M7: links that go to a page open at a chosen zoom (edit.action-goto) (#5277)

crates/annot/src/links.rs

@@ -8,13 +8,77 @@ use crate::{AnnotError, annots, page_ref, page_refs, set_annots};
 /// Where a link goes.
 #[derive(Clone, Debug, PartialEq)]
 pub enum LinkAction {
-    /// A page of this document (0-based), shown fitting the window (`/Fit`).
-    Page(usize),
+    /// A page of this document (0-based), shown at `zoom`.
+    Page {
+        page: usize,
+        zoom: LinkZoom,
+    },
     Uri(String),
     /// Something PdfCraft doesn't edit yet (named destination, JavaScript…): kept as is.
     Other(String),
 }
 
+/// How a go-to-page link shows its page: Acrobat's Go to a page view zoom, written as an
+/// explicit destination (ISO 32000-2 §12.3.2.2, Table 149). Positions are written `null`, so the
+/// reader keeps its position in that direction, as a new bookmark does.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum LinkZoom {
+    /// `/Fit`: the whole page in the window.
+    FitPage,
+    /// `/FitH null`: the page's width across the window.
+    FitWidth,
+    /// `/FitV null`: the page's height down the window.
+    FitHeight,
+    /// `/FitB`: the page's content (its bounding box) in the window.
+    FitVisible,
+    /// `/XYZ null null null`: the reader's zoom is kept.
+    Inherit,
+    /// `/XYZ null null z` with z = percent / 100; 100 is Actual Size. A new zoom is written
+    /// within 1–6400%; a link rewritten with the zoom it has keeps its own factor.
+    Percent(f64),
+}
+
+impl LinkZoom {
+    /// The zoom an explicit destination array (`[page /XYZ …]`, `[page /Fit]`, …) asks for. The
+    /// boxed variants read as their unboxed ones, and a `/FitR` rectangle or a missing or unknown
+    /// type as Fit Page, the view links had before they carried a zoom. A link whose page and zoom
+    /// are unchanged is not rewritten, so its position is kept; one given a new page keeps how its
+    /// zoom is written (`write_action`) but not its position.
+    fn of_dest(doc: &Document, dest: &[Object]) -> Self {
+        let kind = dest.get(1).map(|k| doc.resolve(k)).and_then(|k| k.as_name().map(<[u8]>::to_vec));
+        match kind.as_deref() {
+            Some(b"FitB") => LinkZoom::FitVisible,
+            Some(b"FitH" | b"FitBH") => LinkZoom::FitWidth,
+            Some(b"FitV" | b"FitBV") => LinkZoom::FitHeight,
+            Some(b"XYZ") => match dest.get(4).and_then(|z| doc.resolve(z).as_f64()) {
+                // Finite even for a factor near f64::MAX. A link given a new page with this zoom
+                // keeps the factor itself, however far outside 1–6400% (`write_action`).
+                Some(z) if z.is_finite() && z > 0.0 => LinkZoom::Percent((z * 100.0).min(f64::MAX)),
+                // A zoom of 0 or null keeps the reader's (Table 149).
+                _ => LinkZoom::Inherit,
+            },
+            _ => LinkZoom::FitPage,
+        }
+    }
+
+    /// The destination's elements after the page reference.
+    fn operands(self) -> Result<Vec<Object>, AnnotError> {
+        Ok(match self {
+            LinkZoom::FitPage => vec![Object::name("Fit")],
+            LinkZoom::FitWidth => vec![Object::name("FitH"), Object::Null],
+            LinkZoom::FitHeight => vec![Object::name("FitV"), Object::Null],
+            LinkZoom::FitVisible => vec![Object::name("FitB")],
+            LinkZoom::Inherit => vec![Object::name("XYZ"), Object::Null, Object::Null, Object::Null],
+            LinkZoom::Percent(p) => {
+                if !(p.is_finite() && p > 0.0) {
+                    return Err(AnnotError::Invalid("the link's zoom must be a positive percentage".into()));
+                }
+                vec![Object::name("XYZ"), Object::Null, Object::Null, Object::Real((p / 100.0).clamp(0.01, 64.0))]
+            }
+        })
+    }
+}
+
 /// Acrobat's Link Properties ▸ Appearance.
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct LinkStyle {
@@ -87,17 +151,18 @@ fn nums(doc: &Document, o: Option<&Object>) -> Vec<f64> {
 }
 
 fn action_of(doc: &Document, d: &Dict, pages: &[ObjRef], uri_budget: &mut usize) -> LinkAction {
-    let dest_page = |dest: &Object| -> Option<usize> {
+    let page_view = |dest: &Object| -> Option<LinkAction> {
         let a = doc.resolve(dest);
-        let first = a.as_array()?.first()?.clone();
-        match first {
-            Object::Ref(r) => pages.iter().position(|p| *p == r),
-            Object::Int(i) => usize::try_from(i).ok(),
+        let a = a.as_array()?;
+        let page = match a.first()? {
+            Object::Ref(r) => pages.iter().position(|p| p == r),
+            Object::Int(i) => usize::try_from(*i).ok(),
             _ => None,
-        }
+        }?;
+        Some(LinkAction::Page { page, zoom: LinkZoom::of_dest(doc, a) })
     };
     if let Some(dest) = d.get(b"Dest") {
-        return dest_page(dest).map_or_else(|| LinkAction::Other("named destination".into()), LinkAction::Page);
+        return page_view(dest).unwrap_or_else(|| LinkAction::Other("named destination".into()));
     }
     let Some(a) = d.get(b"A").map(|a| doc.resolve(a)).and_then(|a| a.as_dict().cloned()) else { return LinkAction::Other("no action".into()) };
     match a.name(b"S") {
@@ -115,7 +180,7 @@ fn action_of(doc: &Document, d: &Dict, pages: &[ObjRef], uri_budget: &mut usize)
                 None => LinkAction::Other("web address too long".into()),
             }
         }
-        Some(b"GoTo") => a.get(b"D").and_then(dest_page).map_or_else(|| LinkAction::Other("named destination".into()), LinkAction::Page),
+        Some(b"GoTo") => a.get(b"D").and_then(page_view).unwrap_or_else(|| LinkAction::Other("named destination".into())),
         Some(s) => LinkAction::Other(String::from_utf8_lossy(s).into_owned()),
         None => LinkAction::Other("no action".into()),
     }
@@ -214,12 +279,52 @@ fn uri_bytes(u: &str) -> Vec<u8> {
     out
 }
 
+/// The explicit destination array link `d` goes to now: its `/Dest`, or a GoTo action's `/D`.
+fn current_dest(doc: &Document, d: &Dict) -> Option<Vec<Object>> {
+    let dest = match d.get(b"Dest") {
+        Some(dest) => doc.resolve(dest),
+        None => {
+            let action = doc.resolve(d.get(b"A")?);
+            let go_to = action.as_dict().filter(|a| a.name(b"S") == Some(b"GoTo"))?;
+            doc.resolve(go_to.get(b"D")?)
+        }
+    };
+    dest.as_array().cloned()
+}
+
 fn write_action(doc: &Document, d: &mut Dict, a: &LinkAction) -> Result<(), AnnotError> {
     match a {
-        LinkAction::Page(p) => {
-            let target = page_ref(doc, *p)?;
+        LinkAction::Page { page, zoom } => {
+            let target = page_ref(doc, *page)?;
+            let mut operands = zoom.operands()?;
+            let current = current_dest(doc, d).filter(|c| LinkZoom::of_dest(doc, c) == *zoom);
+            if let Some(c) = current {
+                // The page and zoom the link has (`link_edit` naming its own page): the
+                // destination is left as it is, position on the page and GoTo form included.
+                let same_page = match c.first() {
+                    Some(Object::Ref(r)) => *r == target,
+                    Some(Object::Int(i)) => usize::try_from(*i).ok() == Some(*page),
+                    _ => false,
+                };
+                if same_page {
+                    return Ok(());
+                }
+                // A new page with the zoom the link has keeps how that zoom is written: a boxed
+                // fit (`/FitBH`, `/FitBV`) and its own `/XYZ` factor, even one outside the 1–6400%
+                // a new zoom is written within. Positions belong to the old page and are dropped.
+                let (slot, own) = match zoom {
+                    LinkZoom::Percent(_) => (operands.get_mut(3), c.get(4)),
+                    LinkZoom::FitWidth | LinkZoom::FitHeight => (operands.get_mut(0), c.get(1)),
+                    _ => (None, None),
+                };
+                if let (Some(slot), Some(own)) = (slot, own) {
+                    *slot = doc.resolve(own).as_ref().clone();
+                }
+            }
+            let mut dest = vec![Object::Ref(target)];
+            dest.extend(operands);
             d.remove(b"A");
-            d.set(b"Dest".to_vec(), Object::Array(vec![Object::Ref(target), Object::name("Fit")]));
+            d.set(b"Dest".to_vec(), Object::Array(dest));
         }
         LinkAction::Uri(u) => {
             let u = u.trim();

crates/annot/src/tests.rs

@@ -1003,12 +1003,12 @@ fn stamps_draw_their_label_and_by_line() {
 
 #[test]
 fn links_are_added_edited_listed_and_removed() {
-    use crate::links::{self, Highlight, LinkAction, LinkStyle};
+    use crate::links::{self, Highlight, LinkAction, LinkStyle, LinkZoom};
     let mut doc = fixture();
     let before = links::list(&doc).len();
     let i = links::add(&mut doc, 0, [10.0, 10.0, 110.0, 30.0], &LinkAction::Uri("https://example.org".into()), &LinkStyle::default()).unwrap();
     let style = LinkStyle { visible: true, color: [1.0, 0.0, 0.0], width: 2.0, dashed: true, underline: false, highlight: Highlight::Outline };
-    links::add(&mut doc, 1, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page(0), &style).unwrap();
+    links::add(&mut doc, 1, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 0, zoom: LinkZoom::FitPage }, &style).unwrap();
     let doc = reopen(&doc);
     let all = links::list(&doc);
     assert_eq!(all.len(), before + 2);
@@ -1017,7 +1017,7 @@ fn links_are_added_edited_listed_and_removed() {
         (web.action.clone(), web.style.visible, web.style.highlight),
         (LinkAction::Uri("https://example.org".into()), false, Highlight::Invert)
     );
-    let page = all.iter().find(|l| l.page == 1 && l.action == LinkAction::Page(0)).unwrap().clone();
+    let page = all.iter().find(|l| l.page == 1 && l.action == LinkAction::Page { page: 0, zoom: LinkZoom::FitPage }).unwrap().clone();
     assert_eq!(page.style, style);
     let mut doc = doc;
     links::set(&mut doc, 1, page.index, Some([0.0, 0.0, 50.0, 20.0]), Some(&LinkAction::Uri("mailto:ada@example.org".into())), None).unwrap();
@@ -1027,7 +1027,201 @@ fn links_are_added_edited_listed_and_removed() {
     assert!(links::delete(&mut doc, 0, 999).is_err(), "no such annotation");
     let n = links::remove_all(&mut doc, None).unwrap();
     assert!(n >= 1 && links::list(&doc).is_empty());
-    assert!(links::add(&mut doc, 0, [0.0, 0.0, 1.0, 1.0], &LinkAction::Page(0), &LinkStyle::default()).is_err(), "too small");
+    assert!(
+        links::add(&mut doc, 0, [0.0, 0.0, 1.0, 1.0], &LinkAction::Page { page: 0, zoom: LinkZoom::FitPage }, &LinkStyle::default()).is_err(),
+        "too small"
+    );
+}
+
+#[test]
+fn page_links_keep_their_zoom() {
+    use crate::links::{self, LinkAction, LinkStyle, LinkZoom};
+    let page1 = page_refs(&fixture()).unwrap()[1];
+    let dest_of = |doc: &Document, obj: ObjRef| doc.get(obj).as_dict().and_then(|d| d.get(b"Dest").cloned());
+    // Each zoom is written as its destination type (Table 149) and reads back after a save.
+    let null = Object::Null;
+    for (zoom, written) in [
+        (LinkZoom::FitPage, vec![Object::name("Fit")]),
+        (LinkZoom::FitWidth, vec![Object::name("FitH"), null.clone()]),
+        (LinkZoom::FitHeight, vec![Object::name("FitV"), null.clone()]),
+        (LinkZoom::FitVisible, vec![Object::name("FitB")]),
+        (LinkZoom::Inherit, vec![Object::name("XYZ"), null.clone(), null.clone(), null.clone()]),
+        (LinkZoom::Percent(100.0), vec![Object::name("XYZ"), null.clone(), null.clone(), Object::Real(1.0)]),
+        (LinkZoom::Percent(250.0), vec![Object::name("XYZ"), null.clone(), null.clone(), Object::Real(2.5)]),
+    ] {
+        let mut doc = fixture();
+        let i = links::add(&mut doc, 0, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 1, zoom }, &LinkStyle::default()).unwrap();
+        let link = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap();
+        let mut expected = vec![Object::Ref(page1)];
+        expected.extend(written);
+        assert_eq!(dest_of(&doc, link.obj.unwrap()), Some(Object::Array(expected)), "{zoom:?}");
+        let doc = reopen(&doc);
+        let link = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap();
+        assert_eq!(link.action, LinkAction::Page { page: 1, zoom }, "{zoom:?} after a save");
+    }
+    // What other writers use reads as the nearest zoom: a zero zoom keeps the reader's, the boxed
+    // fits as the plain ones, a rectangle as Fit Page, and a GoTo action like a /Dest.
+    let mut doc = fixture();
+    let i = links::add(&mut doc, 0, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 1, zoom: LinkZoom::FitPage }, &LinkStyle::default()).unwrap();
+    let obj = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().obj.unwrap();
+    let dest = |kind: &str, operands: Vec<Object>| {
+        let mut d = vec![Object::Ref(page1), Object::name(kind)];
+        d.extend(operands);
+        Object::Array(d)
+    };
+    for (key, value, zoom) in [
+        ("Dest", dest("XYZ", vec![Object::Int(100), Object::Int(700), Object::Int(0)]), LinkZoom::Inherit),
+        ("Dest", dest("FitBH", vec![Object::Int(500)]), LinkZoom::FitWidth),
+        ("Dest", dest("FitBV", vec![Object::Int(20)]), LinkZoom::FitHeight),
+        ("Dest", dest("FitR", vec![Object::Int(0), Object::Int(0), Object::Int(10), Object::Int(10)]), LinkZoom::FitPage),
+        ("A", dest("XYZ", vec![null.clone(), null.clone(), Object::Real(1.5)]), LinkZoom::Percent(150.0)),
+        // A factor outside what PdfCraft writes reads as the destination has it, not capped, so
+        // it agrees with the viewer's `destination`; one whose percentage overflows stays finite.
+        ("Dest", dest("XYZ", vec![null.clone(), null.clone(), Object::Real(100.0)]), LinkZoom::Percent(10000.0)),
+        ("Dest", dest("XYZ", vec![null.clone(), null.clone(), Object::Real(0.005)]), LinkZoom::Percent(0.5)),
+        ("Dest", dest("XYZ", vec![null.clone(), null.clone(), Object::Real(1e307)]), LinkZoom::Percent(f64::MAX)),
+    ] {
+        let mut d = doc.get(obj).as_dict().cloned().unwrap();
+        d.remove(b"Dest");
+        d.remove(b"A");
+        if key == "A" {
+            let mut go_to = pdfcraft_cos::Dict::new();
+            go_to.set(b"S".to_vec(), Object::name("GoTo"));
+            go_to.set(b"D".to_vec(), value);
+            d.set(b"A".to_vec(), Object::Dict(go_to));
+        } else {
+            d.set(b"Dest".to_vec(), value);
+        }
+        doc.set(obj, Object::Dict(d));
+        let link = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap();
+        assert_eq!(link.action, LinkAction::Page { page: 1, zoom }, "{key}");
+    }
+    // A zoom that isn't a positive percentage is refused before anything is written.
+    for p in [0.0, -50.0, f64::NAN, f64::INFINITY] {
+        let before = links::list(&doc).len();
+        let refused =
+            links::add(&mut doc, 0, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 1, zoom: LinkZoom::Percent(p) }, &LinkStyle::default());
+        assert!(refused.is_err(), "{p}");
+        assert_eq!(links::list(&doc).len(), before, "{p}: no link added");
+    }
+}
+
+/// A link rewritten with the zoom it has keeps its own `/XYZ` factor, however far outside the
+/// 1–6400% a new zoom is written within: giving it a new page (Link Properties' OK, `link_edit`
+/// without `zoom`) must not change its zoom. A zoom chosen anew is still written within 1–6400%.
+#[test]
+fn a_rewritten_link_keeps_its_own_zoom_factor() {
+    use crate::links::{self, LinkAction, LinkStyle, LinkZoom};
+    let pages = page_refs(&fixture()).unwrap();
+    let dest_of = |doc: &Document, obj: ObjRef| doc.get(obj).as_dict().and_then(|d| d.get(b"Dest").cloned());
+    let xyz = |page: ObjRef, factor: Object| Object::Array(vec![Object::Ref(page), Object::name("XYZ"), Object::Null, Object::Null, factor]);
+    for (key, factor) in [
+        ("Dest", Object::Real(0.005)),
+        ("Dest", Object::Real(100.0)),
+        ("Dest", Object::Int(100)),
+        ("Dest", Object::Real(1e307)),
+        ("A", Object::Real(0.005)),
+    ] {
+        let mut doc = fixture();
+        let i =
+            links::add(&mut doc, 0, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 1, zoom: LinkZoom::FitPage }, &LinkStyle::default()).unwrap();
+        let obj = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().obj.unwrap();
+        let mut d = doc.get(obj).as_dict().cloned().unwrap();
+        d.remove(b"Dest");
+        if key == "A" {
+            let mut go_to = pdfcraft_cos::Dict::new();
+            go_to.set(b"S".to_vec(), Object::name("GoTo"));
+            go_to.set(b"D".to_vec(), xyz(pages[1], factor.clone()));
+            d.set(b"A".to_vec(), Object::Dict(go_to));
+        } else {
+            d.set(b"Dest".to_vec(), xyz(pages[1], factor.clone()));
+        }
+        doc.set(obj, Object::Dict(d));
+        let LinkAction::Page { zoom, .. } = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().action else {
+            panic!("{key} {factor:?}")
+        };
+        links::set(&mut doc, 0, i, None, Some(&LinkAction::Page { page: 0, zoom }), None).unwrap();
+        assert_eq!(dest_of(&doc, obj), Some(xyz(pages[0], factor.clone())), "{key} {factor:?}: the factor is the link's own");
+        let doc = reopen(&doc);
+        assert_eq!(
+            links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().action,
+            LinkAction::Page { page: 0, zoom },
+            "{key} {factor:?}"
+        );
+    }
+    // A zoom other than the link's is written within 1–6400%.
+    let mut doc = fixture();
+    let i = links::add(&mut doc, 0, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 1, zoom: LinkZoom::Percent(50.0) }, &LinkStyle::default())
+        .unwrap();
+    let obj = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().obj.unwrap();
+    links::set(&mut doc, 0, i, None, Some(&LinkAction::Page { page: 1, zoom: LinkZoom::Percent(10000.0) }), None).unwrap();
+    assert_eq!(dest_of(&doc, obj), Some(xyz(pages[1], Object::Real(64.0))));
+}
+
+/// A go-to edited without a change (its own page and zoom, as `link_edit` naming its page does)
+/// is left as it is: the `/XYZ` position, a fit's position and the GoTo form stay. Given a new
+/// page with its zoom, a link keeps how that zoom is written, a boxed fit (`/FitBH`, `/FitBV`)
+/// included, but not its position, which belongs to the old page.
+#[test]
+fn an_unchanged_go_to_keeps_its_destination_and_a_new_page_keeps_its_fit() {
+    use crate::links::{self, LinkAction, LinkStyle, LinkZoom};
+    let pages = page_refs(&fixture()).unwrap();
+    let dest = |page: ObjRef, kind: &str, operands: Vec<Object>| {
+        let mut d = vec![Object::Ref(page), Object::name(kind)];
+        d.extend(operands);
+        Object::Array(d)
+    };
+    let link_with = |key: &str, value: Object| {
+        let mut doc = fixture();
+        let i =
+            links::add(&mut doc, 0, [10.0, 10.0, 60.0, 30.0], &LinkAction::Page { page: 1, zoom: LinkZoom::FitPage }, &LinkStyle::default()).unwrap();
+        let obj = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().obj.unwrap();
+        let mut d = doc.get(obj).as_dict().cloned().unwrap();
+        d.remove(b"Dest");
+        if key == "A" {
+            let mut go_to = pdfcraft_cos::Dict::new();
+            go_to.set(b"S".to_vec(), Object::name("GoTo"));
+            go_to.set(b"D".to_vec(), value);
+            d.set(b"A".to_vec(), Object::Dict(go_to));
+        } else {
+            d.set(b"Dest".to_vec(), value);
+        }
+        doc.set(obj, Object::Dict(d));
+        (doc, i, obj)
+    };
+    let (num, null) = (|n: i64| Object::Int(n), Object::Null);
+    // The same page and zoom: nothing is rewritten.
+    for (key, value) in [
+        ("Dest", dest(pages[1], "XYZ", vec![num(72), num(500), Object::Real(2.0)])),
+        ("Dest", dest(pages[1], "FitBH", vec![num(250)])),
+        ("Dest", dest(pages[1], "FitV", vec![num(20)])),
+        ("A", dest(pages[1], "XYZ", vec![num(72), num(500), Object::Real(0.005)])),
+    ] {
+        let (mut doc, i, obj) = link_with(key, value);
+        let before = doc.get(obj).as_dict().cloned();
+        let LinkAction::Page { page, zoom } = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().action else {
+            panic!("{key}")
+        };
+        links::set(&mut doc, 0, i, None, Some(&LinkAction::Page { page, zoom }), None).unwrap();
+        assert_eq!(doc.get(obj).as_dict().cloned(), before, "{key} {zoom:?}: left as it is");
+    }
+    // A new page: the fit's kind and the factor stay, positions go.
+    for (value, written) in [
+        (dest(pages[1], "FitBH", vec![num(250)]), dest(pages[0], "FitBH", vec![null.clone()])),
+        (dest(pages[1], "FitBV", vec![num(20)]), dest(pages[0], "FitBV", vec![null.clone()])),
+        (dest(pages[1], "FitH", vec![num(250)]), dest(pages[0], "FitH", vec![null.clone()])),
+        (
+            dest(pages[1], "XYZ", vec![num(72), num(500), Object::Real(2.0)]),
+            dest(pages[0], "XYZ", vec![null.clone(), null.clone(), Object::Real(2.0)]),
+        ),
+    ] {
+        let (mut doc, i, obj) = link_with("Dest", value.clone());
+        let LinkAction::Page { zoom, .. } = links::list(&doc).into_iter().find(|l| l.page == 0 && l.index == i).unwrap().action else {
+            panic!("{value:?}")
+        };
+        links::set(&mut doc, 0, i, None, Some(&LinkAction::Page { page: 0, zoom }), None).unwrap();
+        assert_eq!(doc.get(obj).as_dict().and_then(|d| d.get(b"Dest").cloned()), Some(written), "{value:?}");
+    }
 }
 
 #[test]

crates/automation/src/links.rs

@@ -2,7 +2,7 @@
 //! all links. Rectangles are points from the top-left of the displayed page.
 
 use pdfcraft_engine::{
-    Edit, LinkAction, LinkHighlight, LinkStyle, read_remote_document, remote_document_path_is_absolute, resolve_remote_document_path,
+    Edit, LinkAction, LinkHighlight, LinkStyle, LinkZoom, read_remote_document, remote_document_path_is_absolute, resolve_remote_document_path,
 };
 use pdfcraft_render::{DestView, LinkTarget, RemoteDestination};
 use serde_json::{Value, json};
@@ -25,18 +25,30 @@ impl Automation {
         Ok(Some([u0[0].min(u1[0]) as f64, u0[1].min(u1[1]) as f64, u0[0].max(u1[0]) as f64, u0[1].max(u1[1]) as f64]))
     }
 
-    fn link_action(&self, a: &Args) -> Result<Option<LinkAction>> {
+    /// The action `url`, `to_page` and `zoom` ask for, if any. `current` is the link's action now
+    /// (link_edit): a new page keeps the link's zoom, and a zoom alone keeps its page.
+    fn link_action(&self, a: &Args, current: Option<&LinkAction>) -> Result<Option<LinkAction>> {
+        let zoom = link_zoom(a)?;
+        let (current_page, current_zoom) = match current {
+            Some(LinkAction::Page { page, zoom }) => (Some(*page), Some(*zoom)),
+            _ => (None, None),
+        };
         match (a.opt_str("url")?, a.opt_int("to_page")?) {
             (Some(_), Some(_)) => Err(bad("pass url or to_page, not both")),
+            (Some(_), None) if zoom.is_some() => Err(bad("zoom goes with to_page, not url")),
             (Some(u), None) => Ok(Some(LinkAction::Uri(u.to_string()))),
             (None, Some(p)) => {
                 let n = self.doc(a)?.info.pages.len() as i64;
                 if p < 1 || p > n {
                     return Err(bad(format!("to_page must be 1–{n}")));
                 }
-                Ok(Some(LinkAction::Page(p as usize - 1)))
+                Ok(Some(LinkAction::Page { page: p as usize - 1, zoom: zoom.or(current_zoom).unwrap_or(LinkZoom::FitPage) }))
             }
-            (None, None) => Ok(None),
+            (None, None) => match (zoom, current_page) {
+                (None, _) => Ok(None),
+                (Some(zoom), Some(page)) => Ok(Some(LinkAction::Page { page, zoom })),
+                (Some(_), None) => Err(bad("zoom needs to_page: the link doesn't go to a page")),
+            },
         }
     }
 
@@ -86,11 +98,16 @@ impl Automation {
                         if let Some(d) = doc.info.pages.get(page).and_then(|p| crate::destination(view, p)) {
                             v["destination"] = d;
                         }
-                        if matches!(action, LinkAction::Other(_)) {
-                            v["named"] = json!(true);
+                        match action {
+                            LinkAction::Page { zoom, .. } => v["zoom"] = zoom_value(*zoom),
+                            LinkAction::Other(_) => v["named"] = json!(true),
+                            LinkAction::Uri(_) => {}
                         }
                     }
-                    (LinkAction::Page(p), None) => v["to_page"] = json!(p + 1),
+                    (LinkAction::Page { page, zoom }, None) => {
+                        v["to_page"] = json!(page + 1);
+                        v["zoom"] = zoom_value(*zoom);
+                    }
                     (LinkAction::Other(o), None) => v["other"] = json!(o),
                 }
                 v
@@ -168,12 +185,13 @@ impl Automation {
     pub(crate) fn link_add(&mut self, a: &Args) -> Result<Value> {
         let page = self.page(a)?;
         let rect = self.view_rect(a, page)?.ok_or_else(|| bad("link_add needs rect"))?;
-        let action = self.link_action(a)?.ok_or_else(|| bad("pass url or to_page"))?;
+        let action = self.link_action(a, None)?.ok_or_else(|| bad("pass url or to_page"))?;
         let style = self.link_style(a, LinkStyle::default())?;
         self.apply(a, Edit::AddLink { page, rect, action, style })
     }
 
-    fn link_index(&self, a: &Args) -> Result<(usize, usize, LinkStyle)> {
+    /// The link `page` and `index` name: its page, index in `/Annots`, appearance and action.
+    fn link_index(&self, a: &Args) -> Result<(usize, usize, LinkStyle, LinkAction)> {
         let page = self.page(a)?;
         let index = a.int("index")?;
         let doc = self.doc(a)?;
@@ -182,19 +200,19 @@ impl Automation {
             .iter()
             .find(|l| l.page == page && l.index as i64 + 1 == index)
             .ok_or_else(|| failed(format!("page {} has no link {index} (see link_list)", page + 1)))?;
-        Ok((page, l.index, l.style))
+        Ok((page, l.index, l.style, l.action.clone()))
     }
 
     pub(crate) fn link_edit(&mut self, a: &Args) -> Result<Value> {
-        let (page, index, style) = self.link_index(a)?;
+        let (page, index, style, current) = self.link_index(a)?;
         let rect = self.view_rect(a, page)?;
-        let action = self.link_action(a)?;
+        let action = self.link_action(a, Some(&current))?;
         let new_style = self.link_style(a, style)?;
         self.apply(a, Edit::SetLink { page, index, rect, action, style: (new_style != style).then_some(new_style) })
     }
 
     pub(crate) fn link_delete(&mut self, a: &Args) -> Result<Value> {
-        let (page, index, _) = self.link_index(a)?;
+        let (page, index, ..) = self.link_index(a)?;
         self.apply(a, Edit::DeleteLink { page, index })
     }
 
@@ -225,6 +243,40 @@ impl Automation {
     }
 }
 
+/// The zoom a `zoom` argument names: fit_page, fit_width, fit_height, fit_visible, actual
+/// (100%), inherit (keep the reader's zoom), or a percentage, kept within 1–6400.
+fn link_zoom(a: &Args) -> Result<Option<LinkZoom>> {
+    match a.get("zoom") {
+        None | Some(Value::Null) => Ok(None),
+        Some(Value::Number(p)) => match p.as_f64() {
+            Some(p) if p.is_finite() && p > 0.0 => Ok(Some(LinkZoom::Percent(p.clamp(1.0, 6400.0)))),
+            _ => Err(bad("zoom must be a positive percentage")),
+        },
+        Some(Value::String(z)) => Ok(Some(match z.as_str() {
+            "fit_page" => LinkZoom::FitPage,
+            "fit_width" => LinkZoom::FitWidth,
+            "fit_height" => LinkZoom::FitHeight,
+            "fit_visible" => LinkZoom::FitVisible,
+            "actual" => LinkZoom::Percent(100.0),
+            "inherit" => LinkZoom::Inherit,
+            o => return Err(bad(format!("unknown zoom {o:?}"))),
+        })),
+        Some(_) => Err(bad("zoom is a name or a percentage")),
+    }
+}
+
+/// How `link_list` reports a link's zoom: the names `link_zoom` reads, a percentage as a number.
+fn zoom_value(zoom: LinkZoom) -> Value {
+    match zoom {
+        LinkZoom::FitPage => json!("fit_page"),
+        LinkZoom::FitWidth => json!("fit_width"),
+        LinkZoom::FitHeight => json!("fit_height"),
+        LinkZoom::FitVisible => json!("fit_visible"),
+        LinkZoom::Inherit => json!("inherit"),
+        LinkZoom::Percent(p) => json!(p),
+    }
+}
+
 fn dest_view_value(view: DestView) -> Value {
     match view {
         DestView::Top => json!({ "kind": "top" }),

crates/automation/src/tools.rs

@@ -812,7 +812,7 @@ pub fn tools() -> Vec<ToolDef> {
         t("content_delete", "Delete added content", "Delete an added item (page, index from content_list). Undoable.")
             .destructive()
             .with(schema(json!({ "doc": doc(), "page": { "type": "integer", "minimum": 1 }, "index": { "type": "integer", "minimum": 1 } }), &["doc", "page", "index"])),
-        t("link_list", "List links", "Every link: page, 1-based index (for link_edit/link_delete), rect (points from the top-left of the page), and where it goes (url or to_page).")
+        t("link_list", "List links", "Every link: page, 1-based index (for link_edit/link_delete), rect (points from the top-left of the page), and where it goes (url, or to_page with its zoom).")
             .ro()
             .with(schema(json!({ "doc": doc() }), &["doc"])),
         t("link_open", "Open a linked PDF", "Follow a local GoToR link in PdfCraft: open the referenced PDF as a new document, respecting --root. page and index use link_list numbering. Named destinations are reported but not applied. Absolute file specifications require allow_absolute: true after reviewing the target; relative links need no opt-in.")
@@ -820,22 +820,24 @@ pub fn tools() -> Vec<ToolDef> {
                 json!({ "doc": doc(), "page": { "type": "integer", "minimum": 1 }, "index": { "type": "integer", "minimum": 1 }, "password": { "type": "string", "description": "Optional password for the linked PDF." }, "allow_absolute": { "type": "boolean", "description": "Explicitly allow an absolute local GoToR target (default false). Existing validation and --root confinement still apply." } }),
                 &["doc", "page", "index"],
             )),
-        t("link_add", "Add a link", "Add a link over rect on page that opens url or goes to to_page. Appearance: visible (rectangle), color, width 1-3, highlight none/invert/outline/inset. Undoable.")
+        t("link_add", "Add a link", "Add a link over rect on page that opens url or goes to to_page, shown at zoom: fit_page (default), fit_width, fit_height, fit_visible, actual, inherit (keep the reader's zoom) or a percentage. Appearance: visible (rectangle), color, width 1-3, highlight none/invert/outline/inset. Undoable.")
             .cmd("edit.link")
             .with(schema(
                 json!({
                     "doc": doc(), "page": { "type": "integer", "minimum": 1 }, "rect": { "type": "array", "items": { "type": "number" }, "minItems": 4, "maxItems": 4 },
                     "url": { "type": "string" }, "to_page": { "type": "integer", "minimum": 1 },
+                    "zoom": { "description": "fit_page, fit_width, fit_height, fit_visible, actual, inherit, or a percentage" },
                     "visible": { "type": "boolean" }, "color": { "type": "string" }, "width": { "type": "number" }, "highlight": { "type": "string", "enum": ["none", "invert", "outline", "inset"] },
                 }),
                 &["doc", "page", "rect"],
             )),
-        t("link_edit", "Edit a link", "Change a link's rect, destination (url or to_page) or appearance. Undoable.")
+        t("link_edit", "Edit a link", "Change a link's rect, destination (url, or to_page and zoom as in link_add; a new to_page keeps the link's zoom, a zoom alone keeps its page) or appearance. Undoable.")
             .with(schema(
                 json!({
                     "doc": doc(), "page": { "type": "integer", "minimum": 1 }, "index": { "type": "integer", "minimum": 1 },
                     "rect": { "type": "array", "items": { "type": "number" }, "minItems": 4, "maxItems": 4 },
                     "url": { "type": "string" }, "to_page": { "type": "integer", "minimum": 1 },
+                    "zoom": { "description": "fit_page, fit_width, fit_height, fit_visible, actual, inherit, or a percentage" },
                     "visible": { "type": "boolean" }, "color": { "type": "string" }, "width": { "type": "number" }, "highlight": { "type": "string", "enum": ["none", "invert", "outline", "inset"] },
                 }),
                 &["doc", "page", "index"],

crates/automation/tests/it/automation.rs

@@ -6201,6 +6201,80 @@ fn links_through_tools() {
     assert!(matches!(a.call("link_add", &json!({ "doc": doc, "page": 1, "rect": [0, 0, 50, 20] })), Err(ToolError::InvalidArgs(_))));
 }
 
+#[test]
+fn link_zoom_through_tools() {
+    let dir = workdir("link-zoom");
+    std::fs::write(dir.join("notes.txt"), "Contents").unwrap();
+    let mut a = auto(&dir);
+    let doc = ok(&mut a, "doc_create", json!({ "from": "text", "path": "notes.txt" }))["doc"].as_u64().unwrap();
+    let link = |a: &mut Automation| ok(a, "link_list", json!({ "doc": doc }))["links"][0].clone();
+    // A page link opens at Fit Page unless told otherwise.
+    ok(&mut a, "link_add", json!({ "doc": doc, "page": 1, "rect": [72, 300, 200, 320], "to_page": 1 }));
+    assert_eq!((link(&mut a)["to_page"].clone(), link(&mut a)["zoom"].clone()), (json!(1), json!("fit_page")));
+    let index = link(&mut a)["index"].clone();
+    // A zoom alone keeps the page; a page alone keeps the zoom.
+    ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": index, "zoom": 200 }));
+    let l = link(&mut a);
+    assert_eq!((l["to_page"].clone(), l["zoom"].clone()), (json!(1), json!(200.0)));
+    assert_eq!(l["destination"]["zoom"], 2.0, "the viewer reads the zoom the link writes: {l}");
+    ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": index, "zoom": "fit_width" }));
+    ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": index, "to_page": 1 }));
+    assert_eq!(link(&mut a)["zoom"], "fit_width");
+    for (name, zoom) in [("actual", json!(100.0)), ("inherit", json!("inherit")), ("fit_visible", json!("fit_visible"))] {
+        ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": index, "zoom": name }));
+        assert_eq!(link(&mut a)["zoom"], zoom, "{name}");
+    }
+    // A zoom needs a page to show: refused with a web address, unknown, or not positive.
+    for args in [
+        json!({ "doc": doc, "page": 1, "rect": [72, 400, 200, 420], "url": "https://example.org", "zoom": "fit_page" }),
+        json!({ "doc": doc, "page": 1, "rect": [72, 400, 200, 420], "zoom": "fit_page" }),
+        json!({ "doc": doc, "page": 1, "rect": [72, 400, 200, 420], "to_page": 1, "zoom": "sideways" }),
+        json!({ "doc": doc, "page": 1, "rect": [72, 400, 200, 420], "to_page": 1, "zoom": 0 }),
+        json!({ "doc": doc, "page": 1, "rect": [72, 400, 200, 420], "to_page": 1, "zoom": [2] }),
+    ] {
+        assert!(matches!(a.call("link_add", &args), Err(ToolError::InvalidArgs(_))), "{args}");
+    }
+    ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": index, "url": "https://example.org" }));
+    assert!(matches!(a.call("link_edit", &json!({ "doc": doc, "page": 1, "index": index, "zoom": 150 })), Err(ToolError::InvalidArgs(_))));
+}
+
+/// `link_edit` with a page and no zoom keeps the link's zoom, and with it the link's own `/XYZ`
+/// factor, even outside the 1–6400% a chosen zoom is written within: 0.5% and 10000% stay so, in
+/// link_list and in the viewer's destination. Naming the link's own page changes nothing, so its
+/// position stays too. A zoom chosen anew is still kept within 1–6400%.
+#[test]
+fn link_edit_keeps_a_links_own_zoom_outside_the_range_it_writes() {
+    let (_base, root) = sandbox("link-own-zoom");
+    let pdf = pdf_of(&[
+        "<< /Type /Catalog /Pages 2 0 R >>",
+        "<< /Type /Pages /Kids [3 0 R 4 0 R] /Count 2 /MediaBox [0 0 300 400] >>",
+        "<< /Type /Page /Parent 2 0 R /Annots [5 0 R 6 0 R 7 0 R] >>",
+        "<< /Type /Page /Parent 2 0 R >>",
+        "<< /Type /Annot /Subtype /Link /Rect [10 10 100 30] /Border [0 0 0] /Dest [3 0 R /XYZ null null 0.005] >>",
+        "<< /Type /Annot /Subtype /Link /Rect [10 50 100 70] /Border [0 0 0] /Dest [3 0 R /XYZ null null 100] >>",
+        "<< /Type /Annot /Subtype /Link /Rect [10 90 100 110] /Border [0 0 0] /Dest [3 0 R /XYZ 72 300 2] >>",
+    ]);
+    std::fs::write(root.join("zooms.pdf"), pdf).unwrap();
+    let mut a = auto(&root);
+    let doc = ok(&mut a, "doc_open", json!({ "path": "zooms.pdf" }))["doc"].as_u64().unwrap();
+    let link = |a: &mut Automation, index: u64| {
+        ok(a, "link_list", json!({ "doc": doc }))["links"].as_array().unwrap().iter().find(|l| l["index"] == index).unwrap().clone()
+    };
+    for (index, percent, factor) in [(1, 0.5, 0.005), (2, 10000.0, 100.0)] {
+        ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": index, "to_page": 2 }));
+        let l = link(&mut a, index);
+        assert_eq!((l["to_page"].clone(), l["zoom"].clone()), (json!(2), json!(percent)), "{l}");
+        let shown = l["destination"]["zoom"].as_f64().unwrap();
+        assert!((shown - factor).abs() <= factor * 1e-6, "the viewer's zoom is the link's own: {l}");
+    }
+    ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": 3, "to_page": 1 }));
+    let l = link(&mut a, 3);
+    // `/XYZ 72 300` on a 400 pt page: 72 from the left and 100 from the top, as the tools measure.
+    assert_eq!((&l["zoom"], &l["destination"]["left"], &l["destination"]["top"]), (&json!(200.0), &json!(72.0), &json!(100.0)), "{l}");
+    ok(&mut a, "link_edit", json!({ "doc": doc, "page": 1, "index": 1, "zoom": 10000 }));
+    assert_eq!(link(&mut a, 1)["zoom"], json!(6400.0));
+}
+
 /// #4168: a Launch action whose file is a PDF (here with Windows `\` separators, relative to the
 /// source as a remote link is) opens that PDF in PdfCraft through link_open, within the root; one
 /// naming a program is listed but never followed.

crates/engine/src/lib.rs

@@ -117,7 +117,7 @@ pub use pdfcraft_fonts::{MAX_SIGNATURE_CHARS, ScriptOutline, script_missing, scr
 
 /// Comment geometry helpers (text-box line breaking) for frontends.
 pub use pdfcraft_annot::appearance as annot_text;
-pub use pdfcraft_annot::links::{Highlight as LinkHighlight, LinkAction, LinkItem, LinkStyle};
+pub use pdfcraft_annot::links::{Highlight as LinkHighlight, LinkAction, LinkItem, LinkStyle, LinkZoom};
 pub use pdfcraft_annot::{
     Activation3d, AppearanceCache, AttachIcon, BorderShape, FillMark, LineEnding, Markup, NOTE_SIZE, NewAnnotation, NoteIcon, OverlayFont,
     OverlayLook, Props as CommentProps, ReviewState, Rgb, Shape, StampGroup, StampKind, Style, rect_quad,

crates/engine/src/tests.rs

@@ -4887,6 +4887,25 @@ fn split_by_size_and_bookmarks_and_page_filters() {
     assert_eq!(filter_pages(info, &all, PageParity::Odd, PageOrientation::Portrait), [0, 2, 4]);
 }
 
+/// A zoomed link follows its target page, not its number: deleting a page before the target keeps
+/// the link on that page at its zoom. Deleting the target page drops the link's destination, as
+/// for any link to a deleted page, and undo brings it back with its zoom.
+#[test]
+fn a_zoomed_link_follows_its_page_and_loses_it_when_the_page_is_deleted() {
+    let (mut s, id) = session_with(3);
+    let zoom = LinkZoom::Percent(200.0);
+    let rect = [10.0, 10.0, 60.0, 30.0];
+    s.apply(id, Edit::AddLink { page: 0, rect, action: LinkAction::Page { page: 2, zoom }, style: LinkStyle::default() }).unwrap();
+    let action = |s: &Session| s.get(id).unwrap().links()[0].action.clone();
+    s.apply(id, Edit::DeletePages { pages: vec![1] }).unwrap();
+    assert_eq!(action(&s), LinkAction::Page { page: 1, zoom }, "the link follows its page");
+    s.apply(id, Edit::DeletePages { pages: vec![1] }).unwrap();
+    // The destination is removed, not left pointing at a page that is gone.
+    assert_eq!(action(&s), LinkAction::Other("no action".into()), "no destination left");
+    s.undo(id).unwrap();
+    assert_eq!(action(&s), LinkAction::Page { page: 1, zoom }, "undo restores the destination and its zoom");
+}
+
 #[test]
 fn links_from_urls_and_link_edits() {
     // One page whose text contains a web address.
@@ -4928,8 +4947,12 @@ fn links_from_urls_and_link_edits() {
     assert_eq!(s.get(id).unwrap().links().len(), 1);
     // Link Properties and delete.
     let l = s.get(id).unwrap().links()[0].clone();
-    s.apply(id, Edit::SetLink { page: 0, index: l.index, rect: None, action: Some(LinkAction::Page(0)), style: None }).unwrap();
-    assert_eq!(s.get(id).unwrap().links()[0].action, LinkAction::Page(0));
+    s.apply(
+        id,
+        Edit::SetLink { page: 0, index: l.index, rect: None, action: Some(LinkAction::Page { page: 0, zoom: LinkZoom::FitPage }), style: None },
+    )
+    .unwrap();
+    assert_eq!(s.get(id).unwrap().links()[0].action, LinkAction::Page { page: 0, zoom: LinkZoom::FitPage });
     s.apply(id, Edit::DeleteLink { page: 0, index: l.index }).unwrap();
     assert!(s.get(id).unwrap().links().is_empty());
     assert!(s.apply(id, Edit::RemoveLinks { pages: None }).is_err(), "nothing left to remove");

crates/ui-egui/src/tools/link_ui.rs

@@ -3,7 +3,7 @@
 //! their outlines, a click selects one, a double-click edits it and Delete removes it.
 
 use egui::{Color32, CornerRadius, Pos2, Rect, Stroke};
-use pdfcraft_engine::{Edit, LinkAction, LinkHighlight, LinkItem, LinkStyle};
+use pdfcraft_engine::{Edit, LinkAction, LinkHighlight, LinkItem, LinkStyle, LinkZoom};
 use pdfcraft_render::{DocInfo, LinkTarget};
 
 use crate::canvas::{DocView, PageToolContext, PageXform};
@@ -46,9 +46,52 @@ pub struct LinkDraft {
     pub url: String,
     /// 1-based target page.
     pub target: usize,
+    /// How the target page is shown.
+    pub zoom: LinkZoom,
+    /// The link's action when the dialog opened (`None` for a new link). OK rewrites the action
+    /// only when it changed, so an appearance edit keeps a destination's position and kind
+    /// (`/XYZ left top`, `/FitR`…) that the dialog doesn't show.
+    pub current: Option<LinkAction>,
     pub style: LinkStyle,
 }
 
+/// The zooms Link Properties offers for a page view.
+const ZOOMS: [LinkZoom; 12] = [
+    LinkZoom::FitPage,
+    LinkZoom::FitWidth,
+    LinkZoom::FitHeight,
+    LinkZoom::FitVisible,
+    LinkZoom::Percent(100.0),
+    LinkZoom::Inherit,
+    LinkZoom::Percent(50.0),
+    LinkZoom::Percent(75.0),
+    LinkZoom::Percent(125.0),
+    LinkZoom::Percent(150.0),
+    LinkZoom::Percent(200.0),
+    LinkZoom::Percent(400.0),
+];
+
+fn zoom_label(zoom: LinkZoom) -> String {
+    match zoom {
+        LinkZoom::FitPage => tl!("Fit Page").to_string(),
+        LinkZoom::FitWidth => tl!("Fit Width").to_string(),
+        LinkZoom::FitHeight => tl!("Fit Height").to_string(),
+        LinkZoom::FitVisible => tl!("Fit Visible").to_string(),
+        LinkZoom::Inherit => tl!("Inherit Zoom").to_string(),
+        LinkZoom::Percent(p) if (p - 100.0).abs() < 1e-9 => tl!("Actual Size").to_string(),
+        // Another writer's factor can be anything up to f64::MAX, or a tiny fraction: exponent
+        // form keeps it short.
+        LinkZoom::Percent(p) if !(0.01..1e6).contains(&p) => format!("{p:.1e}%"),
+        // A fractional one (another writer's 0.5% or 62.5%) shows up to two places, so it agrees
+        // with what link_list reports instead of rounding to 0%.
+        LinkZoom::Percent(p) if p.fract() != 0.0 => {
+            let places = format!("{p:.2}");
+            format!("{}%", places.trim_end_matches('0').trim_end_matches('.'))
+        }
+        LinkZoom::Percent(p) => format!("{p:.0}%"),
+    }
+}
+
 fn screen_rect(xf: &PageXform, info: &DocInfo, page: usize, r: [f64; 4]) -> Rect {
     xf.user_rect(info, page, [r[0] as f32, r[1] as f32, r[2] as f32, r[3] as f32])
 }
@@ -202,9 +245,14 @@ impl PdfCraftApp {
                     _ => "https://".into(),
                 },
                 target: match l.action {
-                    LinkAction::Page(p) => p + 1,
+                    LinkAction::Page { page, .. } => page + 1,
                     _ => 1,
                 },
+                zoom: match l.action {
+                    LinkAction::Page { zoom, .. } => zoom,
+                    _ => LinkZoom::FitPage,
+                },
+                current: Some(l.action.clone()),
                 style: l.style,
             },
             None => LinkDraft {
@@ -215,6 +263,8 @@ impl PdfCraftApp {
                 web: true,
                 url: "https://".into(),
                 target: 1,
+                zoom: LinkZoom::FitPage,
+                current: None,
                 style: LinkStyle::default(),
             },
         };
@@ -339,6 +389,19 @@ pub(crate) fn body(ui: &mut egui::Ui, d: &mut LinkDraft, pages: usize, t: &Token
                 ui.add(egui::DragValue::new(&mut d.target).range(1..=pages.max(1)));
                 ui.label(crate::i18n::fmt(tl!("of {name}"), &[("name", &pages.to_string())]));
             });
+            ui.horizontal(|ui| {
+                ui.add_space(24.0);
+                let label = ui.label(tl!("Zoom"));
+                craft_ui::ComboBox::from_id_salt("link-zoom")
+                    .selected_text(zoom_label(d.zoom))
+                    .show_ui(ui, |ui| {
+                        for z in ZOOMS {
+                            ui.selectable_value(&mut d.zoom, z, zoom_label(z));
+                        }
+                    })
+                    .response
+                    .labelled_by(label.id);
+            });
         });
     }
     let ok = d.preserve_action || !d.web || (d.url.trim().len() > 3 && d.url.trim() != "https://");
@@ -358,21 +421,20 @@ pub(crate) fn body(ui: &mut egui::Ui, d: &mut LinkDraft, pages: usize, t: &Token
     (a, c)
 }
 
+/// The action a confirmed draft sets.
+fn action_for(d: &LinkDraft) -> LinkAction {
+    if d.web { LinkAction::Uri(d.url.trim().to_string()) } else { LinkAction::Page { page: d.target.saturating_sub(1), zoom: d.zoom } }
+}
+
 /// The edit for a confirmed draft.
 pub(crate) fn edit_for(d: &LinkDraft) -> Edit {
     match d.index {
-        None => Edit::AddLink {
-            page: d.page,
-            rect: d.rect,
-            action: if d.web { LinkAction::Uri(d.url.trim().to_string()) } else { LinkAction::Page(d.target.saturating_sub(1)) },
-            style: d.style,
-        },
+        None => Edit::AddLink { page: d.page, rect: d.rect, action: action_for(d), style: d.style },
         Some(index) => Edit::SetLink {
             page: d.page,
             index,
             rect: None,
-            action: (!d.preserve_action)
-                .then(|| if d.web { LinkAction::Uri(d.url.trim().to_string()) } else { LinkAction::Page(d.target.saturating_sub(1)) }),
+            action: (!d.preserve_action).then(|| action_for(d)).filter(|a| d.current.as_ref() != Some(a)),
             style: Some(d.style),
         },
     }
@@ -380,13 +442,54 @@ pub(crate) fn edit_for(d: &LinkDraft) -> Edit {
 
 #[cfg(test)]
 mod tests {
-    use super::{LinkDraft, edit_for};
-    use pdfcraft_engine::{Edit, LinkStyle};
+    use super::{LinkDraft, edit_for, zoom_label};
+    use pdfcraft_engine::{Edit, LinkAction, LinkStyle, LinkZoom};
+
+    fn draft(current: LinkAction) -> LinkDraft {
+        LinkDraft {
+            page: 0,
+            rect: [0.0; 4],
+            index: Some(3),
+            preserve_action: matches!(current, LinkAction::Other(_)),
+            web: false,
+            url: String::new(),
+            target: 1,
+            zoom: LinkZoom::FitPage,
+            current: Some(current),
+            style: LinkStyle::default(),
+        }
+    }
 
     #[test]
     fn appearance_edit_preserves_an_existing_unsupported_action() {
         let style = LinkStyle::default();
-        let draft = LinkDraft { page: 0, rect: [0.0; 4], index: Some(3), preserve_action: true, web: false, url: String::new(), target: 1, style };
+        let draft = draft(LinkAction::Other("named destination".into()));
         assert_eq!(edit_for(&draft), Edit::SetLink { page: 0, index: 3, rect: None, action: None, style: Some(style) });
     }
+
+    #[test]
+    fn only_a_changed_destination_is_rewritten() {
+        // A page view the dialog shows as it is: OK leaves the destination (and its position) alone.
+        let mut d = draft(LinkAction::Page { page: 0, zoom: LinkZoom::Percent(200.0) });
+        d.zoom = LinkZoom::Percent(200.0);
+        assert!(matches!(edit_for(&d), Edit::SetLink { action: None, .. }));
+        d.zoom = LinkZoom::FitWidth;
+        assert!(matches!(edit_for(&d), Edit::SetLink { action: Some(LinkAction::Page { page: 0, zoom: LinkZoom::FitWidth }), .. }));
+        d.zoom = LinkZoom::Percent(200.0);
+        d.target = 2;
+        assert!(matches!(edit_for(&d), Edit::SetLink { action: Some(LinkAction::Page { page: 1, .. }), .. }));
+    }
+
+    #[test]
+    fn a_zoom_label_stays_short_for_any_factor() {
+        assert_eq!(zoom_label(LinkZoom::Percent(200.0)), "200%");
+        // The destination's own zoom, past what PdfCraft writes, is shown as it is.
+        assert_eq!(zoom_label(LinkZoom::Percent(10000.0)), "10000%");
+        assert_eq!(zoom_label(LinkZoom::Percent(f64::MAX)), "1.8e308%");
+        // A fractional zoom keeps its places instead of rounding to 0%.
+        assert_eq!(zoom_label(LinkZoom::Percent(0.5)), "0.5%");
+        assert_eq!(zoom_label(LinkZoom::Percent(62.5)), "62.5%");
+        assert_eq!(zoom_label(LinkZoom::Percent(33.333)), "33.33%");
+        assert_eq!(zoom_label(LinkZoom::Percent(0.001)), "1.0e-3%");
+    }
 }

crates/ui-egui/tests/it/fill_sign.rs

@@ -1055,7 +1055,7 @@ fn image_signature_preview_follows_pointer_at_page_size_with_zoom_and_rotation()
     h.state_mut().apply_edit(pdfcraft_engine::Edit::AddLink {
         page: 0,
         rect: [30.0, 230.0, 60.0, 270.0],
-        action: pdfcraft_engine::LinkAction::Page(0),
+        action: pdfcraft_engine::LinkAction::Page { page: 0, zoom: pdfcraft_engine::LinkZoom::FitPage },
         style: pdfcraft_engine::LinkStyle::default(),
     });
     h.state_mut().signature = Some(SavedSig::Image(image));

crates/ui-egui/tests/it/pdf_links.rs

@@ -77,13 +77,72 @@ fn drawing_editing_and_deleting_links() {
     }
     h.get_by_label("OK").click();
     h.run_steps(3);
-    assert_eq!(links(&h)[0].action, LinkAction::Page(0));
+    assert_eq!(links(&h)[0].action, LinkAction::Page { page: 0, zoom: pdfcraft_engine::LinkZoom::FitPage });
     // Delete the selected link.
     h.key_press(egui::Key::Delete);
     h.run_steps(3);
     assert!(links(&h).is_empty());
 }
 
+#[test]
+fn link_properties_sets_the_page_view_zoom() {
+    use egui::accesskit::Role;
+    use pdfcraft_engine::LinkZoom;
+    let mut h = harness();
+    assert!(h.state_mut().execute("edit.link"));
+    let (a, b) = (at(&h, 40.0, 300.0), at(&h, 160.0, 320.0));
+    drag(&mut h, a, b);
+    h.get_by_label("Create Link");
+    h.get_by_label("Go to a page view").click();
+    h.run_steps(3);
+    // The toolbar has a zoom box of its own; the link's shows Fit Page until changed.
+    h.get_by(|n| n.role() == Role::ComboBox && n.value().as_deref() == Some("Fit Page")).click();
+    h.run_steps(3);
+    h.get_by_role_and_label(Role::Button, "200%").scroll_to_me();
+    h.run_steps(3);
+    h.get_by_role_and_label(Role::Button, "200%").click();
+    h.run_steps(2);
+    h.get_by_label("OK").click();
+    h.run_steps(3);
+    assert_eq!(links(&h)[0].action, LinkAction::Page { page: 0, zoom: LinkZoom::Percent(200.0) });
+}
+
+/// One page with a link whose destination has a position, which Link Properties doesn't show.
+const POSITIONED: &[u8] = b"%PDF-1.7
+1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj
+2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj
+3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 300 400] /Annots [4 0 R] >> endobj
+4 0 obj << /Type /Annot /Subtype /Link /Rect [40 40 160 60] /Border [0 0 0] /Dest [3 0 R /XYZ 100 300 2] >> endobj
+trailer << /Root 1 0 R >>
+%%EOF";
+
+#[test]
+fn an_appearance_edit_keeps_the_destination_as_written() {
+    use pdfcraft_render::{DestView, LinkTarget};
+    let mut h = Harness::builder().with_size(egui::vec2(1400.0, 900.0)).build_eframe(|_cc| {
+        let mut app = PdfCraftApp::new();
+        app.set_option("language", "en").unwrap();
+        app.open_bytes("positioned.pdf", None, POSITIONED.to_vec()).unwrap();
+        app
+    });
+    h.run_steps(6);
+    let positioned = LinkTarget::Page(0, DestView::Xyz { left: Some(100.0), top: Some(300.0), zoom: Some(2.0) });
+    let target = |h: &Harness<'static, PdfCraftApp>| {
+        let s = h.state();
+        s.session.get(s.views[0].id).unwrap().info.links[0].target.clone()
+    };
+    assert_eq!(target(&h), positioned);
+    h.state_mut().views[0].links.open_existing = Some((0, 0));
+    h.run_steps(3);
+    assert_eq!(h.state().dialog, Some(Dialog::LinkProps));
+    h.state_mut().link_draft.as_mut().unwrap().style.color = [1.0, 0.0, 0.0];
+    h.run_steps(3);
+    h.get_by_label("OK").click();
+    h.run_steps(3);
+    assert_eq!(links(&h)[0].style.color, [1.0, 0.0, 0.0], "the edit applied");
+    assert_eq!(target(&h), positioned, "the destination is not rewritten without its position");
+}
+
 #[test]
 fn removing_all_links_and_undo() {
     let mut h = harness();

parity/acrobat-features.toml

@@ -2333,9 +2333,9 @@ tier = "P1"
 milestone = "M7"
 status = "partial"
 commands = ["edit.link"]
-tools = ["link_add"]
-evidence = ["crates/annot/src/tests.rs::links_are_added_edited_listed_and_removed", "crates/ui-egui/tests/it/pdf_links.rs::drawing_editing_and_deleting_links"]
-notes = "go to a page (Fit view); named destinations and zoom pending"
+tools = ["link_add", "link_edit", "link_list"]
+evidence = ["crates/annot/src/tests.rs::links_are_added_edited_listed_and_removed", "crates/ui-egui/tests/it/pdf_links.rs::drawing_editing_and_deleting_links", "crates/annot/src/tests.rs::page_links_keep_their_zoom", "crates/automation/tests/it/automation.rs::link_zoom_through_tools", "crates/ui-egui/tests/it/pdf_links.rs::link_properties_sets_the_page_view_zoom", "crates/ui-egui/tests/it/pdf_links.rs::an_appearance_edit_keeps_the_destination_as_written", "crates/annot/src/tests.rs::a_rewritten_link_keeps_its_own_zoom_factor", "crates/annot/src/tests.rs::an_unchanged_go_to_keeps_its_destination_and_a_new_page_keeps_its_fit", "crates/automation/tests/it/automation.rs::link_edit_keeps_a_links_own_zoom_outside_the_range_it_writes"]
+notes = "go to a page at a zoom: Fit Page, Fit Width, Fit Height, Fit Visible, Actual Size, Inherit Zoom or a percentage (Link Properties ▸ Zoom; link_add and link_edit zoom), written as /Fit, /FitH, /FitV, /FitB or /XYZ with the position null (ISO 32000-2 Table 149). Links other tools wrote read as the nearest zoom. One given a new page with its zoom unchanged keeps how that zoom is written (a /FitBH or /FitBV fit, its own /XYZ factor even outside the 1–6400% a chosen zoom is written within) but not its position; one edited with its own page and zoom (Link Properties, link_edit) is left as it is, position included. Missing: named destinations as targets, and a position on the page (Acrobat's Set Link takes the current view)"
 
 [[feature]]
 id = "edit.action-uri"