Hello Everybody,
I would like to use a C++ gui library with the following (simplified) interface
in Python.
#include <stdio.h>
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
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