ios - Swift - Compare colors at CGPoint -

i have 2 pictures want compare, if pixel color same save it. detect color of pixel uiimage extension function:

func getpixelcolor(pos: cgpoint) -> ??? {      let pixeldata = cgdataprovidercopydata(cgimagegetdataprovider(self.cgimage))     let data: unsafepointer<uint8> = cfdatagetbyteptr(pixeldata)      let pixelinfo: int = ((int(self.size.width) * int(pos.y)) + int(pos.x)) * 4      let r = cgfloat(data[pixelinfo]) / cgfloat(255.0)     let g = cgfloat(data[pixelinfo+1]) / cgfloat(255.0)     let b = cgfloat(data[pixelinfo+2]) / cgfloat(255.0)     let = cgfloat(data[pixelinfo+3]) / cgfloat(255.0)      return ??? } 

for example, run scanner on picture 1 , save in array? or dictionary? , after run scanner on picture 2 , when have information 2 pictures compare function?

i want see on cgpoint pixels colors identical 2 images?

update: update getpixelcolor return me "(pos)(r)(g)(b)(a)" , after created function left duplicates (before using function have .sort() array!)

extension array element : equatable {     var duplicates: [element] {         var arr:[element] = []         var start = 0         var start2 = 1         _ in 0...self.count{             if(start2<self.count){                 if(self[start] == self[start2]){                     if(arr.contains(self[start])==false){                         arr.append(self[start])                     }                 }                 start+=1                 start2+=1             }         }         return arr     } } 

this returns me this: "(609.0, 47.0)1.01.01.01.0" know color black @ point x-536 fit iphone 5 screen , when make attempt draw again draws wrong... maybe can't properly.. help?

have uiimage extension return uicolor. use method compare each pixel of 2 images. if both pixels match, add color array of arrays.

extension uiimage {     func getpixelcolor(pos: cgpoint) -> uicolor {          let pixeldata = cgdataprovidercopydata(cgimagegetdataprovider(self.cgimage))         let data: unsafepointer<uint8> = cfdatagetbyteptr(pixeldata)          let pixelinfo: int = ((int(self.size.width) * int(pos.y)) + int(pos.x)) * 4          let r = cgfloat(data[pixelinfo]) / cgfloat(255.0)         let g = cgfloat(data[pixelinfo+1]) / cgfloat(255.0)         let b = cgfloat(data[pixelinfo+2]) / cgfloat(255.0)         let = cgfloat(data[pixelinfo+3]) / cgfloat(255.0)          return uicolor(red: r, green: g, blue: b, alpha: a)     } }   func findmatchingpixels(aimage: uiimage, _ bimage: uiimage) -> [[uicolor?]] {     guard aimage.size == bimage.size else { fatalerror("images must same size") }      var matchingcolors: [[uicolor?]] = []     y in 0..<int(aimage.size.height) {         var currentrow = [uicolor?]()         x in 0..<int(aimage.size.width) {             let acolor = aimage.getpixelcolor(cgpoint(x: x, y: y))             let colorsmatch = bimage.getpixelcolor(cgpoint(x: x, y: y)) == acolor             currentrow.append(colorsmatch ? acolor : nil)         }         matchingcolors.append(currentrow)     }     return matchingcolors } 

used this:

let matchingpixels = findmatchingpixels(uiimage(named: "imagea.png")!, uiimage(named: "imageb.png")!) if let colorfororigin = matchingpixels[0][0] {    print("the images have same color, is: \(colorfororigin)") } else {    print("the images not have same color @ (0,0)") } 

for simplicity made findmatchingpixels() require images same size, wouldn't take allow different sized images.

update

if want pixels match, i'd return tuple this:

func findmatchingpixels(aimage: uiimage, _ bimage: uiimage) -> [(cgpoint, uicolor)] {     guard aimage.size == bimage.size else { fatalerror("images must same size") }      var matchingcolors = [(cgpoint, uicolor)]()     y in 0..<int(aimage.size.height) {         x in 0..<int(aimage.size.width) {             let acolor = aimage.getpixelcolor(cgpoint(x: x, y: y))             guard bimage.getpixelcolor(cgpoint(x: x, y: y)) == acolor else { continue }              matchingcolors.append((cgpoint(x: x, y: y), acolor))         }     }     return matchingcolors }