如何在python中为ZoomGestureHandler添加相对缩放

Question

我目前正在努力在 Python 中为我的移动图形库实现自定义缩放手势。尽管尝试了多种解决方案，包括探索 ChatGPT，我还是遇到了代码无法正常运行的问题。

当我捏合并放大、松开并尝试再次放大时，就会出现问题。缩放重置而不是继续放大，这不是预期的行为。

我非常感谢社区为解决此问题提供的任何帮助。预先感谢您的帮助。

import sys
import sdl2
import sdl2.ext
import numpy as np
import math as ml
from spectrax import operations as op

class ZoomGestureHandler:
    def __init__(self, window):
        self.zoom_level = 1.0
        self.zoom_factor = 0.01
        self.max_zoom = 2.0
        self.min_zoom = 0.5
        self.window = window
        self.finger_positions = [[0, 0], [0, 0]]
        self.finger_positions_pre = [[0, 0], [0, 0]]
        self.finger_count = 0
        self.zooming = False
        self.image_zoom = 0
        
    def get_zoom(self):
        # Use this function to retrieve the zoom_level
        zoom = abs(ml.dist(*self.finger_positions)) * 10
        return zoom if zoom > 1 else 1
    
    def event_handler(self, event):
        zoom_handler = self
        
        fingers = event.touch_gestures.fingers
        if event.mouse.press and "0" in fingers and "1" in fingers and event.touch_gestures.finger_count > 1:
            f1 = event.touch_gestures.fingers["0"].xy
            f2 = event.touch_gestures.fingers["1"].xy
            self.finger_positions = [f1, f2]
            self.zooming = True
        else:
            self.zooming = False