Line data    Source code

       1             : # SPDX-FileCopyrightText: 2025 Pairinteraction Developers
       2             : # SPDX-License-Identifier: LGPL-3.0-or-later
       3             : 
       4           1 : from typing import Optional
       5             : 
       6           1 : import matplotlib.pyplot as plt
       7           1 : import numpy as np
       8           1 : from matplotlib.backends.backend_qtagg import FigureCanvasQTAgg
       9           1 : from PySide6.QtCore import Qt, QTimer
      10           1 : from PySide6.QtGui import QWheelEvent
      11           1 : from PySide6.QtWidgets import QWidget
      12             : 
      13             : 
      14           1 : class MatplotlibCanvas(FigureCanvasQTAgg):
      15             :     """Canvas for matplotlib figures."""
      16             : 
      17           1 :     def __init__(self, parent: Optional[QWidget] = None) -> None:
      18             :         """Initialize the canvas with a figure."""
      19           1 :         self.fig, self.ax = plt.subplots()
      20           1 :         super().__init__(self.fig)
      21             : 
      22           1 :         self.setup_zoom()
      23             : 
      24           1 :     def setup_zoom(self) -> None:
      25             :         """Set up mouse wheel zoom functionality."""
      26             :         # Wheel event accumulation variables
      27           1 :         self.wheel_accumulation: float = 0
      28           1 :         self.last_wheel_pos: list[list[float]] = []
      29           1 :         self.wheel_timer = QTimer(self)
      30           1 :         self.wheel_timer.setSingleShot(True)
      31           1 :         self.wheel_timer.timeout.connect(self.apply_accumulated_zoom)
      32           1 :         self.setFocusPolicy(Qt.FocusPolicy.StrongFocus)
      33           1 :         self.setMouseTracking(True)
      34             : 
      35           1 :     def wheelEvent(self, event: QWheelEvent) -> None:
      36             :         """Handle mouse wheel events for zooming."""
      37           0 :         self.wheel_accumulation += event.angleDelta().y() / 120
      38           0 :         self.last_wheel_pos.append([event.position().x(), event.position().y()])
      39           0 :         self.wheel_timer.start(100)  # Apply zoom after 100ms of inactivity
      40             : 
      41           1 :     def apply_accumulated_zoom(self) -> None:
      42             :         """Apply the accumulated zoom from wheel events."""
      43           0 :         if not self.wheel_accumulation:
      44           0 :             return
      45             : 
      46           0 :         x_min, x_max = self.ax.get_xlim()
      47           0 :         y_min, y_max = self.ax.get_ylim()
      48             : 
      49           0 :         scale_factor = 1 - 0.1 * self.wheel_accumulation
      50             : 
      51             :         # Get the mouse position in data coordinates
      52           0 :         wheel_pos_mean = np.mean(self.last_wheel_pos, axis=0)
      53           0 :         x_data, y_data = self.ax.transData.inverted().transform(wheel_pos_mean)
      54           0 :         y_data = -(y_data - (y_max + y_min) / 2) + (y_max + y_min) / 2  # y_data is mirrored bottom / top
      55             : 
      56           0 :         self.wheel_accumulation = 0
      57           0 :         self.last_wheel_pos = []
      58             : 
      59           0 :         if x_data > x_max or y_data > y_max or (x_data < x_min and y_data < y_min):
      60           0 :             return
      61             : 
      62           0 :         if x_min <= x_data <= x_max:
      63           0 :             x_min_new = x_data - (x_data - x_min) * scale_factor
      64           0 :             x_max_new = x_data + (x_max - x_data) * scale_factor
      65           0 :             self.ax.set_xbound(x_min_new, x_max_new)
      66           0 :             self.ax.set_autoscalex_on(False)
      67             : 
      68           0 :         if y_min <= y_data <= y_max:
      69           0 :             y_min_new = y_data - (y_data - y_min) * scale_factor
      70           0 :             y_max_new = y_data + (y_max - y_data) * scale_factor
      71           0 :             self.ax.set_ybound(y_min_new, y_max_new)
      72           0 :             self.ax.set_autoscaley_on(False)
      73             : 
      74             :         # Redraw the canvas
      75           0 :         self.draw()