From: srowen <srowen@59b500cc-1b3d-0410-9834-0bbf25fbcc57>
Date: Wed, 7 Nov 2007 19:18:50 +0000 (+0000)
Subject: Adjust tolerance of method that decides whether a finder/alignment pattern has been... 
X-Git-Url: http://git.rot13.org/?p=zxing.git;a=commitdiff_plain;h=6980903e85309b4f167d21206d86b467cc6ef4f9

Adjust tolerance of method that decides whether a finder/alignment pattern has been crossed so that it passes on low resolution images more correctly -- just a matter of resorting to some floating point math.

git-svn-id: http://zxing.googlecode.com/svn/trunk@18 59b500cc-1b3d-0410-9834-0bbf25fbcc57
---

diff --git a/core/src/com/google/zxing/qrcode/detector/AlignmentPatternFinder.java b/core/src/com/google/zxing/qrcode/detector/AlignmentPatternFinder.java
index b4e35502..e68d3a18 100644
--- a/core/src/com/google/zxing/qrcode/detector/AlignmentPatternFinder.java
+++ b/core/src/com/google/zxing/qrcode/detector/AlignmentPatternFinder.java
@@ -164,8 +164,9 @@ final class AlignmentPatternFinder {
    */
   private boolean foundPatternCross(int[] stateCount) {
     float moduleSize = this.moduleSize;
+    float maxVariance = moduleSize / 2.5f;
     for (int i = 0; i < 3; i++) {
-      if (2.0f * Math.abs(moduleSize - stateCount[i]) >= moduleSize) {
+      if (Math.abs(moduleSize - stateCount[i]) >= maxVariance) {
         return false;
       }
     }
diff --git a/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java b/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
index 4ef3d58c..0c8a91e7 100755
--- a/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
+++ b/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
@@ -178,13 +178,14 @@ final class FinderPatternFinder {
     if (totalModuleSize < 7) {
       return false;
     }
-    int moduleSize = totalModuleSize / 7;
-    // Allow less than 50% deviance from 1-1-3-1-1 pattern
-    return  Math.abs(moduleSize - stateCount[0]) << 1 <= moduleSize &&
-            Math.abs(moduleSize - stateCount[1]) << 1 <= moduleSize &&
-            Math.abs(3 * moduleSize - stateCount[2]) << 1 <= 3 * moduleSize &&
-            Math.abs(moduleSize - stateCount[3]) << 1 <= moduleSize &&
-            Math.abs(moduleSize - stateCount[4]) << 1 <= moduleSize;
+    float moduleSize = (float) totalModuleSize / 7.0f;
+    float maxVariance = moduleSize / 2.5f;
+    // Allow less than 40% variance from 1-1-3-1-1 proportions
+    return  Math.abs(moduleSize - stateCount[0]) < maxVariance &&
+            Math.abs(moduleSize - stateCount[1]) < maxVariance &&
+            Math.abs(3.0f * moduleSize - stateCount[2]) < 3.0f * maxVariance &&
+            Math.abs(moduleSize - stateCount[3]) < maxVariance &&
+            Math.abs(moduleSize - stateCount[4]) < maxVariance;
   }
 
   /**