Hello Everybody,
I would like to use a C++ gui library with the following (simplified) interface in Python.
#include
class Gui;
class GuiObject { public: GuiObject(Gui *Gui) {printf("creating GuiObject(gui: %X)\n", Gui);} ~GuiObject() {printf("deleting GuiObject\n");} void Move(int x, int y) {printf("GuiObject move(%d, %d)\n", x, y);}; };
class Gui { public: Gui() {printf("creating Gui\n");} ~Gui() {printf("deleting Gui\n");} GuiObject* AddImage() { GuiObject* ob = new GuiObject(this); return ob; } void Print() {printf("Gui: %X\n", this);} };
int main() { Gui *gui = new Gui(); gui->Print(); GuiObject *obj = gui->AddImage(); obj->Move(50, 50); /*GuiObject *obj2 = new GuiObject(gui); // not allowed delete obj2;*/ delete obj; delete gui; return 0; }
I created the Python Gui and GuiObject classes (PyTypeObject), and added it to main module (PyModule_AddObject). It works, but there is a problem at the Gui::AddImage(), with constructs a new GuiObject, which is available in Python layer but finally it is not collected and freed by GC:
... obj = _PyObject_New(&GuiObjectType); PyObject_Init(obj, &GuiObjectType); ...
I cannot invoke the GuiObject object constructor directly from Python, because of the implementation of the C++ gui library (in this case it would be collected). I use the embedded CPython as an interpreter, so I cannot add additional external .py file for it.
So the following Python code would be the target:
gui = GUI();
background = gui.AddImage(); #background = GuiObject(gui); <-- Collected but not allowed background.ImageFile("bg.jpg"); background.Move(0, 0); ...
How could I implement the AddImage function in order to be freed the constructed object at the end?
Thanks in advance!
All-the-best,
Csaba