fix scaler

Author: awxkee

JxlCoder.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
     s.name             = 'JxlCoder'
-    s.version          = '1.3.5'
+    s.version          = '1.3.6'
     s.summary          = 'JXL coder for iOS and MacOS'
     s.description      = 'Provides support for JXL files in iOS and MacOS'
     s.homepage         = 'https://github.com/awxkee/jxl-coder-swift'

Sources/JxlCoder/JXLCoder.swift

@@ -50,6 +50,7 @@ public class JXLCoder {
     }
 
     /***
+     - Parameter scale: scale of UIImage
      - Parameter rescale: image will be rescaled to provided size
      - Returns: Decoded JXL image if this is the valid one
      **/
@@ -62,6 +63,7 @@ public class JXLCoder {
     }
 
     /***
+     - Parameter scale: scale of UIImage
      - Parameter sampleSize: if image size larger than sampler then it will be resized to sample
      - Returns: Decoded JXL image if this is the valid one
      **/
@@ -78,6 +80,7 @@ public class JXLCoder {
     }
 
     /***
+     - Parameter scale: scale of UIImage
      - Parameter rescale: image will be rescaled to provided size
      - Returns: Decoded JXL image if this is the valid one
      **/

Sources/jxlc/ScaleInterpolator.cpp

@@ -218,9 +218,9 @@ inline T LanczosWindow(T x, const T a) {
 
 template <typename T>
 inline T HannWindow(T x, const T length) {
-    const float size = length * 2 - 1;
+    const float size = length * 2 + 1;
     if (abs(x) <= size) {
-        return 0.5f * (1 - fastCos(T(2)*T(M_PI) * size / length));
+        return 0.5f * (1 - fastCos(T(2)*T(M_PI) * x / length));
     }
     return T(0);
 }