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ChrisBarker-NOAAChrisBarker-NOAA
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added a bit about code-generated GUIs
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‎week-09/code/CalculatorDemo.py‎

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#!/usr/bin/env python
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"""
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wxPython Calculator Demo in 50 lines of code
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This demo was pulled from the wxPython Wiki:
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http://wiki.wxpython.org/CalculatorDemo
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by Miki Tebeka
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It has been altered to allow it to be "driven" by an external script,
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plus a little layout improvement
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See CalcualtorDemoDriver.py
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for an example
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"""
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# Calculator GUI:
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# ___________v
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# [7][8][9][/]
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# [4][5][6][*]
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# [1][2][3][-]
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# [0][.][C][+]
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# [ = ]
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from __future__ import division # So that 8/3 will be 2.6666 and not 2
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import wx
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from math import * # So we can evaluate "sqrt(8)"
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class Calculator(wx.Panel):
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'''Main calculator dialog'''
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def __init__(self, *args, **kwargs):
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wx.Panel.__init__(self, *args, **kwargs)
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sizer = wx.BoxSizer(wx.VERTICAL) # Main vertical sizer
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self.display = wx.ComboBox(self, -1) # Current calculation
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sizer.Add(self.display, 0, wx.EXPAND|wx.BOTTOM, 8) # Add to main sizer
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# [7][8][9][/]
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# [4][5][6][*]
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# [1][2][3][-]
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# [0][.][C][+]
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gsizer = wx.GridSizer(4, 4, 8, 8)
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for row in (("7", "8", "9", "/"),
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("4", "5", "6", "*"),
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("1", "2", "3", "-"),
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("0", ".", "C", "+")):
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for label in row:
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b = wx.Button(self, label=label, size=(40,-1))
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gsizer.Add(b)
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b.Bind(wx.EVT_BUTTON, self.OnButton)
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sizer.Add(gsizer, 1, wx.EXPAND)
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# [ = ]
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b = wx.Button(self, label="=")
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b.Bind(wx.EVT_BUTTON, self.OnButton)
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sizer.Add(b, 0, wx.EXPAND|wx.ALL, 8)
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self.equal = b
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# Set sizer and center
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self.SetSizerAndFit(sizer)
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def OnButton(self, evt):
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'''Handle button click event'''
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# Get title of clicked button
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label = evt.GetEventObject().GetLabel()
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if label == "=": # Calculate
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self.Calculate()
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elif label == "C": # Clear
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self.display.SetValue("")
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else: # Just add button text to current calculation
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self.display.SetValue(self.display.GetValue() + label)
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self.display.SetInsertionPointEnd()
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self.equal.SetFocus() # Set the [=] button in focus
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def Calculate(self):
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"""
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do the calculation itself
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in a separate method, so it can be called outside of a button event handler
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"""
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try:
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compute = self.display.GetValue()
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# Ignore empty calculation
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if not compute.strip():
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return
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# Calculate result
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result = eval(compute)
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# Add to history
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self.display.Insert(compute, 0)
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# Show result
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self.display.SetValue(str(result))
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except Exception, e:
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wx.LogError(str(e))
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return
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def ComputeExpression(self, expression):
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"""
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Compute the expression passed in.
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This can be called from another class, module, etc.
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"""
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print "ComputeExpression called with:", expression
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self.display.SetValue(expression)
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self.Calculate()
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class MainFrame(wx.Frame):
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def __init__(self, *args, **kwargs):
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kwargs.setdefault('title', "Calculator")
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wx.Frame.__init__(self, *args, **kwargs)
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self.calcPanel = Calculator(self)
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# put the panel on -- in a sizer to give it some space
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S = wx.BoxSizer(wx.VERTICAL)
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S.Add(self.calcPanel, 1, wx.GROW|wx.ALL, 10)
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self.SetSizerAndFit(S)
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self.CenterOnScreen()
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if __name__ == "__main__":
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# Run the application
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app = wx.App(False)
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frame = MainFrame(None)
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frame.Show()
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app.MainLoop()
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‎week-09/presentation-week09.pdf‎

4.98 KB
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‎week-09/presentation-week09.tex‎

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@@ -50,7 +50,7 @@ \section{Introduction}
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{\large Traditional Graphical User Interface Applications}
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\vfill
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{\large Run entirely on machine -- interative, interface and logic code in one process}
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{\large Run entirely on machine -- interactive, interface and logic code in one process}
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\vfill
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\end{frame}
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%---------------------------------
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\begin{frame}[fragile]{Code-generated GUIs...}
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\vfill
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{\large You shouldn't write the same repetitive code for a GUI..}
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\vfill
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{\large Or even need to build a GUI to match data at run time.}
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\vfill
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{\large Lots of ways to do that with wxPython -- Sizers help a lot.}
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\vfill
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{\large Try to do it whenever you find yourself writing repetitive code...}
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\vfill
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{\large The key is how to do the event Binding}
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\begin{verbatim}
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def OnButton(self, evt):
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label = evt.GetEventObject().GetLabel()
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do_somethign_with_label(label)
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\end{verbatim}
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\vfill
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example: \verb`code/CalculatorDemo.py`
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\end{frame}
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%---------------------------------
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\begin{frame}[fragile]{Code-generated GUIs...}
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\vfill
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{\Large The ``lambda trick''}
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\vfill
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{\large -- a way to pass custom data to an event handler:}
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\vfill
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{\large The key is how to do the event Binding}
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\begin{verbatim}
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for name in ["first", "second", "third"]:
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btn = wx.Button(self, label=name)
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btn.Bind(wx.EVT_BUTTON,
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lambda evt, n=name: self.OnButton(evt, n) )
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....
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def OnButton(self, Event, name):
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print "In OnButton:", name
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\end{verbatim}
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\vfill
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\url{http://wiki.wxpython.org/Passing%20Arguments%20to%20Callbacks}
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\end{frame}
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\section{Miscellaneous}
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%-------------------------------
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\begin{frame}[fragile]{Long Running Tasks}
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\end{frame}
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\section{Miscellaneous}
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%-------------------------------
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\begin{frame}[fragile]{CallAfter}
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\end{frame}
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%-------------------------------
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\begin{frame}[fragile]{BILS}
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