First instance image on canvas disappears when second instance is created

user_14934390 0
Viewed 103

So I've created a method on a class that creates instances of the class resistor, and when a resistor is created, and image will appear on the tkinter canvas. Theres also a method that allows the image to be moved, so what happens is that when I create the first instance, I move the image, and then create the second instance, but when I do this, the first image disappears, but I believe that what happens is that is moves exactly where the second image is, but I don't know why this happens. Here's the code:

class SideBar():
    def createResistor(self, value, name):       # Method used to create instance of class Resistor
        Res1 = Resistor(self.root, value, name)
        self.resList.append(Res1)

class Resistor():
    def cargarimg(self, archivo): # Se carga imagen
        ruta = os.path.join('img', archivo)
        imagen = PhotoImage(file = ruta)
        return imagen

    def show_res(self):
        resImage = self.cargarimg('Res.png')
        MA.MP.paintWindow.image = resImage
        MA.MP.paintWindow.create_image(100, 100, image = resImage)

    def move(self, e):   # Method that allows image to be moved
        resImage = self.cargarimg('Res.png')
        MA.MP.paintWindow.image = resImage
        MA.MP.paintWindow.create_image(e.x, e.y, image = resImage)    
    
    def __init__(self, root, resistance, name):
        self.root = root
        self.resistance = resistance
        self.name = name
        self.x = 50
        self.y = 50
        self.show_res()
        MA.MP.paintWindow.bind('<B1-Motion>', self.move)

Update I've done tests by making a the coordinates x and y parameters, but the first image still disappears, this makes me believe that either for some reason the first image was deleted or it is replaced by the second image.

tkinter-canvas tkinter python
1 Answers

The easiest way to fix this is by using an lru_cache on the loading method.

from functools import lru_cache

class Resistor():
    @lru_cache(None)
    def cargarimg(self, archivo): # Se carga imagen
        ruta = os.path.join('img', archivo)
        imagen = PhotoImage(file = ruta)
        return imagen

This replaces the image reference saving, so you can remove this line from all your methods.

    MA.MP.paintWindow.image = resImage
user_22299450
Related