Actually moved images, and fixed DHash method to be more consistent and pretty :)

src/main/scala/com/sothr/imagetools/hash/DHash.scala

@@ -11,17 +11,22 @@ object DHash extends PerceptualHasher with Logging {
     val width = imageData.length
     val height = imageData(0).length
     debug(s"Image data size: ${width}x${height}")
-    var hash = 0L
-    for (row <- 0 until width) {
-      var previousPixel = imageData(row)(0)
-      var previousLocation = (row, 0)
     
+    //calculate dhash
+    var hash = 0
+    var previousPixel = imageData(height-1)(width-1)
+    var previousLocation = (height-1, width-1)
+    if (height % 2 == 0) {
+      previousPixel = imageData(height-1)(0)
+      previousLocation = (height-1, 0)   
+    }
+    
+    for (row <- 0 until height by 2) {
       //process each column
-      for (col <- 0 until height) {
-        debug(s"previousPixel: $previousPixel previousLocation: $previousLocation")
-        //println(f"Column: $col%d")
+      for (col <- 0 until width by 1) {
         hash <<= 1
         val pixel = imageData(row)(col)
+        //debug(s"previousPixel: $previousPixel currentPixel: $pixel previousLocation: $previousLocation currentLocation: (${row},${col})")
         //binary or the current bit based on whether the value
         //of the current pixel is greater or equal to the previous pixel
         if (pixel >= previousPixel) hash |= 1 else hash |= 0
@@ -29,7 +34,24 @@ object DHash extends PerceptualHasher with Logging {
         previousPixel = pixel
         previousLocation = (row, col)
       }
+      
+      if ((row +1) < width) {
+          val nextRow = row + 1
+          //process each column
+          for (col <- (width - 1) to 0 by -1) {
+            hash <<= 1
+            val pixel = imageData(nextRow)(col)
+            //debug(s"previousPixel: $previousPixel currentPixel: $pixel previousLocation: $previousLocation currentLocation: (${nextRow},${col})")
+            //binary or the current bit based on whether the value
+            //of the current pixel is greater or equal to the previous pixel
+            if (pixel >= previousPixel) hash |= 1 else hash |= 0
+            //debug(s"hash: $hash")
+            previousPixel = pixel
+            previousLocation = (nextRow, col)
+          }
+      }
     }
+    debug(s"Computed Hash: $hash from ${width * height} pixels")
     hash
   }
 }

src/test/scala/com/sothr/imagetools/hash/HashServiceTest.scala

@@ -51,8 +51,8 @@ class HashServiceTest extends BaseTest {
     val image = ImageIO.read(sample)
     debug(s"Image: width: ${image.getWidth} height: ${image.getHeight}")
     val hash = HashService.getDhash(image)
-    debug(s"Testing that $hash = -5198308484644955238L")
-    assert(hash == -5198308484644955238L)
+    debug(s"Testing that $hash = -1689609389L")
+    assert(hash == -1689609389L)
   }
   
   test("Calculate DHash Medium Sample Image 1") {
@@ -62,8 +62,8 @@ class HashServiceTest extends BaseTest {
     val image = ImageIO.read(sample)
     debug(s"Image: width: ${image.getWidth} height: ${image.getHeight}")
     val hash = HashService.getDhash(image)
-    debug(s"Testing that $hash = -5198308484644955238L")
-    assert(hash == -5198308484644955238L)
+    debug(s"Testing that $hash = -1689609389L")
+    assert(hash == -1689609389L)
   }
   
   test("Calculate DHash Small Sample Image 1") {
@@ -73,8 +73,8 @@ class HashServiceTest extends BaseTest {
     val image = ImageIO.read(sample)
     debug(s"Image: width: ${image.getWidth} height: ${image.getHeight}")
     val hash = HashService.getDhash(image)
-    debug(s"Testing that $hash = -5198299688551933030L")
-    assert(hash == -5198299688551933030L)
+    debug(s"Testing that $hash = -1689609389L")
+    assert(hash == -1689609389L)
   }
   
   test("DHash Of Large, Medium, And Small Sample 1 Must Be Similar") {