====== BlinkStröm ======

==== Dokumentation der im Space vorhandenen BlinkStrömAdvanced-Geräte ====

Es existiert ein Gerät in jeweils blau und rot. Direkt nach dem ersten Auftauchen am 20. November 2k12 wurden erfolgreich Konverter implementiert um über die FAT16-formatierte SD-Karte eigene Daten anzuzeigen.

=== Externe Dokumentation ===

  * [[http://wiki.blinkenarea.org/index.php/BlinkstroemAdvanced|blinkenarena]] hat dazu Details
  * vermutlich aus dem [[http://wiki.blinkenarea.org/index.php/BlinkenLEDsPlus|BlinkenLEDsPlus]] hervorgegangen

=== Code-Schnippsel ===

(Oder besser irgendwo in ein public code repo?)

Common Lisp code for viewing and generating new animations: [[https://github.com/plops/cl-blinkstroem]]

== quick&dirty Python Converter ==

<file python>
# -*- coding: utf-8 -*-
# use it as you like, feel free to improve!

import sys
import os.path
from math import log10
# using numpy for convienent bytewise array manipulation
import numpy as np
# using Qt for reading arbitrary full color image files
from PyQt4.QtGui import QImage, QColor

WIDTH, HEIGHT = 18, 8 # display dimension

def readAnim(inFile, outDir):
    assert os.path.isfile(inFile), \
        "Given file '{0}' does not exist!".format(inFile)
    assert os.path.isdir(outDir), \
        "Given target directory '{0}' does not exist!".format(outDir)
    data = None
    with open(inFile, 'rb') as fd:
        data = bytearray(fd.read())
    prefixSize = 2
    frameSize = WIDTH * HEIGHT + prefixSize
    frameCount = len(data) / frameSize
    fnfmt = "{0:0"+str(int(log10(frameCount) + 1.))+"5d}.png"
    for img in range(0, frameCount):
        framedata = np.array(data[frameSize*img:frameSize*(img+1)])
        # strip duration bytes and convert to 4 byte value
        framedata = framedata[2:].astype(np.uint32)
        frame = QImage(framedata, WIDTH, HEIGHT, QImage.Format_RGB32)
        # create proper image and save
        outFile = os.path.join(outDir, fnfmt.format(img))
        frame.save(outFile)
    print "Wrote {0} files to '{1}'.".format(frameCount, outDir)

def writeAnim(imageFile, frameCount, outFile):
    assert os.path.isfile(imageFile)
    print "using image '{0}' ...".format(imageFile)
    if os.path.isfile(outFile):
        print "Overwriting '{0}'!".format(outFile)

    duration = 500 # ms
    intensitySteps = 7
    frame = QImage(imageFile)
    dimension = WIDTH, HEIGHT
    assert frame.width() in dimension and frame.height() in dimension, \
        "Input image as to be of dimension '{}'!".format(dimension)
    bytesPerPixel = frame.depth() / 8
    # read a color image as bytearray into a numpy array
    framedata = np.array(bytearray(frame.bits().asstring(frame.byteCount())),
                         dtype = np.dtype("u{0}".format(bytesPerPixel)))
    # reshape as matrix with multiple bytes per pixel
    framedata = framedata.reshape(frame.height(), frame.width(), bytesPerPixel)
    # sum up all colors
    framedata = np.add.reduce(framedata, axis = 2)
    # normalize: substract constant alpha value, scale intensity, fixed pixel size
    framedata -= framedata.min()
    framedata /= int(float(framedata.max()) / intensitySteps)
    framedata = framedata.astype(np.uint8).T
    blankframe = np.zeros_like(framedata)
    fd = open(outFile, "wb")
    duration = np.array((int(duration/20),), dtype=np.uint16).byteswap(True)
    # for comparison with ref.bin
    # duration = np.array((50,), dtype=np.uint16).byteswap(True)
    for img in range(0, frameCount):
        fd.write(duration)
        # every second frame is a blank one == blinking
        if img%2 == 0:
            fd.write(framedata.ravel())
        else:
            fd.write(blankframe.ravel())
    print "done."

def usage():
    print """
usage:
  {0} <input image file> <output file>
    Creates a .bin file containing provided image blinking.

  {0} <input file> <output directory>
    Parses the given .bin file and extracts all frame as
    single PNG images to the given directory.
"""

args = sys.argv
if len(args) > 1 and os.path.isdir(args[-1]) and os.path.isfile(args[-2]):
    readAnim(args[-2], args[-1])
elif len(args) > 1 and os.path.isfile(args[-2]):
    frameCount = 1000
    writeAnim(args[-2], frameCount, args[-1])
else:
    usage()

</file>