basic text editor

from guizero import*

app = App(title="texteditor")

# function for reading files
def open_file():
    with open(file_name.value, "r") as f:
        editor.value = f.read()

# function for writing files
def save_file():
    with open(file_name.value, "w") as f:
        f.write(editor.value)

#change font function
def change_font():
    editor.font = font.value

def change_text_size():
    editor.text_size = size.value
    # resize the widget because if the text is made bigger, this might affect the size of the TextBox so guizero needs to know how to maintain the intended layout
    editor.resize(1, 1)
    editor.resize("fill", "fill")

#change colour function
def change_color(value):
   editor.text_color = value

# create a box to house the controls, we want the box to span the entire width of the app
file_controls = Box(app, align="top", width="fill")

preferences_controls = Box(app, align="top", width="fill", border=True)
font = Combo(preferences_controls, options=["courier", "times new roman", "verdana"], align="left", command=change_font)

# create a TextBox for the file name
file_name = TextBox(file_controls, text="text_file.txt", width=50, align="left")

# create a save button which uses the save_file function
save_button = PushButton(file_controls, text="Save",  align="right", command = save_file)

# create an open button which uses the open_file function
open_button = PushButton(file_controls, text="Open",  align="right", command = open_file)

# create a TextBox which is not in the box and fills the rest of the GUI
editor = TextBox(app, multiline=True, height="fill", width="fill")

#slider to control font size
size = Slider(preferences_controls,  align="left", command=change_text_size, start=10, end=18)

#change colour listbox
lb_colour = ListBox(
    app,
    items=["red", "green", "blue", "yellow", "purple", "turquoise", "pink", "orange", "black", "brown", "cyan"],
    selected="black",
    command=change_color,
    scrollbar=True)


app.display()