feat: Flipped Exif orientations (#8057)

Before, sending of images flipped in Exif led to images having wrong orientation.

src/blob.rs

@@ -10,8 +10,8 @@ use anyhow::{Context as _, Result, ensure, format_err};
 use base64::Engine as _;
 use futures::StreamExt;
 use image::ImageReader;
-use image::codecs::jpeg::JpegEncoder;
 use image::{DynamicImage, GenericImage, GenericImageView, ImageFormat, Pixel, Rgba};
+use image::{codecs::jpeg::JpegEncoder, metadata::Orientation};
 use num_traits::FromPrimitive;
 use tokio::{fs, task};
 use tokio_stream::wrappers::ReadDirStream;
@@ -362,7 +362,10 @@ impl<'a> BlobObject<'a> {
                 return Ok(name);
             }
             let mut img = imgreader.decode().context("image decode failure")?;
-            let orientation = exif.as_ref().map(|exif| exif_orientation(exif, context));
+            let orientation = exif
+                .as_ref()
+                .map(|exif| exif_orientation(exif, context))
+                .unwrap_or(Orientation::NoTransforms);
             let mut encoded = Vec::new();
 
             if *vt == Viewtype::Sticker {
@@ -381,13 +384,7 @@ impl<'a> BlobObject<'a> {
                     return Ok(name);
                 }
             }
-
-            img = match orientation {
-                Some(90) => img.rotate90(),
-                Some(180) => img.rotate180(),
-                Some(270) => img.rotate270(),
-                _ => img,
-            };
+            img.apply_orientation(orientation);
 
             // max_wh is the maximum image width and height, i.e. the resolution-limit.
             // target_wh target-resolution for resizing the image.
@@ -551,18 +548,17 @@ fn image_metadata(file: &std::fs::File) -> Result<(u64, Option<exif::Exif>)> {
     Ok((len, exif))
 }
 
-fn exif_orientation(exif: &exif::Exif, context: &Context) -> i32 {
-    if let Some(orientation) = exif.get_field(exif::Tag::Orientation, exif::In::PRIMARY) {
-        // possible orientation values are described at http://sylvana.net/jpegcrop/exif_orientation.html
-        // we only use rotation, in practise, flipping is not used.
-        match orientation.value.get_uint(0) {
-            Some(3) => return 180,
-            Some(6) => return 90,
-            Some(8) => return 270,
-            other => warn!(context, "Exif orientation value ignored: {other:?}."),
-        }
+fn exif_orientation(exif: &exif::Exif, context: &Context) -> Orientation {
+    if let Some(orientation) = exif.get_field(exif::Tag::Orientation, exif::In::PRIMARY)
+        && let Some(val) = orientation.value.get_uint(0)
+        && let Ok(val) = TryInto::<u8>::try_into(val)
+    {
+        return Orientation::from_exif(val).unwrap_or({
+            warn!(context, "Exif orientation value ignored: {val:?}.");
+            Orientation::NoTransforms
+        });
     }
-    0
+    Orientation::NoTransforms
 }
 
 /// All files in the blobdir.

src/blob/blob_tests.rs

@@ -305,7 +305,7 @@ async fn test_recode_image_2() {
         has_exif: true,
         original_width: 2000,
         original_height: 1800,
-        orientation: 270,
+        orientation: Some(Orientation::Rotate270),
         compressed_width: 1800,
         compressed_height: 2000,
         ..Default::default()
@@ -336,6 +336,28 @@ async fn test_recode_image_2() {
     assert_correct_rotation(&img_rotated);
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_recode_image_vflipped() {
+    let bytes = include_bytes!("../../test-data/image/rectangle200x180-vflipped.jpg");
+    let img_rotated = SendImageCheckMediaquality {
+        viewtype: Viewtype::Image,
+        media_quality_config: "0",
+        bytes,
+        extension: "jpg",
+        has_exif: true,
+        original_width: 200,
+        original_height: 180,
+        orientation: Some(Orientation::FlipVertical),
+        compressed_width: 200,
+        compressed_height: 180,
+        ..Default::default()
+    }
+    .test()
+    .await
+    .unwrap();
+    assert_correct_rotation(&img_rotated);
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_recode_image_bad_exif() {
     // `exiftool` reports for this file "Bad offset for IFD0 XResolution", still Exif must be
@@ -530,7 +552,7 @@ struct SendImageCheckMediaquality<'a> {
     pub(crate) has_exif: bool,
     pub(crate) original_width: u32,
     pub(crate) original_height: u32,
-    pub(crate) orientation: i32,
+    pub(crate) orientation: Option<Orientation>,
     pub(crate) res_viewtype: Option<Viewtype>,
     pub(crate) compressed_width: u32,
     pub(crate) compressed_height: u32,
@@ -546,7 +568,7 @@ impl SendImageCheckMediaquality<'_> {
         let has_exif = self.has_exif;
         let original_width = self.original_width;
         let original_height = self.original_height;
-        let orientation = self.orientation;
+        let orientation = self.orientation.unwrap_or(Orientation::NoTransforms);
         let res_viewtype = self.res_viewtype.unwrap_or(Viewtype::Image);
         let compressed_width = self.compressed_width;
         let compressed_height = self.compressed_height;