[X2go-dev] [Pkg-x2go-devel] Getting things started with x2goclient

[John A. Sullivan III]

On Thu, 2011-02-03 at 08:00 -0500, John A. Sullivan III wrote:
> On Thu, 2011-02-03 at 10:42 +0100, Erik Auerswald wrote:
> <snip>
> > 
> > What I tried with some kind of success across an analog modem link years ago
> > was the Differential X Protocoll Compressor (dxpc)
> > http://www.vigor.nu/dxpc/ .
> Just took a very quick look at this and it looks very interesting!
> Thanks for digging it out - John
> <snip>
<snip>
Had a chance to read a bit more and it looks quite nice.  The only thing
that concerns me from their DESIGN document is this statement:

Image Compression
-----------------

dxpc compresses images differently, depending upon their type:

  * For monochrome images with width-to-height ratios greater than 10
    and heights less than or equal to 32, it transposes the images from
    row-major to column-major representation and applies a variant of
the
    text-compression algorithm using 'h'-bit "characters," where 'h' is
    the image height.  (Why would it do something so strange?  Well...
    FrameMaker draws bitmapped text one line at a time, and this
algorithm
    compresses the bitmapped text much more effectively than anything
else
    I could come up with.)

  * For other monochrome images, it uses a variant of Group 4 FAX
encoding.

  * For 8-bit color images, it uses a CharCache to hold previous pixel
    values and encodes them using technique 4.

  * For anything else, it sends the whole image, uncompressed.

I do not know how NX compresses images but it seemed like there were a
wealth of settings (I know we found best results with 16m-png-jpeg) so
this might be a big step backwards.  I'll defer to those who know more
than I - John