add screensaver functionality to display server

Author: Bartzi

assets/fonts/dotmat.ttf

@@ -1,8 +1,22 @@
+import time
+import math
+
+from collections import namedtuple
+
+from PIL import Image
+from PIL import ImageDraw
+from PIL import ImageFont
+from datetime import datetime, timedelta
+
 import socket
 import struct
+import threading
 import zlib
 
 
+Size = namedtuple('Size', ['height', 'width'])
+
+
 class DataListener:
     def __init__(self,  controller, ip='', port=1337):
         self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
@@ -36,10 +50,82 @@ def __iter__(self):
                 #     continue
             elif len(data) != self.frame_size:
                 self.log('Error receiving UDP frame: Invalid frame size: {}'.format(len(data)))
-                continue
+                continue0
             yield 'udp:'+addr, data
 
 
+class PauseFiller(threading.Thread):
+
+    def __init__(self, motd, controller):
+        super().__init__()
+        self.motd = motd
+        self.controller = controller
+        self.stop = False
+        self.font = ImageFont.truetype('assets/fonts/dotmat.ttf', 10)
+
+    def get_pad_data(self, image, image_data, window_size):
+        height, width, channels = image_data.shape
+
+        height_padding = window_size.height - height
+        padding_top = height_padding // 2
+        padding_top_data = np.zeros((padding_top, image.width, channels))
+        padding_bottom = math.ceil(height_padding / 2)
+        padding_bottom_data = np.zeros((padding_bottom, image.width, channels))
+
+        return padding_top_data, padding_bottom_data
+
+    def display_text(self, image, slide_image=False):
+        image_data = np.array(image)
+        window_size = Size(height=self.controller.image_height, width=self.controller.image_width)
+        window_position = 0
+
+        padding_top, padding_bottom = self.get_pad_data(image, image_data, window_size)
+        image_data = np.vstack((padding_top, image_data, padding_bottom))
+
+        while True:
+            if self.stop:
+                break
+
+            data = image_data.copy()[:, window_position:min(window_position + window_size[1], image.width), ...]
+            height, width, channels = data.shape
+
+            width_padding = np.zeros((window_size.height, window_size.width - width, channels))
+            data = np.hstack((data, width_padding))
+
+            self.controller.display(data)
+            if slide_image:
+                window_position += 1
+                if window_position >= image.width:
+                    window_position = 0
+            time.sleep(1000 / 20 / 1000)
+
+    def run(self):
+        text_image = Image.new('RGB', self.font.getsize(self.motd))
+        draw = ImageDraw.Draw(text_image)
+        draw.fontmode = "1"
+        draw.text((0, 0), self.motd, font=self.font, fill=(255, 255, 255))
+
+        self.display_text(text_image, slide_image=True)
+
+
+class IdleWatcher(threading.Thread):
+
+    def __init__(self, idle_time):
+        super().__init__()
+        self.idle_time = idle_time
+
+    def run(self):
+        global pause_filler
+        while True:
+            time.sleep(timedelta(seconds=self.idle_time).total_seconds())
+            time_now = datetime.utcnow()
+            time_delta = (time_now - last_frame).total_seconds()
+
+            if time_delta > self.idle_time and not pause_filler.is_alive():
+                pause_filler = PauseFiller(args.motd, controller)
+                pause_filler.start()
+
+
 if __name__ == "__main__":
     import argparse
     import numpy as np
@@ -48,14 +134,25 @@ def __iter__(self):
     parser = argparse.ArgumentParser(description="Remote Display Server that shows already rendered images")
     parser.add_argument('config', help='path to config file for matelight')
     parser.add_argument('-p', '--port', type=int, default=1337, help='port to listen on')
+    parser.add_argument('--idle-time', type=int, default=20, help='max. number of seconds matelight shall idle')
+    parser.add_argument('--motd', default='Contribute on code.ilexlux.xyz!')
 
     args = parser.parse_args()
 
     controller = LEDController(args.config)
     server = DataListener(controller, port=args.port)
+    last_frame = datetime.utcnow()
+
+    pause_filler = PauseFiller(args.motd, controller)
+    pause_filler.start()
+
+    idle_watcher = IdleWatcher(args.idle_time)
+    idle_watcher.start()
 
     try:
         for _, frame in server:
+            last_frame = datetime.utcnow()
+            pause_filler.stop = True
             frame = np.fromstring(frame, dtype=np.uint8).reshape(controller.image_height, controller.image_width, 3)
             controller.display(frame)