add fading strip, with dummy mode

v2/backend/processing/FadingStrip/FadingStrip.pyde

@@ -0,0 +1,72 @@
+add_library('net')
+from network import send_TCP
+from prepare import prepare
+import random
+
+# Config, will be checked upstream
+height = 25
+width = 15
+framerate = 10
+brightness = 0.5
+#####################################
+#receiver_IP = "10.2.113.151"
+#receiver_IP = "10.24.147.20"
+receiver_IP = "dummy"
+receiver_port = 9999
+
+# Do we have one single long line?
+long_line = True
+
+# TODO: test with real serial
+# https://www.pjrc.com/teensy/td_uart.html
+
+ledTCP = None
+data = None
+current_px = 0
+
+cur_color = None
+cur_len = 0
+len_change_choice = [7, 11, 13, 17, 19]
+
+def setup():
+    global ledTCP
+    global data
+    global cur_color
+    global len_change
+    len_change = random.choice(len_change_choice)
+    background(0)
+    cur_color = color(random.randint(0, 255), random.randint(0, 255), random.randint(0, 255))
+
+    ledTCP, data = prepare(Client, receiver_IP, receiver_port, height, width, framerate, brightness)
+    send_TCP(ledTCP, data, long_line)
+
+def draw():
+    global cur_len
+    global current_px
+    global cur_color
+    global len_change
+    if cur_len == 0:
+        pixels[current_px] = cur_color
+    else:
+        px = current_px
+        for i in range(cur_len):
+            if px == 0:
+                prec_col = pixels[len(pixels) - 1]
+            else:
+                prec_col = pixels[px - 1]
+            col = color(red(prec_col) / 1.1, green(prec_col) / 1.1, blue(prec_col) / 1.1)
+            pixels[px] = col
+            px -=1
+    updatePixels()
+
+    if cur_len == len_change:
+        cur_color = color(random.randint(0, 255), random.randint(0, 255), random.randint(0, 255))
+        cur_len = 0
+        len_change = random.choice(len_change_choice)
+    else:
+        cur_len += 1
+    if current_px >= len(pixels) - 1:
+        current_px = 0
+    else:
+        current_px += 1
+    send_TCP(ledTCP, data, long_line)

v2/backend/processing/FadingStrip/data_generator.py

@@ -0,0 +1,71 @@
+import jarray
+import math
+import itertools
+
+_byte_lookup = {}
+brightness_max = 0.5
+
+# Bit values which represent the zero and one bit pulses.
+_ZERO = bytearray([0b00000000])
+_ONE = bytearray([0b11111111])
+
+def _build_byte_lookup():
+    """Return lookup table to map from every byte value 0-255 and the associated raw SPI data."""
+    lookup = {}
+    for i in range(256):
+        value = bytearray()
+        for j in range(7, -1, -1):
+            if ((i >> j) & 1) == 0:
+                value += _ZERO
+            else:
+                value += _ONE
+        lookup[i] = value
+    return lookup
+
+def color_to_rgb(c):
+    """Convert a 24 bit color to RGB triplets."""
+    return ((c >> 16) & 0xFF, (c >> 8) & 0xFF, c & 0xFF)
+
+def _encode_color_grb(c):
+    """Encode an RGB tuple into NeoPixel GRB 24 byte SPI bit stream."""
+    return _byte_lookup[int(c[1] * brightness)] + _byte_lookup[int(c[0] * brightness)] + _byte_lookup[int(c[2] * brightness)]
+
+def _encode_pixel(c):
+    """Encode an RGB tuple into NeoPixel GRB 24 byte SPI bit stream."""
+    rgb = color_to_rgb(c)
+    encoded = _encode_color_grb(rgb)
+    return encoded
+
+def prepare_data(dimension, b):
+    global brightness
+    global _byte_lookup
+    if b > brightness_max:
+        brightness = brightness_max
+    else:
+        brightness = b
+    _byte_lookup = _build_byte_lookup()
+    data = jarray.zeros(dimension * 24 + 1, "b")
+    return data
+
+def image2data(data, long_line):
+    offset = 0
+    pixel_nb = 0
+    loadPixels()
+    for x in range(0, height):
+        pixel_line = pixels[pixel_nb:pixel_nb+width]
+        if long_line and pixel_nb/width%2 == 1:
+            pixel_line = reversed(pixel_line)
+        for px in pixel_line:
+            py_bytes = _encode_pixel(px)
+            for b in py_bytes:
+                if b > 127:
+                    # Convert to signed bytes (expected by jarray)
+                    b -= 256
+                    data[offset] = b
+                else:
+                    data[offset] = b
+                offset += 1
+            pixel_nb +=1
+    # New line
+    data[-1] = 10
+    return data

v2/backend/processing/FadingStrip/network.py

@@ -0,0 +1,36 @@
+import jarray
+import time
+import struct
+from data_generator import image2data
+
+def TCPConfigure(cl_class, server, port):
+    return cl_class(this, server, port)
+
+def receive_config(socket):
+    max_height = jarray.zeros(4, "b")
+    max_width = jarray.zeros(4, "b")
+    max_framerate = jarray.zeros(4, "b")
+    while True:
+        available_bytes = socket.available()
+        if available_bytes > 0:
+            break
+        time.sleep(1)
+    socket.readBytes(max_height)
+    socket.readBytes(max_width)
+    socket.readBytes(max_framerate)
+    max_height = struct.unpack("<i", max_height)[0]
+    max_width = struct.unpack("<i", max_width)[0]
+    max_framerate = struct.unpack("<i", max_framerate)[0]
+    return max_height, max_width, max_framerate
+
+def send_config(socket, height, width, framerate):
+    socket.write(struct.pack('<i', height))
+    socket.write(struct.pack('<i', width))
+    socket.write(struct.pack('<i', framerate))
+
+def send_TCP(socket, data, long_line):
+    if socket is None:
+        # Dummy mode
+        return
+    image2data(data, long_line)
+    socket.write(data)

v2/backend/processing/FadingStrip/prepare.py

@@ -0,0 +1,29 @@
+from network import receive_config, send_config, TCPConfigure
+from data_generator import prepare_data
+
+def check_config(max_height, max_width, max_framerate, height, width, framerate):
+    if height <= 0 or height > max_height:
+        return False, "height cannot be higher than {}. Current: {}.".format(max_height, height)
+    if width <= 0 or width > max_width:
+        return False, "width cannot be higher than {}. Current: {}.".format(max_width, width)
+    if framerate <= 0 or framerate > max_framerate:
+        return False, "framerate cannot be higher than {}. Current: {}.".format(max_framerate, framerate)
+    return True, None
+
+def prepare(cl_class, server_ip, server_port, height, width, framerate, brightness):
+    # Just to make sure pixels[] is initialized.
+    if server_ip == 'dummy':
+        size(width, height)
+        loadPixels()
+        return None, None
+    ledTCP = TCPConfigure(cl_class, server_ip, server_port)
+    max_height, max_width, max_framerate = receive_config(ledTCP)
+    good, reason = check_config(max_height, max_width, max_framerate, height, width, framerate)
+    if not good:
+        raise Exception(reason)
+    send_config(ledTCP, height, width, framerate)
+    size(width, height)
+    loadPixels()
+    dimension = width * height
+    data = prepare_data(dimension, brightness)
+    return ledTCP, data