From 24690a49a625e42b81d386688f698cebf372d543 Mon Sep 17 00:00:00 2001
From: srowen <srowen@59b500cc-1b3d-0410-9834-0bbf25fbcc57>
Date: Fri, 21 Dec 2007 18:32:49 +0000
Subject: [PATCH] Be more forgiving about endpoints that transform to be just
 off the image

git-svn-id: http://zxing.googlecode.com/svn/trunk@128 59b500cc-1b3d-0410-9834-0bbf25fbcc57
---
 .../zxing/qrcode/detector/GridSampler.java    | 30 ++++++++++++++-----
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/core/src/com/google/zxing/qrcode/detector/GridSampler.java b/core/src/com/google/zxing/qrcode/detector/GridSampler.java
index 36f99311..533e9184 100644
--- a/core/src/com/google/zxing/qrcode/detector/GridSampler.java
+++ b/core/src/com/google/zxing/qrcode/detector/GridSampler.java
@@ -107,20 +107,36 @@ public abstract class GridSampler {
    * This method actually only checks the endpoints since the points are assumed to lie
    * on a line.</p>
    *
+   * <p>This method will actually "nudge" the endpoints back onto the image if they are found to be barely
+   * (less than 1 pixel) off the image. This accounts for imperfect detection of finder patterns in an image
+   * where the QR Code runs all the way to the image border.</p>
+   *
    * @param image image into which the points should map
    * @param points actual points in x1,y1,...,xn,yn form
    * @throws ReaderException if an endpoint is lies outside the image boundaries
    */
   protected static void checkEndpoint(MonochromeBitmapSource image, float[] points) throws ReaderException {
-    int x = (int) points[0];
-    int y = (int) points[1];
-    if (x < 0 || x >= image.getWidth() || y < 0 || y >= image.getHeight()) {
+    int width = image.getWidth();
+    int height = image.getHeight();
+    checkOneEndpoint(points, (int) points[0], (int) points[1], width, height);
+    checkOneEndpoint(points, (int) points[points.length - 2], (int) points[points.length - 1], width, height);
+  }
+
+  private static void checkOneEndpoint(float[] points, int x, int y, int width, int height) throws ReaderException {
+    if (x < -1 || x > width || y < -1 || y > height) {
       throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
     }
-    x = (int) points[points.length - 2];
-    y = (int) points[points.length - 1];
-    if (x < 0 || x >= image.getWidth() || y < 0 || y >= image.getHeight()) {
-      throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
+    if (x == -1) {
+      points[0] = 0.0f;
+    }
+    if (y == -1) {
+      points[1] = 0.0f;
+    }
+    if (x == width) {
+      points[0] = width - 1;
+    }
+    if (y == height) {
+      points[1] = height - 1;
     }
   }
 
-- 
2.20.1