A lot of beginner tutorials start with “Hello World” examples. There are plenty of websites that use a calculator application as a kind of “Hello World” for GUI beginners. Calculators are a good way to learn because they have a set of widgets that you need to lay out in an orderly fashion. They also require a certain amount of logic to make them work correctly. For this calculator, let’s focus on being able to do the following:

• Addition
• Subtraction
• Multiplication
• Division

I think that supporting these four functions is a great starting place and also give you plenty of room for enhancing the application on your own. Continue reading Creating a Calculator with wxPython →

The wxPython GUI toolkit has a very rich and powerful Grid widget that I have written about previously on this blog. It allows you to create sheets of cells similar to those in Microsoft Excel.

There is also a neat mixin that allows you to apply a custom renderer to the labels on the columns and rows of the grid.

Let’s take a look at that and see how it works:

import wx
import wx.grid as grid
import wx.lib.mixins.gridlabelrenderer as glr
 
class MyGrid(grid.Grid, glr.GridWithLabelRenderersMixin):
 
    def __init__(self, *args, **kw):
        grid.Grid.__init__(self, *args, **kw)
        glr.GridWithLabelRenderersMixin.__init__(self)
 
class MyColLabelRenderer(glr.GridLabelRenderer):
 
    def __init__(self, bgcolor):
        self._bgcolor = bgcolor
 
    def Draw(self, grid, dc, rect, col):
        dc.SetBrush(wx.Brush(self._bgcolor))
        dc.SetPen(wx.TRANSPARENT_PEN)
        dc.DrawRectangle(rect)
        hAlign, vAlign = grid.GetColLabelAlignment()
        text = grid.GetColLabelValue(col)
        self.DrawBorder(grid, dc, rect)
        self.DrawText(grid, dc, rect, text, hAlign, vAlign)
 
class MyPanel(wx.Panel):
 
    def __init__(self, parent):
        wx.Panel.__init__(self, parent)
 
        grid = MyGrid(self, size=(100, 100))
        grid.CreateGrid(numRows=10, numCols=10)
 
        for col in range(0, 10, 3):
            grid.SetColLabelRenderer(
                col+0, MyColLabelRenderer('#e0ffe0'))
            grid.SetColLabelRenderer(
                col+1, MyColLabelRenderer('#e0e0ff'))
            grid.SetColLabelRenderer(
                col+2, MyColLabelRenderer('#ffe0e0'))
 
        main_sizer = wx.BoxSizer(wx.VERTICAL)
        main_sizer.Add(grid, 1, wx.EXPAND)
        self.SetSizer(main_sizer)
 
class MyFrame(wx.Frame):
 
    def __init__(self):
        wx.Frame.__init__(self, None, title='Custom Grid Renderers')
        panel = MyPanel(self)
        self.Show()
 
if __name__ == '__main__':
    app = wx.App(False)
    frame = MyFrame()
    app.MainLoop()

Let’s break this down a bit. You will notice at the top of the code that we need to import the Grid widget separately in wxPython. We also need to import a mixin called GridWithLabelRenderersMixin. We subclass the Grid class and add in the mixin and then initialize both.

Next we create a subclass of GridLabelRenderer, which is also from the mixin. This allows us to create a spacing Draw method that will give us the ability to apply different colors or fonts to the labels in our Grid. In this case, I just made it so that we could change the color of the text in the labels.

The last piece of code that we are interested in is in the MyPanel class where we actually instantiate the Grid and change the color of the background of the labels in the columns. Here is what the grid ended up looking like:

Wrapping up

The wxPython toolkit has dozens of pre-built widgets that you can use to create cross-platform user interfaces. The wxPython demo has a much more involved example than this article does that you might also find interesting. If you haven’t given wxPython a try, you really should go get it. It is pip installable from PyPI and compatible with Python 3.

I see questions relating to the title of this article a lot. How do I open a second frame / window? How do I get all the frames to close when I close the main application? When you are first learning wxPython, these kinds of questions can be kind of hard to find answers for as you aren’t familiar enough with the framework or the terminology to know how to search for the answers.

Hopefully this article will help. We will learn how to open multiple frames and how to make them all close too. Let’s get started! Continue reading wxPython: How to Open a Second Window / Frame →