       let cropping_rect = cgrect(x: 0, y: 0, width: 118*screen_size_scale_factor, height: 66*screen_size_scale_factor)        uigraphicsbeginimagecontextwithoptions(cgsize(width: 118, height: 66), true, 0.0)        backgroundview!.drawhierarchy(in: rect, afterscreenupdates: true)        let capturedimage: uiimage = uigraphicsgetimagefromcurrentimagecontext()!       let ciimage: ciimage = ciimage(image: capturedimage)!        uigraphicsendimagecontext()        let gaussianfilter: cifilter = cifilter(name:"cigaussianblur")!       gaussianfilter.setdefaults()       gaussianfilter.setvalue(ciimage, forkey: kciinputimagekey)       gaussianfilter.setvalue(10, forkey: kciinputradiuskey)        let outputimage: ciimage = gaussianfilter.outputimage!       let finalimage: uiimage = uiimage(ciimage: outputimage.cropping(to: cropping_rect), scale: screen_size_scale_factor, orientation: uiimageorientation.up)        return finalimage  } 

one of problems see code think gaussian blur applied whole image (because of uiscreen.main.bounds used drawhierarchy rectangle).

i hoping there way of doing resizablesnapshotview() of screen, doing drawhierarchy in view , extracting image - alas, not work (although seems in simulator, not on phone renders black).

any suggestions on how make more performant capture , blur method?

cheers!

try using extension snapshot view , blur this, seems work on both simulator , device:

extenstion uiview {     /// more efficient way snapshot uiview other uiview.snapshot /// /// - returns: uiimage representing snapshot of uiview public func snapshotimage() -> uiimage? {     uigraphicsbeginimagecontextwithoptions(bounds.size, isopaque, 0)     drawhierarchy(in: bounds, afterscreenupdates: false)     let snapshotimage = uigraphicsgetimagefromcurrentimagecontext()     uigraphicsendimagecontext()     return snapshotimage }  public func snapshotview() -> uiview? {     if let snapshotimage = snapshotimage() {         return uiimageview(image: snapshotimage)     } else {         return nil     } } }