From 6b9564c60d1ec480c48a73b6b1341ade6c6f12ad Mon Sep 17 00:00:00 2001
From: dotCooCoo <RobertLeeLW@gmail.com>
Date: Sat, 14 Nov 2026 10:48:45 -0800
Subject: [PATCH] PDF: PDF/X-1a test covers a tagged gray JPEG

The PDF/X-1a case of tagged_tiffs_keep_their_icc_profile also exports a
gray JPEG with a gray profile, kept as it is, resampled and compressed
with JPEG, and checks that it is written in DeviceGray without the
profile. The comments on decoded_image, recode and the test say that
PDF/X-1a allows no ICC-based color spaces.
---
 crates/pdf/src/images.rs            |  6 +++---
 crates/pdf/src/tests/compression.rs | 12 +++++++++---
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/crates/pdf/src/images.rs b/crates/pdf/src/images.rs
index eee79ee3bb..0085f07538 100644
--- a/crates/pdf/src/images.rs
+++ b/crates/pdf/src/images.rs
@@ -144,8 +144,8 @@ pub(crate) fn from_decoded(img: DynamicImage, icc: Option<Vec<u8>>, interpolate:
 }
 
 /// Image `bytes` decoded within [`limits`], with the ICC profile it carries ([`source_icc`]) when
-/// `profiles` allows it (not in PDF/X-1a, which has device colours only), as [`from_decoded`]
-/// writes it. `None` when it can't be decoded.
+/// `profiles` allows it (not in PDF/X-1a, which allows no ICC-based color spaces), as
+/// [`from_decoded`] writes it. `None` when it can't be decoded.
 pub(crate) fn decoded_image(bytes: &[u8], interpolate: bool, sixteen_bit: bool, profiles: bool) -> Option<Image> {
     from_decoded(decoded(bytes)?, profiles.then(|| source_icc(bytes)).flatten(), interpolate, sixteen_bit)
 }
@@ -371,7 +371,7 @@ fn resample_channels(img: DynamicImage, r: &Rule, (w, h): (u32, u32)) -> Dynamic
 /// Encoded image `bytes` placed `size` points wide and high, as the Compression settings `c` ask:
 /// resampled when its resolution is above the threshold, compressed with ZIP or JPEG, its colours
 /// converted by `convert` (colour images). Pixels that keep their colours keep the ICC profile
-/// they carry when `profiles` allows it (not in PDF/X-1a, which has device colours only).
+/// they carry when `profiles` allows it (not in PDF/X-1a, which allows no ICC-based color spaces).
 /// `interpolate` lets viewers smooth it. An image that can't be decoded is kept as it is.
 pub(crate) fn recode(
     bytes: &[u8],
diff --git a/crates/pdf/src/tests/compression.rs b/crates/pdf/src/tests/compression.rs
index 30e9d57e4b..8b88a0731d 100644
--- a/crates/pdf/src/tests/compression.rs
+++ b/crates/pdf/src/tests/compression.rs
@@ -292,6 +292,11 @@ fn tagged(img: &DynamicImage, icc: &[u8], format: ImageFormat) -> Vec<u8> {
             enc.set_icc_profile(icc.to_vec()).unwrap();
             img.write_with_encoder(enc).unwrap();
         }
+        ImageFormat::Jpeg => {
+            let mut enc = image::codecs::jpeg::JpegEncoder::new(&mut out);
+            enc.set_icc_profile(icc.to_vec()).unwrap();
+            img.write_with_encoder(enc).unwrap();
+        }
         _ => {
             let mut enc = image::codecs::png::PngEncoder::new(&mut out);
             enc.set_icc_profile(icc.to_vec()).unwrap();
@@ -423,11 +428,12 @@ fn tagged_tiffs_keep_their_icc_profile() {
         let spaces = export(&tiff(&colour(), &rgb), json!({"output": {"conversion": "destination", "destination": destination}}));
         assert!(spaces.len() == 1 && spaces[0].icc.as_deref() != Some(rgb.as_slice()), "converted to {destination}: {spaces:?}");
     }
-    // PDF/X-1a has device colours only: a tagged gray TIFF or PNG is written in DeviceGray, kept as
-    // it is, resampled or compressed with JPEG.
+    // PDF/X-1a allows no ICC-based color spaces: a tagged gray TIFF, PNG or JPEG is written in
+    // DeviceGray, kept as it is, resampled or compressed with JPEG.
     let compressions = [json!({}), json!({"gray": {"downsample": "bicubic", "ppi": 150, "abovePpi": 225}}), json!({"gray": {"compression": "jpeg"}})];
     let png = doc(tagged(&colour().grayscale(), &gray, ImageFormat::Png), "image/png");
-    for (format, d) in [("TIFF", tiff(&colour().grayscale(), &gray)), ("PNG", png)] {
+    let jpeg = doc(tagged(&colour().grayscale(), &gray, ImageFormat::Jpeg), "image/jpeg");
+    for (format, d) in [("TIFF", tiff(&colour().grayscale(), &gray)), ("PNG", png), ("JPEG", jpeg)] {
         for compression in &compressions {
             let mut settings: PdfSettings =
                 serde_json::from_value(json!({"standard": "pdfX1a", "compatibility": "1.3", "compression": compression.clone()})).unwrap();