class_docstr:   This is an interactive example of how to display text on app.Canvas.
    The text rendering will respond to standard C escape sequences.
  
    - Scroll for changing text font size
    - Press left and right arrows for changing text anchor positions
    - Press up and down arrows for changing text content
  
    Standard C escape sequences:
        -     ->  alert (beep, bell)
        -     ->  Backspace
        -     ->  Formfeed
        -   
  ->  Newline
        -   
    ->  Carriage Return
        -         ->  Horizontal Tab
        -     ->  Vertical Tab
        -   \  ->  Backslash
        -   '  ->  Single quotation mark
        -   "  ->  Double quotation mark
    
code: def on_key_release(self, event):
      if "Down" in str(event.key):
          if self.str_ind == 0:
              self.str_ind = len(self.string_alternatives) - 1
          else:
              self.str_ind -= 1
      if "Up" in str(event.key):
          if self.str_ind == len(self.string_alternatives) - 1:
              self.str_ind = 0
          else:
              self.str_ind += 1
      if "Left" in str(event.key):
          if self.anchor_ind == 0:
              self.anchor_ind = len(self.anchor_variants) - 1
          else:
              self.anchor_ind -= 1
      if "Right" in str(event.key):
          if self.anchor_ind == len(self.anchor_variants) - 1:
              self.anchor_ind = 0
          else:
              self.anchor_ind += 1
      if event.key == "b":
          self.text.bold = not self.text.bold
      if event.key == "i":
          self.text.italic = not self.text.italic
      self.update_text()
  
file_path: vispy/examples/basics/visuals/text_visual.py
imports: from vispy import app, gloo, visuals
  import numpy
label_desc: Use image node_id 5 for calling the Canvas obj's underlying member method code with example usage: obj.on_key_release(event) without return types