Fix #414: select, move and delete ruler guides with the selection tools

Guides dragged out of the rulers could not be touched again: no tool hit-tested
them, so a click on a guide went to the art under it.

- The Selection, Direct Selection and Group Selection tools pick a ruler guide
  within the selection tolerance (over the art; Direct Selection takes an
  anchor on it first) through a shared tools::rulerguide::GuideEdit. A drag
  moves the selected guides in one undo step (Alt copies them, Shift snaps the
  dragged one to the ruler's ticks, otherwise it snaps to pixels, the grid or,
  with Smart Guides, the art's edges, centres and anchors); dropped off the
  canvas onto its ruler, the guide is deleted. Hidden or locked guides can't be
  picked; the pointer shows which way a guide moves.
- Selection::guides holds the selected guides (on their own, like slices); the
  canvas draws them in the selection colour. Delete/Backspace (edit.clear)
  delete them, the arrow keys (object.nudge) nudge them, Lock Guides and Hide
  Guides deselect them.
- Commands for agents: guide.list, guide.select {indexes, toggle?},
  guide.move {dx?, dy?, copy?} (besides {index, pos}) and guide.remove {index?};
  guide positions out of range are refused. Documented in docs/mcp.md.
- Shift while dragging a new guide out of a ruler snaps it to the ticks too
  (Unit::ruler_step, shared with the rulers' drawing).

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

crates/engine/src/cmd/docmenu.rs

@@ -155,8 +155,34 @@ pub fn specs() -> Vec<CommandSpec> {
             clear_guides
         ),
         cmd!("guide.add", "Add Guide", [], None, "{vertical: bool, pos: pt (x for vertical, y for horizontal)} → {index}", has_doc, guide_add),
-        cmd!("guide.remove", "Remove Guide", [], None, "{index}", guides_unlocked, guide_remove),
-        cmd!("guide.move", "Move Guide", [], None, "{index, pos: pt}", guides_unlocked, guide_move),
+        cmd!(query "guide.list", "Guides", [], None, "{} → [{index, vertical, pos, selected}…] the ruler guides", has_doc, guide_list),
+        cmd!(
+            "guide.select",
+            "Select Guides",
+            [],
+            None,
+            "{indexes: [index…], toggle?: bool} select ruler guides on their own (deselecting the art); toggle adds or removes them instead → {selected: [index…]}",
+            guides_unlocked,
+            guide_select
+        ),
+        cmd!(
+            "guide.remove",
+            "Remove Guide",
+            [],
+            None,
+            "{index?} delete ruler guide `index`, else the selected ones (as Delete / edit.clear does) → {count}",
+            guides_unlocked,
+            guide_remove
+        ),
+        cmd!(
+            "guide.move",
+            "Move Guide",
+            [],
+            None,
+            "{index, pos: pt} put ruler guide `index` at `pos` | {dx?, dy?: pt, copy?: bool} move the selected guides (vertical ones by dx, horizontal ones by dy); copy leaves them and selects the moved copies",
+            guides_unlocked,
+            guide_move
+        ),
         cmd!("file.closeAll", "Close All", ["File"], Some("Cmd+Alt+W"), "{} → {closed}", has_doc, close_all),
         cmd!(
             "file.documentColorMode",
@@ -428,6 +454,10 @@ fn release_guides(s: &mut Session, _: &Value) -> Result<Value> {
 fn lock_guides(s: &mut Session, p: &Value) -> Result<Value> {
     let v = p.get("locked").and_then(Value::as_bool).unwrap_or(!s.menu.guides_locked);
     s.menu.guides_locked = v;
+    // Locked guides can't stay selected.
+    if v && !s.doc()?.selection.guides.is_empty() {
+        s.select(|_, sel| sel.guides.clear())?;
+    }
     Ok(json!({ "locked": v }))
 }
 
@@ -458,28 +488,95 @@ fn guide_add(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(json!({ "index": i }))
 }
 
-fn guide_index(s: &Session, p: &Value, cmd: &str) -> Result<usize> {
-    let i = p.get("index").and_then(Value::as_u64).ok_or_else(|| bad(cmd, "missing index"))? as usize;
+fn guide_list(s: &mut Session, _: &Value) -> Result<Value> {
+    let st = s.doc()?;
+    let row = |(i, g): (usize, &Guide)| json!({ "index": i, "vertical": g.vertical, "pos": g.pos, "selected": st.selection.guides.contains(&i) });
+    Ok(Value::Array(st.doc.guides.iter().enumerate().map(row).collect()))
+}
+
+/// Ruler guide `index` of the active document (`index` validated).
+fn guide_index(s: &Session, v: Option<&Value>, cmd: &str) -> Result<usize> {
+    let i = v.and_then(Value::as_u64).and_then(|i| usize::try_from(i).ok()).ok_or_else(|| bad(cmd, "an index must be a whole number"))?;
     if i >= s.doc()?.doc.guides.len() {
-        return Err(bad(cmd, "no such guide"));
+        return Err(bad(cmd, format!("no guide {i}")));
     }
     Ok(i)
 }
 
-fn guide_remove(s: &mut Session, p: &Value) -> Result<Value> {
-    let i = guide_index(s, p, "guide.remove")?;
-    s.edit("Delete Guide", |d, _| {
-        d.guides.remove(i);
-        Ok(())
-    })?;
-    ok()
+fn guide_select(s: &mut Session, p: &Value) -> Result<Value> {
+    let list = p.get("indexes").and_then(Value::as_array).ok_or_else(|| bad("guide.select", "missing indexes"))?;
+    let picked = list.iter().map(|v| guide_index(s, Some(v), "guide.select")).collect::<Result<Vec<_>>>()?;
+    if bool_or(p, "toggle", false) {
+        let mut now = s.doc()?.selection.guides.clone();
+        for i in picked {
+            if let Some(k) = now.iter().position(|g| *g == i) {
+                now.remove(k);
+            } else {
+                now.push(i);
+            }
+        }
+        s.select(|_, sel| sel.set_guides(now))?;
+    } else {
+        s.select(|_, sel| sel.set_guides(picked))?;
+    }
+    Ok(json!({ "selected": s.doc()?.selection.guides }))
 }
 
-fn guide_move(s: &mut Session, p: &Value) -> Result<Value> {
-    let i = guide_index(s, p, "guide.move")?;
-    let pos = f64_req(p, "pos", "guide.move")?;
-    s.edit("Move Guide", |d, _| {
-        d.guides[i].pos = pos;
+/// Delete ruler guide `index`, else the selected guides, in one undo step → {count}.
+pub(crate) fn guide_remove(s: &mut Session, p: &Value) -> Result<Value> {
+    let gone: Vec<usize> = match p.get("index") {
+        Some(v) => vec![guide_index(s, Some(v), "guide.remove")?],
+        None => s.doc()?.selection.guides.clone(),
+    };
+    if gone.is_empty() {
+        return Err(bad("guide.remove", "no guide selected"));
+    }
+    let label = if gone.len() == 1 { "Delete Guide" } else { "Delete Guides" };
+    s.edit(label, |d, sel| {
+        let kept = |i: &usize| !gone.contains(i);
+        // The guides left selected keep their place among the rest.
+        let left: Vec<usize> = sel.guides.iter().filter(|i| kept(i)).map(|i| i - gone.iter().filter(|g| *g < i).count()).collect();
+        d.guides = std::mem::take(&mut d.guides).into_iter().enumerate().filter(|(i, _)| kept(i)).map(|(_, g)| g).collect();
+        sel.set_guides(left);
+        Ok(())
+    })?;
+    Ok(json!({ "count": gone.len() }))
+}
+
+/// Put ruler guide `index` at `pos`, else move (or copy) the selected guides, in one undo step.
+pub(crate) fn guide_move(s: &mut Session, p: &Value) -> Result<Value> {
+    if let Some(v) = p.get("index") {
+        let i = guide_index(s, Some(v), "guide.move")?;
+        let pos = f64_req(p, "pos", "guide.move")?;
+        s.edit("Move Guide", |d, _| {
+            if let Some(g) = d.guides.get_mut(i) {
+                g.pos = pos;
+            }
+            Ok(())
+        })?;
+        return ok();
+    }
+    let moving = s.doc()?.selection.guides.clone();
+    if moving.is_empty() {
+        return Err(bad("guide.move", "no guide selected (or give an index)"));
+    }
+    let (dx, dy, copy) = (f64_or(p, "dx", 0.0), f64_or(p, "dy", 0.0), bool_or(p, "copy", false));
+    s.edit(if copy { "Copy Guide" } else { "Move Guide" }, |d, sel| {
+        let mut copies = vec![];
+        for &i in &moving {
+            let Some(g) = d.guides.get_mut(i) else { continue };
+            let moved = Guide { vertical: g.vertical, pos: g.pos + if g.vertical { dx } else { dy } };
+            if copy {
+                copies.push(moved);
+            } else {
+                *g = moved;
+            }
+        }
+        if copy {
+            let first = d.guides.len();
+            d.guides.extend(copies);
+            sel.set_guides(first..d.guides.len());
+        }
         Ok(())
     })?;
     ok()

crates/engine/src/cmd/edit.rs

@@ -85,7 +85,15 @@ pub fn specs() -> Vec<CommandSpec> {
             has_clipboard,
             |s, p| paste(s, p, PasteMode::AllArtboards)
         ),
-        cmd!("edit.clear", "Clear", ["Edit"], Some("Delete"), "{ids?}", has_selection, clear),
+        cmd!(
+            "edit.clear",
+            "Clear",
+            ["Edit"],
+            Some("Delete"),
+            "{ids?} delete the objects `ids`, else the selection (direct-selected anchors, else objects, else ruler guides)",
+            has_selection_or_guides,
+            clear
+        ),
         cmd!("edit.duplicate", "Duplicate", [], None, "{dx?, dy?} duplicate the selection in place (offset optional)", has_selection, duplicate),
     ]
 }
@@ -224,6 +232,10 @@ fn clear(s: &mut Session, p: &Value) -> Result<Value> {
     if ids_param(p, "ids").is_none() && !s.doc()?.selection.anchors.is_empty() {
         return super::path::delete_anchors(s, p);
     }
+    // Selected ruler guides (selected on their own).
+    if ids_param(p, "ids").is_none() && s.doc()?.selection.is_empty() {
+        return super::docmenu::guide_remove(s, &json!({}));
+    }
     let ids = match ids_param(p, "ids") {
         Some(v) => v,
         None => selected_roots(s)?,

crates/engine/src/cmd/mod.rs

@@ -144,6 +144,11 @@ pub fn has_selection(s: &Session) -> std::result::Result<(), String> {
     let st = s.active().ok_or("no document open")?;
     if st.selection.is_empty() { Err("nothing selected".into()) } else { Ok(()) }
 }
+/// Objects or ruler guides are selected (what Delete and the arrow keys act on).
+pub fn has_selection_or_guides(s: &Session) -> std::result::Result<(), String> {
+    let st = s.active().ok_or("no document open")?;
+    if st.selection.has_objects_or_guides() { Ok(()) } else { Err("nothing selected".into()) }
+}
 pub fn has_anchors(s: &Session) -> std::result::Result<(), String> {
     let st = s.active().ok_or("no document open")?;
     if st.selection.anchors.values().all(|a| a.is_empty()) { Err("no anchor points selected".into()) } else { Ok(()) }

crates/engine/src/cmd/object.rs

@@ -68,8 +68,8 @@ pub fn specs() -> Vec<CommandSpec> {
             "Nudge",
             [],
             None,
-            "{dx: -1|0|1, dy: -1|0|1, big?: bool (×10), copy?: bool} arrow-key nudge by the keyboard increment",
-            has_selection,
+            "{dx: -1|0|1, dy: -1|0|1, big?: bool (×10), copy?: bool} arrow-key nudge by the keyboard increment (the selected anchors, else objects, else ruler guides)",
+            has_selection_or_guides,
             nudge
         ),
         cmd!("object.arrange.bringToFront", "Bring to Front", ["Object", "Arrange"], Some("Cmd+Shift+]"), "{}", has_selection, |s, _| arrange(
@@ -268,6 +268,9 @@ fn nudge(s: &mut Session, p: &Value) -> Result<Value> {
     if !s.doc()?.selection.anchors.is_empty() {
         return super::path::move_anchors(s, &json!({ "dx": dx, "dy": dy }));
     }
+    if s.doc()?.selection.is_empty() {
+        return super::docmenu::guide_move(s, &json!({ "dx": dx, "dy": dy, "copy": bool_or(p, "copy", false) }));
+    }
     let ids = selected_roots(s)?;
     apply_transform(s, "Move", ids, Affine::translate((dx, dy)), p)
 }