request save on exit wip

engine/canvas.cpp

@@ -462,6 +462,7 @@ void ui::Canvas::stroke_commit()
 {
     if (!m_dirty || m_layers.empty())
         return;
+    m_unsaved = true;
     m_dirty = false;
     m_dirty_stroke = true; // new stroke ready for timelapse capture
     App::I.redraw = true;
@@ -805,6 +806,7 @@ bool ui::Canvas::create(int width, int height)
     }
     m_smask.create(width*2, height*2, "mask");
     m_smask.clear({1, 1, 1, 1});
+    m_unsaved = true;
     return true;
 }
 
@@ -1452,6 +1454,7 @@ void ui::Canvas::project_save_thread(std::string file_path)
     pb->destroy();
     App::I.async_update();
     App::I.async_end();
+    m_unsaved = false;
 }
 
 void ui::Canvas::project_open(std::string file_path, std::function<void()> on_complete)
@@ -1597,6 +1600,7 @@ void ui::Canvas::project_open_thread(std::string file_path)
         gl.restore();
         App::I.async_end();
     }
+    m_unsaved = false;
 }
 
 ui::Image ui::Canvas::thumbnail_generate(int w, int h)