pyrustic/gaspium-demo.md

## gaspium-demo.md

      
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              gaspium-demo.md
            
          
    Gaspium Demo

This is a demo for Gaspium.
Gaspium is a framework to build Python apps with the GASP metaphor.
To play with this demo, copy-paste the Python code below and then run it after installing Gaspium.
To install Gaspium:
$ pip install gaspium
Description

In short, the app contains four pages: home, login, config, and about. The home page cannot open until you submit a random username and password on the login page. In fact, when the home page is about to be opened, the on_open callback is called. Inside this callback, a conditional redirection is performed: the login page is opened instead of the home depending on whether you are authenticated or not.
Screenshots

These are two screenshots of the demo running on Ubuntu

    
    The login form
    

    The home page
    

The source code

Run the source code below to get an app with four pages, a decent login form, a nice colorful pattern, and the ability to launch each page directly from the command line.


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## gaspium_demo.py
import tkinter as tk
import subrun
from tkinter.scrolledtext import ScrolledText
from gaspium import App
from megawidget import Toast
from cyberpunk_theme.widget.button import get_button_red_style


# ====== PAGES =======


def home_page(context):
    """
    Define the home page
    """
    body = tk.Frame(context.root)
    # rowconfigure and columnconfigure
    for i in range(3):
        body.rowconfigure(i, weight=1)
        body.columnconfigure(i, weight=1)
    # rows
    rows = [("#CCCC00", "#CCCC00", "#BD0000"),
            ("#B200B2", "#121C20", "#BD0000"),
            ("#B200B2", "#0000B3", "#0000B3")]
    # Here we loop over rows of colors to create a beautiful grid
    for row, colors in enumerate(rows):
        for col, color in enumerate(colors):
            tk.Frame(body, bg=color).grid(column=col, row=row,
                                          sticky="nswe")
    return body


def login_page(context):
    """
    Define the login page
    """
    body = tk.Frame(context.root)
    # stringvars
    username_strvar = tk.StringVar()
    password_strvar = tk.StringVar()
    # Login Frame
    title_frame = get_title_frame(body)
    title_frame.pack(fill=tk.X, padx=5, pady=5)
    # Form Frame
    form_frame = get_form_frame(body, username_strvar, password_strvar)
    form_frame.pack(fill=tk.X, padx=5, pady=5)
    # Buttons frame
    buttons_frame = get_buttons_frame(context.app, body, username_strvar, password_strvar)
    buttons_frame.pack(fill=tk.X, padx=5, pady=5)
    return body


def config_page(context):
    """
    Define the config page
    """
    body = tk.Frame(context.root)
    # Label
    font = ("Liberation Mono", 15, "bold")
    label = tk.Label(body, text="Config", fg="#C6C6AD", font=font)
    label.pack(side=tk.LEFT, anchor="n", padx=5, pady=5)
    return body


def about_page(context):
    """
    Define the about page
    """
    body = tk.Frame(context.root)
    # Capture the output of the Zen of Python with Subrun
    info = subrun.capture("python -m this")
    text = info.output.decode("utf-8")
    # Install the textwidget
    textwidget = ScrolledText(body, wrap="word")
    textwidget.pack(expand=1, fill=tk.BOTH)
    # Populate the textwidget witht the Zen of Python
    textwidget.insert("1.0", text)
    # Readonly mode
    textwidget.config(state=tk.DISABLED)
    return body


# ====== CALLBACKS =======


def on_open_home(context):
    """
    This callback is called when the home_page is opened
    """
    app = context.app
    # redirection: open the login_page if the user is not yet authenticated
    username = app.data.get("username")
    if not username:
        app.open("login")


def clear_form(username_strvar, password_strvar):
    """
    This callback is called when the user clicks the 'Clear' button on the login_page
    """
    username_strvar.set("")
    password_strvar.set("")


def login(app, username, password):
    """
    This callback is called when the user clicks the 'Submit' button on the login_page.
    """
    accepted = False
    if not username or not password:
        msg = "Please fill the form !"
    else:
        accepted = True
        msg = "Welcome {} !".format(username)
    # Pop-up a message to the user with the method 'toast'.
    toast = Toast(app.root, message=msg)
    toast.wait_window()  # block the flow of execution
    if accepted:
        # store the username in the 'data' dictionary provided by 'app'.
        app.data["username"] = username
        # Open the home_page by providing its pid (page id) to the method 'open'.
        app.open("home")


# ====== LAYOUTS FOR LOGIN PAGE ======


def get_title_frame(parent):
    body = tk.Frame(parent)
    # Label
    font = ("Liberation Mono", 15, "bold")
    label = tk.Label(body, text="Login", fg="#C6C6AD", font=font)
    label.pack(side=tk.LEFT)
    return body


def get_form_frame(parent, username_strvar, password_strvar):
    body = tk.Frame(parent)
    # rowconfigure and columnconfigure
    for i in range(3):
        body.rowconfigure(i, pad=5)
        body.columnconfigure(i, pad=5)
    # == Username Label and Entry
    # username_label
    username_label = tk.Label(body, text="Username")
    username_label.grid(row=0, column=0, sticky="w")
    # username_entry
    username_entry = tk.Entry(body, textvariable=username_strvar)
    username_entry.grid(row=1, column=0, sticky="w")
    # == Password Label and Entry
    # password_label
    password_label = tk.Label(body, text="Password")
    password_label.grid(row=0, column=1, sticky="w")
    # password_entry
    password_entry = tk.Entry(body, show="*", textvariable=password_strvar)
    password_entry.grid(row=1, column=1, sticky="w")
    return body


def get_buttons_frame(app, parent, username_strvar, password_strvar):
    body = tk.Frame(parent)
    # clear button
    command = (lambda username_strvar=username_strvar,
                      password_strvar=password_strvar:
               clear_form(username_strvar, password_strvar))
    clear_button = tk.Button(body, text="Clear", command=command)
    clear_button.pack(side=tk.LEFT)
    # apply red style to Clear Button
    button_red_style = get_button_red_style()
    button_red_style.apply(clear_button)
    # submit button
    command = (lambda app=app, username_strvar=username_strvar,
                      password_strvar=password_strvar:
                login(app, username_strvar.get(), password_strvar.get()))
    submit_button = tk.Button(body, text="Submit", command=command)
    submit_button.pack(side=tk.LEFT, padx=5)
    return body


# ====== APPLICATION =======


def main():
    # the app
    app = App(title="Demo", geometry="500x400", caching=True)

    # add home_page (the first added page is de facto the home page)
    app.add(home_page, title="Home", on_open=on_open_home)

    # add login_page (this page won't be referenced in the menu bar)
    app.add(login_page, pid="login", title="Login", indexable=False)

    # add config_page (referenced in the menu bar under the 'Help' dropdown menu)
    app.add(config_page, pid="config", title="Config", category="Help")

    # add about_page (referenced in the menu bar under the 'Help' dropdown menu)
    app.add(about_page, pid="about", title="About", category="Help")

    # start the app
    app.start()


if __name__ == "__main__":
    main()
	import tkinter as tk
	import subrun
	from tkinter.scrolledtext import ScrolledText
	from gaspium import App
	from megawidget import Toast
	from cyberpunk_theme.widget.button import get_button_red_style


	# ====== PAGES =======


	def home_page(context):
	"""
	Define the home page
	"""
	body = tk.Frame(context.root)
	# rowconfigure and columnconfigure
	for i in range(3):
	body.rowconfigure(i, weight=1)
	body.columnconfigure(i, weight=1)
	# rows
	rows = [("#CCCC00", "#CCCC00", "#BD0000"),
	("#B200B2", "#121C20", "#BD0000"),
	("#B200B2", "#0000B3", "#0000B3")]
	# Here we loop over rows of colors to create a beautiful grid
	for row, colors in enumerate(rows):
	for col, color in enumerate(colors):
	tk.Frame(body, bg=color).grid(column=col, row=row,
	sticky="nswe")
	return body


	def login_page(context):
	"""
	Define the login page
	"""
	body = tk.Frame(context.root)
	# stringvars
	username_strvar = tk.StringVar()
	password_strvar = tk.StringVar()
	# Login Frame
	title_frame = get_title_frame(body)
	title_frame.pack(fill=tk.X, padx=5, pady=5)
	# Form Frame
	form_frame = get_form_frame(body, username_strvar, password_strvar)
	form_frame.pack(fill=tk.X, padx=5, pady=5)
	# Buttons frame
	buttons_frame = get_buttons_frame(context.app, body, username_strvar, password_strvar)
	buttons_frame.pack(fill=tk.X, padx=5, pady=5)
	return body


	def config_page(context):
	"""
	Define the config page
	"""
	body = tk.Frame(context.root)
	# Label
	font = ("Liberation Mono", 15, "bold")
	label = tk.Label(body, text="Config", fg="#C6C6AD", font=font)
	label.pack(side=tk.LEFT, anchor="n", padx=5, pady=5)
	return body


	def about_page(context):
	"""
	Define the about page
	"""
	body = tk.Frame(context.root)
	# Capture the output of the Zen of Python with Subrun
	info = subrun.capture("python -m this")
	text = info.output.decode("utf-8")
	# Install the textwidget
	textwidget = ScrolledText(body, wrap="word")
	textwidget.pack(expand=1, fill=tk.BOTH)
	# Populate the textwidget witht the Zen of Python
	textwidget.insert("1.0", text)
	# Readonly mode
	textwidget.config(state=tk.DISABLED)
	return body


	# ====== CALLBACKS =======


	def on_open_home(context):
	"""
	This callback is called when the home_page is opened
	"""
	app = context.app
	# redirection: open the login_page if the user is not yet authenticated
	username = app.data.get("username")
	if not username:
	app.open("login")


	def clear_form(username_strvar, password_strvar):
	"""
	This callback is called when the user clicks the 'Clear' button on the login_page
	"""
	username_strvar.set("")
	password_strvar.set("")


	def login(app, username, password):
	"""
	This callback is called when the user clicks the 'Submit' button on the login_page.
	"""
	accepted = False
	if not username or not password:
	msg = "Please fill the form !"
	else:
	accepted = True
	msg = "Welcome {} !".format(username)
	# Pop-up a message to the user with the method 'toast'.
	toast = Toast(app.root, message=msg)
	toast.wait_window() # block the flow of execution
	if accepted:
	# store the username in the 'data' dictionary provided by 'app'.
	app.data["username"] = username
	# Open the home_page by providing its pid (page id) to the method 'open'.
	app.open("home")


	# ====== LAYOUTS FOR LOGIN PAGE ======


	def get_title_frame(parent):
	body = tk.Frame(parent)
	# Label
	font = ("Liberation Mono", 15, "bold")
	label = tk.Label(body, text="Login", fg="#C6C6AD", font=font)
	label.pack(side=tk.LEFT)
	return body


	def get_form_frame(parent, username_strvar, password_strvar):
	body = tk.Frame(parent)
	# rowconfigure and columnconfigure
	for i in range(3):
	body.rowconfigure(i, pad=5)
	body.columnconfigure(i, pad=5)
	# == Username Label and Entry
	# username_label
	username_label = tk.Label(body, text="Username")
	username_label.grid(row=0, column=0, sticky="w")
	# username_entry
	username_entry = tk.Entry(body, textvariable=username_strvar)
	username_entry.grid(row=1, column=0, sticky="w")
	# == Password Label and Entry
	# password_label
	password_label = tk.Label(body, text="Password")
	password_label.grid(row=0, column=1, sticky="w")
	# password_entry
	password_entry = tk.Entry(body, show="*", textvariable=password_strvar)
	password_entry.grid(row=1, column=1, sticky="w")
	return body


	def get_buttons_frame(app, parent, username_strvar, password_strvar):
	body = tk.Frame(parent)
	# clear button
	command = (lambda username_strvar=username_strvar,
	password_strvar=password_strvar:
	clear_form(username_strvar, password_strvar))
	clear_button = tk.Button(body, text="Clear", command=command)
	clear_button.pack(side=tk.LEFT)
	# apply red style to Clear Button
	button_red_style = get_button_red_style()
	button_red_style.apply(clear_button)
	# submit button
	command = (lambda app=app, username_strvar=username_strvar,
	password_strvar=password_strvar:
	login(app, username_strvar.get(), password_strvar.get()))
	submit_button = tk.Button(body, text="Submit", command=command)
	submit_button.pack(side=tk.LEFT, padx=5)
	return body


	# ====== APPLICATION =======


	def main():
	# the app
	app = App(title="Demo", geometry="500x400", caching=True)

	# add home_page (the first added page is de facto the home page)
	app.add(home_page, title="Home", on_open=on_open_home)

	# add login_page (this page won't be referenced in the menu bar)
	app.add(login_page, pid="login", title="Login", indexable=False)

	# add config_page (referenced in the menu bar under the 'Help' dropdown menu)
	app.add(config_page, pid="config", title="Config", category="Help")

	# add about_page (referenced in the menu bar under the 'Help' dropdown menu)
	app.add(about_page, pid="about", title="About", category="Help")

	# start the app
	app.start()


	if __name__ == "__main__":
	main()