PixelPaint: Add option to make new layer from selection

New actions in the Layer Menu allows for the creation of a new layer
from the current selection. Layers can be made by copying the
selection or cutting it from the current layer. The new layer will be
sized to the bounding box of the selection. The newly produced layer
will be added to the layer stack.

Userland/Applications/PixelPaint/MainWidget.cpp

@@ -2,6 +2,7 @@
  * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021-2022, Mustafa Quraish <mustafa@serenityos.org>
  * Copyright (c) 2021-2022, Tobias Christiansen <tobyase@serenityos.org>
+ * Copyright (c) 2022, Timothy Slater <tslater2006@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -579,6 +580,17 @@ void MainWidget::initialize_menubar(GUI::Window& window)
         }));
 
     m_layer_menu = window.add_menu("&Layer");
+
+    m_layer_menu->on_visibility_change = [this](bool visible) {
+        if (!visible)
+            return;
+
+        bool image_has_selection = !current_image_editor()->active_layer()->image().selection().is_empty();
+
+        m_layer_via_copy->set_enabled(image_has_selection);
+        m_layer_via_cut->set_enabled(image_has_selection);
+    };
+
     m_layer_menu->add_action(GUI::Action::create(
         "New &Layer...", { Mod_Ctrl | Mod_Shift, Key_N }, g_icon_bag.new_layer, [&](auto&) {
             auto* editor = current_image_editor();
@@ -597,6 +609,31 @@ void MainWidget::initialize_menubar(GUI::Window& window)
             }
         }));
 
+    m_layer_via_copy = GUI::Action::create(
+        "Layer via Copy", { Mod_Ctrl | Mod_Shift, Key_C }, g_icon_bag.new_layer, [&](auto&) {
+            auto add_layer_success = current_image_editor()->add_new_layer_from_selection();
+            if (add_layer_success.is_error()) {
+                GUI::MessageBox::show_error(&window, add_layer_success.release_error().string_literal());
+                return;
+            }
+            current_image_editor()->did_complete_action("New Layer via Copy"sv);
+            m_layer_list_widget->select_top_layer();
+        });
+    m_layer_menu->add_action(*m_layer_via_copy);
+
+    m_layer_via_cut = GUI::Action::create(
+        "Layer via Cut", { Mod_Ctrl | Mod_Shift, Key_X }, g_icon_bag.new_layer, [&](auto&) {
+            auto add_layer_success = current_image_editor()->add_new_layer_from_selection();
+            if (add_layer_success.is_error()) {
+                GUI::MessageBox::show_error(&window, add_layer_success.release_error().string_literal());
+                return;
+            }
+            current_image_editor()->active_layer()->erase_selection(current_image_editor()->image().selection());
+            current_image_editor()->did_complete_action("New Layer via Cut"sv);
+            m_layer_list_widget->select_top_layer();
+        });
+    m_layer_menu->add_action(*m_layer_via_cut);
+
     m_layer_menu->add_separator();
     m_layer_menu->add_action(GUI::Action::create(
         "Add M&ask", { Mod_Ctrl | Mod_Shift, Key_M }, g_icon_bag.add_mask, [&](auto&) {

Userland/Applications/PixelPaint/MainWidget.h

@@ -101,6 +101,9 @@ private:
     RefPtr<GUI::Action> m_show_guides_action;
     RefPtr<GUI::Action> m_show_rulers_action;
     RefPtr<GUI::Action> m_show_active_layer_boundary_action;
+
+    RefPtr<GUI::Action> m_layer_via_copy;
+    RefPtr<GUI::Action> m_layer_via_cut;
 };
 
 }