Made the RGB to luminance approximation/optimization a little faster -- one less...

[zxing.git] / android / src / com / google / zxing / client / android / RGBMonochromeBitmapSource.java

diff --git a/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java b/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java
index 962c905..100a9d4 100755 (executable)
--- a/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java
+++ b/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java
@@ -83,7 +83,6 @@ final class RGBMonochromeBitmapSource implements MonochromeBitmapSource {
       int width = image.width();
       int height = image.height();
       int[] histogram = new int[LUMINANCE_BUCKETS];
-      float biasTowardsWhite = 1.0f;
       if (method.equals(BlackPointEstimationMethod.TWO_D_SAMPLING)) {
         int minDimension = width < height ? width : height;
         int startI = height == minDimension ? 0 : (height - width) >> 1;
@@ -96,7 +95,6 @@ final class RGBMonochromeBitmapSource implements MonochromeBitmapSource {
         if (argument < 0 || argument >= height) {
           throw new IllegalArgumentException("Row is not within the image: " + argument);
         }
-        biasTowardsWhite = 2.0f;
         int[] pixelRow = new int[width];
         image.getPixels(pixelRow, 0, width, 0, argument, width, 1);
         for (int x = 0; x < width; x++) {
@@ -105,7 +103,7 @@ final class RGBMonochromeBitmapSource implements MonochromeBitmapSource {
       } else {
         throw new IllegalArgumentException("Unknown method: " + method);
       }
-      blackPoint = BlackPointEstimator.estimate(histogram, biasTowardsWhite) << LUMINANCE_SHIFT;
+      blackPoint = BlackPointEstimator.estimate(histogram) << LUMINANCE_SHIFT;
       lastMethod = method;
       lastArgument = argument;
     }
@@ -142,9 +140,9 @@ final class RGBMonochromeBitmapSource implements MonochromeBitmapSource {
     // corrupts the conversion. Not significant for our purposes.
     //
     // But we can get even cleverer and eliminate a few shifts:
-    return (((pixel & 0x00FF0000) >> 8)  +
-            ((pixel & 0x0000FF00) << 1) +
-            ((pixel & 0x000000FF) << 8)) >> 10;
+    return (((pixel & 0x00FF0000) >> 16)  +
+            ((pixel & 0x0000FF00) >>  7) +
+            ( pixel & 0x000000FF       )) >> 2;
   }
 
 }
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