title: How to create arrow in a tkinter.ttk.Button and control it's size?
body: <p>I would like to create ttk.button with an arrow in it and have the arrow size changable. </p>
  
  <p>I discovered 'TButton' inherently contains StyleNames <code>TButton.leftarrow</code> which is not exposed by the ttk.Style().layout().  </p>
  
  <p><strong>Questions:</strong> 
  (1) How do I activate these StyleNames? 
  (2) How do I control the size of <code>.leftarrow</code>? I notice it has a <code>arrowsize</code> option . How do I use it?</p>
  
  <pre><code>import tkinter as tk
  import tkinter.ttk as ttk
  
  class App(ttk.Frame):
  
          def __init__(self, parent):
              ttk.Frame.__init__(self, parent)
              self.parent = parent
              self.setStyle()
              self.setWidget()
  
          def setStyle(self):
              style = ttk.Style()
              print('Left.TButton layout are:', style.layout('Left.TButton'))
              print("Left.TButton.leftarrow style.element_options: ",
                    style.element_options('Left.TButton.leftarrow'))
  
              style.configure('Left.TButton', background='yellow')
              style.configure('Left.TButton.leftarrow', background='white',
                              arrowsize=20)
  
          def setWidget(self):
              self.lbutton = ttk.Button(self.parent, style='Left.TButton')
              self.lbutton2 = ttk.Button(self.parent, style='Left.TButton.leftarrow')
              self.lbutton.pack()
              self.lbutton2.pack()
  
  
      if __name__ == '__main__':
          root = tk.Tk()
          root.title('Test')
          root.geometry('200x50')
          app = App(root)
          app.pack(expand=1, fill='both')
  </code></pre>