Simplified EXIF code (#12)

* Use break in switch

* Use walrus operator

* Do not add irot and imir flags if orientation is default

* Do not potentially call Exif tobytes() twice

* Simplified code by only setting info["exif"] once

---------

Co-authored-by: Andrew Murray <radarhere@users.noreply.github.com>

src/PIL/AvifImagePlugin.py

@@ -96,20 +96,21 @@ class AvifImageFile(ImageFile.ImageFile):
 
         if icc:
             self.info["icc_profile"] = icc
-        if exif:
-            self.info["exif"] = exif
         if xmp:
             self.info["xmp"] = xmp
 
-        if exif_orientation != 1 or exif is not None:
+        if exif_orientation != 1 or exif:
             exif_data = Image.Exif()
-            orig_orientation = 1
+            if exif:
-            if exif is not None:
                 exif_data.load(exif)
-                orig_orientation = exif_data.get(ExifTags.Base.Orientation, 1)
+                original_orientation = exif_data.get(ExifTags.Base.Orientation, 1)
-            if exif_orientation != orig_orientation:
+            else:
+                original_orientation = 1
+            if exif_orientation != original_orientation:
                 exif_data[ExifTags.Base.Orientation] = exif_orientation
-                self.info["exif"] = exif_data.tobytes()
+                exif = exif_data.tobytes()
+        if exif:
+            self.info["exif"] = exif
 
     def seek(self, frame: int) -> None:
         if not self._seek_check(frame):
@@ -180,22 +181,18 @@ def _save(
     autotiling = bool(info.get("autotiling", tile_rows_log2 == tile_cols_log2 == 0))
 
     icc_profile = info.get("icc_profile", im.info.get("icc_profile"))
-    exif = info.get("exif")
+    exif_orientation = 1
-    if exif:
+    if exif := info.get("exif"):
         if isinstance(exif, Image.Exif):
             exif_data = exif
-            exif = exif.tobytes()
         else:
             exif_data = Image.Exif()
             exif_data.load(exif)
-        exif_orientation = exif_data.pop(ExifTags.Base.Orientation, 0)
+        if ExifTags.Base.Orientation in exif_data:
-        if exif_orientation != 0:
+            exif_orientation = exif_data.pop(ExifTags.Base.Orientation)
-            if len(exif_data):
+            exif = exif_data.tobytes() if exif_data else b""
-                exif = exif_data.tobytes()
+        elif isinstance(exif, Image.Exif):
-            else:
+            exif = exif_data.tobytes()
-                exif = None
-    else:
-        exif_orientation = 0
 
     xmp = info.get("xmp")
 

src/_avif.c

@@ -126,16 +126,6 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
     // Orientation to irot and imir boxes as defined in HEIF ISO/IEC 28002-12:2021
     // sections 6.5.10 and 6.5.12.
     switch (orientation) {
-        case 1:  // The 0th row is at the visual top of the image, and the 0th column is
-                 // the visual left-hand side.
-            image->transformFlags = otherFlags;
-            image->irot.angle = 0;  // ignored
-#if AVIF_VERSION_MAJOR >= 1
-            image->imir.axis = 0;  // ignored
-#else
-            image->imir.mode = 0;  // ignored
-#endif
-            return;
         case 2:  // The 0th row is at the visual top of the image, and the 0th column is
                  // the visual right-hand side.
             image->transformFlags = otherFlags | AVIF_TRANSFORM_IMIR;
@@ -145,7 +135,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 1;
 #endif
-            return;
+            break;
         case 3:  // The 0th row is at the visual bottom of the image, and the 0th column
                  // is the visual right-hand side.
             image->transformFlags = otherFlags | AVIF_TRANSFORM_IROT;
@@ -155,7 +145,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 0;  // ignored
 #endif
-            return;
+            break;
         case 4:  // The 0th row is at the visual bottom of the image, and the 0th column
                  // is the visual left-hand side.
             image->transformFlags = otherFlags | AVIF_TRANSFORM_IMIR;
@@ -165,7 +155,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 0;
 #endif
-            return;
+            break;
         case 5:  // The 0th row is the visual left-hand side of the image, and the 0th
                  // column is the visual top.
             image->transformFlags =
@@ -177,7 +167,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 0;
 #endif
-            return;
+            break;
         case 6:  // The 0th row is the visual right-hand side of the image, and the 0th
                  // column is the visual top.
             image->transformFlags = otherFlags | AVIF_TRANSFORM_IROT;
@@ -187,7 +177,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 0;  // ignored
 #endif
-            return;
+            break;
         case 7:  // The 0th row is the visual right-hand side of the image, and the 0th
                  // column is the visual bottom.
             image->transformFlags =
@@ -199,7 +189,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 0;
 #endif
-            return;
+            break;
         case 8:  // The 0th row is the visual left-hand side of the image, and the 0th
                  // column is the visual bottom.
             image->transformFlags = otherFlags | AVIF_TRANSFORM_IROT;
@@ -209,7 +199,7 @@ exif_orientation_to_irot_imir(avifImage *image, int orientation) {
 #else
             image->imir.mode = 0;  // ignored
 #endif
-            return;
+            break;
     }
 }
 
@@ -529,7 +519,7 @@ AvifEncoderNew(PyObject *self_, PyObject *args) {
                 return NULL;
             }
         }
-        if (exif_orientation > 0) {
+        if (exif_orientation > 1) {
             exif_orientation_to_irot_imir(image, exif_orientation);
         }