Introduction
This lab will guide you through creating a wxPython application that displays math text in a wx.Bitmap for display in various controls on wxPython. It uses the Matplotlib library to convert text to images and the wxPython library to display the images.
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Install Required Libraries
To complete this lab, you need to have the following libraries installed:
- wxPython
- Matplotlib
You can install these libraries using pip.
pip install wxPython
pip install matplotlib
Create a wxPython Application
Create a new Python file and import the required libraries.
import wx
import numpy as np
from io import BytesIO
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas
from matplotlib.figure import Figure
Convert Mathtext to wx.Bitmap
Define a function that converts math text to a wx.Bitmap. This function uses Matplotlib to draw the text at position (0, 0) but then relies on facecolor="none"
and bbox_inches="tight", pad_inches=0
to get a transparent mask that is then loaded into a wx.Bitmap.
def mathtext_to_wxbitmap(s):
fig = Figure(facecolor="none")
text_color = (
np.array(wx.SystemSettings.GetColour(wx.SYS_COLOUR_WINDOWTEXT)) / 255)
fig.text(0, 0, s, fontsize=10, color=text_color)
buf = BytesIO()
fig.savefig(buf, format="png", dpi=150, bbox_inches="tight", pad_inches=0)
s = buf.getvalue()
return wx.Bitmap.NewFromPNGData(s, len(s))
Define Functions
Define a list of functions that the application will display. Each function is defined by a math text and a lambda function that takes an input value and returns an output value.
functions = [
(r'$\sin(2 \pi x)$', lambda x: np.sin(2*np.pi*x)),
(r'$\frac{4}{3}\pi x^3$', lambda x: (4/3)*np.pi*x**3),
(r'$\cos(2 \pi x)$', lambda x: np.cos(2*np.pi*x)),
(r'$\log(x)$', lambda x: np.log(x))
]
Create a Canvas Frame
Create a new class that inherits from wx.Frame. This class creates a canvas that displays the selected function.
class CanvasFrame(wx.Frame):
def __init__(self, parent, title):
super().__init__(parent, -1, title, size=(550, 350))
self.figure = Figure()
self.axes = self.figure.add_subplot()
self.canvas = FigureCanvas(self, -1, self.figure)
self.change_plot(0)
self.sizer = wx.BoxSizer(wx.VERTICAL)
self.add_buttonbar()
self.sizer.Add(self.canvas, 1, wx.LEFT | wx.TOP | wx.GROW)
self.SetSizer(self.sizer)
self.Fit()
Add a Button Bar
Add a button bar to the application that displays icons for each function. When a button is clicked, the application will display the corresponding function.
def add_buttonbar(self):
self.button_bar = wx.Panel(self)
self.button_bar_sizer = wx.BoxSizer(wx.HORIZONTAL)
self.sizer.Add(self.button_bar, 0, wx.LEFT | wx.TOP | wx.GROW)
for i, (mt, func) in enumerate(functions):
bm = mathtext_to_wxbitmap(mt)
button = wx.BitmapButton(self.button_bar, 1000 + i, bm)
self.button_bar_sizer.Add(button, 1, wx.GROW)
self.Bind(wx.EVT_BUTTON, self.OnChangePlot, button)
self.button_bar.SetSizer(self.button_bar_sizer)
Add a Toolbar
Add a toolbar to the application that allows the user to zoom in and out, pan, and save the plot as an image. This toolbar is added to the bottom of the frame.
def add_toolbar(self):
self.toolbar = NavigationToolbar2Wx(self.canvas)
self.toolbar.Realize()
self.sizer.Add(self.toolbar, 0, wx.LEFT | wx.EXPAND)
self.toolbar.update()
Change the Plot
Define a function that changes the plot based on the selected function. This function takes a plot_number as input and changes the plot accordingly.
def change_plot(self, plot_number):
t = np.arange(1.0, 3.0, 0.01)
s = functions[plot_number][1](t)
self.axes.clear()
self.axes.plot(t, s)
self.canvas.draw()
Create the Application
Create a new class that inherits from wx.App. This class creates the frame and starts the event loop.
class MyApp(wx.App):
def OnInit(self):
frame = CanvasFrame(None, "wxPython mathtext demo app")
self.SetTopWindow(frame)
frame.Show(True)
return True
Run the Application
Run the application by creating an instance of the MyApp class.
if __name__ == "__main__":
app = MyApp()
app.MainLoop()
Summary
In this lab, you learned how to create a wxPython application that displays math text in a wx.Bitmap. You used the Matplotlib library to convert text to images and the wxPython library to display the images. You also learned how to create a button bar and a toolbar in the application and how to change the plot based on the selected function.
Want to learn more?
- 🚀 Practice Mathtext Wx Sgskip
- 🌳 Learn the latest Matplotlib Skill Trees
- 📖 Read More Matplotlib Tutorials
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