Import: stills respect their Exif orientation

A photo taken with the camera held sideways (or a mirrored scan) imported
as stored, lying on its side. Probing now reports the size the picture is
seen at, and the still and smart-object decodes apply the rotation or
mirroring to the pixels. A missing or invalid tag decodes as stored.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/media/src/layered.rs

@@ -81,7 +81,7 @@ pub(crate) fn decode(path: &str, bytes: &[u8], footage: &Footage, op: AlphaOp) -
                 let inner = effectcraft_psd::Psd::parse(data.to_vec()).map_err(|e| MediaError::Decode(format!("{path} (smart object): {e}")))?;
                 inner.composite().map_err(|e| MediaError::Decode(format!("{path} (smart object): {e}")))?
             } else {
-                let img = image::load_from_memory(data).map_err(|e| MediaError::Decode(format!("{path} (smart object): {e}")))?;
+                let img = crate::probe::load_oriented(data).map_err(|e| MediaError::Decode(format!("{path} (smart object): {e}")))?;
                 let rgba = img.to_rgba32f();
                 effectcraft_psd::Pixels { width: rgba.width(), height: rgba.height(), data: rgba.pixels().map(|p| p.0).collect() }
             };

crates/media/src/pool.rs

@@ -738,7 +738,7 @@ impl Inner {
                 {
                     return Err(MediaError::Decode(format!("{path}: {why}")));
                 }
-                let img = match image::load_from_memory(&bytes) {
+                let img = match crate::probe::load_oriented(&bytes) {
                     Ok(img) => img,
                     // A multi-layer OpenEXR file without an unnamed RGB layer: its colour layer.
                     Err(e) => crate::exr_channels::cached_layered_image(path, bytes).ok_or_else(|| MediaError::Decode(format!("{path}: {e}")))?,

crates/media/src/probe.rs

@@ -5,6 +5,7 @@ use std::sync::Arc;
 
 use effectcraft_project::{AlphaMode, Footage, FootageKind};
 use effectcraft_time::{FrameRate, Tick};
+use image::metadata::Orientation;
 
 use crate::{MediaError, Result, ext_of, rate_from_fc};
 
@@ -165,7 +166,12 @@ fn probe_still_bytes(path: &str, bytes: &[u8], fmt: image::ImageFormat) -> Resul
     }
     let reader = image::ImageReader::with_format(std::io::Cursor::new(bytes), fmt);
     let (w, h, has_alpha) = match reader.into_decoder() {
-        Ok(dec) => (dec.dimensions().0, dec.dimensions().1, dec.color_type().has_alpha()),
+        Ok(mut dec) => {
+            // The size as displayed: an Exif orientation of a quarter turn swaps the sides.
+            let (w, h) = dec.dimensions();
+            let (w, h) = if swaps_sides(dec.orientation().unwrap_or(Orientation::NoTransforms)) { (h, w) } else { (w, h) };
+            (w, h, dec.color_type().has_alpha())
+        }
         Err(e) => {
             // A multi-layer OpenEXR file without an unnamed RGB layer.
             let img = (fmt == image::ImageFormat::OpenExr).then(|| crate::exr_channels::layered_image(bytes)).flatten();
@@ -175,3 +181,20 @@ fn probe_still_bytes(path: &str, bytes: &[u8], fmt: image::ImageFormat) -> Resul
     };
     Ok(still_footage(path, w, h, fmt, has_alpha))
 }
+
+/// Whether an Exif orientation turns the picture a quarter turn (its width and height trade places).
+fn swaps_sides(o: Orientation) -> bool {
+    matches!(o, Orientation::Rotate90 | Orientation::Rotate270 | Orientation::Rotate90FlipH | Orientation::Rotate270FlipH)
+}
+
+/// Decode a still the way it is meant to be seen: its Exif orientation (a camera held sideways, a
+/// mirrored scan) is applied to the pixels, as image viewers do. A file without
+/// the tag, or with a broken one, decodes as stored.
+pub(crate) fn load_oriented(bytes: &[u8]) -> image::ImageResult<image::DynamicImage> {
+    use image::ImageDecoder;
+    let mut dec = image::ImageReader::new(std::io::Cursor::new(bytes)).with_guessed_format()?.into_decoder()?;
+    let orientation = dec.orientation().unwrap_or(Orientation::NoTransforms);
+    let mut img = image::DynamicImage::from_decoder(dec)?;
+    img.apply_orientation(orientation);
+    Ok(img)
+}

crates/media/tests/exif_orientation.rs

@@ -0,0 +1,84 @@
+//! A still's Exif orientation (a camera held sideways, a mirrored scan) is applied on import: the
+//! footage has the size the picture is seen at, and its frames are the picture the right way up.
+
+use std::sync::Arc;
+
+use effectcraft_media::{MediaPool, probe_bytes};
+use effectcraft_project::FootageKind;
+use effectcraft_time::Tick;
+
+const RED: [f32; 3] = [1.0, 0.0, 0.0];
+const GREEN: [f32; 3] = [0.0, 1.0, 0.0];
+const BLUE: [f32; 3] = [0.0, 0.0, 1.0];
+const WHITE: [f32; 3] = [1.0, 1.0, 1.0];
+
+/// A 32×16 JPEG with red, green / blue, white quarters, tagged with Exif orientation `tag`
+/// (`None`: no Exif at all).
+fn quartered_jpeg(tag: Option<u8>) -> Vec<u8> {
+    let img = image::RgbImage::from_fn(32, 16, |x, y| {
+        let c = match (x < 16, y < 8) {
+            (true, true) => RED,
+            (false, true) => GREEN,
+            (true, false) => BLUE,
+            (false, false) => WHITE,
+        };
+        image::Rgb(c.map(|v| (v * 255.0) as u8))
+    });
+    let mut jpeg = Vec::new();
+    image::codecs::jpeg::JpegEncoder::new_with_quality(&mut jpeg, 100).encode_image(&img).expect("encode");
+    let Some(tag) = tag else { return jpeg };
+    // APP1 "Exif": a big-endian TIFF header and one IFD holding Orientation (0x0112, SHORT).
+    let mut app1 = vec![0xFF, 0xE1, 0x00, 0x22];
+    app1.extend_from_slice(b"Exif\0\0MM\0\x2A\0\0\0\x08");
+    app1.extend_from_slice(&[0x00, 0x01, 0x01, 0x12, 0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, tag, 0x00, 0x00]);
+    app1.extend_from_slice(&[0x00; 4]);
+    // (Straight after the SOI marker.)
+    jpeg.splice(2..2, app1);
+    jpeg
+}
+
+/// The footage size and the colours of its four corners (top-left, top-right, bottom-left,
+/// bottom-right), as imported.
+fn imported(tag: Option<u8>) -> ((u32, u32), [[f32; 3]; 4]) {
+    let name = format!("oriented-{tag:?}.jpg");
+    let bytes: Arc<[u8]> = quartered_jpeg(tag).into();
+    let f = probe_bytes(&name, bytes.clone()).expect("probe");
+    assert_eq!(f.kind, FootageKind::Still);
+    let pool = MediaPool::new();
+    pool.add_bytes(&name, bytes);
+    let img = pool.frame_at(&f, Tick::ZERO).expect("frame");
+    assert_eq!((img.width, img.height), (f.width, f.height), "orientation {tag:?}: the frame has the probed size");
+    let (w, h) = (img.width as usize, img.height as usize);
+    let at = |x: usize, y: usize| {
+        let p = img.data[y * w + x];
+        [p[0], p[1], p[2]]
+    };
+    ((f.width, f.height), [at(2, 2), at(w - 3, 2), at(2, h - 3), at(w - 3, h - 3)])
+}
+
+#[test]
+fn exif_orientation_is_applied_to_stills() {
+    let (landscape, portrait) = ((32, 16), (16, 32));
+    let cases = [
+        (None, landscape, [RED, GREEN, BLUE, WHITE]),
+        (Some(1), landscape, [RED, GREEN, BLUE, WHITE]),
+        (Some(2), landscape, [GREEN, RED, WHITE, BLUE]),
+        (Some(3), landscape, [WHITE, BLUE, GREEN, RED]),
+        (Some(4), landscape, [BLUE, WHITE, RED, GREEN]),
+        (Some(5), portrait, [RED, BLUE, GREEN, WHITE]),
+        (Some(6), portrait, [BLUE, RED, WHITE, GREEN]),
+        (Some(7), portrait, [WHITE, GREEN, BLUE, RED]),
+        (Some(8), portrait, [GREEN, WHITE, RED, BLUE]),
+        // (Not an orientation: the picture as stored.)
+        (Some(0), landscape, [RED, GREEN, BLUE, WHITE]),
+        (Some(9), landscape, [RED, GREEN, BLUE, WHITE]),
+    ];
+    for (tag, size, corners) in cases {
+        let (got_size, got) = imported(tag);
+        assert_eq!(got_size, size, "orientation {tag:?}: size");
+        for (i, (g, want)) in got.iter().zip(corners).enumerate() {
+            let near = g.iter().zip(want).all(|(a, b)| (a - b).abs() < 0.2);
+            assert!(near, "orientation {tag:?}: corner {i} is {g:?}, expected {want:?}");
+        }
+    }
+}