用python生成一边录音一边显示FFT画布canvas.draw()的多线程程序

以下是一个使用PyAudio和matplotlib库实现一边录音一边显示FFT画布的多线程程序：

import pyaudio
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import QThread, pyqtSignal

CHUNK_SIZE = 1024
FORMAT = pyaudio.paFloat32
CHANNELS = 1
RATE = 44100
FFT_SIZE = 2048

class AudioThread(QThread):
    signal = pyqtSignal(np.ndarray)

    def __init__(self):
        super().__init__()
        self.p = pyaudio.PyAudio()
        self.stream = self.p.open(format=FORMAT,
                                  channels=CHANNELS,
                                  rate=RATE,
                                  input=True,
                                  frames_per_buffer=CHUNK_SIZE)

    def run(self):
        while True:
            data = np.frombuffer(self.stream.read(CHUNK_SIZE), dtype=np.float32)
            self.signal.emit(data)

    def close(self):
        self.stream.stop_stream()
        self.stream.close()
        self.p.terminate()

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Real-time FFT")
        self.setGeometry(100, 100, 800, 600)

        self.fig, self.ax = plt.subplots()
        self.canvas = FigureCanvas(self.fig)
        self.setCentralWidget(self.canvas)

        self.audio_thread = AudioThread()
        self.audio_thread.signal.connect(self.update_canvas)
        self.audio_thread.start()

    def update_canvas(self, data):
        fft = np.abs(np.fft.fft(data, n=FFT_SIZE))
        freqs = np.fft.fftfreq(FFT_SIZE, 1/RATE)[:FFT_SIZE//2]
        self.ax.clear()
        self.ax.plot(freqs, fft[:FFT_SIZE//2])
        self.ax.set_xlim(0, 5000)
        self.ax.set_ylim(0, 100)
        self.canvas.draw()

    def closeEvent(self, event):
        self.audio_thread.close()
        self.audio_thread.wait()

if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()

程序首先定义了一些常量，如音频数据的块大小、格式、通道数、采样率和FFT大小。它创建了一个名为AudioThread的QThread子类，该子类负责从音频流中读取数据并发出信号以更新绘图画布。MainWindow类是一个简单的窗口应用程序，它使用matplotlib创建一个绘图画布，并在启动时启动AudioThread线程。update_canvas方法是用于更新绘图画布的槽函数，它将输入数据的FFT计算和绘图操作放入matplotlib的绘图区域中，并调用canvas.draw()方法以更新画布。

注意，在关闭主窗口时，必须注意正确关闭音频线程以避免资源泄漏。closeEvent方法是在主窗口关闭时调用的，它调用AudioThread的close方法以停止音频流并等待线程结束。