Merge PR #559 from NikitkaRa: View: movable drawing guides saved with the presentation

# Conflicts:
#	crates/engine/src/tools.rs
#	crates/model/src/defaults.rs
#	crates/model/src/lib.rs
#	crates/ui-egui/src/canvas.rs
#	crates/ui-egui/src/lib.rs

crates/engine/src/cmd/arrange.rs

@@ -9,6 +9,18 @@ use crate::{Result, Session};
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
+        cmd!(
+            "guide.add",
+            "Add Guide",
+            ["View", "Show", "Guides"],
+            None,
+            "{vertical: bool, pos?: pt (default: the slide's centre)} → {index}. `defaults: true` adds the two centre guides when there are none",
+            has_doc,
+            guide_add
+        ),
+        cmd!("guide.move", "Move Guide", [], None, "{index, pos: pt}", has_doc, guide_move),
+        cmd!("guide.delete", "Delete Guide", [], None, "{index}", has_doc, guide_delete),
+        cmd!(query "guide.list", "Guides", [], None, "{} → [{vertical, pos}]", has_doc, guide_list),
         cmd!("arrange.bringToFront", "Bring to Front", ["Arrange"], Some("Cmd+Shift+]"), "{ids?}", has_selection, |s, p| order(s, p, 2)),
         cmd!("arrange.bringForward", "Bring Forward", ["Arrange"], Some("Cmd+]"), "{ids?}", has_selection, |s, p| order(s, p, 1)),
         cmd!("arrange.sendBackward", "Send Backward", ["Arrange"], Some("Cmd+["), "{ids?}", has_selection, |s, p| order(s, p, -1)),
@@ -338,3 +350,76 @@ fn distribute(s: &mut Session, p: &Value) -> Result<Value> {
         Ok(())
     })
 }
+
+/// Guides are kept on the slide; a file can hold at most this many.
+const MAX_GUIDES: usize = 200;
+
+fn guide_limit(s: &Session, vertical: bool) -> Result<f64> {
+    let size = s.doc()?.doc.slide_size;
+    Ok(if vertical { size.width } else { size.height })
+}
+
+fn guide_add(s: &mut Session, p: &Value) -> Result<Value> {
+    if bool_or(p, "defaults", false) {
+        if !s.doc()?.doc.guides.is_empty() {
+            return Ok(json!({"added": 0}));
+        }
+        let size = s.doc()?.doc.slide_size;
+        return s.edit(|doc, _| {
+            doc.guides = vec![
+                deckcraft_model::DrawGuide { vertical: true, pos: size.width / 2.0 },
+                deckcraft_model::DrawGuide { vertical: false, pos: size.height / 2.0 },
+            ];
+            Ok(json!({"added": 2}))
+        });
+    }
+    let vertical = bool_or(p, "vertical", true);
+    let limit = guide_limit(s, vertical)?;
+    let pos = p.get("pos").and_then(Value::as_f64).filter(|v| v.is_finite()).unwrap_or(limit / 2.0).clamp(0.0, limit);
+    if s.doc()?.doc.guides.len() >= MAX_GUIDES {
+        return Err(bad("guide.add", "too many guides"));
+    }
+    s.edit(|doc, _| {
+        doc.guides.push(deckcraft_model::DrawGuide { vertical, pos });
+        Ok(json!({"index": doc.guides.len() - 1}))
+    })
+}
+
+fn guide_index(s: &Session, p: &Value, cmd: &str) -> Result<usize> {
+    let i = usize_param(p, "index").ok_or_else(|| bad(cmd, "missing `index`"))?;
+    if i >= s.doc()?.doc.guides.len() {
+        return Err(bad(cmd, "no such guide"));
+    }
+    Ok(i)
+}
+
+fn guide_move(s: &mut Session, p: &Value) -> Result<Value> {
+    let i = guide_index(s, p, "guide.move")?;
+    let vertical = s.doc()?.doc.guides.get(i).is_some_and(|g| g.vertical);
+    let limit = guide_limit(s, vertical)?;
+    let pos = p.get("pos").and_then(Value::as_f64).filter(|v| v.is_finite()).ok_or_else(|| bad("guide.move", "missing `pos`"))?.clamp(0.0, limit);
+    s.edit(|doc, _| {
+        if let Some(g) = doc.guides.get_mut(i) {
+            g.pos = pos;
+        }
+        Ok(json!({"index": i, "pos": pos}))
+    })
+}
+
+fn guide_delete(s: &mut Session, p: &Value) -> Result<Value> {
+    let i = guide_index(s, p, "guide.delete")?;
+    s.edit(|doc, _| {
+        if i < doc.guides.len() {
+            doc.guides.remove(i);
+        }
+        ok()
+    })
+}
+
+fn guide_list(s: &mut Session, _p: &Value) -> Result<Value> {
+    Ok(serde_json::to_value(&s.doc()?.doc.guides).unwrap_or_default())
+}
+
+#[cfg(test)]
+#[path = "guides_tests.rs"]
+mod guides_tests;

crates/engine/src/cmd/guides_tests.rs

@@ -0,0 +1,76 @@
+//! Drawing guides: commands, dragging a guide with the pointer, snapping shapes to guides, and
+//! the PPTX round trip.
+
+use serde_json::json;
+
+use crate::Session;
+use crate::tools::{Mods, PointerEvent, PointerKind};
+
+fn ev(s: &mut Session, kind: PointerKind, x: f64, y: f64) {
+    s.pointer(PointerEvent { kind, x, y, mods: Mods::default(), tol: 4.0 }).unwrap();
+}
+
+#[test]
+fn add_move_delete_and_undo() {
+    let mut s = Session::with_new();
+    assert_eq!(s.execute("guide.add", &json!({"defaults": true})).unwrap()["added"], 2);
+    assert_eq!(s.execute("guide.add", &json!({"defaults": true})).unwrap()["added"], 0, "only when there are none");
+    let i = s.execute("guide.add", &json!({"vertical": false, "pos": 100})).unwrap()["index"].as_u64().unwrap();
+    assert_eq!(i, 2);
+    s.execute("guide.move", &json!({"index": 2, "pos": 5000})).unwrap();
+    assert_eq!(s.doc().unwrap().doc.guides[2].pos, 540.0, "kept on the slide");
+    assert!(s.execute("guide.move", &json!({"index": 9, "pos": 1})).is_err());
+    assert!(s.execute("guide.move", &json!({"index": 0, "pos": null})).is_err());
+    s.execute("guide.delete", &json!({"index": 0})).unwrap();
+    assert_eq!(s.execute("guide.list", &json!({})).unwrap().as_array().unwrap().len(), 2);
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(s.doc().unwrap().doc.guides.len(), 3);
+}
+
+#[test]
+fn drag_a_guide_drop_it_off_the_slide_and_snap_shapes_to_it() {
+    let mut s = Session::with_new();
+    s.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    s.execute("guide.add", &json!({"vertical": true, "pos": 300})).unwrap();
+    // Hidden guides can't be grabbed: the press starts a marquee instead.
+    ev(&mut s, PointerKind::Down, 300.0, 50.0);
+    ev(&mut s, PointerKind::Up, 300.0, 50.0);
+    assert_eq!(s.doc().unwrap().doc.guides[0].pos, 300.0);
+    s.tool.guides_visible = true;
+    ev(&mut s, PointerKind::Down, 301.0, 50.0);
+    ev(&mut s, PointerKind::Drag, 350.4, 60.0);
+    assert_eq!(s.tool.guide_drag, Some((0, 350.0)), "whole points while dragging");
+    ev(&mut s, PointerKind::Up, 350.4, 60.0);
+    assert_eq!(s.doc().unwrap().doc.guides[0].pos, 350.0);
+    assert_eq!(s.tool.guide_drag, None);
+
+    // A shape dragged near the guide snaps its left edge onto it.
+    let id = s.execute("shape.insert", &json!({"preset": "rect", "rect": [100, 200, 80, 60]})).unwrap()["id"].as_u64().unwrap();
+    s.prefs.snap_to_grid = false;
+    ev(&mut s, PointerKind::Down, 140.0, 230.0);
+    ev(&mut s, PointerKind::Drag, 200.0, 230.0);
+    ev(&mut s, PointerKind::Drag, 388.0, 231.0);
+    ev(&mut s, PointerKind::Up, 388.0, 231.0);
+    let x = s.doc().unwrap().shapes().iter().find(|sh| sh.id.0 as u64 == id).and_then(|sh| sh.xfrm).unwrap();
+    assert!((x.x - 350.0).abs() < 0.01, "{x:?}");
+
+    // Dropped off the slide: gone, and undo brings it back.
+    ev(&mut s, PointerKind::Down, 350.0, 10.0);
+    ev(&mut s, PointerKind::Drag, -40.0, 10.0);
+    ev(&mut s, PointerKind::Up, -40.0, 10.0);
+    assert!(s.doc().unwrap().doc.guides.is_empty());
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(s.doc().unwrap().doc.guides.len(), 1);
+}
+
+#[test]
+fn guides_round_trip_through_pptx() {
+    let mut s = Session::with_new();
+    s.execute("guide.add", &json!({"vertical": true, "pos": 123.5})).unwrap();
+    s.execute("guide.add", &json!({"vertical": false, "pos": 400})).unwrap();
+    let bytes = deckcraft_pptx::export(&s.doc().unwrap().doc).unwrap();
+    let back = deckcraft_pptx::import(&bytes).unwrap();
+    assert_eq!(back.guides, s.doc().unwrap().doc.guides);
+    let none = deckcraft_pptx::import(&deckcraft_pptx::export(&deckcraft_model::Presentation::default()).unwrap()).unwrap();
+    assert!(none.guides.is_empty());
+}