use variance-style combined fuzz

Author: Cristy

magick/color-private.h

@@ -34,12 +34,12 @@ extern MagickPrivate MagickBooleanType
 
 static inline double GetFuzzyColorDistance(const Image *p,const Image *q)
 {
-  double
-    fuzz;
-
-  fuzz=(double) MagickMax(MagickMax(p->fuzz,q->fuzz),(double)
-    MagickSQ1_2);
-  return(fuzz*fuzz);
+  /*
+    Variance-style combined fuzz.
+  */
+  if (q == (const Image *) NULL)
+    return(p->fuzz*p->fuzz);
+  return(p->fuzz*p->fuzz+q->fuzz*q->fuzz);
 }
 
 static inline MagickBooleanType IsColorEqual(const PixelPacket *p,

magick/color.c

@@ -1681,8 +1681,7 @@ MagickExport MagickBooleanType IsColorSimilar(const Image *image,
     distance,
     scale;
 
-  fuzz=(double) MagickMax(image->fuzz,(MagickRealType) MagickSQ1_2);
-  fuzz*=fuzz;
+  fuzz=GetFuzzyColorDistance(image,(const Image *) NULL);
   scale=1.0;
   distance=0.0;
   if (image->matte != MagickFalse)
@@ -1903,16 +1902,11 @@ MagickPrivate MagickBooleanType IsIntensitySimilar(const Image *image,
     fuzz,
     pixel;
 
-  MagickRealType
-    distance;
-
   if (GetPixelIntensity(image,p) == GetPixelIntensity(image,q))
     return(MagickTrue);
-  fuzz=(MagickRealType) MagickMax(image->fuzz,MagickSQ1_2);
-  fuzz*=fuzz;
+  fuzz=GetFuzzyColorDistance(image,(const Image *) NULL);
   pixel=GetPixelIntensity(image,p)-GetPixelIntensity(image,q);
-  distance=pixel*pixel;
-  if (distance > fuzz)
+  if ((pixel*pixel) > fuzz)
     return(MagickFalse);
   return(MagickTrue);
 }
@@ -1973,9 +1967,7 @@ MagickExport MagickBooleanType IsMagickColorSimilar(const MagickPixelPacket *p,
 
   if ((p->fuzz == 0.0) && (q->fuzz == 0.0))
     return(IsMagickColorEqual(p,q));
-  fuzz=(MagickRealType) MagickMax(MagickMax(p->fuzz,q->fuzz),(double)
-    MagickSQ1_2);
-  fuzz*=fuzz;
+  fuzz=p->fuzz*p->fuzz+q->fuzz*q->fuzz;
   scale=1.0;
   distance=0.0;
   if ((p->matte != MagickFalse) || (q->matte != MagickFalse))
@@ -2080,18 +2072,13 @@ MagickExport MagickBooleanType IsOpacitySimilar(const Image *image,
     fuzz,
     pixel;
 
-  MagickRealType
-    distance;
-
   if (image->matte == MagickFalse)
     return(MagickTrue);
   if (GetPixelOpacity(p) == GetPixelOpacity(q))
     return(MagickTrue);
-  fuzz=MagickMax(image->fuzz,(double) MagickSQ1_2);
-  fuzz*=fuzz;
+  fuzz=GetFuzzyColorDistance(image,(const Image *) NULL);
   pixel=(MagickRealType) GetPixelOpacity(p)-(MagickRealType) GetPixelOpacity(q);
-  distance=pixel*pixel;
-  if (distance > fuzz)
+  if ((pixel*pixel) > fuzz)
     return(MagickFalse);
   return(MagickTrue);
 }

magick/compare.c

@@ -396,8 +396,7 @@ static MagickBooleanType GetAESimilarity(const Image *image,
   /*
     Compute the absolute difference in pixels between two images.
   */
-  fuzz=0.5*(image->fuzz,reconstruct_image->fuzz);
-  fuzz*=fuzz;
+  fuzz=GetFuzzyColorDistance(image,reconstruct_image);
   SetImageCompareBounds(image,reconstruct_image,&columns,&rows);
   image_view=AcquireVirtualCacheView(image,exception);
   reconstruct_view=AcquireVirtualCacheView(reconstruct_image,exception);
@@ -542,8 +541,7 @@ static MagickBooleanType GetFUZZSimilarity(const Image *image,
     i,
     y;
 
-  fuzz=0.5*(image->fuzz,reconstruct_image->fuzz);
-  fuzz*=fuzz;
+  fuzz=GetFuzzyColorDistance(image,reconstruct_image);
   SetImageCompareBounds(image,reconstruct_image,&columns,&rows);
   image_view=AcquireVirtualCacheView(image,exception);
   reconstruct_view=AcquireVirtualCacheView(reconstruct_image,exception);