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#!/usr/bin/env python3
# Python Stream Deck Library
# Released under the MIT license
#
# dean [at] fourwalledcubicle [dot] com
# www.fourwalledcubicle.com
#
# Example script showing basic library usage - updating key images with new
# tiles generated at runtime, and responding to button state change events.
"""
This is my annotation of this file to get an understanding of how we are supposed to interact with the Stream Deck. Note that I will for simplicity's sake only consider the original stream deck for code expansion.
"""
import os
import threading
from PIL import Image, ImageDraw, ImageFont
from StreamDeck.DeviceManager import DeviceManager
from StreamDeck.ImageHelpers import PILHelper
# Folder location of image assets used by this example.
ASSETS_PATH = os.path.join(os.path.dirname(__file__), "Assets")
# Generates a custom tile with run-time generated text and custom image via the
# PIL module.
def render_key_image(deck, icon_filename, font_filename, label_text):
# Resize the source image asset to best-fit the dimensions of a single key,
# leaving a margin at the bottom so that we can draw the key title
# afterwards.
icon = Image.open(icon_filename)
image = PILHelper.create_scaled_key_image(deck, icon, margins=[0, 0, 20, 0])
# Load a custom TrueType font and use it to overlay the key index, draw key
# label onto the image a few pixels from the bottom of the key.
draw = ImageDraw.Draw(image)
font = ImageFont.truetype(font_filename, 14)
draw.text((image.width / 2, image.height - 5), text=label_text, font=font, anchor="ms", fill="white")
return PILHelper.to_native_key_format(deck, image)
# Returns styling information for a key based on its position and state.
def get_key_style(deck, key, state):
# Last button in the example application is the exit button.
exit_key_index = deck.key_count() - 1
if key == exit_key_index:
name = "exit"
icon = "{}.png".format("Exit")
font = "Roboto-Regular.ttf"
label = "Bye" if state else "Exit"
else:
name = "emoji"
icon = "{}.png".format("Pressed" if state else "Released")
font = "Roboto-Regular.ttf"
label = "Pressed!" if state else "Key {}".format(key)
return {
"name": name,
"icon": os.path.join(ASSETS_PATH, icon),
"font": os.path.join(ASSETS_PATH, font),
"label": label
}
# Creates a new key image based on the key index, style and current key state
# and updates the image on the StreamDeck.
def update_key_image(deck, key, state):
# Determine what icon and label to use on the generated key.
key_style = get_key_style(deck, key, state)
# Generate the custom key with the requested image and label.
image = render_key_image(deck, key_style["icon"], key_style["font"], key_style["label"])
# Use a scoped-with on the deck to ensure we're the only thread using it
# right now.
with deck:
# Update requested key with the generated image.
deck.set_key_image(key, image)
# Prints key state change information, updates rhe key image and performs any
# associated actions when a key is pressed.
def key_change_callback(deck, key, state):
# Print new key state
print("Deck {} Key {} = {}".format(deck.id(), key, state), flush=True)
# Update the key image based on the new key state.
update_key_image(deck, key, state)
# Check if the key is changing to the pressed state.
if state:
key_style = get_key_style(deck, key, state)
# When an exit button is pressed, close the application.
if key_style["name"] == "exit":
# Use a scoped-with on the deck to ensure we're the only thread
# using it right now.
with deck:
# Reset deck, clearing all button images.
deck.reset()
# Close deck handle, terminating internal worker threads.
deck.close()
if __name__ == "__main__":
"""
Breakdown of the line below:
What this does is it goes into DeviceManager.py, creates a giant list of all of the possible devices that it may connect to, thenuse the enumerate() method provided by hidapi to check if there is a device with said ids connected to the machine. We receive essentially a list of tuples. The first item is the index, the next is an OBJECT representing the StreamDeck (not directly interacting with the stuff)
"""
streamdecks = DeviceManager().enumerate() # So this is a list of Stream Deck objects
print("Found {} Stream Deck(s).\n".format(len(streamdecks)))
for index, deck in enumerate(streamdecks):
# Now we are going through each device that we detected and attempt to open it and establish a connection
# This example only works with devices that have screens.
if not deck.is_visual():
continue
"""
Expansion of deck.open:
self.device.open() // Open the device (this calls hidapi's open function)
self._reset_key_stream() // Part of clean up to prevent corruption
self._setup_reader(self._read) // I believe this sets up the communication channel with the device
Expansion of deck.reset:
payload = bytearray(17)
payload[0:2] = [0x0B, 0x63]
self.device.write_feature(payload)
Expansion of _reset_key_stream:
payload = bytearray(self.IMAGE_REPORT_LENGTH)
payload[0] = 0x02
self.device.write(payload)
Expansion of _setup_reader:
if self.read_thread is not None:
self.run_read_thread = False
try:
self.read_thread.join()
except RuntimeError:
pass
if callback is not None:
self.run_read_thread = True
self.read_thread = threading.Thread(target=callback)
self.read_thread.daemon = True
self.read_thread.start():write
Breakdown
So in our list of things that we got from line 112, 'deck' is an object that represents data about the streamdeck.
so self.device.open() attempts to open the device.
"""
deck.open()
deck.reset()
print("Opened '{}' device (serial number: '{}', fw: '{}')".format(
deck.deck_type(), deck.get_serial_number(), deck.get_firmware_version()
))
# Set initial screen brightness to 30%.
deck.set_brightness(30)
# Set initial key images.
for key in range(deck.key_count()):
update_key_image(deck, key, False)
# Register callback function for when a key state changes.
deck.set_key_callback(key_change_callback)
# Wait until all application threads have terminated (for this example,
# this is when all deck handles are closed).
for t in threading.enumerate():
try:
t.join()
except RuntimeError:
pass
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