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# Display a big character (Upper case and lower case) in the middle of
# the screen when a letter is typed. Plays a corresponding song for
# that letter. This program can be used as a starting point to
# develop music playing capability with GStreamer 1.0 and beyond, or
# to learn Gtk programming with Python.
# It can also be used to teach children how to recognize the alphabet.
# This program is easy to use, it gives children a 26-key jukebox, and
# is not attractive enough to get them to spend countless hours in
# front of it.
# I hope you find this program instructive and useful.
# bigChar Copyright (C) 2016 Vikram Aggarwal
# This program comes with ABSOLUTELY NO WARRANTY
# This is free software, and you are welcome to redistribute it
# under certain conditions.
import datetime, string, os
import gi
gi.require_version('Gst', '1.0')
from gi.repository import Gst, Gtk, Pango, Gdk, GObject
class AudioPlayer():
""" A class that plays OGG Vorbis files. """
def __init__(self):
""" Initialize the Audio Player and set up Gstreamer """
self.started = False
# Change this location to indicate where the songs are stored.
self.music_path = os.path.dirname(os.path.realpath(__file__)) + "/music/"
print self.music_path
# Create a pipeline
self.pipeline ="pipe")
self.source = Gst.ElementFactory.make('filesrc')
demux = Gst.ElementFactory.make('oggdemux')
# The demux does not expose any pads till it has a file. Attach
# a callback when pads are added
demux.connect("pad-added", self.demuxer_callback)
self.decoder = Gst.ElementFactory.make('vorbisdec')
converter = Gst.ElementFactory.make('audioconvert')
sink = Gst.ElementFactory.make('autoaudiosink')
# Attach all the elements to the pipeline
# Attach source -> demux & decoder -> converter -> sink
# demux -> decoder is done in the demuxer_callback
# Attach a signal handler for being turned on
bus = self.pipeline.get_bus()
bus.connect("message", self.on_message)
def start(self, alphabet):
"""Starts playing music for the alphabet indicated.
The alphabet is currently upper case, so your music files have
to be X.ogg, Y.ogg, etc.
if (self.started):
# Specify <current_dir>/music/S.ogg as the file to play when
# the letter 's' or 'S' is pressed.
filename = self.music_path + ("%s.ogg" % alphabet)
# Set this as the source filename
self.source.set_property("location", filename)
# Start playing the pipeline
self.started = True
def on_message(self, bus, message):
""" Graciously handle End Of Stream and Error cases."""
t = message.type
if t == Gst.MessageType.EOS:
self.started = False
elif t == Gst.MessageType.ERROR:
err, debug = message.parse_error()
print "Error: %s" % err, debug
self.started = False
def demuxer_callback(self, demuxer, pad):
"Connects the demux to the vorbis decoder"
# Get the decoder pad that will accept the demultiplexed output
decoder_pad = self.decoder.get_static_pad("sink")
# And connect the newly formed pad to it, thereby joining the
# demultiplexer to the decoder.
def stop(self):
if (self.started):
self.started = False
class BigChar():
""" Create a Gtk window for a single giant textview that accepts
all keyboard input. """
def on_key_press(self, widget, data=None):
""" Intercept all keypress events and show ascii
characters. This requires the CAPS_LOCK to be off. We
don't intercept CAPS NUM or SCROLL lock, probably
# Set the time, even if the keypress is irrelevant
ascii_value = data.keyval
# Print the keycode received
# print ascii_value
# Uppercase and lowercase letters
if (ascii_value >= 97 and ascii_value <= 122):
self.display_alphabet(ascii_value - 97)
if (ascii_value >= 65 and ascii_value <= 90):
self.display_alphabet(ascii_value - 65)
# Numbers
if (ascii_value >= 48 and ascii_value <= 57):
self.display_number(ascii_value - 48)
# Number pad
if (ascii_value >= 65456 and ascii_value <= 65466):
self.display_number(ascii_value - 65456)
# Special characters on the number pad.
if (ascii_value == 65450):
if (ascii_value == 65451):
if (ascii_value == 65454):
if (ascii_value == 65453):
# Backspace should produce a left-pointing arrow.
if (ascii_value == 65288):
if (ascii_value == 65515):
def display(self, text):
""" Show the text in the textbox."""
start = self.textBuffer.get_start_iter()
end = self.textBuffer.get_end_iter()
self.textBuffer.apply_tag_by_name("real_big", start, end)
def display_alphabet(self, index):
""" Show the English alphabet (CAPS and lower) at 0 indexed
position 'A a' = 0, 'B b' = 1, ...
Also plays the song corresponding to the alphabet. """
big = string.ascii_uppercase[index]
small = string.ascii_lowercase[index]
self.display(big + " " + small)
def display_number(self, number):
""" Show the Number and play the song corresponding to it"""
self.display("%d" % number)
def realize_handler(self, widget):
pixmap = GdkPixbuf.Pixbuf(None, 1, 1, 1)
color = Gdk.Color(0, 0, 0)
cursor = Gdk.Cursor(pixmap, color, 0, 0)
def set_time(self):
"""Set the progress indicator to the current time. Shows time
in a horizontal access with the morning being near the left
edge and night being near the right edge."""
current_time =
# Total hours past since (assume children wake up at 6am)
minutes_past = ((current_time.hour - 6)
* 60.0 + current_time.minute)
if (minutes_past < self.day_end):
fraction = minutes_past / self.day_end
fraction = 1.0
def __init__(self):
""" Create a window with a single giant text view. Disables
all chrome. """
# Foreground and background color are read from here.
#background_color = "black"
#foreground_color = "#1111ff"
background_color = "green"
foreground_color = "black"
self.audio_player = AudioPlayer()
self.w = Gtk.Window(Gtk.WindowType.TOPLEVEL)
# No border
# Take over the entire screen
# Connect the callback on_key_press to the signal key_press.
self.w.connect("key_press_event", self.on_key_press)
# self.w.connect("realize", self.realize_handler)
# Make the widget aware of the signal to catch.
# Add a text view to show the key pressed
textView = Gtk.TextView()
# Disable a cursor in the text view.
# Show the single character in the middle
# This is the place we will write the character to
self.textBuffer = textView.get_buffer()
# Make the text view huge and bold
fontdesc = Pango.FontDescription("monospace bold 400")
# Creates a tag that is applied to the text every time
tag = self.textBuffer.create_tag(
, background=background_color
, foreground=foreground_color)
# The progress bar shows the current proportion of awake-time
# for a child.
# Minutes are capped at 8am, which is when kids go to
# bed. Expressed as minutes after 6am.
self.day_end = ((20 - 6) * 60.0)
self.progress = Gtk.ProgressBar()
# Make the text view take the entire window
vbox = Gtk.VBox(homogeneous=True, spacing=0)
color = Gdk.Color.parse(background_color)[1]
self.w.modify_bg(Gtk.StateType.NORMAL, color)
self.progress.modify_bg(Gtk.StateType.NORMAL, color)
textView.modify_bg(Gtk.StateType.NORMAL, color)
vbox.pack_start(textView, fill=True, expand=False, padding=0)
vbox.pack_start(self.progress, fill=False, expand=False, padding=0)
def show(self):
""" Show the window"""
if __name__ == '__main__':
# Create a bigchar window, and show it.
bigchar = BigChar()