Fixed behaviour change from python-pillow#5901 endian fix

radarhere · Apr 12, 2022 · 950d0ad · 950d0ad
1 parent a04d691
commit 950d0ad
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Showing 3 changed files with 9 additions and 2 deletions.
diff --git a/Tests/images/issue_6194.j2k b/Tests/images/issue_6194.j2k
diff --git a/Tests/test_file_jpeg2k.py b/Tests/test_file_jpeg2k.py
@@ -298,6 +298,11 @@ def test_16bit_jp2_roundtrips():
         assert_image_equal(im, jp2)
 
 
+def test_issue_6194():
+    with Image.open("Tests/images/issue_6194.j2k") as im:
+        assert im.getpixel((5, 5)) == 31
+
+
 def test_unbound_local():
     # prepatch, a malformed jp2 file could cause an UnboundLocalError exception.
     with pytest.raises(OSError):

diff --git a/src/libImaging/Jpeg2KDecode.c b/src/libImaging/Jpeg2KDecode.c
@@ -180,11 +180,13 @@ j2ku_gray_i(
         case 2:
             for (y = 0; y < h; ++y) {
                 const UINT16 *data = (const UINT16 *)&tiledata[2 * y * w];
-                UINT8 *row = (UINT8 *)im->image[y0 + y] + x0;
+                UINT16 *row = (UINT16 *)im->image[y0 + y] + x0;
                 for (x = 0; x < w; ++x) {
                     UINT16 pixel = j2ku_shift(offset + *data++, shift);
+                    #ifdef WORDS_BIGENDIAN
+                        pixel = (pixel >> 8) | (pixel << 8);
+                    #endif
                     *row++ = pixel;
-                    *row++ = pixel >> 8;
                 }
             }
             break;