[Image-SIG] Monochrome image tostring length problems

[Fredrik Lundh]

tom wrote:

> I'm having a real problem at the moment trying to figure out how to pass 
> strings of 1bit image data between PIL and the g15daemon which supports 
> the logitech g15 keyboards lcd.  Basically, it's 160x143 in resolution.  
> The g15 python bindings have two methods of note.  The 
> loader_10_ascii_format method loads a file which is formatted as 
> 1001101110001 etc, and converts it in to a string of the form 
> \x00\x01\x01\x00 etc.... this string has a len of 6880, which is the 
> length it should be, being 160x43. If i try to do anything with a PIL 
> created image initialised like
> 
> i = Image.new('1', (160, 43))
> 
> and then, with s being the string returned from the g15 ascii loader, do 
> something like this
> 
> i.fromstring(s)
> 
> then you have a problem illustrated like so:
> 
> len(i.tostring('raw', '1'))
> returns 860  (6880 / 8)
> 
> len(i.tostring('raw', '1').encode('string-escape')
> returns 3440    half the number i need...
> 
> I cannot send this string to the g15daemon.set_buffer method as it needs 
> to be a string which is 6880 in length

try using

     i = Image.new('L', (160, 43))

instead.

</F>