Fixes wrong EXIF Orientation from Irot Imir (#2729)

Add test and CHANGELOG entry.

---------

Co-authored-by: Yannis Guyon <[email protected]>

Author: joojoooo

CHANGELOG.md

@@ -20,6 +20,10 @@ The changes are relative to the previous release, unless the baseline is specifi
 * Update libsharpyuv: v1.5.0
 * Update libxml2.cmd/LocalLibXml2.cmake: v2.14.0
 * Update libyuv.cmd: dc47c71b3 (1907)
+* Fix wrong Exif orientation set in JPEG or PNG output by avifdec when the input
+  AVIF file has an ImageRotation property with angle set to 1 or 3, has no
+  ImageMirror property, and carries an Exif chunk. Note that Exif orientation is
+  usually ignored in PNG files, so this mainly impacts JPEG files.
 
 ## [1.2.1] - 2025-03-17
 

apps/shared/avifexif.c

@@ -13,7 +13,7 @@ uint8_t avifImageGetExifOrientationFromIrotImir(const avifImage * image)
             }
             return 5; // 90 degrees anti-clockwise then swap top and bottom.
         }
-        return 6; // 90 degrees anti-clockwise.
+        return 8; // 90 degrees anti-clockwise.
     }
     if ((image->transformFlags & AVIF_TRANSFORM_IROT) && (image->irot.angle == 2)) {
         if (image->transformFlags & AVIF_TRANSFORM_IMIR) {
@@ -31,7 +31,7 @@ uint8_t avifImageGetExifOrientationFromIrotImir(const avifImage * image)
             }
             return 7; // 270 degrees anti-clockwise then swap top and bottom.
         }
-        return 8; // 270 degrees anti-clockwise.
+        return 6; // 270 degrees anti-clockwise.
     }
     if (image->transformFlags & AVIF_TRANSFORM_IMIR) {
         if (image->imir.axis) {

tests/CMakeLists.txt

@@ -126,7 +126,7 @@ if(AVIF_GTEST)
     add_avif_gtest_with_data(avifiostatstest)
     add_avif_gtest_with_data(avifkeyframetest)
     add_avif_gtest_with_data(aviflosslesstest)
-    add_avif_gtest_with_data(avifmetadatatest)
+    add_avif_internal_gtest_with_data(avifmetadatatest)
 
     if(AVIF_ENABLE_EXPERIMENTAL_MINI)
         add_avif_gtest(avifminitest)

tests/gtest/avifmetadatatest.cc

@@ -9,6 +9,8 @@
 
 #include "avif/avif.h"
 #include "avif/avif_cxx.h"
+#include "avif/internal.h"
+#include "avifexif.h"
 #include "avifjpeg.h"
 #include "avifpng.h"
 #include "aviftest_helpers.h"
@@ -284,6 +286,22 @@ TEST(MetadataTest, ExifOrientation) {
   EXPECT_EQ(image->width, temp_image->width /* should be height here */);
 }
 
+TEST(MetadataTest, AllExifOrientations) {
+  const ImagePtr image =
+      testutil::ReadImage(data_path, "paris_exif_orientation_5.jpg");
+  ASSERT_NE(image, nullptr);
+  image->transformFlags = AVIF_TRANSFORM_NONE;
+  for (uint8_t orientation = 1; orientation <= 8; ++orientation) {
+    // Check roundtrip.
+    ASSERT_EQ(avifSetExifOrientation(&image->exif, orientation),
+              AVIF_RESULT_OK);
+    ASSERT_EQ(avifImageExtractExifOrientationToIrotImir(image.get()),
+              AVIF_RESULT_OK);
+    ASSERT_EQ(avifImageGetExifOrientationFromIrotImir(image.get()),
+              orientation);
+  }
+}
+
 TEST(MetadataTest, ExifOrientationAndForcedImir) {
   const ImagePtr image =
       testutil::ReadImage(data_path, "paris_exif_orientation_5.jpg");