Images with alpha channel break kmeans and wallfix

[coxley]

If kmeans is installed from pypi, it's broken because themer passes (r, g, b, a) to it where it only expects (r, g, b). See the below exception

$ themer generate color-squares downloads/JmTbnY8.png
# example value ((31, 124, 141, 255), 1)
Traceback (most recent call last):
  File "/home/coxley/.local/bin/themer", line 323, in <module>
    generate(color_file, config, template_dir, theme_name, options.bright)
  File "/home/coxley/.local/bin/themer", line 170, in generate
    colors = parse.read()
  File "/home/coxley/.local/lib/python3.6/site-packages/themer/parsers/__init__.py", line 159, in read
    colors = self.get_dominant_colors()
  File "/home/coxley/.local/lib/python3.6/site-packages/themer/parsers/__init__.py", line 142, in get_dominant_colors
    rgbs = kmeans.kmeans(points, self.k)
  File "/home/coxley/.local/lib/python3.6/site-packages/kmeans/__init__.py", line 104, in kmeans
    tolerance=tolerance, max_iterations=max_iterations)
  File "/home/coxley/.local/lib/python3.6/site-packages/kmeans/__init__.py", line 61, in _kmeans
    (r, g, b), count = center
ValueError: too many values to unpack (expected 3)

Removing kmeans/manually patching fixes this however then it gets stopped writing

Falling back to python kmeans implementation.
            Consider installing 'kmeans' from PyPI for much faster image sampling
Activate now? yN y
Traceback (most recent call last):
  File "/home/coxley/.local/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 602, in _save
    rawmode = RAWMODE[im.mode]
KeyError: 'RGBA'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/coxley/.local/bin/themer", line 336, in <module>
    activate(theme_name)
  File "/home/coxley/.local/bin/themer", line 157, in activate
    act.activate()
  File "/home/coxley/.local/lib/python3.6/site-packages/themer/activators/wallfix.py", line 90, in activate
    self.crop_wallpaper(wallpaper)
  File "/home/coxley/.local/lib/python3.6/site-packages/themer/activators/wallfix.py", line 76, in crop_wallpaper
    cropped.save(dest_jpg, 'JPEG', quality=100)
  File "/home/coxley/.local/lib/python3.6/site-packages/PIL/Image.py", line 1893, in save
    save_handler(self, fp, filename)
  File "/home/coxley/.local/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 604, in _save
    raise IOError("cannot write mode %s as JPEG" % im.mode)
OSError: cannot write mode RGBA as JPEG

[s-ol]

quick workaround is convert -flatten wallpaper.png wallpaper-flattened.png

real alpha handling beyond just ignoring that channel I think will not be implemented ever (but the wallfix'd image should contain it again)