[lua] Add app.editor.spritePos/mousePos and app.editor:cancel()

Added properties needed to know where the mouse position is on the
editor canvas + a method to cancel app.editor:askPoint() from Lua.

Related to aseprite/Attachment-System#102

src/app/script/editor_class.cpp

@@ -15,6 +15,7 @@
 #include "app/script/registry.h"
 #include "app/ui/editor/editor.h"
 #include "app/ui/editor/select_box_state.h"
+#include "ui/display.h"
 
 #ifdef ENABLE_UI
 
@@ -94,10 +95,10 @@ public:
                 RegistryRef&& onclick,
                 RegistryRef&& onchange,
                 RegistryRef&& oncancel) {
-    // Cancel previous askPoint()
     if (m_askPoint) {
-      onQuickboxCancel(m_editor);
-      ASSERT(!m_askPoint);
+      // Don't call onQuickboxCancel() to avoid calling oncancel, the
+      // script should know that it called askPoint() previously.
+      m_editor->backToPreviousState();
     }
 
     m_askPoint = std::make_unique<AskPoint>(L);
@@ -119,6 +120,13 @@ public:
     m_editor->setState(state);
   }
 
+  void cancel() {
+    if (m_askPoint) {
+      m_askPoint.reset();
+      m_editor->backToPreviousState();
+    }
+  }
+
   // EditorObserver impl
   void onDestroyEditor(Editor* editor) override {
     ASSERT(editor == m_editor);
@@ -250,6 +258,13 @@ int Editor_askPoint(lua_State* L)
   return 0;
 }
 
+int Editor_cancel(lua_State* L)
+{
+  auto obj = get_obj<EditorObj>(L, 1);
+  obj->cancel();
+  return 0;
+}
+
 int Editor_get_sprite(lua_State* L)
 {
   auto obj = get_obj<EditorObj>(L, 1);
@@ -257,15 +272,33 @@ int Editor_get_sprite(lua_State* L)
   return 1;
 }
 
+int Editor_get_spritePos(lua_State* L)
+{
+  auto obj = get_obj<EditorObj>(L, 1);
+  push_obj(L, obj->editor()->screenToEditor(
+                obj->editor()->display()->lastMousePos()));
+  return 1;
+}
+
+int Editor_get_mousePos(lua_State* L)
+{
+  auto obj = get_obj<EditorObj>(L, 1);
+  push_obj(L, obj->editor()->display()->lastMousePos());
+  return 1;
+}
+
 const luaL_Reg Editor_methods[] = {
   { "__gc", Editor_gc },
   { "__eq", Editor_eq },
   { "askPoint", Editor_askPoint },
+  { "cancel", Editor_cancel },
   { nullptr, nullptr }
 };
 
 const Property Editor_properties[] = {
   { "sprite", Editor_get_sprite, nullptr },
+  { "spritePos", Editor_get_spritePos, nullptr },
+  { "mousePos", Editor_get_mousePos, nullptr },
   { nullptr, nullptr, nullptr }
 };
 

src/app/ui/editor/editor.h

@@ -450,6 +450,10 @@ namespace app {
 
     DocView* m_docView;
 
+    // Last known mouse position received by this editor when the
+    // mouse button was pressed. Used for auto-scrolling. To get the
+    // current mouse position on the editor you can use
+    // ui::Display::lastMousePos().
     gfx::Point m_oldPos;
 
     EditorFlags m_flags;

src/ui/display.h

@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2019-2022  Igara Studio S.A.
+// Copyright (C) 2019-2023  Igara Studio S.A.
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -75,6 +75,9 @@ namespace ui {
 
     gfx::Size workareaSizeUIScale();
 
+    const gfx::Point& lastMousePos() const { return m_lastMousePos; }
+    void updateLastMousePos(const gfx::Point& pos) { m_lastMousePos = pos; }
+
     void _setParentDisplay(Display* parentDisplay) {
       m_parentDisplay = parentDisplay;
     }
@@ -86,6 +89,7 @@ namespace ui {
     std::vector<Window*> m_windows; // Sub-windows in this display
     gfx::Region m_invalidRegion;    // Invalid region (we didn't receive paint messages yet for this).
     gfx::Region m_dirtyRegion;      // Region to flip to the os::Display
+    gfx::Point m_lastMousePos;
   };
 
 } // namespace ui

src/ui/manager.cpp

@@ -784,8 +784,14 @@ void Manager::handleWindowZOrder()
 void Manager::updateMouseWidgets(const gfx::Point& mousePos,
                                  Display* display)
 {
-  gfx::Point screenPos = (display ? display->nativeWindow()->pointToScreen(mousePos):
-                                    mousePos);
+  gfx::Point screenPos;
+  if (display) {
+    screenPos = display->nativeWindow()->pointToScreen(mousePos);
+    display->updateLastMousePos(mousePos);
+  }
+  else {
+    screenPos = mousePos;
+  }
 
   // Get the list of widgets to send mouse messages.
   mouse_widgets_list.clear();