Move tool on a locked layer: Photoshop's message (#2249)

* Move tool on a locked layer: Photoshop's message

Dragging with the Move tool (or Cmd with another tool) on a layer it can't
move showed nothing: the Background or a position-locked layer with no
selection, or a locked layer whose selected pixels can't float. Photoshop
puts up "Could not use the move tool because the layer is locked." when
the drag starts (a plain click says nothing); move_lock.rs does the same
with the Error dialog, translated in every catalogue. The float lock rule
moves to float_cmds::locked_for_float so the UI can ask before the press
goes anywhere.

Also in Dutch and Ukrainian. The Cmd-with-a-painting-tool case lands with
the Cmd-as-Move change, whichever merges second.

* Fix merge: close the lock-message test

---------

Co-authored-by: Brandon Thomas <echelon@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/float_cmds.rs

@@ -130,14 +130,19 @@ fn can_float(s: &Session) -> std::result::Result<(), String> {
     if !matches!(l.content, LayerContent::Raster(_)) {
         return Err("the active layer has no pixels to move".into());
     }
-    let locks = st.doc.effective_locks(l.id);
-    // The Background is position-locked, but its selected pixels move (Photoshop).
-    if locks.all || (locks.position && !crate::extra_cmds::is_background(l)) {
+    if locked_for_float(&st.doc, l) {
         return Err(format!("layer \"{}\" is locked", l.name));
     }
     Ok(())
 }
 
+/// Do `l`'s locks (its own, or a locked group's: `effective_locks`) stop its selected pixels
+/// floating? The Background is position-locked, but its selected pixels move (Photoshop).
+pub fn locked_for_float(doc: &Document, l: &photocraft_doc::Layer) -> bool {
+    let locks = doc.effective_locks(l.id);
+    locks.all || (locks.position && !crate::extra_cmds::is_background(l))
+}
+
 fn float(s: &mut Session, p: &Value) -> Result<Value> {
     let (dx, dy) = (int_param(p, "dx"), int_param(p, "dy"));
     let copy = p.get("copy").and_then(Value::as_bool).unwrap_or(false);

crates/ui-egui/src/canvas.rs

@@ -3690,6 +3690,25 @@ pub fn tool_event(app: &mut PhotocraftApp, ev: ToolEvent, mods: egui::Modifiers)
             ToolEvent::Up { .. } => return,
         }
     }
+    // A locked layer (the Background without a selection, say): no drag, and Photoshop's message
+    // once the pointer moves (a click says nothing). ⌘ with a selection tool here (#896); the Move
+    // tool below, once Auto-Select has picked the layer.
+    match ev {
+        ToolEvent::Down { x, y, .. } if tool != Tool::Move && app.ui.transform.is_none() && crate::move_lock::blocked(app, tool, [x, y], mods) => {
+            app.move_blocked = true;
+            return;
+        }
+        ToolEvent::Move { .. } if app.move_blocked => {
+            app.move_blocked = false;
+            crate::move_lock::prompt(app);
+            return;
+        }
+        ToolEvent::Up { .. } if app.move_blocked => {
+            app.move_blocked = false;
+            return;
+        }
+        _ => {}
+    }
     // Move tool over a guide drags the guide (off the canvas deletes it).
     match ev {
         ToolEvent::Down { x, y, pressure } if tool == Tool::Move => {
@@ -3697,8 +3716,20 @@ pub fn tool_event(app: &mut PhotocraftApp, ev: ToolEvent, mods: egui::Modifiers)
                 app.guide_drag = Some(crate::rulers::GuideDrag { vertical, index: Some(i), pos: if vertical { x } else { y } });
                 return;
             }
+            // Auto-Select (or ⌘-click while it is off) picks the layer under the pointer first
+            // (not when the selected pixels move: those are the active layer's).
+            if !crate::move_ui::moves_selected_pixels(app) && app.ui.tool_options.move_auto_select != mods.command {
+                let target = app.ui.tool_options.move_target.clone();
+                let mode = if mods.shift { "add" } else { "replace" };
+                let _ = app.run("layer.pickAt", json!({"x": x, "y": y, "target": target, "mode": mode}));
+            }
+            // A locked layer: no drag, and Photoshop's message once the pointer moves (`move_lock`).
+            if crate::move_lock::blocked(app, tool, [x, y], mods) {
+                app.move_blocked = true;
+                return;
+            }
             // With a selection: cut the selected pixels (⌥ copies them) and drag them as a floating
-            // piece, from anywhere, as a marquee ⌘-drag does (no Auto-Select pick).
+            // piece, from anywhere, as a marquee ⌘-drag does.
             if crate::move_ui::moves_selected_pixels(app) {
                 if crate::move_ui::float_selected(app, mods.alt, 0.0, 0.0) {
                     let mut d = Drag::new(tool, [x, y], vec![[x, y, pressure as f64]], mods, false);
@@ -3707,12 +3738,6 @@ pub fn tool_event(app: &mut PhotocraftApp, ev: ToolEvent, mods: egui::Modifiers)
                 }
                 return;
             }
-            // Auto-Select (or ⌘-click while it is off) picks the layer under the pointer first.
-            if app.ui.tool_options.move_auto_select != mods.command {
-                let target = app.ui.tool_options.move_target.clone();
-                let mode = if mods.shift { "add" } else { "replace" };
-                let _ = app.run("layer.pickAt", json!({"x": x, "y": y, "target": target, "mode": mode}));
-            }
         }
         ToolEvent::Move { x, y, .. } => {
             if let Some(d) = app.guide_drag.as_mut().filter(|d| d.index.is_some()) {
@@ -3953,7 +3978,7 @@ pub fn selection_drag_kind(app: &PhotocraftApp, tool: Tool, p: [f64; 2], mods: e
 /// Does a ⌘ (⌘⌥) press with selection tool `tool` at `p` move the whole layer (a duplicate with
 /// ⌥), as the Move tool would? Outside the selection or without one; inside it, ⌘ drags the
 /// selected pixels instead (`selection_drag_kind`).
-fn command_moves_layer(app: &PhotocraftApp, tool: Tool, p: [f64; 2], mods: egui::Modifiers) -> bool {
+pub(crate) fn command_moves_layer(app: &PhotocraftApp, tool: Tool, p: [f64; 2], mods: egui::Modifiers) -> bool {
     let selection_tool = matches!(tool, Tool::RectMarquee | Tool::EllipseMarquee | Tool::Lasso | Tool::PolygonLasso | Tool::MagicWand);
     let floating = app.session.active().is_some_and(|st| photocraft_engine::float_cmds::floating(st).is_some());
     selection_tool && mods.command && !mods.shift && !floating && app.ui.polygon.is_empty() && !inside_selection(app, p)

crates/ui-egui/src/i18n/cs.tsv

@@ -1636,6 +1636,7 @@
 	Millimeters	Milimetry
 	Mobile	Mobilní zařízení
 	Move Tool	Nástroj přesun
+	Could not use the move tool because the layer is locked.	Nástroj Přesun nelze použít, protože vrstva je zamčená.
 	Multiply	Násobit
 	My Brushes	Moje štětce
 	Neutrals	Neutrální

crates/ui-egui/src/i18n/de.tsv

@@ -1616,6 +1616,7 @@
 	Millimeters	Millimeter
 	Mobile	Mobil
 	Move Tool	Verschieben-Werkzeug
+	Could not use the move tool because the layer is locked.	Das Verschieben-Werkzeug konnte nicht verwendet werden, weil die Ebene gesperrt ist.
 	Multiply	Multiplizieren
 	My Brushes	Meine Pinsel
 	Neutrals	Neutrale

crates/ui-egui/src/i18n/el.tsv

@@ -3215,6 +3215,7 @@ cameraRaw	Yellow	Κίτρινο
 	Magic Eraser Tool	Μαγική γόμα (Magic Eraser Tool)
 	Magic Wand Tool	Μαγικό ραβδί (Magic Wand Tool)
 	Move Tool	Μετακίνηση (Move Tool)
+	Could not use the move tool because the layer is locked.	Δεν ήταν δυνατή η χρήση του εργαλείου Μετακίνηση, επειδή το επίπεδο είναι κλειδωμένο.
 	Note Tool	Σημείωση (Note Tool)
 	Object Selection Tool	Επιλογή αντικειμένου (Object Selection Tool)
 	Paint Bucket Tool	Κουβάς γεμίσματος (Paint Bucket Tool)

crates/ui-egui/src/i18n/es.tsv

@@ -1620,6 +1620,7 @@
 	Millimeters	Milímetros
 	Mobile	Móvil
 	Move Tool	Herramienta Mover
+	Could not use the move tool because the layer is locked.	No se pudo usar la herramienta Mover porque la capa está bloqueada.
 	Multiply	Multiplicar
 	My Brushes	Mis pinceles
 	Neutrals	Neutros

crates/ui-egui/src/i18n/fr.tsv

@@ -1599,6 +1599,7 @@
 	Millimeters	Millimètres
 	Mobile	Mobile
 	Move Tool	Outil Déplacement
+	Could not use the move tool because the layer is locked.	Impossible d'utiliser l'outil Déplacement, car le calque est verrouillé.
 	Multiply	Produit
 	My Brushes	Mes pinceaux
 	Neutrals	Neutres

crates/ui-egui/src/i18n/id.tsv

@@ -1593,6 +1593,7 @@
 	Millimeters	Milimeter
 	Mobile	Seluler
 	Move Tool	Alat Pindah
+	Could not use the move tool because the layer is locked.	Tidak dapat menggunakan alat Pindahkan karena layer terkunci.
 	Multiply	Multiply
 	My Brushes	Kuas Saya
 	Neutrals	Netral

crates/ui-egui/src/i18n/it.tsv

@@ -1618,6 +1618,7 @@
 	Millimeters	Millimetri
 	Mobile	Mobile
 	Move Tool	Strumento Sposta
+	Could not use the move tool because the layer is locked.	Impossibile usare lo strumento Sposta perché il livello è bloccato.
 	Multiply	Moltiplica
 	My Brushes	I miei pennelli
 	Neutrals	Neutri

crates/ui-egui/src/i18n/ja.tsv

@@ -1625,6 +1625,7 @@
 	Millimeters	ミリメートル
 	Mobile	モバイル
 	Move Tool	移動ツール
+	Could not use the move tool because the layer is locked.	レイヤーがロックされているため、移動ツールを使用できません。
 	Multiply	乗算
 	My Brushes	マイブラシ
 	Neutrals	中間色系

crates/ui-egui/src/i18n/ko.tsv

@@ -1595,6 +1595,7 @@
 	Millimeters	밀리미터
 	Mobile	모바일
 	Move Tool	이동 도구
+	Could not use the move tool because the layer is locked.	레이어가 잠겨 있어 이동 도구를 사용할 수 없습니다.
 	Multiply	곱하기
 	My Brushes	내 브러시
 	Neutrals	중립색

crates/ui-egui/src/i18n/nl.tsv

@@ -1608,6 +1608,7 @@
 	Millimeters	Millimeter
 	Mobile	Mobiel
 	Move Tool	Verplaatsgereedschap
+	Could not use the move tool because the layer is locked.	Kan het verplaatsgereedschap niet gebruiken omdat de laag is vergrendeld.
 	Multiply	Vermenigvuldigen
 	My Brushes	Mijn penselen
 	Neutrals	Neutrale tinten

crates/ui-egui/src/i18n/pl.tsv

@@ -1618,6 +1618,7 @@
 	Millimeters	Milimetry
 	Mobile	Urządzenia mobilne
 	Move Tool	Narzędzie Przesunięcie
+	Could not use the move tool because the layer is locked.	Nie można użyć narzędzia Przesunięcie, ponieważ warstwa jest zablokowana.
 	Multiply	Mnożenie
 	My Brushes	Moje pędzle
 	Neutrals	Neutralne

crates/ui-egui/src/i18n/pt-br.tsv

@@ -1598,6 +1598,7 @@
 	Millimeters	Milímetros
 	Mobile	Dispositivos móveis
 	Move Tool	Ferramenta Mover
+	Could not use the move tool because the layer is locked.	Não foi possível usar a ferramenta Mover porque a camada está bloqueada.
 	Multiply	Multiplicação
 	My Brushes	Meus pincéis
 	Neutrals	Neutros

crates/ui-egui/src/i18n/ru.tsv

@@ -1500,6 +1500,7 @@
 	Adjustment Layer	Корректирующий слой
 	{name} Properties	Свойства: {name}
 	Move Tool	Перемещение
+	Could not use the move tool because the layer is locked.	Не удалось использовать инструмент «Перемещение», потому что слой заблокирован.
 	Rectangular Marquee Tool	Прямоугольная область
 	Elliptical Marquee Tool	Овальная область
 	Brush Tool	Кисть

crates/ui-egui/src/i18n/uk.tsv

@@ -1485,6 +1485,7 @@
 	Adjustment Layer	Коригувальний шар
 	{name} Properties	Властивості: {name}
 	Move Tool	Інструмент «Переміщення»
+	Could not use the move tool because the layer is locked.	Не вдалося використати інструмент «Переміщення», бо шар заблоковано.
 	Rectangular Marquee Tool	Інструмент «Прямокутне виділення»
 	Elliptical Marquee Tool	Інструмент «Еліптичне виділення»
 	Brush Tool	Інструмент «Пензель»

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -1633,6 +1633,7 @@
 	Millimeters	毫米
 	Mobile	移动设备
 	Move Tool	移动工具
+	Could not use the move tool because the layer is locked.	无法使用移动工具，因为图层已锁定。
 	Multiply	正片叠底
 	My Brushes	我的画笔
 	Neutrals	中性色

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -1626,6 +1626,7 @@
 	Millimeters	公釐
 	Mobile	行動裝置
 	Move Tool	移動工具
+	Could not use the move tool because the layer is locked.	無法使用移動工具，因為圖層已鎖定。
 	Multiply	色彩增值
 	My Brushes	我的筆刷
 	Neutrals	中間色

crates/ui-egui/src/lib.rs

@@ -98,6 +98,7 @@ pub mod menu_catalog;
 pub mod menu_nav;
 pub mod menus;
 pub mod monitor_status;
+pub mod move_lock;
 pub mod move_mods;
 pub mod move_ui;
 pub mod native_menu;
@@ -371,6 +372,9 @@ pub struct PhotocraftApp {
     monitors: monitor_status::State,
     checker: Option<egui::TextureHandle>,
     drag: Option<canvas::Drag>,
+    /// A Move-tool press landed on a locked layer: the first pointer move shows Photoshop's
+    /// message (`move_lock`), a plain click shows nothing.
+    pub(crate) move_blocked: bool,
     /// The tool pointer events go to this frame when it isn't the selected one: the Move tool
     /// while ⌘ is held (`hold_keys::cmd_moves`). Set by the canvas for its gestures, never saved.
     pub(crate) tool_override: Option<state::Tool>,
@@ -571,6 +575,7 @@ impl PhotocraftApp {
             monitors: Default::default(),
             checker: None,
             drag: None,
+            move_blocked: false,
             tool_override: None,
             live_stroke: None,
             trail: None,

crates/ui-egui/src/marquee_tests.rs

@@ -409,6 +409,93 @@ fn alt_with_nothing_selected_draws_a_new_selection() {
     assert!(after.is_none_or(|r| r.is_empty() || r != before), "⌥ subtracted: {before:?} -> {after:?}");
 }
 
+fn error_dialogs(app: &PhotocraftApp) -> Vec<String> {
+    app.ui.dialogs.iter().filter(|d| d.kind == crate::state::DialogKind::Error).filter_map(|d| d.fields.get("message")?.as_str().map(String::from)).collect()
+}
+
+/// Photoshop's "Could not use the move tool because the layer is locked." when a Move-tool drag
+/// (the Move tool, or ⌘ with a marquee) starts on a layer it can't move: the Background with no
+/// selection, a position-locked layer; a plain click says nothing, and the drag never starts.
+#[test]
+fn move_on_the_background_without_a_selection_shows_photoshops_lock_message() {
+    let mut app = PhotocraftApp::new(photocraft_engine::Session::new(), crate::Services::default());
+    app.run("file.new", json!({"width": 80, "height": 60})).unwrap();
+    app.sync_views();
+    app.ui.tool = Tool::Move;
+    app.ui.tool_options.move_auto_select = false;
+    let steps = app.session.active().unwrap().history.past_len();
+    use crate::canvas::{ToolEvent, tool_event};
+    // A click: no message.
+    tool_event(&mut app, ToolEvent::Down { x: 20.0, y: 20.0, pressure: 1.0 }, Modifiers::NONE);
+    tool_event(&mut app, ToolEvent::Up { x: 20.0, y: 20.0 }, Modifiers::NONE);
+    assert!(error_dialogs(&app).is_empty() && !app.move_blocked);
+    // A drag: the message once, nothing moved, no drag in progress.
+    tool_event(&mut app, ToolEvent::Down { x: 20.0, y: 20.0, pressure: 1.0 }, Modifiers::NONE);
+    tool_event(&mut app, ToolEvent::Move { x: 30.0, y: 20.0, pressure: 1.0 }, Modifiers::NONE);
+    tool_event(&mut app, ToolEvent::Move { x: 40.0, y: 20.0, pressure: 1.0 }, Modifiers::NONE);
+    tool_event(&mut app, ToolEvent::Up { x: 40.0, y: 20.0 }, Modifiers::NONE);
+    assert_eq!(error_dialogs(&app), [crate::move_lock::MESSAGE]);
+    assert!(app.drag.is_none(), "no drag started");
+    assert_eq!(app.session.active().unwrap().history.past_len(), steps);
+    app.ui.dialogs.clear();
+    // ⌘-drag with a marquee (the Move tool for the drag, #896): the same.
+    app.ui.tool = Tool::RectMarquee;
+    drag(&mut app, [20.0, 20.0], [40.0, 20.0], Modifiers::COMMAND);
+    assert_eq!(error_dialogs(&app), [crate::move_lock::MESSAGE]);
+    app.ui.dialogs.clear();
+    // A position-locked layer: the same; unlocked, it moves.
+    app.run("layer.new.layer", json!({})).unwrap();
+    app.session
+        .edit("lock", |doc, a| {
+            doc.layer_mut(a.unwrap()).unwrap().locks.position = true;
+            Ok(())
+        })
+        .unwrap();
+    drag(&mut app, [20.0, 20.0], [40.0, 20.0], Modifiers::COMMAND);
+    assert_eq!(error_dialogs(&app).len(), 1);
+    app.ui.dialogs.clear();
+    app.session
+        .edit("unlock", |doc, a| {
+            doc.layer_mut(a.unwrap()).unwrap().locks.position = false;
+            Ok(())
+        })
+        .unwrap();
+    drag(&mut app, [20.0, 20.0], [40.0, 20.0], Modifiers::COMMAND);
+    assert!(error_dialogs(&app).is_empty());
+}
+
+/// With a selection the Background's pixels do move (its lock is partial: transparency and
+/// position), so no message; a layer locked all over gets it, with the marquee's ⌘-drag inside the
+/// selection as with the Move tool.
+#[test]
+fn selected_pixels_move_off_the_background_but_not_off_a_fully_locked_layer() {
+    let mut app = PhotocraftApp::new(photocraft_engine::Session::new(), crate::Services::default());
+    app.run("file.new", json!({"width": 80, "height": 60})).unwrap();
+    app.sync_views();
+    app.ui.extras.snap = false;
+    app.ui.view.show.smart_guides = false;
+    app.ui.tool = Tool::RectMarquee;
+    app.run("select.rect", json!({"x": 10, "y": 10, "width": 20, "height": 20})).unwrap();
+    drag(&mut app, [20.0, 20.0], [50.0, 20.0], Modifiers::COMMAND);
+    assert!(error_dialogs(&app).is_empty());
+    assert_eq!(photocraft_engine::float_cmds::floating(app.session.active().unwrap()).map(|f| f.offset), Some((30, 0)));
+    let (mut app, layer) = painted();
+    app.session
+        .edit("lock", |doc, _| {
+            doc.layer_mut(layer).unwrap().locks.all = true;
+            Ok(())
+        })
+        .unwrap();
+    // ⌘ with the Brush is the Move tool too (#2248).
+    for (tool, m) in [(Tool::RectMarquee, Modifiers::COMMAND), (Tool::Move, Modifiers::NONE), (Tool::Brush, Modifiers::COMMAND)] {
+        app.ui.tool = tool;
+        drag(&mut app, [20.0, 20.0], [40.0, 20.0], m);
+        assert_eq!(error_dialogs(&app), [crate::move_lock::MESSAGE], "{tool:?}");
+        assert!(photocraft_engine::float_cmds::floating(app.session.active().unwrap()).is_none(), "{tool:?}");
+        app.ui.dialogs.clear();
+    }
+}
+
 /// Photoshop's cursor over a selection: the move cursor where a marquee press moves the outline,
 /// scissors where ⌘ (or the Move tool) cuts the selected pixels, a double arrow where ⌥ copies
 /// them, a hollow arrowhead while they are dragged, and a plain arrow over the floating piece.

crates/ui-egui/src/move_lock.rs

@@ -0,0 +1,48 @@
+//! Photoshop's "Could not use the move tool because the layer is locked." A Move-tool press (the
+//! Move tool itself, or ⌘ with a selection tool, `canvas::command_moves_layer`) on a layer it
+//! can't move opens that message in a dialog instead
+//! of silently doing nothing: the Background and any position-locked layer when there is no
+//! selection, and a layer whose selected pixels can't float
+//! (`photocraft_engine::float_cmds::locked_for_float`) when there is one. As in Photoshop the
+//! message comes when the pointer starts to drag; a plain click says nothing. OK closes it.
+
+use serde_json::json;
+
+use crate::PhotocraftApp;
+use crate::state::{DialogKind, Tool};
+
+pub const MESSAGE: &str = "Could not use the move tool because the layer is locked.";
+
+/// Would a press at document point `p` with `tool` in effect and `mods` held be a move that
+/// fails because of a lock?
+pub fn blocked(app: &PhotocraftApp, tool: Tool, p: [f64; 2], mods: egui::Modifiers) -> bool {
+    let Some(st) = app.session.active() else { return false };
+    let floating = photocraft_engine::float_cmds::floating(st).is_some();
+    // The selected pixels: only a fresh cut can be refused.
+    let pixels_locked =
+        || !floating && st.active_layer.and_then(|id| st.doc.layer(id)).is_some_and(|l| photocraft_engine::float_cmds::locked_for_float(&st.doc, l));
+    // The layers: any of them locked in place refuses the whole move.
+    let layers_locked = || {
+        photocraft_engine::layer_multi_cmds::move_targets(&st.doc, &st.selected_layers()).iter().any(|id| {
+            let locks = st.doc.effective_locks(*id);
+            locks.position || locks.all
+        })
+    };
+    if tool == Tool::Move {
+        // `moves_selected_pixels` is false for a layer whose pixels can't float: then the Move tool
+        // moves the layer, which its position lock refuses too.
+        if crate::move_ui::moves_selected_pixels(app) {
+            return pixels_locked();
+        }
+        return !floating && st.doc.selection.is_some() && pixels_locked() || layers_locked();
+    }
+    if crate::canvas::command_moves_layer(app, tool, p, mods) {
+        return layers_locked();
+    }
+    crate::canvas::selection_drag_kind(app, tool, p, mods) == Some(true) && mods.command && pixels_locked()
+}
+
+/// Opens the message. The dialog is ordinary UI state (`ui.dialog.confirm` closes it).
+pub fn prompt(app: &mut PhotocraftApp) {
+    app.ui.open_dialog(DialogKind::Error, json!({"message": tl!(MESSAGE)}).as_object().cloned().unwrap_or_default());
+}