- added ability for the app to detect the current DPI used on the screen; applied this information in the Film Tool when exporting PNG files

- found that Pillow v >= 7.2 breaks Reportlab 3.5.53 (latest version) and creates an error in Film Tool when exporting PNG files. Pillow 7.2 still works.

FlatCAM.py

@@ -90,6 +90,6 @@ if __name__ == '__main__':
         style = settings.value('style', type=str)
         app.setStyle(style)
 
-    fc = App()
+    fc = App(qapp=app)
     sys.exit(app.exec_())
     # app.exec_()