Matplotlib在PyQt4的應用

Matplotlib作為Python中著名的數據可視化工具，其官網也提供了在PyQt4中使用的源碼，這裡舉一個應用實例，以備不時之需。

1) 利用Qt Designer創建GUI界面

Demo的GUI界面，如圖1所示，其中利用QFrame作為放置Matplotlib界面的容器。然後調用pyuic4.bat -o ui_maindialog.py maindialog.ui編譯UI界面。

圖1 GUI設計界面

2) maindialog.py程式代碼

#!/usr/bin/env python
#-*- coding: utf-8 -*-

import numpy as np
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from ui_maindialog import Ui_MainDialog
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas # Matplotlib對PyQt4的支持
from matplotlib.figure import Figure

class MainDialog(QDialog, Ui_MainDialog):
    def __init__(self, parent=None):
        super(MainDialog, self).__init__(parent)
        self.setupUi(self)
        self._createFigures()
        self._createLayouts()

　　# 創建Matplotlib的畫布
    def _createFigures(self):
        self._fig = Figure(figsize=(8, 6), dpi=100, tight_layout=True) 
        self._fig.set_facecolor("#F5F5F5") # 背景色
        self._fig.subplots_adjust(left=0.08, top=0.92, right=0.95, bottom=0.1) # 四周Margin
        self._canvas = FigureCanvas(self._fig) # 畫布
        self._ax = self._fig.add_subplot(111) # 增加subplot
        self._ax.hold(True)
        self._initializeFigure()

    def _createLayouts(self):
        layout = QHBoxLayout(self.frame)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.addWidget(self._canvas) # Add Matplotli

    def _initializeFigure(self):
        Font = {'family': 'Tahoma',
                'weight': 'bold',
                'size': 10}
        # Abscissa
        self._ax.set_xlim([380, 780])
        self._ax.set_xticks([380, 460, 540, 620, 700, 780])
        self._ax.set_xticklabels([380, 460, 540, 620, 700, 780], fontdict=Font)
        self._ax.set_xlabel("Wavelength (nm)", fontdict=Font)
        # Ordinate
        self._ax.set_ylim([0.0, 1.0])
        self._ax.set_yticks(np.arange(0.0, 1.1, 0.2))
        self._ax.set_yticklabels(np.arange(0.0, 1.1, 0.2), fontdict=Font)
        self._ax.set_ylabel("Spectral Radiance (W/(m$^2$*sr*nm))", fontdict=Font)

        self._ax.grid(True)  # Grid On

    def _updateFigures(self):
        Font = {'family': 'Tahoma',
                'weight': 'bold',
                'size': 10}

        self._ax.clear()

        maxY = 0.0

        x = np.arange(380, 781)
        y = np.random.rand(401)

        self._ax.plot(x, y, 'r', label="Data")

　　　　 maxY = max(y)
        if maxY <= 0:
            self._initializeFigure()
        else:
            self._fig.subplots_adjust(left=0.11, top=0.92, right=0.95, bottom=0.1)
            # Abscissa
            self._ax.set_xlim([380, 780])
            self._ax.set_xticks([380, 460, 540, 620, 700, 780])
            self._ax.set_xticklabels([380, 460, 540, 620, 700, 780], fontdict=Font)
            self._ax.set_xlabel("Wavelength (nm)", fontdict=Font)
            # Ordinate
            self._ax.set_ylim([0.0, maxY])
            self._ax.set_yticks([0.0, maxY / 4.0, maxY / 2.0, maxY * 3 / 4.0, maxY])
            self._ax.set_yticklabels(
                ["%.1e" % 0.0, "%.1e" % (maxY / 4.0), "%.1e" % (maxY / 2.0), "%.1e" % (maxY * 3.0 / 4.0),
                 "%.1e" % maxY], fontdict=Font)
            self._ax.set_ylabel("Spectral Radiance (W/(m$^2$*sr*nm))", fontdict=Font)

        self._ax.grid(True)
        self._ax.legend(loc="best", fontsize="small").draggable(state=True)  # Legend
        self._canvas.draw()

    @pyqtSlot()
    def on_plotPushButton_clicked(self):
        self._updateFigures()

初始界面如圖2所示：

圖2 GUI初始界面

3) 點擊plot按鍵後

界面顯示見圖3：

圖3 點擊Plot按鍵後界面