diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/1024.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/1024.png
new file mode 100644
index 0000000..8889fb6
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diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/114.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/114.png
new file mode 100644
index 0000000..e992964
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diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/120.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/120.png
new file mode 100644
index 0000000..48f498c
Binary files /dev/null and b/DemoSPM/Assets.xcassets/AppIcon.appiconset/120.png differ
diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/180.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/180.png
new file mode 100644
index 0000000..0f0c4e9
Binary files /dev/null and b/DemoSPM/Assets.xcassets/AppIcon.appiconset/180.png differ
diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/29.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/29.png
new file mode 100644
index 0000000..7337c95
Binary files /dev/null and b/DemoSPM/Assets.xcassets/AppIcon.appiconset/29.png differ
diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/40.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/40.png
new file mode 100644
index 0000000..3e71f88
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diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/57.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/57.png
new file mode 100644
index 0000000..7a74e33
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diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/58.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/58.png
new file mode 100644
index 0000000..6c25ce4
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diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/60.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/60.png
new file mode 100644
index 0000000..389b160
Binary files /dev/null and b/DemoSPM/Assets.xcassets/AppIcon.appiconset/60.png differ
diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/80.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/80.png
new file mode 100644
index 0000000..ffc5e50
Binary files /dev/null and b/DemoSPM/Assets.xcassets/AppIcon.appiconset/80.png differ
diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/87.png b/DemoSPM/Assets.xcassets/AppIcon.appiconset/87.png
new file mode 100644
index 0000000..ab7bcc2
Binary files /dev/null and b/DemoSPM/Assets.xcassets/AppIcon.appiconset/87.png differ
diff --git a/DemoSPM/Assets.xcassets/AppIcon.appiconset/Contents.json b/DemoSPM/Assets.xcassets/AppIcon.appiconset/Contents.json
index d8db8d6..73d3b7f 100644
--- a/DemoSPM/Assets.xcassets/AppIcon.appiconset/Contents.json
+++ b/DemoSPM/Assets.xcassets/AppIcon.appiconset/Contents.json
@@ -1,98 +1 @@
-{
-  "images" : [
-    {
-      "idiom" : "iphone",
-      "size" : "20x20",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "20x20",
-      "scale" : "3x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "29x29",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "29x29",
-      "scale" : "3x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "40x40",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "40x40",
-      "scale" : "3x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "60x60",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "iphone",
-      "size" : "60x60",
-      "scale" : "3x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "20x20",
-      "scale" : "1x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "20x20",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "29x29",
-      "scale" : "1x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "29x29",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "40x40",
-      "scale" : "1x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "40x40",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "76x76",
-      "scale" : "1x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "76x76",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "ipad",
-      "size" : "83.5x83.5",
-      "scale" : "2x"
-    },
-    {
-      "idiom" : "ios-marketing",
-      "size" : "1024x1024",
-      "scale" : "1x"
-    }
-  ],
-  "info" : {
-    "version" : 1,
-    "author" : "xcode"
-  }
-}
\ No newline at end of file
+{"images":[{"size":"60x60","expected-size":"180","filename":"180.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"40x40","expected-size":"80","filename":"80.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"40x40","expected-size":"120","filename":"120.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"60x60","expected-size":"120","filename":"120.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"57x57","expected-size":"57","filename":"57.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"1x"},{"size":"29x29","expected-size":"58","filename":"58.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"29x29","expected-size":"29","filename":"29.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"1x"},{"size":"29x29","expected-size":"87","filename":"87.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"57x57","expected-size":"114","filename":"114.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"20x20","expected-size":"40","filename":"40.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"20x20","expected-size":"60","filename":"60.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"1024x1024","filename":"1024.png","expected-size":"1024","idiom":"ios-marketing","folder":"Assets.xcassets/AppIcon.appiconset/","scale":"1x"}]}
\ No newline at end of file
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/1024.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/1024.png
new file mode 100644
index 0000000..8889fb6
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/1024.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/114.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/114.png
new file mode 100644
index 0000000..e992964
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/114.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/120.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/120.png
new file mode 100644
index 0000000..48f498c
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/120.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/180.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/180.png
new file mode 100644
index 0000000..0f0c4e9
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/180.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/29.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/29.png
new file mode 100644
index 0000000..7337c95
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/29.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/40.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/40.png
new file mode 100644
index 0000000..3e71f88
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/40.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/57.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/57.png
new file mode 100644
index 0000000..7a74e33
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/57.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/58.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/58.png
new file mode 100644
index 0000000..6c25ce4
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/58.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/60.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/60.png
new file mode 100644
index 0000000..389b160
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/60.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/80.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/80.png
new file mode 100644
index 0000000..ffc5e50
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/80.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/87.png b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/87.png
new file mode 100644
index 0000000..ab7bcc2
Binary files /dev/null and b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/87.png differ
diff --git a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/Contents.json b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/Contents.json
index 9221b9b..73d3b7f 100644
--- a/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/Contents.json
+++ b/RangeUISliderDemo/Assets.xcassets/AppIcon.appiconset/Contents.json
@@ -1,98 +1 @@
-{
-  "images" : [
-    {
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "20x20"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "20x20"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "29x29"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "29x29"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "40x40"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "40x40"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "60x60"
-    },
-    {
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "60x60"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "20x20"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "20x20"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "29x29"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "29x29"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "40x40"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "40x40"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "76x76"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "76x76"
-    },
-    {
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "83.5x83.5"
-    },
-    {
-      "idiom" : "ios-marketing",
-      "scale" : "1x",
-      "size" : "1024x1024"
-    }
-  ],
-  "info" : {
-    "author" : "xcode",
-    "version" : 1
-  }
-}
+{"images":[{"size":"60x60","expected-size":"180","filename":"180.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"40x40","expected-size":"80","filename":"80.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"40x40","expected-size":"120","filename":"120.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"60x60","expected-size":"120","filename":"120.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"57x57","expected-size":"57","filename":"57.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"1x"},{"size":"29x29","expected-size":"58","filename":"58.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"29x29","expected-size":"29","filename":"29.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"1x"},{"size":"29x29","expected-size":"87","filename":"87.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"57x57","expected-size":"114","filename":"114.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"20x20","expected-size":"40","filename":"40.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"2x"},{"size":"20x20","expected-size":"60","filename":"60.png","folder":"Assets.xcassets/AppIcon.appiconset/","idiom":"iphone","scale":"3x"},{"size":"1024x1024","filename":"1024.png","expected-size":"1024","idiom":"ios-marketing","folder":"Assets.xcassets/AppIcon.appiconset/","scale":"1x"}]}
\ No newline at end of file
diff --git a/Source/Constraint/MarginConstraintFactory.swift b/Source/Constraint/MarginConstraintFactory.swift
index 2fdeed3..f39e972 100644
--- a/Source/Constraint/MarginConstraintFactory.swift
+++ b/Source/Constraint/MarginConstraintFactory.swift
@@ -6,7 +6,6 @@
 //  2021 Fabrizio Duroni. All rights reserved.
 //
 
-import Foundation
 import UIKit
 
 class MarginConstraintFactory {