Add possibility to paste as new file from clipboard on Home tab

Feature request:
https://community.aseprite.org/t/pasting-on-home-screen/21476

src/app/ui/home_view.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2022  Igara Studio S.A.
+// Copyright (C) 2019-2024  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -25,6 +25,7 @@
 #include "app/ui/workspace.h"
 #include "app/ui/workspace_tabs.h"
 #include "app/ui_context.h"
+#include "app/util/clipboard.h"
 #include "base/exception.h"
 #include "fmt/format.h"
 #include "ui/label.h"
@@ -192,6 +193,71 @@ void HomeView::onWorkspaceViewSelected()
   StatusBar::instance()->showDefaultText();
 }
 
+
+void HomeView::onNewInputPriority(InputChainElement* element,
+                                 const ui::Message* msg)
+{
+  // Do nothing
+}
+
+bool HomeView::onCanCut(Context* ctx)
+{
+  return false;
+}
+
+bool HomeView::onCanCopy(Context* ctx)
+{
+  return false;
+}
+
+bool HomeView::onCanPaste(Context* ctx)
+{
+  return (ctx->clipboard()->format() == ClipboardFormat::Image);
+}
+
+bool HomeView::onCanClear(Context* ctx)
+{
+  return false;
+}
+
+bool HomeView::onCut(Context* ctx)
+{
+  return false;
+}
+
+bool HomeView::onCopy(Context* ctx)
+{
+  return false;
+}
+
+bool HomeView::onPaste(Context* ctx)
+{
+  auto clipboard = ctx->clipboard();
+  if (clipboard->format() == ClipboardFormat::Image) {
+    // Create new sprite from the clipboard image.
+    Params params;
+    params.set("ui", "false");
+    params.set("fromClipboard", "true");
+    ctx->executeCommand(
+      Commands::instance()->byId(CommandId::NewFile()),
+      params);
+    return true;
+  }
+  else
+    return false;
+}
+
+bool HomeView::onClear(Context* ctx)
+{
+  // Do nothing
+  return false;
+}
+
+void HomeView::onCancel(Context* ctx)
+{
+  // Do nothing
+}
+
 void HomeView::onNewFile()
 {
   Command* command = Commands::instance()->byId(CommandId::NewFile());

src/app/ui/home_view.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2021  Igara Studio S.A.
+// Copyright (C) 2019-2024  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -10,6 +10,7 @@
 #pragma once
 
 #include "app/check_update_delegate.h"
+#include "app/ui/input_chain_element.h"
 #include "app/ui/tabs.h"
 #include "app/ui/workspace_view.h"
 #include "ui/box.h"
@@ -34,6 +35,7 @@ namespace app {
   class HomeView : public app::gen::HomeView
                  , public TabView
                  , public WorkspaceView
+                 , public app::InputChainElement
 #ifdef ENABLE_UPDATER
                  , public CheckUpdateDelegate
 #endif
@@ -61,6 +63,20 @@ namespace app {
     void onAfterRemoveView(Workspace* workspace) override;
     void onTabPopup(Workspace* workspace) override;
     void onWorkspaceViewSelected() override;
+    InputChainElement* onGetInputChainElement() override { return this; }
+
+    // InputChainElement impl
+    void onNewInputPriority(InputChainElement* element,
+                            const ui::Message* msg) override;
+    bool onCanCut(Context* ctx) override;
+    bool onCanCopy(Context* ctx) override;
+    bool onCanPaste(Context* ctx) override;
+    bool onCanClear(Context* ctx) override;
+    bool onCut(Context* ctx) override;
+    bool onCopy(Context* ctx) override;
+    bool onPaste(Context* ctx) override;
+    bool onClear(Context* ctx) override;
+    void onCancel(Context* ctx) override;
 
   protected:
     void onResize(ui::ResizeEvent& ev) override;