diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs index e20cbc596e..fc1a8d2074 100644 --- a/crates/engine/src/lib.rs +++ b/crates/engine/src/lib.rs @@ -232,6 +232,10 @@ pub struct DocId(pub u64); /// Undo/redo depth. Snapshots share unchanged data, so this is memory-cheap. const MAX_UNDO: usize = 100; +/// The highest resolution a document that allows only low-resolution printing (Table 22, bit 12 +/// clear) is printed at. +const LOW_RESOLUTION_PRINT_DPI: f64 = 150.0; + /// The passwords that go with one state of a document (protection can change them). #[derive(Clone, Debug, Default, PartialEq)] struct Keys { @@ -4522,9 +4526,15 @@ impl Session { if !doc.allows_printing() { return Err(EditError::NotPermitted("printing")); } + // Table 22, bit 12 clear: only a low-level representation may be printed, so the pages + // always go as pictures, at no more than the low resolution. + let low_res = doc.permissions().is_some_and(|p| !p.print_high_quality()).then(|| print::Raster { + dpi: settings.raster.map_or(LOW_RESOLUTION_PRINT_DPI, |r| r.dpi.min(LOW_RESOLUTION_PRINT_DPI)), + grayscale: settings.raster.is_some_and(|r| r.grayscale), + }); // Print as image: the pages used become pictures first, then the picture document is // imposed in their place (its page k is the k-th distinct source page used). - if let Some(raster) = &settings.raster { + if let Some(raster) = low_res.as_ref().or(settings.raster.as_ref()) { let mut distinct: Vec = Vec::new(); for &p in &settings.pages { if !distinct.contains(&p) { diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs index f93e765260..2d67305445 100644 --- a/crates/engine/src/tests.rs +++ b/crates/engine/src/tests.rs @@ -1340,6 +1340,38 @@ fn print_restricted_documents_disable_print_unless_opened_by_the_owner() { assert!(enabled(&s, low, "print.dialog"), "low-resolution printing is printing"); } +/// Table 22, bit 12 clear: printing is limited to a low-level representation. Whatever the +/// settings ask for, the print-ready PDF carries each page as a picture of at most 150 dpi, with +/// no text or vector artwork left; the owner password lifts the limit. +#[test] +fn low_resolution_printing_prints_pictures_of_at_most_150_dpi() { + let bytes = protected("", "owner", -1 ^ (1 << 11)); + let mut s = Session::new(); + let low = s.open("low.pdf", None, bytes.clone(), None).unwrap(); + let width = f64::from(s.get(low).unwrap().info.pages[0].width); + let actual = print::Settings { pages: vec![0], layout: print::Layout::Size(print::SizeMode::Actual), ..Default::default() }; + for raster in [None, Some(print::Raster { dpi: 600.0, grayscale: false })] { + let printed = s.print_pdf(low, &print::Settings { raster, ..actual.clone() }).unwrap(); + let mut s2 = Session::new(); + let id2 = s2.open("print.pdf", None, Arc::new(printed.clone()), None).unwrap(); + assert!(page_texts(&s2, id2).iter().all(|t| t.trim().is_empty()), "{raster:?}: no text is left"); + let doc = pdfcraft_cos::Document::open(Arc::new(printed)).unwrap(); + let widths: Vec = doc + .scan_objects() + .filter_map(|(_, o)| match &*o { + pdfcraft_cos::Object::Stream(st) if st.dict.name(b"Subtype") == Some(b"Image") => st.dict.int(b"Width"), + _ => None, + }) + .collect(); + assert!(!widths.is_empty() && widths.iter().all(|&w| w as f64 <= width * 150.0 / 72.0 + 1.0), "{raster:?}: {widths:?} px for {width} pt"); + } + let owner = s.open("low.pdf", None, bytes, Some("owner")).unwrap(); + let printed = s.print_pdf(owner, &actual).unwrap(); + let mut s2 = Session::new(); + let id2 = s2.open("print.pdf", None, Arc::new(printed), None).unwrap(); + assert!(page_texts(&s2, id2).iter().any(|t| !t.trim().is_empty()), "the owner prints the pages themselves"); +} + #[test] fn the_permissions_password_unlocks_an_open_document() { // Only a permissions password (#995, #1077): opens without asking. Changes are allowed,