使用 wxmplot 交互模块放大 plot 后如何访问数据？

Question

I am creating a script to interactively explore data visualizations using wxPython and wxmPlot.interactive module .

When a file is opened after the Open Button is pressed using a wxPython FileDialog, it is read into a pandas DataFrame. Pressing the Plot Button results in the data being plotted on an interactive plot. If I can access the x values for the new plot when clicking on the plot and dragging to select an area of interest, I will be able to find the matching y coordinates in the pandas DataFrame. Or is there a direct way to access x and y limits on the zoomed plot using the returned PlotFrame object from the plot() method? So far I can open a csv file, plot it and zoom in a region of interest. What I need is to understand how to get the coordinates of the new zoomed in plot in order to save the corresponding data to a file with just that data in the zoomed region. Any help with this would be greatly appreciated.

My code is as follows:

import wx
import pandas as pd
import wxmplot.interactive as wi
import os

class MyFrame(wx.Frame):    
    def __init__(self):
        super().__init__(parent=None, title="Data Exploration Tool ")
        panel = wx.Panel(self)
        self.df = None
        self.title = ''
        my_sizer = wx.BoxSizer(wx.HORIZONTAL)        
        open_btn = wx.Button(panel, label='Open')
        open_btn.Bind(wx.EVT_BUTTON, self.OnOpen)
        my_sizer.Add(open_btn, 0, wx.ALL | wx.CENTER, 5)        
        plot_btn = wx.Button(panel, label='Plot')
        plot_btn.Bind(wx.EVT_BUTTON, self.OnPlot)
        my_sizer.Add(plot_btn, 0, wx.ALL | wx.CENTER, 5)        
        panel.SetSizer(my_sizer)        
        self.Show()
       
    def OnPlot(self, event):
        x = pd.to_datetime(self.df.iloc[:, 0], format='%m/%d/%y %H:%M %p' )
        for i in range(1, len(self.df.columns)):
            wi.plot(x, self.df.iloc[:, i], show_legend=True, 
                    title=self.title, wintitle=self.title)
                 
    def OnOpen(self, event):
        #  ask the user what new file to open
        defDir=''
        defFile=''
        fileDialog = wx.FileDialog(self, "Open CSV file", 
                        defDir, defFile,
                        wildcard="(*.csv;*.xlsx)|*.csv;*.xlsx",
                        style=wx.FD_OPEN | wx.FD_FILE_MUST_EXIST)
        if fileDialog.ShowModal() == wx.ID_CANCEL:
            return     # the user changed their mind
        # Proceed loading the file chosen by the user
        pathname = fileDialog.GetPath()
        print(pathname)
     
        self.df = pd.read_csv(pathname, skiprows=12, parse_dates=True)
        self.title = os.path.basename(pathname) 
    
if __name__ == '__main__':
    app = wx.App()

    frame = MyFrame()
    app.MainLoop()

  

Answer 1

You can get the limits for the "current view" with something like this:

import numpy as np
import wxmplot.interactive as wi
x = np.linspace(-20, 20, 601)
y = np.sin(x/4.5) + x/50

display = wi.plot(x, y, label='test')

# now do some zooming, panning, etc

print(display.panel.get_viewlimits())

which might print something like:

(-21.0, 21.0, -1.2026941911431666, 1.2026941911431666)

I think that is what you are looking for.